L Flanagan1, E Winslow2, T Bennett3, M Hebart1, D Rutley4, C Trengove1
1University of Adelaide; 2South Australian Research and Development Institute; 3Primary Industries and Regions South Australia; 4MPSC Australia Pty Ltd
Ecchymosis causes an undesirable appearance in meat, with lesions heavily trimmed during processing. As a consequence, cost associated with labour and loss of meat yield is increased. The aim of this study was to identify nutritional, pre-slaughter management and abattoir factors that predispose the occurrence of ecchymosis. The association between the incidence of ecchymosis and sheep breed, age, slaughter shift (am or pm) and date, direct or market consignment, hot carcass weight (kg), fat depth (mm), lairage time (hours) as well as liver copper (mmol/kg) and selenium (U/g) was investigated. Sheep carcasses, over seven days, were scored (0, 1, 2 or 3) based on the severity of ecchymosis; which was analysed as a binary trait (carcasses were either affected by ecchymosis or not). Liver samples were collected from direct consignments of lambs from single vendors. Lambs had a higher prevalence of ecchymosis when compared to mutton (14% vs. 1%; P<0.0001), with significant variation in prevalence between lines of lambs (P<0.0001). The prevalence of ecchymosis increased with kill day (P>0.01), deviation of an individual from average lot weight (standard units; P<0.001) and lairage time (P<0.001). It also increased with annual rainfall (P<0.001), fat (P<0.001), hot weight (P<0.05), lairage time (P<0.001) and the coefficient of variation of average hot weight (P<0.001) when considered at the average lot level. Liver copper and selenium had no effect on ecchymosis prevalence. It can be concluded that ecchymosis is a significant condition in lambs and the prevalence increases with the deviation of an individual from average hot weight, fat depth and lairage time, as well as in lambs from a low rainfall area. It is recommended that future research includes a prospective investigation of these factors from birth to slaughter. Minimising ecchymosis within the sheep industry will dramatically reduce costs associated with trimming and meat wastage.
Leesa has a demonstrated history of casual work in the farming industry with a particular passion in animal nutrition. Leesa graduated from University of Adelaide with a Bachelor of Science (Animal Science) in early 2018 and with a first class Honours in 2019 for her investigation into ecchymosis in sheep in South Australia. Leesa’s keen interest in ruminant nutrition has led her to starting a PhD with the School of Animal and Veterinary Sciences, University of Adelaide.