ORCID Profile
0000-0001-7499-9986
Current Organisation
Murdoch University
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Publisher: CSIRO Publishing
Date: 2006
DOI: 10.1071/AR05424
Abstract: The aim of this study was to determine the effect of time off feed (TOF) prior to slaughter on muscle glycogen metabolism and rate of pH decline in sheep muscle. All animals were maintained on a roughage diet for 6 weeks and were then subjected to either 0, 2, or 4 days TOF with access to water, prior to slaughter. Glycogen concentrations were determined post-slaughter for 3 different muscles, M. longissimus thoracis et lumborum (LTL), M. semimembranosus (SM), and M. semitendinosus (ST), as well as measuring pH declines for all animals in each of the 3 muscles under both electrically stimulated and control conditions. Ultimate pH values (pHu) were determined 48 h post-slaughter. Both the 2-day and 4-day TOF groups lost liveweight during their curfew period, whereas the control (0-day) group gained weight. TOF had no effect on post-slaughter carcass characteristics, muscle glycogen concentrations, pHu, or rate of pH decline. Increased muscle glycogen concentrations resulted in faster rates of pH decline. This response was curvilinear, plateauing at a glycogen concentration of about 56 mmol/kg muscle. Muscle glycogen concentration also affected the response of pH decline to electrical stimulation, interacting with muscle and pre-stimulation pH. Low muscle glycogen levels limited delta pH only in the SM and ST and only in muscles of lower pre-stimulation pH.
Publisher: Elsevier BV
Date: 2016
Publisher: CSIRO Publishing
Date: 2014
DOI: 10.1071/AN14356
Abstract: Dark cutting is detrimental to meat quality and therefore is the major cause of carcass downgrades under the Meat Standards Australia grading system. This study quantified the variation between months in the incidence of dark cutting, in southern Australia. Four years of Meat Standards Australia grading data, from nine in idual beef processors in Western Australia, South Australia, Victoria and Tasmania, was utilised for the analysis. The dataset contained 42 162 slaughter groups, of 10 or more grass-fed cattle, which allowed for the percentage of dark cutters per slaughter group to be analysed. The interaction between month, year and state was significant (P 0.001). The lowest risk of dark cutting for South Australia and Western Australia was in October (1.53% ± 0.75 and 6.96% ± 0.76) and November in Tasmania and Victoria (7.34% ± 0.9 and 5.27% ± 0.81) potentially when feed availability and quality is highest. The incidence of dark cutting was highest for all states during the period from February to June. Lower pasture availability and quality in combination with higher levels of stress due to extreme high or low temperatures during this time could all contribute to the higher incidences. The findings of this study show that procurement and management decisions made by cattle buyers, producers and processors need to change throughout the year to help mitigate the incidence of dark cutting carcasses and reduce financial loss.
Publisher: Elsevier BV
Date: 10-2018
DOI: 10.1016/J.MEATSCI.2018.06.035
Abstract: Major efforts in the sheep industry to control eating quality have resulted in reduced product variability. Yet inconsistent eating quality for consumers remains, due to a degree of inaccurate representation of cut quality. Eating quality defined through a complex interplay of different factors can be predicted for in idual cuts, and Meat Standards Australia (MSA) grading schemes have been developed to achieve these defined quality outcomes. This review outlines the justifications to refine the current sheepmeat MSA pathways system to transition into a cuts-based prediction model and details some of the factors affecting sheepmeat eating quality as key factors under consideration into the new model. The development of the new sheepmeat MSA prediction model will allow for more efficient carcass sorting to underpin a value based payment system throughout the supply chain. However it requires the inclusion of in idual carcass yield and eating quality measurements (i.e. IMF). Furthermore, the adoption challenges internationally of an MSA like model are discussed.
Publisher: Elsevier BV
Date: 06-2016
DOI: 10.1016/J.MEATSCI.2016.02.013
Abstract: This study assessed the effect of paternal Australian Sheep Breeding Values for post weaning c-site eye muscle depth (PEMD) and fat depth (PFAT), and post weaning weight (PWWT) on the composition of lamb carcasses. Composition was measured using computed tomography scans of 1665 lambs which were progeny of 85 Maternal, 115 Merino and 155 Terminal sires. Reducing sire PFAT decreased carcass fat weight by 4.8% and increased carcass bone by 1.3% per unit of PFAT (range 5.1 mm). Increasing sire PEMD reduced carcass fat weight by 3.8% in Maternal and 2% in Terminal sired lambs per unit of PEMD (range 4.3 and 7.8 mm), with no impact on bone. Increasing sire PWWT reduced carcass fat weight, but only at some experimental locations. Differences in composition varied between sire types with Maternal sired lambs having the most fat and Merino sired lambs the greatest bone weight. Genetic effects on fatness were greater than the environmental or production factor effects, with the converse true of bone.
Publisher: Springer Science and Business Media LLC
Date: 12-2011
Abstract: In livestock populations the genetic contribution to muscling is intensively monitored in the progeny of industry sires and used as a tool in selective breeding programs. The genes and pathways conferring this genetic merit are largely undefined. Genetic variation within a population has potential, amongst other mechanisms, to alter gene expression via cis- or trans-acting mechanisms in a manner that impacts the functional activities of specific pathways that contribute to muscling traits. By integrating sire-based genetic merit information for a muscling trait with progeny-based gene expression data we directly tested the hypothesis that there is genetic structure in the gene expression program in ovine skeletal muscle. The genetic performance of six sires for a well defined muscling trait, longissimus lumborum muscle depth, was measured using extensive progeny testing and expressed as an Estimated Breeding Value by comparison with contemporary sires. Microarray gene expression data were obtained for longissimus lumborum s les taken from forty progeny of the six sires (4-8 progeny/sire). Initial unsupervised hierarchical clustering analysis revealed strong genetic architecture to the gene expression data, which also discriminated the sire-based Estimated Breeding Value for the trait. An integrated systems biology approach was then used to identify the major functional pathways contributing to the genetics of enhanced muscling by using both Estimated Breeding Value weighted gene co-expression network analysis and a differential gene co-expression network analysis. The modules of genes revealed by these analyses were enriched for a number of functional terms summarised as muscle sarcomere organisation and development, protein catabolism (proteosome), RNA processing, mitochondrial function and transcriptional regulation. This study has revealed strong genetic structure in the gene expression program within ovine longissimus lumborum muscle. The balance between muscle protein synthesis, at the levels of both transcription and translation control, and protein catabolism mediated by regulated proteolysis is likely to be the primary determinant of the genetic merit for the muscling trait in this sheep population. There is also evidence that high genetic merit for muscling is associated with a fibre type shift toward fast glycolytic fibres. This study provides insight into mechanisms, presumably subject to strong artificial selection, that underpin enhanced muscling in sheep populations.
Publisher: Wiley
Date: 25-04-2016
DOI: 10.1111/AVJ.12428
Abstract: To develop molecular tools for the investigation of the prevalence, species and faecal shedding of Yersinia in sheep. A quantitative PCR (qPCR) targeting the β subunit of the Yersinia spp. RNA polymerase gene was developed and validated. The prevalence of pathogenic Y. enterocolitica was determined by screening for the virulent yst gene. These qPCR assays were used to determine Yersinia spp. prevalence and faecal shedding concentration from 3412 faecal s les collected from approximately 1189 lambs (100-180 lambs/flock) on eight farms across Australia. This was a longitudinal study, with sheep s led on three occasions (weaning, post-weaning and pre-slaughter). A subset of up to five positive s les from each s ling on each farm (n = 111) was sequenced. Yersinia spp. (including both pathogenic and non-pathogenic species) were identified in all flocks, with 60.7% of lambs shedding Yersinia spp. on at least one s ling occasion. Point prevalence ranged from 4% to 91% across farms and s ling occasions. Median Yersinia spp. bacterial concentration was 1.1 × 10(6) , 2.8 × 10(6) and 5.6 × 10(5) organisms/g faeces at weaning, post-weaning and pre-slaughter, respectively, across all farms. Pathogenic Y. enterocolitica was identified in all eight flocks s led, with 14.8% of lambs shedding pathogenic Y. enterocolitica on at least one s ling occasion. Yersinia spp. and pathogenic Y. enterocolitica in particular were commonly identified in a s le of Australian sheep flocks using molecular techniques. Further studies into associations between faecal shedding of pathogenic Yersinia spp. and sheep productivity or clinical disease may utilise qPCR in conjunction with other diagnostic tools.
Publisher: Elsevier BV
Date: 11-2014
DOI: 10.1016/J.TVJL.2014.08.001
Abstract: Faecal excretion of C ylobacter spp. and Salmonella enterica in sheep in Australia was determined using a quantitative multiplex PCR (qPCR) targeting the C ylobacter spp. purine biosynthesis gene (PurA) and the S. enterica outer membrane protein (ompF). The mutiplex qPCR was specific and C ylobacter spp. and S. enterica were each detected with a sensitivity of 5 organisms/µL faecal DNA extract. This multiplex qPCR was used to determine the prevalence and concentration of C ylobacter spp. and S. enterica in 3412 faecal s les collected from 1189 lambs on eight farms across South Australia (n = 2 farms), New South Wales (n = 1), Victoria (n = 2) and Western Australia (n = 3) at three s ling periods (weaning, post-weaning and pre-slaughter). The overall prevalences of C ylobacter spp. and S. enterica were 13.3% and 5.0%, respectively, with the highest prevalence for C ylobacter spp. in South Australia and the highest prevalence for S. enterica in New South Wales. C ylobacter jejuni was the only C ylobacter sp. identified from a subset of 120 positive s les sequenced at the 16S locus. S. enterica serovar Typhimurium was the only serovar of S. enterica identified from a subset of 120 positive s les sequenced at the ompF locus. Across all states, C ylobacter spp. had the highest median bacterial concentration in faeces at weaning and post-weaning (medians of 3.4 × 10(6) and 1.1 × 10(5), respectively), whereas S. enterica had the highest median bacterial concentration at pre-slaughter (1.8 × 10(5)/g faeces).
Publisher: Elsevier BV
Date: 09-2021
Publisher: CSIRO Publishing
Date: 2020
DOI: 10.1071/AN20081
Abstract: Context The anticoagulant properties of heparin have led to the routine use of heparinised saline flushes to prevent thrombus formation and to prolong the patency of indwelling cannulas. However, limited work exists on very low-dose heparin used to retain cannula patency for the purpose of repeated blood s ling for metabolic studies. Of particular interest is whether low-dose heparin will cause increases in plasma non-esterified fatty acid (NEFA) concentration. This is most relevant in metabolic studies involving repeated s ling, as this may erroneously elevate apparent plasma NEFA concentrations. Aims The objective of the present study was to evaluate the impacts of low- and high-dose heparin administration on plasma NEFA response in lambs. Methods In total, 14 merino (3 female, 4 wether) and terminal (4 female, 3 wether) sired lambs were selected from the Katanning, Western Australia, site of the Meat and Livestock Australia genetic resource flock All lambs were subjected to the following three treatments: low heparin (0.25 mL, 250 IU), high heparin (1 mL, 1000 IU) or control (1 mL of 0.9% NaCl saline), with each challenge being randomly allocated over 1.5 days. Blood s les were collected at the following time points: –30, –15, –10, –5, 0, 2.5, 5, 10, 15, 20, 30, 45, 60, 90, 120, 125 and 130 min relative to the administration of the challenge (Time 0) and tested for NEFA concentration. A derived exponential function was fitted to the raw data, enabling the plasma NEFA concentration response curve to be modelled at different time pointspre- and post-challenge, using the area under curve (AUC), maximum concentration and return to basal concentration, to quantify the NEFA response. Results Heparin-challenge dose had a significant (P & 0.01) impact on peak NEFA response at 10 min following challenge administration (NEFA AUC10), with the values after high-heparin challenge (1.03 ± 0.086 mmol/L per 10 min) being ~25% higher (P & 0.05) than those after the low-heparin challenge (0.78 ± 0.086 mmol/L per 10 min). The NEFA AUC10 values with low-dose heparin and high-dose heparin were 0.76 units and 1.02 units higher than those with the saline treatment (0.02 ± 0.086 mmol/L per 10 min P & 0.01). Heparin-challenge dose also had a significant impact on the maximum NEFA concentration (P & 0.05). The high-heparin challenge (0.32 ± 0.057 mmol/L) had 20% higher maximum NEFA concentrations than the low-heparin challenge (0.26 ± 0.057 mmol/L). Both high and low heparin-challenge groups had maximum NEFA concentrations that were 72% and 36% higher respectively, than for the saline-challenge (0.19 ± 0.057 mmol/L) group. NEFA returned to basal concentrations by 60 min for both challenges, although the high heparin-challenge group demonstrated a slower rate of return (P & 0.05). Conclusions High and low doses of heparin caused an increase in plasma NEFA response as measured by AUC10 and maximum NEFA concentration, but returned to basal concentrations within 1 h. Implications Results indicated that heparin as an anticoagulant should be avoided where frequent blood s les are required within intervals of less than 1 h. However, for repeated s ling at intervals greater than 1 h, judicious flushing with heparinised saline is unlikely to have an impact on plasma NEFA concentrations.
Publisher: CSIRO Publishing
Date: 2007
DOI: 10.1071/EA07058
Abstract: This study aimed to compare limb bone growth between offspring of typical crosses used in Australian prime lamb production. Limb bones from sheep of five genotypes – Merino (M × M), Border Leicester sire × Merino (BL × M), Poll Dorset sires selected for growth × Merino (PDg × M), Poll Dorset sires selected for eye muscle depth (PDm × M) × Merino, or second cross (PDg × BLM) – at four time points from 4 to 22 months of age (n = 593) were dissected, measured and weighed. Growth curves were fitted within genotype groups and used to compare (i) overall limb bone growth in terms of length and weight, (ii) differences in allometric growth coefficients for in idual bones, (iii) relative limb bone proportions, and (iv) maturity proportion. Results showed two distinct phenotypes in terms of limb bone growth: (i) relative bone hypotrophy of lambs from PDm × M, suggesting that selection for loin depth (PEMD EBV) may be linked with smaller limb size and that their higher muscle : bone ratio may be due to a relative decrease in bone rather than increase muscle weight and (ii) Merinos were found to have comparable limb length to terminal sire crosses, although distal limb elements were proportionately longer at the expense of the proximal segments that are associated larger muscles. There was a general lack of major differences in bone growth between sheep very different in other production traits, particularly when compared allometrically. Thus, differences in bone growth, proportion or skeletal maturation were greater between ewes and wethers than between these ergent genotypes. PDm × M and BL × M were found to be earlier maturing in terms of limb length, although the bone mineral profile (magnesium content) of PDm × M was suggestive of relative physiological immaturity.
