ORCID Profile
0000-0003-1215-2848
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: Medpharm Publications
Date: 06-2022
Publisher: Elsevier BV
Date: 06-2020
Publisher: MDPI AG
Date: 25-04-2017
DOI: 10.3390/ANI7050034
Publisher: CSIRO Publishing
Date: 2020
DOI: 10.1071/AN19340
Abstract: Aims The study investigated critical biosecurity control points and dairy farmers’ motivations towards biosecurity practices among selected dairy farmers across Australia. Methods A questionnaire template was administered via an online survey. A three-stage process was used to develop the questionnaire by pooling of potential questions, selection and reduction of the questions to fit an 8–10 min survey. Key results A total of 55 responses were obtained. Mixed species rearing was practiced on 69% of the farms, with a majority keeping either sheep or beef cattle within the same property as dairy cattle. Approximately half of the farms (49%) did not provide formal training to new staff on aspects of animal health, as well as not conducting bull breeding soundness. Most of the farms (98%) required staff to use personal protective equipment, such as overalls and gumboots, but only a few of the farms (34%) had designated areas to clean footwear and a system for recording visitors (17%). Record keeping pertaining to animal health, maintenance of good fences and use of vendor declaration forms was practiced in a majority of the farms. The practice of quarantining new stock before mixing with other stock was practiced in only 45% of the farms. Monthly herd health visits by a veterinarian were utilised by 55% of the farms. Multivariable analysis showed positive significant associations between mixed species rearing with the practice of regular pest control (P = 0.004) and use of footbaths (P = 0.024) and no biosecurity plan (P = 0.025). Furthermore, a positive significant association was also recorded on the presence of a biosecurity plan and the presence of a designated area to clean footwear (P = 0.002) and no regular deworming (P = 0.024). Animal and human health reasons were the main motivators for implementing and maintaining ‘best practice’ biosecurity practices, whereas government regulation was the lowest motivator. Conclusions It is concluded that the biosecurity practices were variable, and animal and human health reasons were the primary motivators for instituting biosecurity practices. Implications There is a need to continue educating farmers on the importance of biosecurity practices.
Publisher: Elsevier BV
Date: 2021
Publisher: CSIRO Publishing
Date: 2018
DOI: 10.1071/AN14797
Abstract: The productivity of 500 Angus cows, ergently selected for either rib fat or residual feed intake (RFI) based on BREEDPLAN estimated breeding values (EBVs) and managed under two levels of nutrition (stocking rates), was evaluated. The study examined the effects of genetic line, nutrition and weaning history on profiles for weight, rib fat depth, fatness (rib fat depth adjusted for weight) and supplementary feed requirements from just before the first joining as heifers through to the weaning of their third calf. Cows gained both weight and fat as they grew older. Observed fluctuations in weight and rib fat depth, within each year, were associated with pasture availability and physiological demands. Cows that did not wean a calf in a given year became heavier and fatter than cows that did and they remained so when they calved the following year. High-fat and High-RFI were always fatter and lighter than Low-fat and Low-RFI cows, respectively. The difference in rib fat and fatness between High- and Low-RFI lines (P 0.001) was similar to, although slightly greater than, the difference between High- and Low-fat lines (P = 0.048) reflecting differences in rib fat EBVs between High-RFI (3.2 ± 1.47) and Low-RFI (–0.7 ± 1.3) compared with High-fat (1.1 ± 0.78) and Low-fat (–1.4 ± 0.67). Cows on High-Nutrition were heavier and fatter than those on Low-Nutrition (P 0.001) but there were no significant interactions between genetic line and nutrition (P 0.05). Supplementary feeding threshold was reached earlier by Low-fat and Low-RFI cows than their counterparts. Calculations based on the data in the present paper estimate that if cows lose condition at a rapid rate (1 condition score/month), then a cow with an extra 1 mm rib fat EBV would take 7.5 days longer to reach the same supplementary feeding threshold. Fat EBVs can, therefore, be a useful tool in assisting beef producers to match genotype to their production system.
