Stress and meat quality. Role of the animal’s genetic background and prior history

Abstract

Stress reactions during the slaughtering procedure affect muscular metabolism before and after slaughter and consequently, meat quality. The phenomenon is principally related to a reduction in muscle glycogenstores and an increase in ATPase activity. The way animals react behaviourally, physiologically and metabolically to stress, depends on the animal's genetic backgroundand prior history. For example, certain breeds are more reactive to human presence or to an unfamiliarenvironment. The effect of physiological changeson metabolism depends amongst others on the numberof functional receptors on or in muscle cells, which appear to vary according to genetic background. Concerning history, the experience of a defeat in anagonistic encounter, of being housed in isolation or attached, may increase behavioural and physiological reactivity to an unfamiliar object or to the distribution of the daily meal. It is likely that such an increase reinforces the effects of slaughter stress on meat quality.The ease of handling, loading and unloading dependson the degree of the animal's familiarity with the situation. For veal calves, the caretaker's attitude towardshis animals has some influence on the calves' reactions towards slaughter procedures and on meat quality. In summary, we have some knowledge of the effects of genetic background, rearing method and stress reactivity towards slaughter procedures on meat quality. It is necessary to extend this knowledge and to elucidate underlying mechanisms.