Publisher: MDPI AG
Date: 22-04-2020
DOI: 10.3390/FOODS9040529
Abstract: Along with animal production factors, it is important to understand whether demographic factors influence untrained consumer perceptions of eating quality. This study examined the impact of demographic factors and sheepmeat consumption preferences on eating quality scores of American, Australian and Chinese untrained consumers. M. longissimus lumborum (LL) and m. semimembranosus (SM) were grilled according to sheep Meat Standards Australia protocols and evaluated by 2160 consumers for tenderness, juiciness, flavour and overall liking. Linear mixed effects models were used to analyse the impact of demographic factors and sheepmeat consumption habits on eating quality scores. Consumer age, gender, number of adults in a household and income had the strongest effect on sensory scores (P ≤ 0.05), although, the impact was often different across countries. Frequency of lamb consumption had an impact on sensory scores of American, Australian and Chinese consumers but larger s le sizes in some underrepresented subclasses for Australian and Chinese consumers are needed. Results suggest it is important to balance sensory panels for demographic factors of age, gender, number of adults and income to ensure sensory preferences are accurately represented for these particular populations.
Publisher: Elsevier BV
Date: 05-2020
DOI: 10.1016/J.MEATSCI.2019.108036
Abstract: Hot boning (HB) is an economical processing technique often resulting in poorer meat quality and tenderness. This study tested a method of partial HB, where the short loin section was removed from the hot carcass and chilled, with the striploin remained in the skeletal system. Thirty six yearling Bos indicus steers carcasses were subjected to either low, high or no electrical stimulation and each side allocated to a cutting treatment of HB, partial HB and conventional (Achillies hung). Striploins were ided into 3 and aged for 5, 14 and 28 days. Warner Bratzler Shear force (WBSF) and sarcomere length were tested. Partial HB resulted in greater tenderization without aging compared to HB. However, optimized electrical stimulation was a requirement. Treatment did not influence sarcomere length. The study also tested the impact of Dry aging of HB striploins, which resulted in further increases in tenderness at 28 days of aging compared to wet aged product, reducing WBSF by 9 N.
Publisher: Elsevier BV
Date: 09-2014
DOI: 10.1016/J.TVJL.2014.05.037
Abstract: The prevalence and faecal shedding of Chlamydia spp. in sheep in Australia has not been well described. Two species-specific quantitative PCRs (qPCRs) targeting the chlamydial outer membrane protein cell surface antigen gene (ompA) were validated and used to determine the prevalence and faecal shedding of C. abortus and C. pecorum from faecal s les of lambs at three s ling times (weaning, post-weaning and pre-slaughter) from eight farms in South Australia, New South Wales, Victoria and Western Australia. A total of 3412 faecal s les were collected and screened from approximately 1189 lambs across the four states. C. abortus was not detected in any of the s les screened. The overall prevalence of C. pecorum was 1027/3412 (30.1%) and median bacterial concentrations at weaning, post-weaning and pre-slaughter were 1.8 × 10(7), 1.2 × 10(7) and 9.6 × 10(5)/g faeces, respectively. A subset of C. pecorum positive s les from each farm, (n = 48) was sequenced to confirm their identity. The present study demonstrates that C. pecorum is prevalent in Australian sheep, highlighting a need for further research on the impact of this bacterium on production.
Publisher: Elsevier BV
Date: 2011
Publisher: Elsevier BV
Date: 2015
Publisher: Asian Australasian Association of Animal Production Societies
Date: 07-2018
DOI: 10.5713/AJAS.18.0090
Publisher: Elsevier BV
Date: 2018
Publisher: Elsevier BV
Date: 12-2014
DOI: 10.1016/J.MEATSCI.2014.06.029
Abstract: This study evaluated the effect of animal temperament measured using flight speed (FS) on plasma lactate, muscle glycogen and lactate concentrations at slaughter plus ultimate pH in 648 lot finished cattle of mixed breed and sex. Muscle s les were collected at slaughter from the m. semimembranosus, m. semitendinosus and m. longissimus thoracis (LT) for analysis of glycogen and lactate concentration. Blood was collected after exsanguination and analysed for plasma lactate concentration and ultimate pH of the LT was measured. FS had no effect on muscle glycogen concentration in any muscle or ultimate pH of the LT (P>0.05). As FS increased from 1 to 5m/s, plasma and muscle lactate concentration increased by 54% and 11.4% (P<0.01). The mechanisms through which temperament contributes to variation in glycogen metabolism remain unclear. The risk of dark cutting was not impacted by temperament, indicating that other production and genetic factors have a greater impact on the incidence of dark cutting.
Publisher: The Kielanowski Institute of Animal Physiology and Nutrition, PAS
Date: 30-08-2004
Publisher: Elsevier BV
Date: 10-2018
DOI: 10.1016/J.MEATSCI.2018.06.020
Abstract: This experiment assessed the ability of an on-line dual energy x-ray absorptiometer (DEXA) installed at a commercial abattoir to determine carcase composition at abattoir chain-speed. 607 lamb carcases from 7 slaughter groups were DEXA scanned and then scanned using computed tomography to determine the proportions of fat (CT fat%), lean (CT lean%), and bone (CT bone%). Data between slaughter groups were standardised relative to a synthetic phantom consisting of Nylon-6. Models were then trained within each dataset using hot carcase weight and DEXA value to predict CT composition, and then validated in the remaining datasets. Results from across-dataset validation tests demonstrated excellent precision for predicting CT fat%, with RMSE and R
Publisher: Elsevier BV
Date: 02-2014
DOI: 10.1016/J.MEATSCI.2013.08.032
Abstract: Spectrophotometric measures were used to determine the redness:browness (R630/R580) of 4238 lamb longissimus muscle after 3 days under simulated display. The results were analysed using linear mixed effects models. Environmental factors represented by effects such as kill group and site of production produced the greatest variation of up to 2.76 units in R630/R580. Isocitrate dehydrogenase activity, reflecting muscle oxidative capacity, reduced R630/R580 by 0.5 units. Selection for high muscling sires increased R630/R580 by 0.27 units, likely due to changes in muscle oxidative capacity. Lamb carcass weight also increased R630/R580 by 0.5 units. Analysis of genotypic factors influencing lamb size and growth rate such as sire type and dam breed further supported that increased growth rate improves meat R630/R580. Our findings suggest that breeding for increased growth rate and increased muscle weight could result in Australian lamb meat retaining its red colour for extended periods whilst on display.
Publisher: Wiley
Date: 15-04-2011
Publisher: Elsevier BV
Date: 09-2017
DOI: 10.1016/J.MEATSCI.2017.05.001
Abstract: The colour of bloomed m. longissimus was measured 24h post slaughter for 8165 lamb carcasses produced over 5years across 8 sites in Australia. Intramuscular fat across a 2 to 8% range and shortloin fat weight were positively associated with meat lightness (L*), redness (a*), yellowness (b*), hue and chroma (P<0.01). Shortloin muscle weight was negatively associated with these meat colour parameters (P<0.01), although this was largely accounted for by correlated changes in intramuscular fat (P<0.01). The effect of sire breeding values for lamb weight, shortloin muscle depth and fat depth on loin L*, a*, b*, hue and chroma were small and varied between lambs of different sire type, dam breed and sex. Thus selection for lean meat yield will have neutral or positive effects on meat colour, while selection for increased intramuscular fat will make the bloomed colour of lamb meat lighter and redder.
Publisher: Elsevier BV
Date: 06-2020
Publisher: Elsevier BV
Date: 07-2018
Publisher: Elsevier BV
Date: 2015
Publisher: Elsevier BV
Date: 10-2021
Publisher: MDPI AG
Date: 27-08-2019
DOI: 10.3390/ANI9090612
Abstract: The study evaluated the relationship between pre-slaughter stress, plasma biomarkers and consumer-evaluated eating quality of pasture raised beef cattle (n = 488). The design tested steer only, heifer only and mixed sex cattle with a comparison of direct kill versus a 14 day rest period in abattoir holding paddocks prior to slaughter. Experiment One sourced cattle from four farms and tested shipping and road transport. Experiment Two sourced cattle from four farms and tested a commercial saleyard pathway. The impact on treatment on untrained consumer eating quality scores were tested on five muscle groups, m. psoas major, m. longissimus dorsi lumborum, m. biceps femoris, m. semitendinosis, and m. infraspinatus. Across all muscles, a two-week rest period had the biggest improvement in sensory score. Mixed groups scored lower in the outside muscle than non-mixed groups. However, the mixing response was inconsistent in the eye round muscle and not significant in the other muscles. Plasma glucose and L-lactate indicated a marked acute stress response at slaughter with a small detrimental impact on consumer score. The muscle damage enzyme markers creatine kinase (CK) and aspartate aminotransferase (AST) were strongly associated with a lower meat quality score (MQ4). Neither β-hydroxybutyrate (βHB) nor non-esterified fatty acids (NEFA) were associated with MQ4, suggesting that fat mobilisation does not impact consumer sensory score.
Publisher: Elsevier BV
Date: 03-2016
Publisher: Elsevier BV
Date: 03-2016
Publisher: Elsevier BV
Date: 2009
DOI: 10.1016/J.MEATSCI.2008.08.004
Abstract: Fifty merino wethers (liveweight range from 44 to 81kg, average of 58.6kg) were lot fed for 42d and scanned through a dual X-ray absorptiometry (DXA) as both a live animal and whole carcass (carcass weight range from 15 to 32kg, average of 22.9kg) producing measures of total tissue, lean, fat and bone content. The carcasses were subsequently boned out into saleable cuts and the weights and yield of boned out muscle, fat and bone recorded. The relationship between chemical lean (protein+water) was highly correlated with DXA carcass lean (r(2)=0.90, RSD=0.674kg) and moderately with DXA live lean (r(2)=0.72, RSD=1.05kg). The relationship between the chemical fat was moderately correlated with DXA carcass fat (r(2)=0.86, RSD=0.42kg) and DXA live fat (r(2)=0.70, RSD=0.71kg). DXA carcass and live animal bone was not well correlated with chemical ash (both r(2)=0.38, RSD=0.3). DXA carcass lean was moderately well predicted from DXA live lean with the inclusion of bodyweight in the regression (r(2)=0.82, RSD=0.87kg). DXA carcass fat was well predicted from DXA live fat (r(2)=0.86, RSD=0.54kg). DXA carcass lean and DXA carcass fat with the inclusion of carcass weight in the regression significantly predicted boned out muscle (r(2)=0.97, RSD=0.32kg) and fat weight, respectively (r(2)=0.92, RSD=0.34kg). The use of DXA live lean and DXA live fat with the inclusion of bodyweight to predict boned out muscle (r(2)=0.83, RSD=0.75kg) and fat (r(2)=0.86, RSD=0.46kg) weight, respectively, was moderate. The use of DXA carcass and live lean and fat to predict boned out muscle and fat yield was not correlated as weight. The future for the DXA will exist in the determination of body composition in live animals and carcasses in research experiments but there is potential for the DXA to be used as an online carcass grading system.
Publisher: CSIRO Publishing
Date: 2006
DOI: 10.1071/AR04319
Abstract: The purpose of this study was to determine if estimated breeding value (EBV) of an animal’s sire and or the animal’s nutrition affected the structure of its M. longissimus thoracis et lumborum (LL) and, hence, the eating quality of meat derived from its carcass. Lambs were chosen based on the EBV of their sires in terms of post-weaning live weight (PWWT), post weaning fat at the C-site (PFAT), and post-weaning eye muscle depth (PEMD). Morphometric techniques were used to characterise muscle structure in terms of the distribution of intramuscular connective tissue the variables together are called fascicular structure. Perimysial seam thickness and fascicular width were both influenced by sire estimated breeding values for PWWT, PFAT, and PEMD. Variation in fascicular structure was associated with an interaction between PEMD-EBV and PFAT-EBV of the sire. Fascicular width decreased with increased PEMD-EBV and increased with PFAT-EBV, but was not affected by PWWT-EBV. When the total seam thickness was adjusted to a common fascicular width, the lambs on a low plane of nutrition had relatively more intramuscular connective tissue than those on a high plane. The total seam thickness was negatively associated with PFAT-EBV and positively associated with PEMD-EBV. Warner Bratzler shear (WBS) peak force (PF) and initial yield were not associated with differences in sire EBV. The residual WBS shear force, peak force minus initial yield (PFIY), and compression values were negatively associated with nutrition but were positively associated with PWWT-EBV and PEMD-EBV of the sires. These latter 2 effects were moderated by nutrition. The data support the hypothesis that morphological characteristics of perimysium are genetically determined and nutritionally responsive. Variance in morphology accounted for some variance in the biophysical attributes of meat and may help explain why sheep with high muscling potential have tougher meat.
Publisher: Elsevier BV
Date: 04-2016
DOI: 10.1016/J.MEATSCI.2015.12.007
Abstract: This study determined the impact of selection for greater muscling in Angus cattle on myofibre characteristics, muscle enzymatics, retail colour stability, pH decline and mineral content of the semimembranosus (SM), semitendinosus (ST) and longissimus thoracis (LT). Muscle from 10 low muscled (low) and 11 high muscled (high) steers were analysed. The high steers had myofibres 22% and 24% larger in cross-sectional area in the SM and ST (P<0.05), and 8.6% less type IIX myofibres in the LT than the low steers (P<0.05). The highs had 4.9% lower lactate dehydrogenase activity, 10.2% and 12.3% higher citrate synthase and isocitrate dehydrogenase activity than lows (P<0.05). The highs had 27% more iron in the LT (P<0.05). The results indicate that the oxidative capacity of muscle can be maintained in more muscular cattle with no detrimental effects to mineral content, pH decline or retail colour stability. Myofibre hypertrophy is one mechanism leading to greater muscle mass of these high muscled cattle.