Publisher: CSIRO Publishing
Date: 2017
DOI: 10.1071/AN15441
Abstract: The aim of this prospective, controlled, randomised trial was to develop a technique for mechanical nociceptive threshold testing (NTT) to assess pain in Bos indicus bull calves undergoing surgical castration. Analgesia was provided by 0.5 mg/kg subcutaneous (SC) meloxicam (M) and/or 2 mg/kg of intra-testicular and SC (at the surgery sites) lidocaine (L). Forty-eight Brahman bull calves at 6–8 months of age were ided into six study groups, each with eight animals: no surgery control surgical castration (C) without analgesia C and Mpre-op C and Mpost-op C, L and Mpost-op C and L. Mechanical NTT was performed the day before surgery (Day –1) and on Days 1, 2, 6, 10 and 13 after surgery. A handheld manual pneumatic device with a 1-mm (diameter) blunt pin was used to deliver a mechanical stimulus to a maximum of 27 Newtons either side of the most dorsal aspect of the sacrum. The most frequent responses to the mechanical stimulus were lifting or kicking of the leg on the same side as the stimulus (31%) and stepping away from the stimulus (24.9%). Data were analysed with a mixed effect linear model with the nociceptive threshold (NT) as the response variable and day and analgesic treatment as predictors (P 0.05 was considered significant). For all groups, there was a trend towards decreasing NT over the study period but there were no significant differences between groups. Step down model selection with day, batch and treatment terms revealed a significant effect of day (P 0.001) and batch (P = 0.007). Mechanical NTT for assessment of pain in Bos indicus bull calves requires further refinement to determine if this is a useful method of pain assessment.
Publisher: CSIRO Publishing
Date: 2016
DOI: 10.1071/AN16210
Abstract: Cattle on pastoral land are subject to potentially painful husbandry procedures. In northern Australia, these practices generally occur once a year after the muster and the procedures are usually performed on animals older than 6 months of age. It is seldom that any pain mitigating medications are administered at this time and there is increasing concern that this perceived impost on the animal’s welfare will become more significant at both an economic and cultural level. There is a need to investigate the possibility of using simple, cost-effective, readily available medications, administered using relatively quick and easily taught techniques to increase the chance of industry adoption. This research used castration of 6–8-month-old Bos indicus calves as the test model because it is arguably one of the most common and most painful procedures endured by the animals. Forty-eight, 6–8-month-old Brahman bulls were surgically castrated after random assignment to six different treatment groups (n = 8): no castration Control (NC) castration (C) castration with post-operative meloxicam (CMpost-op) castration with lignocaine (CL) castration with lignocaine and post-operative meloxicam (CLMpost-op) castration with pre-operative meloxicam (CMpre-op). Serial measures of weight, blood cortisol concentrations, balk score, crush score, and daily activity (steps taken, number and duration of rest bouts) were taken. Linear mixed modelling was used to compare experimental groups. Bulls that were castrated and did not receive post-operative meloxicam (C and CL) had significantly lower average weights at all time points (Days 0–13, P 0.001) of 170.9 kg and 168.6 kg, respectively, than those that did (CMpost-op and CLMpost-op) at 174.7 kg and 173.7 kg, respectively. When lignocaine was not administered before castration, Day 1 post-operative cortisol concentrations were significantly lower when post-operative meloxicam was provided than when it was not (CMpost-op: 47.2 nmol/L vs C: 65.5 nmol/L). When post-operative meloxicam was not given, animals that were given lignocaine before castration had significantly lower cortisol concentrations than those that received no lignocaine (CL: 52.7 nmol/L vs C: 65.5 nmol/L). Animals that were given pre-operative meloxicam had, on average, significantly lower Day 1 post-operative cortisol concentrations than animals that received no lignocaine or meloxicam (CMpre-op: 44.8 nmol/L vs C: 65.5 nmol/L). Analysis of Day 1 (the day following castration) data showed that animals that were given pre-operative meloxicam (CMpre-op) were significantly more active than animals in all other treatment groups (P = 0.038). It was concluded that 6–8-month old, Bos indicus bulls benefit from the administration of both lignocaine before surgery and peri-operative meloxicam. The analgesic methods used are readily adoptable by industry with respect to cost, efficiency and degree of technical skill required.
