Abstract
The objective of this study was to determine the difference between summer and winter in blood composition at the time of slaughter and meat quality of beef steers. Fifteen steers in summer (18.9-28.4℃) and 20 steers in winter (4.9-7.0℃) were transported to the nearest commercial slaughterhouse by truck. After an overnight lairage in the holding pen in the slaughterhouse, the steers were slaughtered individually. Plasma cortisol and blood glucose concentrations were significantly higher in summer than in winter (both P<0.01). Serum pH and serum total protein concentration were significantly lower in summer than in winter (both P<0.01). These results suggest a severer condition for steers in summer, which should be mainly caused by water deprivation the night before slaughter. Serum NEFA concentration (P<0.01), and AST and ALT activity (both P<0.05) were significantly higher in winter than in summer. The main cause of these physiological responses should be food deprivation the night before slaughter. However, these physiological responses of steers did not have much effect on meat quality. In addition the frequency of human handling during loading and unloading was not significantly different by season. As implementation, the results in this study recommend that completely removing water the night before slaughter should be avoided.