Publisher: CSIRO Publishing
Date: 2006
DOI: 10.1071/AR04318
Abstract: The objective of this study was to establish the extent to which lamb myofibre characteristics at ~8 months of age were influenced by sire (n = 9) estimated breeding values (EBVs) and pasture-based nutritional systems (low and high quality and availability, LOW and HIGH) from birth to slaughter (n = 56). Immunostaining of myosin heavy chain isoforms in longissimus muscle fibres revealed that as the post-weaning eye muscle depth EBV (PEMD) increased, the percentage of type 2B/X myofibres increased and the percentage of type 2A myofibres decreased. The percentage of type 2B/X myofibres also increased with increasing PEMD in the semimembranosus muscle, but not in the semitendinosus muscle. Post-weaning fat depth (PFAT) EBV was negatively related with the percentage of type 2B/X myofibres in longissimus and semitendinosus muscles and with the relative area of more glycolytic to more oxidative fibre types, although there was an interaction with nutritional system in the semitendinosus muscle, with this ratio increasing with the PFAT EBV among the LOW nutrition lambs. Overall, post-weaning weight (PWWT) EBV had less effect on myofibre characteristics than PEMD and PFAT EBVs. Average cross-sectional area of myofibres was more affected by the LOW than HIGH nutritional system in longissimus muscle (–25%) compared with semitendinosus (–21%) and semimembranosus (–15%) muscles. LOW nutrition resulted in a significantly smaller cross-sectional area of all myofibre types in longissimus muscle and of types 2A, 2AB/X, and 2B/X in semimembranosus and semitendinosus muscles. Overall, the relative area of glycolytic myofibres increased and/or more oxidative myofibre types decreased in LOW compared with HIGH nutritional system lambs in longissimus and semimembranosus, but not in semitendinosus muscle. The results demonstrate significant influences of sire EBVs on myofibre characteristics of lambs, the extent of which depends upon muscle type and nutritional regimen. More specifically, they suggest continued selection for increased muscling and reduced fatness in lambs are associated with shifts in the proportions of myofibre types, with potential for adverse effects on eating quality. They also show that the direction and magnitude of the effects of chronic, moderate postnatal nutritional restriction at pasture on myofibre characteristics vary between muscles with different contractile, metabolic, and/or functional characteristics.
Publisher: Elsevier BV
Date: 10-2018
DOI: 10.1016/J.MEATSCI.2018.06.011
Abstract: The on-farm factors increasing the incidence of dark cutting were studied in 3145 pasture raised cattle consigned in 66 lots. Animal, environmental and farm management factors were recorded and pasture quantity, quality and mycotoxin concentrations were measured. The relative risk of dark cutting decreased by 26% in cattle grazing pastures with magnesium concentrations exceeding 0.24%. There was a 50% increase in relative dark cutting risk of cattle drinking from dams compared to drinking from troughs. Feeding supplements (hay/silage) in the last 7 days prior to slaughter reduced the relative risk of dark cutting by 25%. A high prevalence of mycotoxins was detected in pastures across all farms. In this case pasture ergot alkaloid concentrations above 600PPB increased the relative risk of dark cutting by 45%, while the presence of FumonisinB1 increased risk by 58%. In contrast the presence of 3acetyldeoxynivalenol reduced the relative dark cutting risk by 37%. Sex also affected the incidence of dark cutting, with heifers less likely to cut dark than steers by 47%.
Publisher: Wageningen Academic Publishers
Date: 11-07-2017
Publisher: CSIRO Publishing
Date: 2006
DOI: 10.1071/AR05364
Abstract: The objective of this study was to establish the effect of sire (n = 9) estimated breeding values (EBVs) and pasture-based nutritional systems (low and high quality and availability) from birth to slaughter on the metabolic characteristics and post-mortem pH changes in muscle of ~8-month-old lambs (n = 56). Nutritional restriction resulted in a general decrease in glycolytic capacity as indicated by the enzymes phosphofructokinase and lactate dehydrogenase (LDH), suggesting greater metabolic efficiency. Alternatively, it also depressed oxidative capacity as indicated by myoglobin and isocitrate dehydrogenase, which aligns with the histological results suggesting a fast glycolytic fibre type characteristic of less mature animals. Increasing PEMD EBV resulted in a marked shift towards a metabolically more glycolytic muscle type as demonstrated by LDH, although this did not correspond strongly with an increase in the proportion of type 2B fibres based on histological assessment of myofibre type using immunostaining of myosin heavy chain isoforms. Myoglobin concentration aligned with this trend, decreasing in all muscles as PEMD EBV increased, suggesting that selection for muscling will lead to a whiter muscle appearance. Rate of pH decline was increased in the low nutrition lambs, and through selection for PEMD EBV, this response aligning with the metabolically more glycolytic muscle type.
Publisher: CSIRO Publishing
Date: 2006
DOI: 10.1071/AR04277
Abstract: Relative abundance of proteins localised in the nuclear-enriched, total cell membrane and cytosolic fractions of the semitendinosus muscle was compared between lambs bred from control (C), high muscling (M), and high growth rate (G) sires. In total, 31 proteins were identified whose abundance was differentially regulated between sire type. Differences in hind-limb muscle development between M lambs and C and G lambs were reflected in levels of proteins that regulate or function in cellular mechanisms of protein and energy metabolism. Despite no apparent difference in hind-limb muscle growth in G lambs compared to C, G lambs exhibited marked differences in proteins involved in regulation and function of energy metabolism. These results detail pathways that can be specifically targeted to enhance muscle accretion and growth in lambs. The development of means to manipulate these cellular mechanisms may yield greater gains in muscle accretion and growth rate than breeding on the basis for genetic capacity alone.
Publisher: Elsevier BV
Date: 11-2018
DOI: 10.1016/J.MEATSCI.2018.07.025
Abstract: This study assessed the ability of computed tomography (CT) to predict intramuscular fat (IMF) % in the M. longissimus thoracis et lumborum of 64 cattle undergoing Meat Standards Australia (MSA) marbling score. The striploin was dissected from carcasses at the 12th rib and CT scanned, with IMF% determined at the 12th rib of the M. longissimus thoracis (LT) and the caudal M. longissimus lumborum (LL). Prediction of IMF% using CT in the LT was moderate (R
Publisher: Elsevier BV
Date: 11-2021
Publisher: CSIRO Publishing
Date: 2016
DOI: 10.1071/AN15217
Abstract: Weight loss due to poor nutrition in adult ewes over summer–autumn is economically expensive due to immediate costs such as feed and labour but also due to ongoing costs to reproductive success and ewe health. We predicted that adult Merino ewes with a higher proportion of fat would be more efficient, both through lower intake and reduced weight loss. Four-year-old Merino ewes (n = 64) were held in single pens and fed a chaff-based diet either ad libitum, with the aim of achieving liveweight maintenance, or a restricted amount to achieve liveweight loss of 100 g/day. Liveweight change and feed intake were measured, and residual liveweight change and residual feed intake were used to indicate efficiency. There was a difference of 2 MJ of metabolisable energy per day between the most efficient and least efficient ewes for residual feed intake, and a difference of 90 g per day between the most efficient and least efficient ewes for residual liveweight change. There was a significant association between blood plasma concentrations of leptin and both liveweight and feed efficiency, so that ewes with high concentrations of leptin had a lower daily intake, and/or lost less weight than did those with low concentrations of leptin. Managing adult Merino ewes to maximise fat-tissue accretion during spring via genetics and/or nutritional management could be a useful strategy to reduce feed requirements during summer–autumn because the ewes will be more efficient and have larger fat reserves to lose before achieving a lower critical limit.
Publisher: CSIRO Publishing
Date: 2001
DOI: 10.1071/AR00108
Abstract: The aims of this study were to develop a muscle biopsy technique which imposed minimal stress on cattle, enabling accurate monitoring of muscle glycogen concentration to develop a method based on exercise, for controlled depletion of glycogen from muscle and to utilise the model to determine the ability of cattle on hay and cereal grain diets to replete muscle glycogen. Expt 1 established the influence of repetitive muscle biopsies on muscle glycogen concentration. It consisted of 3 trials in which cattle received 4 serial biopsies every 36 h over a 108-h period. Repetitive biopsy had minimal impact on M. semimembranosus (SM) glycogen concentrations, although it did reduce concentration in the M. semitendinosus (ST), particularly when animals were penned in idually. Expt 2 established an exercise regimen in which cattle were trotted at 9 km/h for five 15-min intervals, with 15 min rest between each interval, depleting muscle glycogen by approximately 50%. Expt 3 determined the repletion rates of muscle glycogen, by utilising the exercise/biopsy model. Cattle were allocated to 4 dietary treatments: hay, silage, hay–barley, and hay–maize. The metabolisable energy (ME) of these rations ranged from 8 to 11.3 MJ/kg. After the exercise regimen, glycogen concentration repleted in a linear fashion over 72 h in the SM of the animals fed maize, barley, and silage. In contrast, the ST of these animals was refractory to glycogen repletion over the same period. Both the SM and ST of the cattle on the hay diet showed no significant repletion following exercise. Repletion following exercise demonstrated a positive linear relationship with ME intake.
Publisher: Elsevier BV
Date: 09-2021
Publisher: Elsevier BV
Date: 11-2021
Publisher: Elsevier BV
Date: 09-2017
DOI: 10.1016/J.MEATSCI.2017.05.011
Abstract: Times for the progressive breakdown of 95 lamb carcases were recorded to determine the impact of carcase weight and GR tissue depth on the time and therefore cost to produce value added retail cuts. Further analysis also assessed the potential to use these carcase traits as predictors of fabrication times. Regression modeling demonstrated there was a limited ability to predict the difference in time to fabricate mid value-added (R
Publisher: Elsevier BV
Date: 12-2012
DOI: 10.1016/J.MEATSCI.2012.05.014
Abstract: This study evaluated the effect of eye muscle area (EMA), ossification, carcass weight, marbling and rib fat depth on the incidence of dark cutting (pH(u)>5.7) using routinely collected Meat Standards Australia (MSA) data. Data was obtained from 204,072 carcasses at a Western Australian processor between 2002 and 2008. Binomial data of pH(u) compliance was analysed using a logit model in a Bayesian framework. Increasing eye muscle area from 40 to 80 cm², increased pH(u) compliance by around 14% (P<0.001) in carcasses less than 350 kg. As carcass weight increased from 150 kg to 220 kg, compliance increased by 13% (P<0.001) and younger cattle with lower ossification were also 7% more compliant (P<0.001). As rib fat depth increased from 0 to 20mm, pH(u) compliance increased by around 10% (P<0.001) yet marbling had no effect on dark cutting. Increasing musculature and growth combined with good nutrition will minimise dark cutting beef in Australia.
Publisher: Wiley
Date: 30-10-2012
Publisher: Elsevier BV
Date: 02-2014
DOI: 10.1016/J.MEATSCI.2013.09.011
Abstract: This paper introduces a series of papers in the form of a special edition that reports phenotypic analyses done in parallel with genotypic analyses for the Australian Sheep Industry Cooperative Research Centre (Sheep CRC) using data generated from the information nucleus flock (INF). This has allowed new knowledge to be gained of the genetic, environment and management factors that impact on the carcase and eating quality, visual appeal, odour and health attributes of Australian lamb meat. The research described involved close collaboration with commercial partners across the supply chain in the sire breeding as well as the meat processing industries. This approach has enabled timely delivery and adoption of research results to industry in an unprecedented way and provides a good model for future research.
Publisher: Elsevier BV
Date: 03-2008
DOI: 10.1016/J.MEATSCI.2007.06.003
Abstract: The associations between the muscle glycogen concentration and form and the rate of post-mortem glycolysis in ovine muscle were investigated. Twenty-two merino wethers (18-24 months) were allocated to either roughage or concentrate pelleted diets for 34 days prior to slaughter. An exercise depletion/repletion model was applied four days prior to slaughter to generate differences in muscle glycogen levels at slaughter. Muscle biopsies were taken from the m. semimembranosus (SM) and m. semitendinosus (ST) prior to and immediately after exercise for muscle glycogen determination. At slaughter, one side was electrically stimulated and both sides were conventionally chilled for 24h. The pH response to electrical stimulation (ΔpH) and the rate of pH decline adjusted to a constant temperature of 38°C over the initial 6h post-mortem period was determined in three muscles (m. longissimus thoracis et lumborum LTL, SM and ST). In addition, the concentrations of glycogen, proglycogen (PG), macroglycogen (MG) and lactate in the three muscles immediately after slaughter were determined. The glycogen loss due to exercise was influenced by diet (P ST) and diet (concentrate>roughage). The available glycogen (glycogen(A)) and MG concentrations at slaughter varied significantly depending on the diet (P<0.01) and muscle (P<0.001). The percentage of MG relative to MG+PG varied between muscles (46%, 50% and 57% for the ST, LTL and SM). The concentration and form of available glycogen at slaughter did not influence the response to electrical stimulation after adjusting for pre-stimulation pH (P SM>ST). Importantly, a positive linear association (P=0.05) was found between muscle glycogen(A) concentration at slaughter and the rate of pH decline (temperature adjusted).
Publisher: Elsevier BV
Date: 11-2015
Publisher: CSIRO Publishing
Date: 2001
DOI: 10.1071/AR00128
Abstract: This study was a series of experiments designed to test the influence of supplemental magnesium oxide (MgO) on muscle glycogen concentration in sheep exposed to stress (exercise) and the commercial slaughter process, and to test the effectiveness of this supplement in the commercial scenario. In Expt 1, Merino wethers maintained on a mixed ration (metabolisable energy 11 MJ/kg and crude protein 16.3% in DM) were supplemented with MgO at the rate of 0%, 0.5%, or 1% of their ration for 10 days prior to a single bout of exercise and for 10 days prior to slaughter at a commercial abattoir. The exercise regimen consisted of 4 intervals of 15 min, with muscle biopsies taken by biopsy drill from the m. semimembranosis (SM) and m. semitendinosis (ST) pre-exercise and immediately post-exercise, and at 36 and 72 h post-exercise. Muscle biopsies were also taken 1 week prior to slaughter from the SM and ST, with further s les taken approximately 30 min post-slaughter. Ultimate pH (pHu) of the SM, ST, and m. longissimus dorsi (LD) was measured 48 h after slaughter. Sheep supplemented with MgO lost less muscle glycogen in the ST during exercise, and repleted more muscle glycogen in the SM during the post-exercise repletion phase, than unsupplemented sheep. The supplemented animals also had higher muscle glycogen concentrations in the ST at slaughter. In Expt 2, MgO was administered to Merino wether lambs for 4 days prior to slaughter in the form of a water-borne slurry at a rate equivalent to 1% of their ration. This treatment resulted in significantly reduced muscle glycogen concentrations in both the SM and ST at slaughter. In Expts 3–5, MgO was used as an ‘in-feed’ supplement in the commercial scenario. In each case, slaughter-weight Merino lambs were supplemented with MgO at the rate of 1% of their ration for 4 days prior to commercial slaughter. Positive responses were seen in 2 of the 3 experiments, with increased glycogen concentrations and a reduced pHu. The animals that demonstrated no response to MgO had the lowest pHu after slaughter, suggesting a minimal stress load, thus providing very little scope for an effect of the MgO supplement. We conclude that MgO can reduce the effects of exercise, leading to a subsequent reduction in glycogen loss, and an increase in the rate of glycogen repletion in skeletal muscle following exercise. The results support MgO supplementation as a viable option for reducing the stress associated with commercial slaughter.