Publisher: Elsevier BV
Date: 09-2021
Publisher: Informa UK Limited
Date: 2021
Publisher: CSIRO Publishing
Date: 2018
DOI: 10.1071/AN14034
Abstract: Cow bodyweight gain, calf weaning weight, feed intake and maternal productivity of 500 Angus cows, in 64 replicate groups, were measured over three parities at two locations (Struan and Vasse) as part of the Beef CRC Maternal Productivity Project. The cows were sourced as heifers from the top and bottom 10% of BREEDPLAN Rib Fat EBV (High-Fat and Low-Fat), and from High and Low residual feed intake (RFI) selection lines (High-RFI and Low-RFI). Each of the four genotypes were run under High- and Low-Nutrition (measured as feed on offer) at both sites. The High-Fat cows were 7% more efficient at producing weaner calves under Low-Nutrition than were the Low-Fat cows. This was driven primarily by the 4% difference between the lines in weaning rate. When weaning rate differences were accounted for (as covariate), there was no difference between the Fat lines in the efficiency of weaner weight production. When the weight gain of the cow was included as an output in addition to calf weaning weight, there was also no difference between the Fat lines in efficiency. Low-RFI cows were always more efficient at producing weaner calves than were the High-RFI cows. This was primarily driven through a 7% reduction in annual feed intake (across both nutrition treatments). However, the Low-RFI cows were leaner, had 6.3% lower weaning rate and calved on average 5.4 days later than did the High-RFI cows. Furthermore, the largest differences in feed intake were in spring when feed availability is greatest. In the context of the results herein, a balanced breeding program should include selection for improved reproduction and low RFI.
Publisher: CSIRO Publishing
Date: 2018
DOI: 10.1071/AN15883
Abstract: Asparagopsis taxiformis concentrates halogenated compounds that are known to inhibit cobamide-dependent methanogenesis in vitro and, therefore, has potential to mitigate enteric methane production. The present study investigated the effect of Asparagopsis on methane (CH4) production from sheep offered a high-fibre pelleted diet (offered at 1.2 × maintenance) at five inclusion levels of Asparagopsis for 72 days (0% (control), 0.5%, 1%, 2% and 3% organic matter basis as offered). In idual animal CH4 measurements were conducted at 21-day intervals using open-circuit respiration chambers. Asparagopsis inclusion resulted in a consistent and dose-dependent reduction in enteric CH4 production over time, with up to 80% CH4 mitigation at the 3% offered rate compared with the group fed no Asparagopsis (P 0.05). Sheep fed Asparagopsis had a significantly lower concentration of total volatile fatty acids and acetate, but a higher propionate concentration. No changes in liveweight gain were identified. Supplementing Asparagopsis in a high-fibre diet ( % organic matter) resulted in significant and persistent decreases in enteric methanogenesis over a 72-day period. Granulomatous and keratotic ruminal mucosa changes were identified in several sheep with Asparagopsis supplementation. While the outcomes of the present study may be extrapolated to feedlot to achieve the antimethanogenic effect associated with Asparagopsis, further work is required to define the long-term effects on productivity and animal health.
Publisher: Elsevier BV
Date: 02-2021
Publisher: Elsevier BV
Date: 02-2019
Publisher: CSIRO Publishing
Date: 2018
DOI: 10.1071/AN13218
Abstract: This paper reports a subset of results from the Beef Cooperative Research Centre-funded Maternal Productivity Project. This research aimed to describe the response of Angus cows of different and ergent genotypes to variable nutritional environments over five breeding seasons. Cows selected for a ergence in either fat depth (HFat vs LFat) or residual feed intake (RFI: HRFI vs LRFI) based on mid-parent estimated breeding values (EBV) for those traits were allocated in replicate groups to either high or low nutritional treatments at two different sites, namely the Vasse Research Centre in Western Australia and the Struan Research Centre in South Australia. The traits reported in this paper include output traits (birth and weaning weight of calves, liveweight change of cows), change traits (change in Rib Fat, P8 fat, eye muscle area and liveweight between specified time points) and reproductive traits [pregnancy rates, percentage calves born alive and days to calving at the days to calving at the second calving opportunity (DC2)]. Having had their first calf, the vulnerability of these young cows to nutritional restriction and how it may adversely affect rebreeding was examined. HFat and HRFI cows were fatter, heavier and had greater eye muscle area than LFat and LRFI, respectively, at all times during the breeding cycle on both levels of nutrition. There was no difference in either days-to-calving or pregnancy rates after the second mating between genotypes. Equally, nutritional treatment had no effect on these traits in this cohort of cows. There was evidence for an implied genetic correlation between Rib Fat EBV, DC2 and pregnancy rates of –0.38 that suggests that selection for leanness may result in reduced fertility of the herd but the effect was not significant herein. As long as producers record the phenotype for both traits and select cows with favourable DC2 as well as low fatness, these problems can be avoided, owing to only 22% of variation in pregnancy rates being explained by DC2 and Rib Fat EBV. Producers can largely be confident that selection for leanness, or increased feed efficiency, has little impact on productivity as long as cows are in adequate body condition to remain healthy and productive.
