Effect of the farm system on the behavioral response preslaughter and on meat quality variation in pigs

Abstract Text: The objective of this study was to assess the impact of the farm system on the behavior response at the plant and on meat quality variation in pigs. A total of 24 loads and 4,679 animals from 12 farms, 5 animal welfare certified farms (n = 1,936; WEL) and 7 conventional (n = 2,743; CON) farms were assessed at unloading (UN) and in the lairage alley (LA) at the plant. The assessment was conducted using an audit protocol, where criteria of the Welfare Quality^® and American Meat Institute protocols were merged. Pigs were loaded onto a two identical pot-belly trailers driven by two drivers (A and B) who were rotated between types of farms each week. A sub-sample of 1,440 pigs (60 pigs/ 2 farms) was randomly chosen at the plant for meat quality evaluation. Meat quality was assessed in the Longissimus thoracis (LT) muscle at 24 h post-mortem by measuring ultimate pH (pHu), color and drip loss. Meat quality and behavior data were analysed by the GLIMMIX and MIXED procedure of SAS. Spearman correlations were performed to determine the relationship between the swine behaviour and meat quality variation using SAS. When transported by driver B, pigs from WEL farms were harder to unload than pigs from CON farms as shown by the greater percentage of turn-back (3.13 vs. 1.12 %; P = 0.01) and slips (8.5 vs. 1.92 %; P < 0.001). The WEL pigs also presented a greater (6.09 vs. 1.19 %; P = 0.02) number of falls in the LA compared to CON. Overall, turn-back attempts and reluctance to move, both indicators of a fear response, appear to contribute to slips at UN (r = 0.52; P < 0.05 and r = 0.60; P < 0.05, respectively). When compared to CON pigs, the LT muscle of WEL pigs presented greater drip loss (3.4 vs. 4.5 %; P = 0.003). The greater number of slips at UN and in the LA appears to contribute to a greater drip loss (r = 0.63; P < 0.05 and r = 0.74; P < 0.001, respectively). The results of this study show that the effect of the farm of origin on meat quality variation can be explained by its impact on the behavior of pigs in response to the preslaughter handling procedures.

Keywords: Behavior, Farm, meat quality