Publisher: Elsevier BV
Date: 12-2019
Publisher: Elsevier BV
Date: 07-2004
Publisher: CSIRO Publishing
Date: 2016
DOI: 10.1071/AN14419
Abstract: Variation in liveweight change in the ewe flock during periods of poor nutrition can affect farm profitability through the effects of liveweight loss on potential stocking rate, management interventions including supplementary feeding, and ewe and lamb survival and productivity. There is variation between in idual animals in their ability to manage periods of poor nutrition, but the links between liveweight change and breeding values in the adult ewe flock have not been quantified. We analysed 5216 liveweight profiles for 2772 ewes managed over 3 years at eight sites across Australia, to define the relative effects of environment, reproductive performance and breeding values on liveweight change. The range in liveweight loss varied from 1.3 kg to 21.6 kg, and for liveweight gain from 0.4 kg to 28.1 kg. Site and year had the largest influence on liveweight change, which demonstrates that seasonal conditions and management were the most important factors influencing liveweight change. Liveweight loss was influenced by previous and current reproductive performance but these effects were small in comparison to the effects of site and year. There were mixed associations with sire breeding values for growth, fat and muscle depending on site. An increase in sire breeding values for fat by 1 mm was associated with a reduction in liveweight loss by up to 1.3 kg regardless of ewe breed, and this was more evident at sites where ewes lost a greater proportion of their liveweight. While management had the greatest effect on liveweight change, there appears to be scope to use breeding values to select sheep that will lose less weight during periods of poor nutrition in some environments.
Publisher: Elsevier BV
Date: 03-2021
Publisher: Elsevier BV
Date: 2015
DOI: 10.1016/J.MEATSCI.2014.07.031
Abstract: Pre-slaughter live weight, dressing percentage, and hot standard carcase weight (HCWT) from the 2007, 2008, 2009 and 2010 birth-years of the Information Nucleus Flock Lambs (n=7325) were analysed using linear mixed effects models. Increasing the sire breeding value for post-weaning weight (PWWT), and c-site eye muscle depth (PEMD), and reducing the sire breeding value for fat depth (PFAT) all had positive impacts on HCWT. The magnitude of the PWWT effect was greater in pure bred Merinos compared to Maternal and Terminal sired progeny. The improved HCWT resulting from increased PEMD was entirely due to its impact on improving dressing percentage, given that it had no impact on pre-slaughter live weight. There were marked differences between sire types and dam breeds, with pure-bred Merinos having lower pre-slaughter weight, reduced dressing percentage, and lower HCWT than progeny from Terminal and Maternal sired lambs or progeny from Maternal (1st cross) dams.
Publisher: Elsevier BV
Date: 11-2021
Publisher: CSIRO Publishing
Date: 2009
DOI: 10.1071/EA07387
Abstract: An experiment was conducted using 105 Merino hoggets to measure the change in tissue glycogen concentration over a 48-h period following an exercise regime. The exercise regime consisted of a 2-km run repeated four times with a 15-min break between each run. After exercise the hoggets were split into treatment groups and fed three different levels (fasting, maintenance and three times maintenance) of the same ration. A subset of each group of hoggets was killed at –24, 0, 12, 24 and 48 h from the time of exercise and s les taken from the liver, skin, rumen, duodenum, colon, kidney, M. semimembranosus, M. semitendinosus, M. longissimus thoracis et lumborum, M. psoas major, M. triceps brachii and M. subscapularis. Exercise caused a reduction in glycogen concentration in the liver and all muscles but not in the kidney, skin, duodenum, or colon tissues. After exercise the most significant changes in glycogen concentration were in the liver, muscle and skin. Metabolisable energy intake influenced the change in the liver and muscle tissue but not in the skin. It was concluded that glycogen concentration increased in liver before muscle and that this effect may contribute to the slower rate of glycogen concentration in muscle for ruminants compared with monogastric animals. Skin may also compete with muscle for glucose during the repletion phase in Merino sheep but the exact nature of this effect remains uncertain.
Publisher: CSIRO Publishing
Date: 2007
DOI: 10.1071/EA06334
Abstract: The meat and eating quality characteristics of 627 crossbred lamb progeny from 20 Poll Dorset sires were studied. The sires were selected on the basis of Australian sheep breeding values (ASBVs) for postweaning growth (PWWT), depth of loin muscle (PEMD) and subcutaneous fat (PFAT). Lambs were either weaned at 20- or 30-kg liveweight and then within each of these groups held at their weaning weight for 55 days or fully fed, giving four treatment groups. Restricted lambs were realimentated subsequent to the period of feed restriction and the lambs within each treatment group were slaughtered when their mean liveweight reached 45 kg.Shear force of the M. longissimus thoracis et lumborum (LL) decreased with temperature at pH 6.0, increased with LL ultimate pH and decreased as sarcomere length increased. Within LL aged for 5 days there was no difference between (P 0.05) between treatments for shear force. There was a treatment effect on M. semimembranosus (SM) shear force, such that for a sire having an average ASBV PWWT of 9.34, topsides from lambs early weaned and restricted had significantly (P 0.05) lower values. Further within these same lambs, i.e. early weaned and restricted, as the sire ASBV PWWT increased there was a significant (P 0.001) reduction in shear force. There was a significant (P 0.05) increase in sensory tenderness as the sire ASBV PFAT increased and across the range of ASBV PFAT this represented a change in sensory tenderness of four points. Overall liking increased with an increase in the temperature at pH 6.0 (P 0.05) with a coefficient of 0.43 ± 0.19. There was a significant (P 0.05) interaction between feeding level and the sire ASBV PFAT, such that for restricted fed lambs overall liking increased as the ASBV PFAT increased (coefficient 2.80 ± 0.89) after adjusting for temperature at pH 6.0, but this is not the case for fully feed lambs (coefficient –0.01 ± 0.89). Subtle interactions between sire ASBVs and growth path suggest that the impact of a period of restriction and refeeding on meat and eating quality will be meditated by the sire genetics.
Publisher: Elsevier BV
Date: 02-2014
DOI: 10.1016/J.MEATSCI.2013.09.007
Abstract: Genetic parameters were estimated for a range of meat quality traits recorded on Australian lamb meat. Data were collected from Merino and crossbred progeny of Merino, terminal and maternal meat breed sires of the Information Nucleus programme. Lambs born between 2007 and 2010 (n=8968) were slaughtered, these being the progeny of 372 sires and 5309 dams. Meat quality traits were found generally to be of moderate heritability (estimates between 0.15 and 0.30 for measures of meat tenderness, meat colour, polyunsaturated fat content, mineral content and muscle oxidative capacity), with notable exceptions of intramuscular fat (0.48), ultimate pH (0.08) and fresh meat colour a* (0.08) and b* (0.10) values. Genetic correlations between hot carcass weight and the meat quality traits were low. The genetic correlation between intramuscular fat and shear force was high (-0.62). Several measures of meat quality (fresh meat redness, retail meat redness, retail oxy/met value and iron content) appear to have potential for inclusion in meat sheep breeding objectives.
Publisher: CSIRO Publishing
Date: 1998
DOI: 10.1071/A96171
Abstract: This experiment investigated the effect of exercise and chromium supplementation on muscle glycogen and subcutaneous fat metabolism. The design of the experiment was a 2×2 factorial with chromium and regular exercise as the treatments. Forty-three Merino wethers (2 years old) were maintained for 10 weeks on a diet based on barley and lupin grain fed at 2·2 times maintenance. The ration was supplemented with 0 or 1 mg/kg DM of chromium, as Chromium Chelavite amino acid chelate. For regular exercise the animals were worked at approximately 60% maximum whole body oxygen consumption for 2 h, 3 times per week, which increased the estimated weekly energy demand by about 9%. Chromium increased the activity ofATP citrate lyase, a marker of the glucose-insulin axis, by 30%, but decreased the fat depth GR, the fat depth over the 12th rib, by 20%. There was no effect on the activity of acetyl CoA carboxylase, the major rate-limiting enzyme of lipogenesis. Thus the potential for glucose contribution to fat synthesis increased but the subcutaneous fat depth decreased, indicating that chromium may cause the redistribution of fat within the carcass due to changes in insulin sensitivity. The chromium treatment did not effect growth rate, carcass weight, or muscle glycogen concentration. Chromium supplementation tended to prevent a decline in the concentration of chromium in the kidney, caused by exercise. The level of exercise was only sufficient to cause a glycogen loading response in one of the muscle tissues s led, the m. semimembranosis. Chromium Chelavite supplementation may be a useful tool for reducing the subcutaneous fat depth of mature ruminants, and may promote the redistribution of fat to other locations within the carcass.
Publisher: Elsevier BV
Date: 04-2018
DOI: 10.1016/J.PREVETMED.2018.02.004
Abstract: Associations between faecal shedding of pathogenic Yersinia enterocolitica (based on the yst virulence gene) with growth, carcass weight and diarrhoea were investigated using an observational longitudinal study of 1200 crossbred prime (meat) lambs on eight Australian farms. Live weight, breech faecal soiling score (scale 1-5) and faecal consistency score (FCS scale 1-5) were recorded, and faecal s les collected from each lamb on three s ling occasions weaning (≈12 weeks of age), post-weaning (≈19 weeks) and pre-slaughter (≈29 weeks). Hot standard carcass weight was measured at slaughter. Faecal s les were screened for presence and concentration of pathogenic Y. enterocolitica using quantitative PCR. Associations of pathogenic Y. enterocolitica detection and shedding intensity with lamb health and production were assessed using general linear models (carcass weight), linear mixed effects models (live weight, FCS and breech soiling score) and non-parametric tests (FCS and breech soiling score). Prevalence for non-pelleted faeces (FCS ≥ 3.0) and diarrhoea (FCS ≥ 4.0) were compared with the two-tailed z-test, odds ratios and relative risk. Lambs shedding pathogenic Y. enterocolitica were 3.78 kg lighter post-weaning (P < 0.001) and 2.61 kg lighter pre-slaughter (P = 0.035) compared to lambs in which pathogenic Y. enterocolitica was not detected. Higher faecal concentration of pathogenic Y. enterocolitica was associated with lower live weight (P < 0.001). There was no association between pathogenic Y. enterocolitica detection and carcass weight. Overall, there was no evidence of association between pathogenic Y. enterocolitica detection and diarrhoea (higher FCS, higher risk for non-pelleted faeces or diarrhoea, or higher breech soiling score). Only one flock had increased relative risk for non-pelleted faeces associated with pathogenic Y. enterocolitica detection, and one other flock had increased relative risk for diarrhoea associated with pathogenic Y. enterocolitica detection. This is the first report of an association between reduced sheep live weight and pathogenic Y. enterocolitica based on the presence of the yst gene for heat stable enterotoxin determined by qPCR in sheep. Notably, impacts on live weight were observed in the absence of diarrhoea.
Publisher: Elsevier BV
Date: 09-2016
DOI: 10.1016/J.VETPAR.2016.08.003
Abstract: Associations between intensity and frequency of Cryptosporidium and Giardia shedding with growth, carcase weight and dressing% were investigated using a longitudinal study of 1182 lambs on eight Australian farms. Live weight was recorded and faecal s les were collected on three s ling occasions weaning (approximately 12 weeks of age), post-weaning (approximately 19 weeks) and pre-slaughter (approximately 29 weeks). Hot standard carcase weight (HSCW) and dressing% were measured at slaughter. Faecal s les were screened for presence and concentration of Cryptosporidium, Giardia and Haemonchus oocysts using a quantitative PCR. Trichostrongylid eggs were quantified with modified McMaster faecal worm egg count (WEC). Protozoan shedding intensity was categorised as high (above median oocyst concentration in positive sheep), low (below median oocyst concentration in positive sheep) or not detected. Shedding was also categorised for shedding type (no shedding, single Giardia infection, single Cryptosporidium infection, concurrent Giardia and Cryptosporidium infection) and lambs were categorised for frequency of shedding (shedding identified on 0, 1, 2 or 3 occasions). Associations of parasite shedding intensity category, shedding type, shedding frequency, WEC and Haemonchus status (positive or negative) with lamb production were assessed using general linear models (HSCW and dressing%) and linear mixed effects models (live weight). High Cryptosporidium parvum shedding was associated with lower live weight, ranging 2.31-4.52kg over the 3 s ling occasions. Cryptosporidium parvum shedding was associated with less HSCW in high (3.22kg less) and low (3.22kg less) shedding lambs post-weaning, and high (2.21kg less) and low (2.60kg less) shedding lambs pre-slaughter as well as lower dressing% (2.7% lower in high shedding lambs post-weaning). Cryptosporidium (all species) shedding pre-slaughter was associated with reduced dressing% in both high (1.25% lower) and low (1.21% lower) shedding lambs. Giardia shedding pre-slaughter was associated with 0.59kg less HSCW in high shedding lambs. Increased frequency of C. parvum and Giardia shedding in a specific animal (repeated detection) were associated with reduced HSCW and dressing%. Concurrent Giardia and Cryptosporidium shedding pre-slaughter was associated with reduced dressing%. No statistically significant main effects for either WEC (P>0.05) or Haemonchus status (P>0.05) were identified for any of the sheep meat productivity measures (live weight, HSCW and dressing%). The findings suggest naturally acquired Cryptosporidium and Giardia infections in grazing sheep are associated with depressed growth, carcase weight and dressing efficiency beyond the neonatal period in sheep representing a range of genetic backgrounds and different sheep production environments.
Publisher: Elsevier BV
Date: 2015
Publisher: CSIRO Publishing
Date: 2014
DOI: 10.1071/AN13463
Abstract: The core body temperature and post slaughter loin temperatures of steers fed on grass pasture was compared with those of steers fed a grain-based feedlot diet. The feeding treatments were grass for 300 days (Grass), grass for 150 days then feedlot for 150 days (Short Feedlot) and feedlot for 300 days (Long Feedlot). Temperature telemeters were inserted under the peritoneum of the steers and temperature measured at intervals of 1 h for the 300 days, and then at intervals of 1 min for the 48-h period before slaughter. The pH and temperature decline post mortem was also measured. The carcasses of the feedlot steers were heavier and fatter than those from the Grass-fed steers. The core body temperature of the steers from the feedlot treatments was 0.3–0.4°C higher than for the Grass treatment at the time of slaughter. The loin temperature was higher in the feedlot treatments than the Grass treatment at all times measured post mortem as was the temperature at pH 6. Feedlotting can increase the likelihood of ‘high rigor temperature’ conditions of high temperature and low pH occurring in beef carcasses, due to an increase in core body temperature before slaughter, a decrease in the rate of cooling and an increase in the rate of pH decline post mortem. These effects are possibly due to a combination of a direct effect of feed type on body temperature as well as indirect effects on bodyweight and condition score.