Publisher: Wiley
Date: 17-01-2019
DOI: 10.1111/JVP.12741
Abstract: To determine the bioavailability and pharmacokinetic properties of the serotonin 5-HT
Publisher: Wiley
Date: 11-2017
Publisher: CSIRO Publishing
Date: 2018
DOI: 10.1071/AN15636
Abstract: The present paper focuses on the economic evaluation of the observed differences in maternal productivity of different genetic lines in Angus cattle that were managed under contrasting nutritional regimes typical of southern Australia. Five hundred Angus cows were managed concurrently at two locations in southern Australia. On each site, the cows were managed under the following two different nutritional treatments: High and Low, to simulate different stocking rates. Cows selected for a ergence in either carcass rib-fat depth or residual feed intake based on mid-parent estimated breeding values for those traits, were allocated in replicate groups to either High- or Low-nutrition treatments. By design, the supplementary feeding regime was the same for the High and Low genetic lines to ensure genetic differences were not confounded with management differences. Animal productivity results from the experiment were used as input data to evaluate the economic performance of the four genetic lines under the two nutritional treatments. Two methods were used the first was a gross-margin calculation of income minus variable costs as AU$ per breeding cow for a 1000-cow herd the second was a whole-farm linear programming model maximising the gross margin. Stocking rates were optimised by matching the energy requirements for the whole herd with the energy available from pasture and supplementary feed on a representative 700-ha farm. Using the two methods of calculating gross margin (per cow and optimised per hectare), including examination of sensitivity to changes in prices of cattle and supplementary feed, the present study demonstrated that genetically leaner cows due to selection of low fat or low residual feed intake, had gross margins superior to those of genetically fatter cows. They generated more income by selling more liveweight due to heavier weights and higher stocking rates. The results are affected by the management system utilised and some confounding with growth (leaner genetic lines had higher growth estimated breeding values), but will assist producers to make more informed decisions about how to manage animal breeding and nutritional interactions.
Publisher: Elsevier BV
Date: 2021
Publisher: CSIRO Publishing
Date: 2016
DOI: 10.1071/WR16153
Abstract: Increased scrutiny of animal welfare in wildlife management has seen a recent proliferation in the use of procedural documents (standard operating procedures, codes of practice etc.). Some procedural documents are presumed to represent ‘best practice’ methods, whereby adherence to prescribed inputs is explicitly purported to generate humane outcomes. However, the relationship between what is done to animals (inputs) and what they experience (outputs), as assessed by animal-based measures, has received little attention. Procedural documents are commonly developed in the absence of empirical animal-based measures, creating uncertainty in animal welfare outcomes. Prescribed procedures are valuable as guidelines for standardising methodology, but the development of ‘welfare standards’ that focus on desired thresholds for animal-based measures offers many advantages for improving animal welfare. Refinement of the use of procedural documents in wildlife management is required to ensure they generate desirable outcomes for animals, and do not preclude the development of improved methods.
