EFFECTS OF FASTING AND WATER RESTRICTION ON CARCASS SHRINK AND PORK QUALITY

Abstract

One hundred and twenty market weight (90 kg) pigs were allocated at random to one of three treatments: immediate slaughter and 24 h or 48 h without feed or water after arrival at an abattoir. All pigs were removed from feed 17 h before arrival at the abattoir. Weights of body organs and the digestive tract full and emptied of digesta were recorded along with warm carcass weight. After chilling for 24 h a pork chop 25 mm thick was removed along with the commercial ham and belly from the left carcass side and frozen for later quality determinations. Live weight shrink over 48 h amounted to 6.8 kg with 75% (5.1 kg) of this loss being attributed to loss in carcass weight. The 24-h holding period also resulted in a significant loss in carcass weight (3 kg). Approximately 20% of the total shrink over 48 h was due to a reduction in digestive tract contents. Body organs showed little change in weight over the 48-h holding period apart from the liver which was reduced in weight by 14.6%. Final longissimus muscle pH was increased and muscle luminosity (fresh longissimus, cured m. semimembranosus and m. biceps femoris) decreased for both the 24-h and 48-h holding treatments but did not result in any dark, firm and dry meat. Drip loss in pork chops decreased with increased ante-mortem holding time. However, processed yields for hams and bacon were not significantly influenced by the holding period pre-slaughter. It was concluded that the time from last feeding to slaughter should be minimized to avoid losses in carcass weight and slightly darker fresh and processed meat. Key words: Fasting, carcass shrink, carcass quality, processed yield