Publisher: CSIRO Publishing
Date: 2014
DOI: 10.1071/AN14434
Abstract: The biochemistry of glycogen metabolism is well characterised, having been extensively studied in laboratory rodents and humans, and from this stems the bulk of our knowledge regarding the metabolism of glycogen in ruminants. With respect to intermediary metabolism, the key tissues include the liver and muscle. The liver glycogen depot plays a central role in intermediary metabolism, storing and mobilising glycogen during the fed and fasted metabolic states, with these responses modulated during pregnancy, lactation, and exercise. Alternatively, the muscle glycogen depot is particularly important for local energy homeostasis, and is likely to be less important as a key post-prandial sink for blood glucose given the reduced absorption of glucose from the gut in ruminant animals. Yet similar to the liver, this depot is also in a constant state of turnover, with the muscle glycogen concentration at any point in time a reflection of the rates of glycogen synthesis and degradation. Muscle glycogen metabolism attracts particular attention given its importance for post-mortem acidification of muscle tissue, with a shortage at slaughter leading to dark cutting meat. Simplistically the concentration of muscle glycogen at slaughter is a function of two key factors, the on-farm starting levels of glycogen minus the amount depleted during the pre-slaughter phase. On-farm concentrations of muscle glycogen are largely a reflection of metabolisable energy intake driving increased rates of muscle glycogen synthesis. Compared with simple-stomached species the rate of glycogen synthesis within ruminants is relatively low. Yet there also appears to be differences between sheep and cattle when fed diets of similar metabolisable energy, with cattle repleting muscle glycogen more slowly after depletion through exercise. While metabolisable energy intake is the key driver, genetic and age-related factors have also been shown to influence glycogen repletion. The amount of muscle glycogen depleted during the pre-slaughter phase is largely associated with stress and adrenaline release, and several recent studies have characterised the importance of factors such as exercise, age and genetics which modulate this stress response. This paper presents a summary of recent experiments in both cattle and sheep that highlight current developments in the understanding of this trait.
Publisher: Elsevier BV
Date: 2016
DOI: 10.1016/J.MEATSCI.2015.08.006
Abstract: The relationship between vitamin E supplementation rate and colour stability was investigated using 70 mixed sex 6-8 month old crossbred lambs. An initial group of 10 were slaughtered, while the remainder were fed a pellet ration containing either 30, 150, 275 or 400 IU vitamin E/kg ration or on green pasture for 56 days. After slaughter, carcases were halved one side packed fresh (5 days) and the other in CO2 (21 days), both at 2°C. Five muscles were set for retail display for 96 h. The oxy/metmyoglobin ratio was measured every 12 h. Colour stability increased with increasing muscle vitamin E until an apparent maximum effect for vitamin E concentration (3.5-4.0mg α-tocopherol/kg tissue) was reached beyond which no further response was evident. This was reached within 3-4 weeks (275 IU treatment), and meat from these lambs should reach 60 h retail display with a satisfactory surface colour. This effect was most apparent in aerobic muscle types and meat aged post slaughter.
Publisher: CSIRO Publishing
Date: 2006
DOI: 10.1071/AR05101
Abstract: This study investigated whether the expression profile of GDF8 (myostatin), myogenic regulatory factors (MRFs: MYF5, MYOD1, MYOG (myogenin), and MYF6), and IGF-system (IGF1, IGF2, IGF1R) genes are correlated with anatomical muscle, nutrition level, and estimated breeding values (EBVs) for muscling, growth, and/or fatness. Real-time PCR was employed to quantitatively measure the mRNA levels of these genes in the semimembranosus (SM) and semitendinosus (ST) muscles of growing lambs. The lambs were sired by Poll Dorset rams with differing EBVs for growth, muscling, and fatness, and were fed either high or low quality and availability pasture from birth to ~8 months of age. With the exception of MYOD1, the mRNA levels of all genes examined in this study showed varying degrees of nutritional regulation. All the MRF mRNA levels were higher in the SM muscle than the ST muscle, whereas myostatin mRNA was higher in the ST muscle than the SM muscle. Interactions between muscle type and nutrition were detected for IGF2, MYF6, and myogenin, while positive correlations between IGF2 and IGF1R and between MYOD1 and myogenin mRNA levels were apparent in both muscles. At the genotypic level, subtle differences in mRNA levels suggested interactions between nutrition and sire EBV. The findings of this study confirm that the MRFs, IGFs, and myostatin genes are differentially affected by a variety of factors that include nutrition, muscle type, and sire EBVs. Together, these data suggest that this suite of genes has important roles during postnatal muscle growth, even at quite late stages of growth and development.
Publisher: Elsevier BV
Date: 02-2014
DOI: 10.1016/J.VETPAR.2013.11.014
Abstract: The prevalence of Cryptosporidium in sheep in the eastern states of Australia has not been well described, therefore a study of the prevalence, oocyst concentration, species and subtypes of Cryptosporidium were assessed from lamb faecal s les at three s ling periods (weaning, post-weaning and pre-slaughter) from eight farms across South Australia, New South Wales, Victoria and Western Australia. A total of 3412 faecal s les were collected from approximately 1182 lambs across the four states and screened for the presence of Cryptosporidium using a quantitative PCR (qPCR) at the actin locus. Positives were typed at the 18S locus and at a second locus using C. parvum and C. hominis specific qPCR primers. The overall prevalence was 16.9% (95% CI: 15.6-18.1%) and of the 576 positives, 500 were successfully genotyped. In general, the prevalence of Cryptosporidium was higher in WA than the eastern states. Cryptosporidium prevalence peaked at 43.9% and 37.1% at Pingelly (WA2) and Arthur River (WA1), respectively during weaning and at Pingelly (WA2) during pre-slaughter (36.4%). The range of oocyst shedding at weaning overall across all states was 63-7.9×10(6) and the median was 3.2 × 10(4) oocysts g(-1). The following species were identified C. xiaoi (69%-345/500), C. ubiquitum (17.6%-88/500), C. parvum (9.8%-49/500), C. scrofarum (0.8%-4/500), mixed C. parvum and C. xiaoi (2.4%-12/500), C. andersoni (0.2%-1/500) and sheep genotype 1 (0.2%-1/500). Subtyping of C. parvum and C. ubiquitum isolates identified IIa and IId subtype families within C. parvum (with IId as the dominant subtype) and XIIa within C. ubiquitum. This is the first published description of C. parvum subtypes detected in lambs in Australia.
Publisher: CSIRO Publishing
Date: 2007
DOI: 10.1071/EA07093
Abstract: The objective of this study was to determine whether genotype, age (4, 8, 14 and 22 months), sex (ewe and wether) and muscle type influence ovine (n = 587) muscle metabolic characteristics. The genotypes represented were Poll Dorsetgrowth × Border Leicester Merino, Poll Dorsetgrowth × Merino, Poll Dorsetmuscling × Merino, Merino × Merino and Border Leicester × Merino. Between 4 and 22 months of age, myoglobin concentration within all muscles and all genotypes doubled, with the bulk of this response occurring between 4 and 8 months of age. Levels in the longissimus thoracis et lumborum (LT) and semimembranosus muscles were double those seen in the semitendinosus (ST) muscle, and Merinos had the lowest myoglobin concentrations of all genotypes. The other aerobic indicator, isocitrate dehydrogenase, had lower activity in the ST compared with the LT, was lower in 22-month-old sheep compared with all other ages, and decreased as selection for leanness increased. Both phosphofructokinase and lactate dehydrogenase activity tended to increase with age, were lower in the ST compared with the LT, and had higher activity in the Border Leicester × Merino sheep. The correlation between the percentage of total myofibre area comprising type 2X myofibres and metabolic markers was far higher for the oxidative indicators isocitrate dehydrogenase and myoglobin, which both decreased as relative area of type 2X fibres increased. However, the strongest correlations were with the relative area of type 2A myofibres, which were consistently high for both oxidative and glycolytic metabolic markers implying positive coregulation with both energy producing pathways.
Publisher: Elsevier BV
Date: 08-2011
DOI: 10.1016/J.VETPAR.2011.03.015
Abstract: Two flocks of pure bred Dorper lambs were managed separately according to sex (283 ewe lambs and 212 ram lambs) in southern Western Australia. Faecal s le collection, weighing and body condition assessments were performed for each lamb on 2 occasions, specifically pre-weaning (approximately 14 weeks of age) and post-weaning (approximately 9 months of age). Body condition score (BCS) was assessed using a scale of 1 (very thin, emaciated) to 5 (excessively fat). Faecal worm egg counts (WECs) were measured using a modified McMaster technique and larval cultures were performed to identify trichostrongylid nematode genera present. Eye muscle and c-site fat depths were measured using ultrasound at post-weaning. Lambs received an abamectin anthelmintic treatment at weaning (18 weeks of age). Worm egg count data was assessed for normality of data distribution and homogeneity of variance. This data was transformed using log(10)(WEC+25) to stabilise variances between groups prior to statistical analyses and general linear models were used to assess relationships between WEC and productivity measures. Mean WECs were 564 eggs per gram of faeces (EPG) and 514 EPG at pre- and post-weaning in the ewe flock and 552 EPG and 480 EPG at pre- and post-weaning in the ram flock. Teladorsagia (Ostertagia) circumcincta, Trichostrongylus spp. and Oesophagostomum spp. larvae were identified. No lambs with WEC 1000 EPG post-weaning. Ewe and ram lambs with WEC>1000 EPG at pre-weaning were 42 (12-145 95% CI) and 37 (9-153) times more likely to have WEC>1000 EPG at post-weaning than lambs with WEC 501-1000 EPG at pre-weaning. There were no significant relationships between WEC and live weight in the ram flock, while relationships between WEC and live weight were inconsistent in the ewe lamb flock. There was no relationship between WEC and eye muscle or c-site fat depth. Significant negative relationships between WEC and BCS were identified at pre- and post-weaning for both flocks. Lambs with WEC 1000 EPG at pre- and post-weaning. In conclusion, high WEC was associated with lower body condition in Dorper lambs, however the relationship between WEC and live weight was inconsistent and there was no effect on eye muscle depth.
Publisher: Elsevier BV
Date: 03-2018
DOI: 10.1016/J.MEATSCI.2017.11.029
Abstract: The purpose of this study was to test if associations exist between plasma indicators of acute and chronic stress and lamb loin Warner Bratzler Shear Force (WBSF). Blood was collected at exsanguination from 2877 lambs from the Meat and Livestock Genetic Research flock with a suite of indicators analysed. Loin (M. longissimus lumborum) WBSF was measured after 5days aging. Plasma indicators of stress did not relate to WBSF, however a positive association was found between WBSF and kill order, indicating that immediate pre-slaughter factors may be causing reduced tenderness in lamb. In addition, selection for decreased fat depth (PFAT) was associated with increased loin WSBF, indicating that genetic selection for increased carcass leanness is negatively affecting lamb loin tenderness.
Publisher: Elsevier BV
Date: 11-2021
Publisher: CSIRO Publishing
Date: 2008
DOI: 10.1071/EA07132
Abstract: This experiment examined the effect of length of exposure of bovine M. longissmus dorsi to high temperatures (37°C) on proteolytic activity during post-mortem aging and subsequent meat tenderness. To avoid confounding between pH decline and incubation treatments, the experiment was conducted on post-rigor meat (pH 5.6), which had entered rigor at 15°C. This meat was first incubated at 15°C until rigor (pH 5.6), whereupon s les were then reheated and maintained at 37°C for 0, 1 or 3 h. Following incubation, s les were aged at 1°C for 1–21 days. Control groups were incubated at either 15 or 37°C until pH 5.6, followed by aging at 1°C. High rigor temperatures accelerated post-mortem proteolysis early in the post-mortem period, as indicated by a rapid decline in shear force (P 0.01), but post-mortem aging ceased at about day 3 post-mortem and the high rigor temperature treatment was ultimately 30% tougher at day 21 post-mortem (P 0.01). The process of reheating s les from 15 to 37°C had minimal effect on tenderness levels, but was associated with a slight increase in proteolysis, identified by myofibril length, and was associated with an increase in cook loss percentage (P 0.05). Shear force in the length of exposure experiment was affected by an incubation time × post-mortem aging interaction (P 0.01). This indicated an initial acceleration of post-mortem aging with increased length of exposure, but also a reduction in the ultimate tenderness of product after extended post-mortem aging. This was presumably due to the loss of proteolytic enzyme activity caused by the instability of proteolytic enzymes at high ionic strength conditions such as those present in post-mortem muscle.
Publisher: MDPI AG
Date: 05-03-2021
Abstract: Lamb (n = 79) meat colour was scored by 879 untrained consumers using a scale of 0 (brown) to 100 (red). This consumer colour score (CCS) was obtained on m. longissimus lumborum (loin) and m. semimembranosus (topside), stored for short (5–7 days), medium (33–35 days), and long periods (110–112 days) and a retail display time of up to 4 days. Consumers perceived topside to be less red initially and changed from red to brown more rapidly when stored for the long-storage period (p 0.01). Whereas, the initial CCS of loin s les were similar across the storage periods (p 0.05). CCS and the instrument measure oxy/met (reflectance of light at wavelengths 630 nm and 580 nm) had a low correlation coefficient of 0.33 (p 0.01). The propensity for lamb growth and leanness indicated by sire breeding values for lamb weight, eye muscle depth, eye muscle fat depth, and loin intramuscular fat had varied and inconsistent effects on CCS. Therefore, even the selection on CCS.
Publisher: Elsevier BV
Date: 2018
Publisher: Elsevier BV
Date: 2020
Publisher: Elsevier BV
Date: 05-2018
DOI: 10.1016/J.MEATSCI.2018.01.005
Abstract: This study investigated the effects of vitamin E, electrical stimulation, aging and packaging system on the colour stability of lamb meat. Eighty crossbred wether lambs, 6-8months old were fed on either vitamin E or control pelleted diet for 31days prior to slaughter. Half of the carcases from each group were electrically stimulated before being split longitudinally into 2. Each side was randomly allocated 1 of the 4 aging periods (5days fresh, 10, 20 and 30days CO
Publisher: Elsevier BV
Date: 10-2015
DOI: 10.1016/J.MEATSCI.2015.06.002
Abstract: Data are obtained from computed tomography scanning of 1665 lambs at locations around Australia. Lambs were progeny of Terminal, Maternal and Merino sires with known Australian Sheep Breeding Values for post weaning c-site eye muscle depth (mm PEMD) and fat depth (mm PFAT), and post weaning weight (kg PWWT). Across the 7.8 unit range of sire PEMD, carcass lean weight increased by 7.7%. This lean was distributed to the saddle section (mid-section) where lean became 3.8% heavier, with fore section lean becoming 3.5% lighter. Reducing sire PFAT across its 5.1 unit range increased carcass lean weight by 9.5%, and distributed lean to the saddle section which was 3.7% heavier. Increasing sire PWWT increased lean at some sites in some years, and on average increased saddle lean by 4% across the 24.7 unit PWWT range. Changes in lean weight and distribution due to selection for carcass breeding values will increase carcass value, particularly through increased weight of high value loin cuts.
