Evaluation du niveau de stress chez les bovins en période de pré- abattage et son influence sur le métabolisme énergétique musculaire post-mortem

Abstract

The sensory and technological qualities of the meat depend on the conditions of development of muscle metabolism at the time of slaughter. These later are largely influenced by the physiological state of the animal especially the potential stress reactions. We were interested on the effects which relate the pre-slaughter procedure and the characteristics of animals (breed, age, sex) on the level of stress in cattle and the early post mortem muscle metabolism. Therefore, the study was carried on two main slaughterhouses;one in the Bejaia department and the other in Setif. The samples were taken from a farm, For the pH measurement, and post-mortem temperature; they were carried out one hour after the slaughter, then every half an hour, to two hours and a half. Stress levels expressed by the cortisol concentration are greater in animals of the local breed, and females. The most factors involved in animal stress are: transport, but also the deprivation of food associated with set expectations at slaughterhouses. In the section based on stress and energy metabolism, it has been demonstrated the effect of age. Thus, our results showed that the combination of stress and physical activity in the hours preceding slaughter, can induce early postmortem pH lowering values with early post mortem higher temperatures. Furthermore, high levels of stress after prolonged hold, associated to the deprivation of food, induces high early postmortem pH values with early lower post mortem temperatures. In comparison to other researches done in other countries, the results are sustained by certain and do not conform to others. This heterogeneity of the results is due to differences in the animal (breed, species), of farming (feeding, intensive or extensive farming), slaughtering procedures, the study itself (applied protocol and number studied factors and parameters).