Publisher: Medpharm Publications
Date: 06-08-2020
Abstract: Potent opioids are known to cause negative alterations to the physiology of immobilised antelope. How these effects differ between species has not been studied. This study aimed to compare time to recumbence and effects of opioid-based immobilisation on the physiology of impala (Aepyceros mel us) and blesbok (Damaliscus pygargus phillipsi). Eight animals of each species were immobilised, with 0.09 mg/kg etorphine and 0.09 mg/kg thiafentanil respectively, in a randomised two-way cross-over study. Variables measured and analysed by means of a linear mixed model included time to recumbence, heart rate, respiratory rate, arterial blood pressure, blood gases, lactate and glucose. In blesbok, mean time to recumbence was not significantly different with either drug (2.5 minutes and 2.2 min, respectively), but in impala thiafentanil achieved a shorter time to recumbence (2.0 min) than etorphine (3.9 min). Mean heart rates of immobilised impala were within reported physiological limits, but lower in immobilised blesbok when both opioids were used (35 beats/min to 44 beats/min vs. 104 ± 1.4 beats/min resting heart rate). Impala developed severe respiratory compromise and hypoxaemia from both opioids (overall mean PaO2 values ranged from 38 mmHg to 59 mmHg over 30 min). In contrast, blesbok developed only moderate compromise. Therefore, significantly different species-specific physiological responses to potent opioid drugs exist in blesbok and impala. Given that these different responses are clinically relevant, extrapolation of immobilising drug effects from one species of African ungulate to another is not recommended.
Publisher: MDPI AG
Date: 28-09-2017
DOI: 10.3390/ANI7100076
Publisher: Elsevier BV
Date: 2019
Publisher: Wiley
Date: 24-06-2021
DOI: 10.1111/AVJ.13096
Abstract: Identifying and quantifying the relative frequency of involuntary losses is an essential first step in developing fit‐for‐purpose herd health programmes. The objective of this study was to provide an estimate of the relative frequency of reasons for mortality among south‐west Western Australian beef and dairy cattle, based on necropsy findings from a university‐based veterinary pathology referral centre over 38 years. A total of 904 cattle were submitted for postmortem examination throughout the study period. Gastrointestinal, cardiopulmonary and reproductive conditions were the most common causes of mortality in cattle submitted for necropsy at Murdoch University for the period 1981–2018. In dairy cattle, the common problems were gastrointestinal (bloat, abomasal displacements) 18% (59/320), cardiovascular (traumatic reticulo‐pericarditis) 9% (30/320) and respiratory conditions (pneumonia) 8% (27/320). In beef cattle, the most common conditions were gastrointestinal (bloat, rumen acidosis) 11% (39/358), reproductive (metritis) 11% (38/358), cardiovascular (traumatic reticulo‐pericarditis) 7% (25/358), respiratory (pneumonia) 7% (24/358), lameness (fractures) 6%, (21/358) and hepatobiliary conditions (blue‐green algae poisoning, hepatotoxicity) 6% (21/358). Selection bias and missing data were potential confounders in this study. Although necropsy investigations provide useful information on animal mortalities and avenues for future herd health programmes, there is a need to standardise data capture methods and disease definition criteria, and conduct more detailed recording of data both at the farm level and at necropsy diagnostic centres.
Publisher: Elsevier BV
Date: 07-2016
DOI: 10.1111/VAA.12389
Publisher: Wiley
Date: 03-11-2020
DOI: 10.1111/AVJ.13038
Publisher: CSIRO Publishing
Date: 2018
DOI: 10.1071/AN13054
Abstract: Australian seedstock cattle breeders have expressed concerns that while there has been genetic improvement in feedlot and abattoir performance of cows, it could have led to a decline in maternal productivity, especially under variable nutritional conditions. This paper describes a substantial project with two components designed to address these issues. The first sub-project was to monitor bodyweight and composition of 7760 young Angus and Hereford cows as they experience variable physiological states (pregnancy and lactation) and seasons. This was conducted on large numbers in seedstock herds. The second sub-project was to monitor more regularly bodyweight, body composition, and calf rearing performance of 500 Angus cows that are genetically ergent for either fat or residual feed intake at two research centres. This also included two levels of nutrition and recording of weekly feed intake of small groups of cows for at least three parities to allow reporting of genotype × nutrition effects on maternal productivity and efficiency. Results from the project are reported in a series of papers with each one having a defined focus.
