Explaining and predicting differences in meat quality through stress reactions at slaughter: The case of Large White and Duroc pigs.

Large White and Duroc pigs (n=42) were group-reared on straw. Durocs were more active in the home pens and had higher basal urinary cortisol levels. During tests, Durocs touched more often an unfamiliar human, but not an unfamiliar object, than Large Whites. Pigs were experimentally (low stress) or industrially (high stress) slaughtered. Meat (Longissimus lumborum (LL), Biceps femoris (BF), Adductor femoris (AF) and Semimembranosus (SM)) was darker, more yellow, had higher ultimate pH and better water holding capacity after high, compared to low-stress slaughter. Large White meat contained less pre-slaughter glycogen, was redder and lost more drip. Slaughter conditions influenced ultimate pH of Large White more than of Duroc meat. Large Whites, and to a lesser extent Durocs, touching the human less often during the test, had faster early post-mortem LL and BF muscle metabolism. Pigs exploring the unfamiliar object more often were more aggressive during pre-slaughter mixing and had higher AF and SM ultimate pH.