Publisher: Elsevier BV
Date: 2011
Publisher: CSIRO Publishing
Date: 2010
DOI: 10.1071/AN09095
Abstract: Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are the n-3 polyunsaturated fatty acids (n-3 PUFA) for which there is le evidence of human health benefits, and these are also the fatty acids for which there are cut-off points for ‘source’ and ‘good source’ claims. Two consecutive experiments were conducted to determine the effect of finishing systems on the n-3 PUFA content of lamb meat in Western Australia. In experiment I, a 4-week feeding experiment was conducted using 48 Poll Dorset × Merino lambs. The lambs were ided into two lots of 24 (12 males and 12 females) and randomly assigned to either concentrate (C1) finishing on commercial lamb finishing pellets or pasture (P) finishing on kikuyu (Pennisetum clandestinum) pasture. In experiment II, 28 lambs were ided into two groups of 14 lambs (seven males and seven females) and assigned to finishing either on concentrate pellets (C2) or concentrate pellets plus linseed (C2-L). This second experiment was conducted indoors for 10 weeks. The initial liveweight (mean ± s.e.) of the lambs was 43 ± 0.6 and 32.5 ± 0.9 kg for experiments I and II, respectively. At the end of experiment II, three chops each were s led from the leg, loin, forequarter and neck region of each carcass. The final liveweight (42 ± 0.8 v. 50 ± 1.2 kg), hot carcass weight (19 ± 0.5 v. 24 ± 0.7 kg) and GR depth (5.6 ± 0.6 v. 12.8 ± 0.6 mm) were lower (P 0.05) for P than C1 lambs. In contrast, C2 and C2-L lambs had similar final liveweight (44 ± 0.7 v. 45 ± 0.9 kg), hot carcass weight (19 ± 0.3 v. 20 ± 0.5 kg) and GR depth (13 ± 1.3 v. 14 ± 1.2 mm). In experiment I, the total n-3 PUFA yields for C1 and P lambs in the M. longissimus lumborum were 67 ± 2.5 and 78 ± 3.2 mg per 100 g muscle, respectively. The EPA plus DHA yields were 17 and 21 mg per 100 g muscle, respectively. The sum of the long-chain (≥C20) n-3 PUFA EPA, docosapentaenoic acid and DHA for C1 and P lambs were 30 and 37 mg per 100 g, respectively. Sex had no effect on any of the n-3 fatty acids. In experiment II, the total n-3 PUFA yields for C2 lambs were 61, 54, 60 and 104 mg per 100 g for leg, loin, forequarter and neck chops, respectively. The respective values for C2-L lambs were 153, 138, 139 and 178 mg per 100 g muscle. The claimable EPA plus DHA yields for C2 lambs were 13, 10, 12 and 15 mg per 100 g of trimmed leg, loin, forequarter and neck chops, respectively. The respective values for C2-L lambs were around 2-fold higher at 27, 21, 25 and 23 mg per 100 g raw meat. All the s les from pasture-finished and linseed-supplemented groups met the 30 mg cut-off point for ‘source’ claim in Australia when the computation was based on 100 g cooked lamb serve (140 g raw). We conclude that pasture-finished lambs have more n-3 PUFA per serve than their counterparts finished indoors on commercial pellets. Further, supplementing indoor-finished lambs with linseed provided equivalent n-3 PUFA per serve to finishing lambs on pasture. Supplementation with an omega-3 source improved omega-3 per serve across the whole carcass irrespective of sex.
Publisher: CSIRO Publishing
Date: 2006
DOI: 10.1071/AR05111
Abstract: The aim of this study was to characterise the allometric growth and bone mineral maturation of forelimb bones in sheep throughout the growth phase. Forelimb bones (scapula to proximal phalanx) were measured in 84 Merino sheep from similar genetic stock of approximately 12, 32, 64, 84, 116, and 168 weeks of age, with approximately equal numbers of wethers and ewes in each age cohort (n = 14). Sheep were selected for ergence of size, body weight, and condition, in order that the effects of age and body size could be assessed independently. Bone magnesium was measured in the metacarpal and humerus. Results demonstrate the highly coordinated, allometric nature of linear bone growth within the ovine forelimb, though allometric growth patterns differed from those previously published for bone weights. We propose that estimates of maturity proportion (M) based on relative limb bone length or limb proportions may present significant advantages over weight- or composition-based maturity indices, or qualitative variables such as dental eruption or USDA-type maturity scores. Sex differences in growth gradients were minimal, although the higher variability and greater gender ergence of metacarpal bone length casts doubt on the use of its growth plate (breakjoint) to indicate maturity. Bone magnesium content was found to decrease rapidly during the growth period and may represent a useful independent estimate of physiological maturity.
Publisher: Springer Science and Business Media LLC
Date: 12-2012
Abstract: An important controversy in the relationship between beef tenderness and muscle characteristics including biochemical traits exists among meat researchers. The aim of this study is to explain variability in meat tenderness using muscle characteristics and biochemical traits available in the Integrated and Functional Biology of Beef (BIF-Beef) database. The BIF-Beef data warehouse contains characteristic measurements from animal, muscle, carcass, and meat quality derived from numerous experiments. We created three classes for tenderness (high, medium, and low) based on trained taste panel tenderness scores of all meat s les consumed (4,366 observations from 40 different experiments). For each tenderness class, the corresponding means for the mechanical characteristics, muscle fibre type, collagen content, and biochemical traits which may influence tenderness of the muscles were calculated. Our results indicated that lower shear force values were associated with more tender meat. In addition, muscles in the highest tenderness cluster had the lowest total and insoluble collagen contents, the highest mitochondrial enzyme activity (isocitrate dehydrogenase), the highest proportion of slow oxidative muscle fibres, the lowest proportion of fast-glycolytic muscle fibres, and the lowest average muscle fibre cross-sectional area. Results were confirmed by correlation analyses, and differences between muscle types in terms of biochemical characteristics and tenderness score were evidenced by Principal Component Analysis (PCA). When the cluster analysis was repeated using only muscle s les from m. Longissimus thoracis (LT), the results were similar only contrasting previous results by maintaining a relatively constant fibre-type composition between all three tenderness classes. Our results show that increased meat tenderness is related to lower shear forces, lower insoluble collagen and total collagen content, lower cross-sectional area of fibres, and an overall fibre type composition displaying more oxidative fibres than glycolytic fibres.
Publisher: MDPI AG
Date: 31-07-2019
DOI: 10.3390/ANI9080503
Abstract: This study considered the relationship between pre-slaughter stressors and plasma biomarkers in 488 pasture-raised cattle across two experiments. The design aimed to test groups consisting of steer only, heifer only, and mixed sex cattle under direct kill versus rested (14 days in abattoir holding paddocks) protocols. In Experiment One, cattle were sourced from four farms, and transported by trucks and ships on the same day. In Experiment Two, cattle were sourced from four farms where a comparison was made between marketing via two commercial saleyards or direct farm gate consignment to abattoir. Blood s les were collected at exsanguination for subsequent analyses and relation to meat quality attributes. Muscle damage, as indicated by creatine kinase, is the biomarker most correlated to ultimate pH and muscle glycogen concentrations. A two-week rest period is effective for lowering this enzyme and improving muscle glycogen concentration. Although the cattle was subjected to a range of stress inducing treatments, we found that plasma biomarkers alone appeared insufficient for use as diagnostic stress indicators.
Publisher: Oxford University Press (OUP)
Date: 02-2014
Abstract: The objective of this study was to investigate whether single nucleotide polymorphisms (SNP) in the calpain 1 (CAPN1), calpain 3 (CAPN3) and calpastatin (CAST) genes, which have been shown to be associated with shear force and tenderness differences in the skeletal muscle of cattle, contribute to phenotypic variation in muscle tenderness by modulating the transcriptional activity of their respective gene. The mRNA expression of the calpain and CAST genes was assessed in the longissimus lumborum muscle (LLM) of cattle from two herds located in distinct production zones on the east (New South Wales, NSW) and west (Western Australia, WA) of Australia. The cattle in the herds were mainly Brahman cattle (Bos indicus) with smaller populations of Angus cattle (Bos taurus). There were 191 steers in the WA herd and 107 steers and 106 heifers in the NSW herd. These herds were established by choosing cattle from the erse population which had different single nucleotide polymorphism (SNP) genotypes at the CAPN1, CAPN3 and CAST loci. Using quantitative reverse transcriptase polymerase chain reaction (qRT-PCR), the transcriptional activities of the CAPN1 and the CAST genes, but not the CAPN3 gene, were found to differ between favorable, positively associated with tenderness, and unfavorable, negatively associated with tenderness, allelic variants of these genes. These findings suggest that the muscle shear force and consumer taste panel differences in tenderness explained by the CAPN1 and CAST gene markers are a consequence of alterations in their mRNA levels, which may ultimately influence the protein activity of these genes, thereby altering the rate and(or) the extent of postmortem proteolysis in skeletal muscle. Of particular importance were the significantly lower type II and type III CAST 5' splice variant mRNA levels that were detected in the LLM muscle of Brahman and Angus cattle with 2 favourable alleles of the CAST:c.2832A > G polymorphism. Moreover, a reduction in the abundance of an alternative polyadenylated variant of the CAST transcript, terminated at the proximal polyadenylation site, provides a unique insight into the potential involvement of a post-transcriptional regulatory mechanism which may influence protein expression levels in bovine skeletal muscle.
Publisher: CSIRO Publishing
Date: 2017
DOI: 10.1071/AN17307
Abstract: The global population is estimated to plateau at 9 billion by the year 2050 however, projected food-production estimates would supply for only 8 billion people, using the ‘business as usual’ approach. In particular, the meat industry would need to increase production by ~50–73%. In response, there are several different options that have the potential to satisfy demand and increase production. Some of these options require advanced technologies and many may be considered as ‘artificial’ by different consumer groups. Within the meat industry itself, available technologies include selective breeding, agroecology systems, animal cloning and genetic modification. Alternatively, meat proteins can be replaced or substituted with proteins from plants, fungi, algae or insects. Finally, meat products could be produced using in vitro culturing and three-dimensional printing techniques. The protein produced by these techniques can be considered in the following three categories: modified livestock systems, synthetic meat systems, and meat substitutes. In the future, it is likely that meat substitutes will increase market share through competition with low-grade cuts of meat, sausages, ground meat and processed meat. However, synthetic meat systems and meat substitutes have significant barriers to commercialisation and widespread adoption that will affect their presence at least in the high-end premium sector in the market. To meet growing demands for protein, and in the face of growing competition from other sectors, the conventional meat industry must adopt new technologies and farming systems. These must be tailored to the challenges facing the industry and must effectively respond to consumer demands and the changing market place.
Publisher: Elsevier BV
Date: 11-2021
Publisher: Elsevier BV
Date: 2019
Publisher: Elsevier BV
Date: 02-2014
DOI: 10.1016/J.MEATSCI.2013.07.037
Abstract: The impact of selecting for lean meat yield using breeding values for increased eye muscle depth (PEMD) and decreased fat depth (PFAT) on the consumer acceptance of lamb meat was evaluated. Consumer sensory scores (tenderness, juiciness, flavour, odour, overall liking) were obtained for the longissimus lumborum (loin) and semimembranosus (topside) muscles of 1471 lambs. On average loin s les were more acceptable for consumers. Sensory scores increased with higher IMF levels, with lower shear force levels, and when animals were younger and less muscular. Increasing PEMD decreased tenderness, overall liking and flavour scores in both muscles, and decreasing PFAT reduced tenderness within the loin s les only. This negative impact of PEMD and PFAT is not solely driven through the phenotypic impact of IMF and shear force on sensory scores. Our results confirm the growing concerns that selecting for lean meat yield would reduce consumer eating quality, and highlight that careful monitoring of selection programmes is needed to maintain lamb eating quality.
Publisher: Wiley
Date: 30-10-2012
Publisher: Elsevier BV
Date: 09-2016
DOI: 10.1016/J.MEATSCI.2016.04.009
Abstract: M. longissimus colour was measured from 8165 lambs at 24h post-mortem using a chromameter. The impact of production factors (site and year of production, slaughter group, sex, age and breed type) and muscle traits (hot carcass weight, pH24, isocitrate dehydrogenase (ICDH) activity, myoglobin, iron and zinc concentrations) on meat lightness (L*), redness (a*), yellowness (b*), hue and chroma were analysed. Greater differences in meat colour were seen between different slaughter groups and sites of production than across the range of any muscle traits. Of the muscle traits analysed, changes in pH24 had the greatest effect on meat a* (2.5 units), while myoglobin had the greatest effect on meat L* (2.9 units). The 3.1 L* unit darkening of meat with increasing lamb age (from 140 to 400days) was accounted for by increased myoglobin concentration. These results suggest that production factors are having substantial effects on lamb colour independent of known influencing muscle traits such as myoglobin concentration and pH.
Publisher: CSIRO Publishing
Date: 2006
DOI: 10.1071/AR05205
Abstract: This study examined influences of sire (n = 9) estimated breeding values (EBVs), sire-group (Muscle, Growth, and Control), and nutrition (low and high quality and availability pasture) from birth to slaughter at ~8 months of age on indices of muscle cellularity and transcriptional and translational capacity in 56 castrate lambs. Effects of nutritional systems to 8 months of age were greater, overall, than those due to EBVs or sire-group. Amount of DNA increased with increasing EBV for post-weaning eye muscle depth (PEMD or Muscle EBV) in longissimus but not in semimembranosus and semitendinosus muscles, while Muscle EBV also had an inverse association with concentration of DNA. Protein to DNA and RNA to DNA were related positively to Muscle EBV, the associations being strongest for the semitendinosus muscle. Post-weaning weight (PWWT or Growth) EBV correlated positively with the RNA to DNA ratio and, among high but not low nutrition lambs, was inversely related to concentration of muscle DNA, whereas post-weaning fat depth (PFAT or Fat) EBV was correlated positively with RNA concentration. Overall, the magnitude of effects of sire-group was less than for sire EBVs, presumably due to differing selection pressures for muscling, fatness, and growth. High nutrition lambs had more protein to DNA than low nutrition lambs in the longissimus and semitendinosus muscles, but not in the semimembranosus muscle. In low compared with high nutrition lambs, concentration of DNA was greater in the longissimus and semitendinosus muscles. Total amount of DNA was reduced by more in low compared with high nutrition in the longissimus and semimembranosus than in the semitendinosus, and amount of protein was reduced by more in low compared with high nutrition in the longissimus than in the other two muscles. We conclude that genetic selection for eye muscle depth in sheep has differing effects on cellular characteristics of the longissimus, semimembranosus, and semitendinosus muscles, and has greater effects on muscle cellular characteristics than genetic selection for post-weaning weight or fat depth.
