Plasma β-endorphin and cortisol concentrations in lambs after handling, transport and slaughter

Abstract

ABSTRACTThe effects of the routine stressful stimuli of handling, transport and slaughter on the plasma concentrations of cortisol and β-endorphin have been studied in lambs. Blood samples were obtained from group 1 lambs after rounding up, after transport and at slaughter. Group 2 lambs were treated similarly except that blood was collected only at slaughter. Group 3 lambs served as controls and were blood sampled twice daily for 5 days to accustom them to handling before being slaughtered. Plasma cortisol and β-endorphin concentrations were increased above control levels by rounding up and transport, and were further increased at slaughter. Group 3 lambs, however, had very much lower β-endorphin levels at slaughter than the other two groups, although their cortisol levels were similar, β-endorphin concentrations declined during the 5-day blood sampling period in group 3 animals but cortisol levels were unchanged. The results suggest that although levels of both hormones are increased by stress, they are not necessarily released concomitantly.