Publisher: Elsevier BV
Date: 11-2019
DOI: 10.1016/J.VAA.2019.06.006
Abstract: To determine whether the R-enantiomer of 8-hydroxy-2-(di-n-propylamino) tetralin (R-8-OH-DPAT) alleviates respiratory depression in antelope species immobilized with etorphine. The experiment also aimed to establish the most clinically effective dose of this serotonin 5- HT A group of six female blesbok and six female impala. Each animal was subjected to four immobilization treatments in a prospective four-way crossover design-control treatment consisting of only etorphine at 0.09 mg kg R-8-OH-DPAT did not influence induction, immobilization or recovery scores. Respiratory rate in blesbok was increased in the medium- and high-dosage R-8-OH-DPAT treatment group. However, this increased respiratory rate did not translate into improvements of arterial partial pressure of oxygen (PaO Previous reports indicated that the racemic mixture of 8-OH-DPAT injected intravenously had a positive effect on blood-gas values in etorphine-treated hypoxemic goats. In this experiment, similar effects could be seen in impala at the higher dosage rates of R-8-OH-DPAT. However, failure to achieve an improvement of blood-gas values in blesbok was an unexpected result. It could be speculated that the dosage, species-specific differences of serotonin receptors or the use of the R-enantiomer of 8-OH-DPAT might play a role.
Publisher: CSIRO Publishing
Date: 2018
DOI: 10.1071/AN13295
Abstract: This experiment evaluated the productivity of 500 Angus cows that differed in genetic merit for either subcutaneous rib fat depth (Fat) or residual feed intake (RFI) based on estimated breeding values (EBVs) and managed under two levels of nutrition. Reproductive rate over four calving opportunities in mature cows and growth performance of progeny to weaning was assessed. Level of nutrition significantly affected all body composition traits for both Fat and RFI line cows. Cows on High-Nutrition were 14–16% heavier (P 0.001) than those on Low-Nutrition. Differences in EBVs for fatness were reflected in phenotypic fatness at maturity. High-RFI line cows were fatter for both scanned rump (P8) and rib (RIB) fat depth relative to their Low-RFI contemporaries. Of those cows that were lactating, there was no significant effect of line or nutrition on pregnancy rate or days to calving (DC). There was, however, a trend (P 0.1) in the Low-Fat line cows towards longer DC compared with the High-Fat line cows. There was no significant effect of either line or nutrition on calf birthweight. Calves with mothers on High-Nutrition were 8% heavier at weaning (P 0.001) than those on Low-Nutrition. Lower EBVs for RFI was associated with higher 200-day growth EBV and heavier calves at weaning. Current carcass BREEDPLAN EBVs can be used to select for changes in cow body composition if desired. In this experiment, Angus cows selected for lower RFI or with below-average fatness EBV and had raised a calf at every previous opportunity were not compromised in pregnancy rate or DC at maturity under varying nutrition such as can be experienced during normal seasonal conditions in southern Australia. However, selection for lower RFI was associated with lower weaning rate (P 0.05), which warrants further investigation to confidently predict the implications for commercial cattle production.
Publisher: CSIRO Publishing
Date: 2018
DOI: 10.1071/AN14583
Abstract: The pregnancy rate of heifers affects the efficiency and profitability of beef herds. Heifers extreme in rib fatness (Fat) or post-weaning residual feed intake (RFI) estimated breeding values (EBVs) were evaluated for their pregnancy rates at two locations in the southern agricultural regions of Australia (Struan and Vasse) as part of the Beef Cooperative Research Centre Maternal Productivity Project. Heifers ergent in Fat (High-Fat and Low-Fat) had differences in fat depth pre-joining at the 12/13th rib (4.4 mm vs 3.5 mm) and P8 rump site (6.1 mm vs 4.8 mm). This was associated with significant differences in pregnancy rates over a 9-week joining period (91.5% vs 83.0%) and an even larger difference when calculated over a 6-week joining period (77.3% vs 65.0%). Heifers ergent in RFI (Vasse only) also differed in rib fat (7.6 mm vs 6.4 mm) and P8 fat (11.0 vs 9.2 mm), but not significantly in pregnancy rates between the two RFI (High-RFI and Low-RFI) genotypes following a 9-week (92.4% vs 88.5%) or 6-week (81.2% vs 73.7%) joining period. The phenotypic analysis of the Fat and RFI heifers together indicated that weight and fat depth were the largest contributing factors to variation in pregnancy rates, and age and pre-joining weight gain were not significant. These phenotypic characteristics indicated that producers can manage heifers to particular weight and fat combinations to improve heifer conception rates. Associations of BREEDPLAN EBVs with heifer fertility showed that a shorter days-to-calving EBV had the biggest impact (P 0.001) on heifer pregnancy rates and rib fat and scrotal size EBVs were close to significant (P 0.10).