Publisher: Elsevier BV
Date: 2016
Publisher: Elsevier BV
Date: 2016
Publisher: Elsevier BV
Date: 09-2006
DOI: 10.1016/J.MEATSCI.2006.04.022
Abstract: This paper reviewed the mechanisms by which glycolytic rate and pre-rigor stretching of muscle impact on meat quality. If muscle is free to shorten during the rigor process extremes in glycolytic rate can impact negatively on meat quality by inducing either cold or rigor shortening. Factors that contribute to variation in glycolytic rate include the glycogen concentration at slaughter and fibre type of the muscle. Glycolysis is highly sensitive to temperature, which is an important factor in heavy grain fed carcasses. An alternative solution to controlling glycolysis is to stretch the muscle pre-rigor so that it cannot shorten, thus providing an insurance against extremes in processing conditions. Results are presented which show a large reduction in variance (both additive and phenotypic) in tenderness caused by pre-rigor stretching. Whilst this did not impact on the heritability of shear force, it did reduce genotype differences. The implications of these results on the magnitude of genotype effects on tenderness is discussed.
Publisher: Elsevier BV
Date: 03-2016
Publisher: American Chemical Society (ACS)
Date: 21-05-2010
DOI: 10.1021/JF100191K
Abstract: In the eyes of the consumer, a red surface color of lamb meat is desirable. This red color is caused by oxymyoglobin however, under conditions of retail display this pigment slowly oxidizes and turns brown, deterring consumers. The antioxidant activity of both glutathione (GSH) and selenium has been suggested to slow myoglobin oxidation, thus improving color stability. The following experiment was designed to test the hypothesis that high muscle GSH will improve the color stability of lamb meat, and this effect of GSH will be further improved by supplementing animals with selenium. Forty-eight 12-month-old Merino wether lambs were selected from a flock for high (n = 24) or low (n = 24) GSH concentration in whole blood. Each GSH group was then randomly allocated into two selenium treatments (supplemented with or without 2.5 mg of selenium/kg for 8 weeks). The lambs were slaughtered, and s les were taken from m. semimembranosus (SM) and m. longissimus dorsi (LD) to measure muscle GSH, selenium, and vitamin E concentrations. Further s les were taken to measure color stability (as oxy/metmyoglobin ratio, reflectance at 630/580 nm) over 96 h of retail display. There was no effect of muscle GSH concentration or selenium supplementation on oxy/metmyoglobin ratio at 60, 48, or 30 h of retail display, with the only exception being the non-selenium-supplemented SM s les, which actually decreased in ratio as the muscle GSH concentration increased (P < 0.05). There was a poor correlation between blood and muscle GSH, with a correlation coefficient of 0.18 for the SM and 0.026 for the LD. Thus, it is apparent that neither GSH nor selenium improved the color stability of meat from merino lambs.
Publisher: Wiley
Date: 26-04-2017
DOI: 10.1111/AVJ.12572
Abstract: Develop a multiplex quantitative PCR assay to investigate the prevalence and shedding of Escherichia coli O157/O145, Salmonella spp. and C ylobacter spp. in sheep at sale yards and abattoirs. A qPCR for E. coli O157/O145 was developed, validated and multiplexed with an existing qPCR for C ylobacter and Salmonella enterica. The absolute numbers of E. coli O157/O145, C ylobacter and Salmonella in control s les was determined using droplet digital PCR. These were then used as the controls in the multiplex qPCR on a total of 474 sheep faecal s les collected from two saleyards over a 4-month period (April-July 2014) and 96 effluent s les from an abattoir. The mutiplex qPCR was specific with a sensitivity of 5 organisms/μL faecal DNA extract for C ylobacter, S. enterica and E. coli O157/O145. The overall prevalence of C ylobacter, S. enterica and E. coli O157/O145 in faecal s les was 5.7%, 3.6% and 8.4% and in effluent s les was 18.8%, 6.3% and 5.2%, respectively. The pathogen loads of C ylobacter, S. enterica and E. coli O157/O145 in faecal and effluent s les was also determined via mutiplex qPCR. The overall prevalences of C ylobacter, S. enterica and E. coli O157/O145 were generally low (<6%), but point prevalences ranged considerably in healthy sheep (up to 26% for E. coli O157/O145). Further work to determine risk factors for shedding of bacterial organisms in meat sheep in the pre-slaughter period (on-farm, sale yards and lairage at abattoirs) could further reduce the risk of contamination of meat products.
Publisher: CSIRO Publishing
Date: 1999
DOI: 10.1071/A98093
Abstract: This experiment compared the metabolism of muscle glycogen and the ultimate pH (pHu) of muscle in Merino and crossbred lambs fed the same diet but subjected to different levels of stress pre-slaughter. Twenty- five Merino, 24 first-cross (Merino dam × Poll Dorset sire), and 23 second-cross (Border Leicester × Merino dam and Poll Dorset sire) wether lambs (6 months old, 30 kg liveweight) were maintained for 8 weeks on a complete pelleted diet based on lupin seed, straw, and barley grain (metabolisable energy, 10.8 MJ/kg protein, 17.4% in dry matter), with a feed intake of 1.3 kg dry matter /day for each breed. At Week 6, muscle biopsies were taken from 15 lambs of each breed, and at Week 8, 5 animals from each breed were slaughtered at an experimental abattoir 10 min after removal from their pens (low pre-slaughter stress). The remaining lambs, separated into breeds, were transported for 2 h and slaughtered after 24 h lairage at a commercial abattoir. Muscle s les were taken at slaughter, and assayed with the biopsy s les for glycogen concentration (corrected for lactate concentration), myoglobin concentration, and citrate synthase activity. The pHu of muscle was measured 48 h post slaughter. Compared with commercially slaughtered lambs, the muscle tissues of lambs subjected to low pre-slaughter stress had higher glycogen concentrations post mortem, lower pHu, and no significant loss of glycogen between pen and slaughter. Breed had no effect on glycogen, pH, or the colour of muscle under low-stress slaughter conditions or when the muscle biopsy was taken. In contrast, breed had a significant influence under commercial slaughter conditions, the muscle of Merino lambs having the lowest glycogen concentration post portem, and the highest pHu and loss of glycogen between pen and slaughter. Irrespective of stress, second-cross lambs had higher myoglobin concentrations and citrate synthase activities than the Merino lambs, indicating greater pigmentation of muscle in the second-cross animals. We conclude that higher proportions of Merino genes are associated with a greater sensitivity to stress in lambs destined for slaughter.
Publisher: Elsevier BV
Date: 02-2015
Publisher: Elsevier BV
Date: 2017
Publisher: CSIRO Publishing
Date: 2010
DOI: 10.1071/AN10130
Abstract: Selection against fatness in the Australian sheep industry has been a priority, but defining the true value of fat requires an understanding of the effects it has on both the value of lamb carcasses and on sheep productivity. A Merino flock with 10 years of reproduction data was used to analyse the correlation between breeding values for fatness at yearling age (YFAT) and the number of lambs born per ewe mated (NLB). In 2 production years, NLB was related (P 0.01) to YFAT resulting in an extra 14 or 24.5 lambs born per 100 ewes mated per mm of YFAT. Based on these relationships, bio-economic modelling was used to assess the whole-farm value of YFAT for different sheep production systems and for years representing a low, medium and high response of NLB to YFAT. The changes in whole-farm profitability for a 1-mm increase in YFAT varied from $1000 (2%) for a wool enterprise with a low response up to $44 000 (25%) for a lamb enterprise with a high response. Appropriate carcass value discounts for higher YFAT were investigated but were not evident because of the small change in GR fat depth associated with the range of YFAT investigated. In most years there is no impact of YFAT on NLB and therefore profitability, yet in years where Merino ewes with higher YFAT produce higher NLB, ewes with an extra 1 mm of YFAT will be up to 25% more profitable. Therefore, care is required in determining the appropriate selection pressure to be placed on YFAT in Merino selection.
Publisher: Elsevier BV
Date: 02-2014
DOI: 10.1016/J.MEATSCI.2013.06.014
Abstract: Selection for lean growth through Australian Sheep Breeding Values (ASBVs) for post weaning weight (PWWT), eye muscle depth (PEMD) and c-site fat depth (PFAT) raises concerns regarding declining intramuscular fat (IMF) levels. Reducing PFAT decreased IMF by 0.84% for Terminal sired lambs. PEMD decreased IMF by 0.18% across all sire types. Female lambs had higher IMF levels and this was unexplained by total carcass fatness. The negative phenotypic association between measures of muscling (shortloin muscle weight, eye muscle area) and IMF, and positive association between fatness and IMF, was consistent with other literature. Hot carcass weight increased IMF by 2.08% between 12 and 40 kg, reflective of development of IMF as lambs approach maturity. Selection objectives with low PFAT sires will reduce IMF, however the lower impact of PEMD and absence of a PWWT effect, will enable continued selection for lean growth without influencing IMF. Alternatively, the negative impact of PFAT could be off-set by inclusion of an IMF ASBV.
Publisher: Elsevier BV
Date: 07-2016
DOI: 10.1016/J.MEATSCI.2016.02.037
Abstract: Lean (muscle), fat, and bone composition of 1554 lamb carcasses from Maternal, Merino and Terminal sired lambs was measured using computed tomography scanning. Lamb sires were erse in their range of Australian Sheep Breeding Values for post weaning c-site eye muscle depth (PEMD) and fat depth (PFAT), and post weaning weight (PWWT). Lean value, representing predicted lean weight multiplied by retail value, was determined for lambs at the same carcass weight or the same age. At the same carcass weight, lean value was increased the most by reducing sire PFAT, followed by increasing PEMD and PWWT. However for lambs of the same age, increasing sire PWWT increased lean value the most. Terminal sired lambs, on average, had greater lean value irrespective of whether comparisons were made at the same age or weight. Lean value was greater in Merino compared to Maternal sired lambs at equal carcass weight, however the reverse was true when comparisons were made at the same age.
Publisher: CSIRO Publishing
Date: 2006
DOI: 10.1071/AR05289
Abstract: The aim of this study was to assess the effect of low or high whole-of-life nutritional planes on bone growth, maturation, and carcass composition in lambs from sires (n = 9) with high estimated breeding values (EBVs) for post-weaning eye muscle depth (PEMD) or liveweight gain (PWWT), compared with sires of industry average for both traits. Lambs (n = 54) were killed at 8 months of age before measurement of forelimb bones, radiographic scoring, and histological measurement of growth plates, and bone ash mineral analysis. A subset of these (n = 36) had carcass composition serially assessed during growth by CAT-scan. Results reveal that the nutritional restriction imposed in this experiment caused significant restriction of skeletal growth, as reflected by shorter, thinner forelimb bones, altered limb proportions, narrowing (and in some cases permanent closure) of growth plates, and an altered bone mineral profile. CAT-scan analysis showed restriction of bone growth was similar to that of muscle growth. Progeny of high muscling (PEMD) sires showed greater muscle growth, but were possibly more susceptible to some of the skeletal effects of nutritional restriction. Greater sire EBVs for PEMD, PWWT, or fat depth were associated with narrower growth plates, suggestive of slower longitudinal bone growth and shorter adult limb length, although bone mass was not affected according to earlier CAT-scan data. Results also suggest that progeny of high PEMD or PWWT sires are earlier maturing in terms of skeletal (or at least limb) growth, although their bone mineral profile (magnesium content) was more consistent with that of physiologically less mature animals.
Publisher: CSIRO Publishing
Date: 2010
DOI: 10.1071/AN10132
Abstract: This study investigated genetic and non-genetic factors affecting the iron, zinc and omega-3 fatty acid levels of fresh lamb meat. Results from the 2007 progeny of the Australian Sheep Industry Cooperative Research Centre Information Nucleus flock, ~2000 lambs, are presented here. The average level of iron and zinc in lamb muscle was 2.05 and 2.31 mg/100 g, respectively. The iron level was 103% of that required to claim lamb as a ‘good source’ of iron for men of all ages and women older than 50 years, and the average level of zinc was 116% of that required to claim lamb as a ‘good source’ of zinc for women, but was insufficient for a ‘good source’ claim for men. The iron and zinc content of muscle were affected (P 0.001) by age at slaughter, sex, site at which the lambs were reared, and sire (independent of breed). Lambs from all sites reached the ‘source’ claim for iron for all adults and lambs from all sites, expect lambs from the Cowra and Hamilton sites, had greater iron levels than that required for a ‘good source’ claim for men and women over 50 years old. For zinc, all sites reached the ‘source’ and ‘good source’ claim for men and women, respectively. The major sources of variation in omega-3 fatty acid levels were site and kill group within site (P 0.001), most likely reflecting nutritional differences associated with the availability of green feed. The eicosapentaenoic acid + docosahexaenoic acid values for all sites indicated that lambs from the Cowra, Rutherglen and Struan sites had adequate levels for a ‘source’ claim of omega-3. The overall average level of eicosapentaenoic acid + docosahexaenoic acid in lamb meat was 23.5 mg/100 g, which is higher than the level required to claim lamb as a ‘source’ of omega-3. The effect of sire on omega-3 fatty acid level was small, but statistically significant (P 0.001). These results confirm that lamb can represent a ‘source’ or ‘good source’ of these nutrients.
Publisher: CSIRO Publishing
Date: 2010
DOI: 10.1071/AN10126
Abstract: Using performance from progeny born in 2007 and 2008 generated by the Information Nucleus program of the Cooperative Research Centre for Sheep Industry Innovation, preliminary estimates of heritability were obtained for a range of novel carcass and meat attributes of lamb relevant to consumers, including carcass characteristics, meat quality and nutritional value of lamb. Phenotypic and genetic correlations of live animal traits with carcass composition and meat quality traits were also estimated. The data were from progeny located at eight sites, sired by 183 rams from Merino, maternal and terminal meat breeds and were representative of the Merino, Border Leicester × Merino, Terminal × Merino and Terminal × Border Leicester-Merino production types of the Australian sheep industry. Data were available from 7176 lambs for weaning weight, 6771 lambs for ultrasound scanning and 4110 lambs for slaughter traits. For the novel meat quality traits, generally moderate to high heritability estimates were obtained for meat quality measures of shear force (0.27 aged 1 day, 0.38 aged 5 days), intramuscular fat (0.39), retail meat colour (range of 0.09 to 0.44) and myoglobin content (0.22). The nutritional value traits of omega-3 fatty acids and iron and zinc contents tended to have low to moderate heritabilities (0.11–0.37), although these were based on fewer records. Fresh meat colour traits were of low to moderate heritability (0.06–0.21) whereas measures of meat pH were of low heritability (~0.10). For the carcass traits, estimates of heritability were moderate to high for the various measures of carcass fat (0.18–0.50), muscle weight (0.22–0.35), meat yield (0.24–0.35), carcass muscle dimensions (0.25–0.34) and bone weight (0.27). Results indicate that for most lamb carcass and meat quality traits there is sufficient genetic variation for selection to alter successfully these characteristics. Additionally, most genetic correlations of live animal assessments of bodyweight, muscle and subcutaneous fat with the carcass and meat quality traits were favourable. Appropriate definition of breeding objectives and design of selection indexes should be able to account for the small unfavourable relationships that exist and achieve the desired outcomes from breeding programs.
