ORCID Profile
0000-0002-5506-5480
Current Organisation
Murdoch University
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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: 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: 11-2021
Publisher: Elsevier BV
Date: 09-2021
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: Elsevier BV
Date: 11-2020
Publisher: CSIRO Publishing
Date: 2020
DOI: 10.1071/AN17588
Abstract: High lamb mortality continues to be a significant economic and welfare problem within the Australian sheep industry, with 20–30% of lambs born in commercial flocks dying mostly within 3 days of birth. Clinical hypocalcaemia and hypomagnesaemia cause ewe mortality, and, subsequently, either fetal or lamb death, but it is not known whether subclinical deficiencies of calcium (Ca) and magnesium (Mg) compromise lamb survival. This review considers the potential mechanisms through which Ca and Mg deficiencies may influence lamb survival, and factors influencing the risk of deficiency. Pastures grazed by lambing ewes may be marginal in calcium (Ca & g/kg DM) and magnesium (Mg & .9 g/kg DM) but also have a high dietary cation–anion difference (& meq/100 g DM) and high concentrations of potassium (K & g/kg DM) and nitrogen. In young cereal crops, sodium concentrations are also often low (& .9 g/kg DM). This combination of minerals and other nutrients creates an imbalance in supply and increases susceptibility to acute Ca (hypocalcaemia) and Mg (hypomagnesaemia) deficiency. Calcium is required for smooth muscle function and has a direct role in uterine contraction, so may influence the duration of parturition. Low Ca and Mg intake both influence insulin release and sensitivity, low Mg results in poor glycaemic control and insulin resistance by impairing both insulin secretion and its action on peripheral tissues, also potentially altering the duration of parturition as well as risk of metabolic disease. Magnesium is also a neuroprotectant that slows the neuronal damage during hypoxia and has been linked with thermogenesis in offspring and increased immunoglobulins in colostrum. These functions indicate potential importance in improving the ease of parturition and improved ability of the newborn lamb to thermoregulate and survive after birth. Subclinical Ca and Mg deficiencies commonly occur in 20% of lambing ewes grazing temperate pastures, so further studies are warranted to investigate whether correction of these deficiencies can improve lamb survival.
No related grants have been discovered for Kate Margaret Windeyer Loudon.