Publisher: CSIRO Publishing
Date: 2016
DOI: 10.1071/AN14913
Abstract: Bauxite residue (Alkaloam®) applied to pasture has been shown significantly to improve pasture production on sub-fertile soil, such as those found in south-west Western Australia, because it increases soil pH. There are concerns that animals grazing Alkaloam-amended pasture may suffer ill health through heavy metal accumulation in tissues, and that this effect could be lified over generations. There are additional concerns that eating exposed animals, or direct exposure to Alkaloam, may be detrimental to human health. Although some literature exists there are no studies that address these issues when the application of Alkaloam occurred several years (20) before grazing. This investigation examined the heavy metal and trace element accumulation in the tissues of Dorper lambs (1 year old) and their dams, Dorper ewes (4–5 years old) grazing Alkaloam-amended pasture. The experiment was conducted on two sites grazed in the Peel region of Western Australia: one site in Coolup, the Control site (Site C), that had had no application of Alkaloam and one site in Wagerup, the Treatment site (Site T), that had had 20 tonnes per hectare of Alkaloam applied in 1993. Both sites had uniform soil and pasture type during the growing season. S les of soil and pasture were collected at each site. Differences in trace element concentrations, pH and conductivity between sites were determined. Ten ewes and 10 lambs were randomly selected at each site, removed and killed on the same day for gross examination of the kidney, liver and lung tissue. S les of the tissues were collected for histopathological examination and chemical analysis to determine concentrations of trace elements. Depending on the concentration of trace elements in each s le, a logistical regression with binomial regression or an ANOVA was performed to determine differences in concentrations between ages, sites and any interactions between age and site. Sheep from Site T had significantly higher concentrations of copper, manganese and molybdenum, whereas sheep from Site C had significantly higher concentrations of cobalt, iron, lead, nickel, selenium, strontium and zinc in tissues. Ewes had significantly higher concentrations of barium, cadmium, cobalt, iron and strontium whereas lambs had significantly higher concentrations of copper, manganese and molybdenum in tissues. Ewes had higher concentrations of cadmium in the kidney compared with lambs, and ewes from Site C had significantly higher concentrations than ewes from Site T. Ewes and lambs from Site C had significantly higher concentrations of selenium in the liver compared with ewes and lambs from Site T. Concentrations of heavy metals (As, Hg, Pb, Th and U) were low in tissues of all sheep. The results show that whereas there were different elemental tissue concentrations between sites and between ages of sheep, there were no detrimental trace element imbalances or accumulation of heavy metals that would cause ill health in any of the sheep that could be associated with the application of Alkaloam to pasture. It is unlikely that humans will suffer any ill effects as a consequence of eating exposed animals. This result supports the premise that bauxite residue can be safely applied to pasture to significantly improve pasture and animal production where animals graze pasture growing on sub-fertile soil.
Publisher: Elsevier BV
Date: 11-2017
DOI: 10.1016/J.VAA.2017.04.009
Abstract: To investigate the mitigating effects of administration of local anaesthetic or systemic meloxicam on the electroencephalographic (EEG) and cardiovascular responses during surgical castration of Bos indicus bull calves. Prospective, randomized, experimental study. Thirty-six 6-8 month-old Bos indicus bull calves, with a mean ± standard deviation weight of 237 ± 19 kg. Animals were allocated randomly to three groups of 12 (group L, 260 mg of 2% lidocaine subcutaneously and intratesticularly 5 minutes prior to castration group M, 0.5 mg kg All EEG variables were significantly different between B and T1 (p ≤ 0.0001). No differences in F The EEG changes indicate nociceptive responses in all three groups during surgical castration, greater in group L compared to groups C and M. Both analgesics attenuated the peracute cardiovascular response. Lidocaine and meloxicam administered prior to castration attenuated these responses in Bos indicus bull calves. These findings provide support for the preoperative administration of lidocaine and potentially meloxicam for castration in Bos indicus bull calves.
Publisher: Wiley
Date: 25-11-2017
No related grants have been discovered for Michael Laurence.