Publisher: Elsevier BV
Date: 02-2014
DOI: 10.1016/J.EXPPARA.2013.12.004
Abstract: A novel quantitative PCR (qPCR) for Giardia at the glutamate dehydrogenase (gdh) locus was developed and validated. The qPCR was used to screen a total of 3412 lamb faecal s les collected from approximately 1189 lambs at three s ling periods (weaning, post-weaning and pre-slaughter) from eight farms across South Australia (SA), New South Wales (NSW), Victoria (Vic) and Western Australia (WA). The overall prevalence was 20.2% (95% CI 18.9-21.6) and of the 690 positives, 473 were successfully typed. In general, the prevalence of Giardia varied widely across the different farms with the highest prevalence in one WA farm (42.1%) at pre-slaughter s ling and the lowest prevalence in one Victorian farm (7.2%) at weaning. The range of cyst shedding at weaning, post-weaning and pre-slaughter overall across all states was 63-1.3×10(9) cysts g(-1) (median=1.7×10(4)), 63-1.1×10(9) cysts g(-1) (median=9.6×10(3)), 63-4.7×10(9) cysts g(-1) (median=8.1×10(4)) respectively. Assemblage specific primers at the triose phosphate isomerase (tpi) locus identified assemblage A in 22.4% (106/473) of positive s les typed, assemblage E in 75.9% (359/473) and mixed A and E assemblages in 1.7% (8/473) of s les. A subset of representative s les from the 8 farms (n=32) were typed at both the gdh and beta-giardin loci and confirmed these results and identified sub-assemblage AII in 16 representative assemblage A isolates across the 8 farms. This demonstrates a prevalence of Giardia previously not recognised in Australian sheep, highlighting a need for further research to quantify the production impacts of this protozoan parasite.
Publisher: Elsevier BV
Date: 10-2014
DOI: 10.1016/J.EXPPARA.2014.06.018
Abstract: The prevalence of Eimeria in sheep in Australia has not been well described, therefore a quantitative PCR (qPCR) was developed, validated and used to study the prevalence and oocyst concentration in lamb faecal s les at three s ling periods (weaning, post-weaning and pre-slaughter) from eight farms across South Australia, New South Wales, Victoria and Western Australia. A total of 3412 faecal s les were collected from approximately 1182 lambs across the 4 states and screened for the presence of Eimeria using this qPCR at the 18S ribosomal RNA (rRNA) locus. A subset of positives was typed by sequence analysis at the 18S locus. The overall prevalence was 18.1% (95% CI 16.8-19.3%) and of the 616 positives, 118 were successfully genotyped. The prevalence of Eimeria was highest in NSW and peaked at 70% during the post-weaning period. The range of oocyst shedding per gram of faeces (g(-1)) at weaning, post-weaning and pre-slaughter overall across all states was 23-2.1×10(7), 23-1.3×10(7) and 23-2.1×10(5), respectively. Median Eimeria shedding g(-1) was higher during post-weaning (1.1×10(3)) and pre-slaughter (1.1×10(3)) than during weaning (206). The following species were identified: Eimeria crandallis, Eimeria ahsata, Eimeria ovinoidalis, Eimeria weybridgensis and Eimeria cylindrica. Of these, E. crandallis and E. ovinoidalis, the most pathogenic species in sheep were responsible for 58.5% of infections typed. This highlights a need for further research to quantify the production impacts of Eimeria in sheep.
Publisher: Elsevier BV
Date: 03-2021
Publisher: Elsevier BV
Date: 09-2015
Publisher: Elsevier BV
Date: 11-2021
Publisher: Elsevier BV
Date: 2011
Publisher: Hindawi Limited
Date: 12-01-2022
DOI: 10.1155/2022/8374473
Abstract: Today, with increasing information technology such as the Internet of Things (IoT) in human life, interconnection and routing protocols need to find optimal solution for safe data transformation with various smart devices. Therefore, it is necessary to provide an enhanced solution to address routing issues with respect to new interconnection methodologies such as the 6LoWPAN protocol. The artificial neural network (ANN) is based on the structure of intelligent systems as a branch of machine interference, has shown magnificent results in previous studies to optimize security-aware routing protocols. In addition, IoT devices generate large amounts of data with variety and accuracy. Therefore, higher performance and better data handling can be achieved when this technology incorporates data for sending and receiving nodes in the environment. Therefore, this study presents a security-aware routing mechanism for IoT technologies. In addition, a comparative analysis of the relationship between previous approaches discusses with quality of service (QoS) factors such as throughput and accuracy for improving routing mechanism. Experimental results show that the use of time- ision multiple access (TDMA) method to schedule the sending and receiving of data and the use of the 6LoWPAN protocol when routing the sending and receiving of data can carry out attacks with high accuracy.
Publisher: Elsevier BV
Date: 2016
Publisher: IEEE
Date: 02-2020
Publisher: MDPI AG
Date: 13-02-2020
DOI: 10.3390/FOODS9020187
Abstract: There is an industry wide perception that new season lamb has better eating quality than old season lamb. This study aims to identify differences in consumer eating quality scores between two age classes in lamb. Consumer eating quality scores from eight cuts across the carcass were evaluated from new season (NS n = 120 average age = 240 days) and old season lambs (OS n = 121 average age = 328 days), sourced from four different flocks. Cuts were grilled (loin, topside, outside, knuckle and rump) or roasted (leg, shoulder, rack) and scored by untrained consumers for tenderness, juiciness, liking of flavour and overall liking. There was no difference in eating quality scores between the two age classes for the loin, leg, shoulder and rack. This was similarly shown in the topside with the exception of juiciness scores where NS lambs were higher than OS lambs. There was also a lack of age difference in the outside with the exception of flock 3 where NS lambs scored higher than OS lambs for all sensory traits. Across all sensory traits, OS lambs received on average 2.8 scores lower for the knuckle and 3.1 scores lower for the rump compared to NS lambs. These results show little difference in eating quality between NS and OS lamb, and highlight the potential to develop high quality OS or “autumn lamb” products, with a similar premium price at retail as NS lambs.
Publisher: CSIRO Publishing
Date: 2019
DOI: 10.1071/AN17337
Abstract: Slower growing Merino sheep often miss the lamb category and become yearlings. Yet, they may still produce meat of acceptable eating quality, thus opening the opportunity to develop high quality yearling products. Consumer sensory differences (tenderness, overall liking, juiciness, liking of flavour and liking of odour) of grilled wet-aged (5 days) steaks from the M. longissimus lumborum (LL) and M. semimembranosus (SM) derived from wether lamb (n = 185 average age 355 days) and wether yearling (n = 206 average age 685 days) Merinos were tested. Additionally, the age effect on carcass and instrumental meat quality traits was analysed. Lambs were born in 2009 and 2010 at two research sites (Kirby, Katanning), and yearlings were born in 2009 at five research sites (Kirby, Cowra, Rutherglen, Struan, Katanning). On average within each muscle, yearlings had lower scores for all sensory attributes (P & 0.01) compared to lambs. Lambs versus yearlings born in the same year and reared at the same research site had greater sensory differences within the SM (P & 0.01), up to 10.0 eating quality scores more for tenderness. In contrast, the LL s les had almost no significant differences between the two age groups. A portion of the differences in overall liking and liking of flavour scores was explained by intramuscular fat. Yearlings were slightly heavier (P & 0.01) but leaner (P & 0.01), compared to lambs, and yearling meat colour was darker (P & 0.01). While the results generally supported the better eating quality of lamb, they demonstrated a very acceptable yearling LL eating quality, and showed the smaller impact of age on the LL muscle in Merinos. Hence, the development of a high quality yearling product for the LL muscle is possible.
Publisher: CSIRO Publishing
Date: 2010
DOI: 10.1071/AN10144
Abstract: This study describes the impact of Australian Sheep Breeding Values (ASBV) for post-weaning weight (PWWT), C-site fatness (PFAT) and eye muscle depth (PEMD) on lamb carcasses within the Australian Sheep Industry CRC Information Nucleus Flock. These results are taken from the 2007 drop progeny, consisting of ~2000 lambs slaughtered at a target weight of 21.5 kg. These lambs were the progeny of sires selected to ensure genetic ersity across various production traits. As expected, the PWWT ASBV increased weight at slaughter, and hot standard carcass weight. Dressing percentage was markedly improved by increasing PEMD ASBV, thus prime lamb producers will be maintaining an animal of similar weight on farm, but delivering a markedly larger carcass at slaughter. Lean meat yield % (LMY%) was highest in the progeny of sires with low PFAT ASBV, which decreased whole carcass fatness and increased muscularity. PWWT ASBV affected carcass composition but had little impact on LMY%, as the decreased fatness was largely offset by increased bone, with relatively little change in muscle content. Lastly, PEMD ASBV had little impact on whole carcass LMY%, but did appear to cause some level of muscle redistribution to the higher value loin cuts, in turn increasing the value of the carcass lean.
Publisher: Elsevier BV
Date: 02-2014
DOI: 10.1016/J.MEATSCI.2013.08.017
Abstract: Selection for increased lean meat yield using Australian Sheep Breeding Values for reduced post-weaning c-site fat depth (PFAT) and increased post-weaning eye muscle depth (PEMD) reduces the oxidative capacity of muscle. Isocitrate dehydrogenase (ICDH) activity and myoglobin concentration were measured in 3178 and 5580 lambs, respectively, to indicate oxidative capacity. In the progeny of sires with a reduced PFAT, ICDH activity and myoglobin concentration were reduced by 0.46 μmol/min/g tissue and 0.67 mg/g tissue across the 5 and 6mm PFAT ranges respectively. In the progeny of sires with an increased PEMD, ICDH activity and myoglobin concentration were reduced by 0.50 μmol/min/g tissue and 0.49 mg/g tissue across the 7 and 6 mm PEMD ranges respectively. However, the sites at which the lambs were raised had a larger impact on oxidative capacity than genetic or other production factors.
Publisher: CSIRO Publishing
Date: 2009
DOI: 10.1071/AN09038
Abstract: Interest in the use of computed tomography (CT) scanning in animal experimentation has increased markedly over the last decade due to the benefits of studying tissue in live subjects over time. In these experiments, the non-carcass components of the scan are removed from the collected data, allowing scientists to study the carcass of a live animal without the need to slaughter the in idual. However, there is not yet a consensus regarding the most appropriate manner in which to convert the CT numbers into a meaningful estimate of area, volume or proportion of tissue present in a carcass at the time of scanning. In this paper we use a Bayesian mixture model to estimate the area of each of three tissue types of interest, fat, muscle and bone present in in idual CT scan slices. We then use the Cavalieri principle to estimate the volume and proportion of the carcass attributable to each of these tissues. The approach is validated by analysis of experimental sheep carcasses.
Publisher: Elsevier BV
Date: 2021
Publisher: Elsevier BV
Date: 02-2014
DOI: 10.1016/J.MEATSCI.2013.08.013
Abstract: There is a concern regarding the possible decline of nutritional value of meat with an increasing selection for lean meat yield. The selection for reduced fatness reduces muscle aerobicity and possible subsequent mineral concentrations. Average concentrations of iron and zinc of 5625 lamb longissimus muscles were 2.03 and 2.43 mg/100 g, qualifying as a good source claim for the majority of the population. Reduced post-weaning fat depth was associated with decreased concentrations of iron but not zinc, whereas post-weaning eye muscle depth and weaning weight were not associated with either mineral. These results confirm that the impact of lean meat yield selection on these minerals is minimal, but should be monitored to avoid lower levels. Both minerals had a positive relationship with age at slaughter, highlighting age as a key determinant of the concentration of these nutrients. The magnitude of the positive associations of isocitrate dehydrogenase and myoglobin with iron was larger than for zinc, but they strongly indicated the association of these aerobic makers with both minerals.
Publisher: Elsevier BV
Date: 11-2021
Publisher: Elsevier BV
Date: 2017
Publisher: Elsevier BV
Date: 2009
DOI: 10.1016/J.MEATSCI.2008.07.017
Abstract: This study investigated the effect of computerised tomography imaging (CT scan), for carcase composition determination, on the oxy/metmyoglobin ratio, hue and L(∗), a(∗) and b(∗) scores of M. longissimus dorsi from both beef and lamb. Beef and lamb M. longissimus dorsi were ided into four proportions and randomly allocated to one of the following treatments CT 30 day aged CT fresh control 30 day aged control fresh. Colour measurements were made over a 96h retail display period. CT scan had little effect on the colour of both lamb and beef across all colour parameters. There was a small negative affect observed in CT aged s les (P<0.05) for ratio, hue, a(∗) and b(∗) values, however these differences were so small that they are unlikely to impact upon the commercial shelf-life of the product. Other factors such as aging, species and vitamin E concentration play a much greater role in colour stability than CT. Aged M. longissimus dorsi clearly had a worse colour stability than the fresh packaged s les, while beef was a lot more colour stable than lamb. It appears that CT scan for the purpose of body composition determination will not have any commercially relevant impact on colour stability of both beef and lamb.
Publisher: CSIRO Publishing
Date: 1996
DOI: 10.1071/EA06010
Abstract: Past studies have identified that electrical stimulation systems not only affect the pH–temperature decline of lamb carcasses, but also affect the tenderness of the product. It is unknown whether these differences are due to the effects of an optimal pH–temperature decline path by which the occurrence of shortening is decreased and proteolytic enzyme activity is increased, or by another mechanism, such as disruption of the muscle myofibres. This study attempted to elucidate this by placing control and mid-voltage electrically stimulated s les of the M. longissimus thoracis et lumborum in a water bath to prevent shortening by imposing an even pH–temperature decline on all s les. In order to obtain a complete understanding of the effects of stimulation on the muscle, s les were taken for indicators of tenderness, myofibre degradation and protein breakdown. No effect of stimulation was seen on tenderness and structural degradation measures aside from the expected rapid lowering of muscle pH. Interesting relationships were observed, however, between the different methods of meat tenderness assessment, with muscle structural protein degradation, shear force and muscle fibre and myofibre breakdown comparisons. These results suggest that the effects of electrical stimulation seen in mid-voltage systems as applied in this study are due only to the prevention of shortening conditions.
Publisher: Elsevier BV
Date: 03-2021
No related grants have been discovered for Graham Gardner.