Industry Partners

Prairie Swine Centre is an affiliate of the University of Saskatchewan

Prairie Swine Centre is grateful for the assistance of the George Morris Centre in developing the economics portion of Pork Insight.

Financial support for the Enterprise Model Project and Pork Insight has been provided by:

Author(s): Rabaste, C., L. Faucitano, L. Saucier, P. Mormède, J. A. Correa, A. Giguère, and R. Bergeron
Publication Date: January 1, 2007
Reference: Canadian Journal of Animal Science: 87: 3–12
Country: Canada


Slaughtering animals with a full stomach is considered a high risk factor for meat safety, as spillage of gut contents, due to more frequent inadvertent puncture of the stomach during the dressing process, can lead to microbial cross-contamination between carcasses (Miller et al. 1997). To reduce the risk of puncturing the stomach, a feed withdrawal of 16 to 24 h before slaughter has been recommended to reduce stomach size (Chevillon 1994). However, industry reports and some studies have revealed a high variability in stomach weights at slaughter, even among pigs that were subjected to the same fasting interval before slaughter (Guise et al. 1995; Turgeon 2003). According to Enck et al. (1989), stress increases intestinal motility, resulting in a greater evacuation of the caecum and large intestine. It also increases the pH of the stomach contents, favouring the survival, proliferation and release of faecal bacteria (such as Salmonella), both towards the internal organs and the surrounding environment (Gregory 1998). Hence, the individual difference in the pig response to preslaughter stress might contribute to stomach weight variation at slaughter. The use of electric prods must be limited in pig handling given their detrimental effects on welfare (flight behaviour, higher heart rate and salivary cortisol level) and meat quality (Brundige et al. 1998; D’Souza et al. 1998; Jongman et al. 2000). Mixing unfamiliar pigs inevitably causes some fighting, which causes skin bruises and poor pork quality (Jones et al. 1994; Warriss 1996). To limit fighting and help pigs rest and recover from transport stress, the current recommendations are either to keep pigs in small groups (10 to 15 pigs) or to mix very large groups (up to 200 pigs) in the lairage pen prior to slaughter (Grandin 1990; Christensen and Barton-Gade 1997). Turner et al. (1999) showed that group size influences drinking behaviour, pigs in large groups (60) spending significantly less time drinking than pigs in smaller groups (20). Hence, it may be hypothesized that the difference in drinking rate between groups of pigs varying in size may contribute to stomach weight variation at slaughter. The aim of this experiment was thus to determine, under commercial conditions, the effects of gentle vs. rough handling practices and large vs. small group size in lairage on behaviour, stomach weight, microbial carcass contamination and meat quality variation of pigs. At unloading and on the way to stunning, 800 barrows were exposed to either gentle handling (GH: slowly with a plastic board or whip) or rough handling (RH: quickly with an electric prod). Pigs were kept in large or small groups (30 or 10 pigs) during lairage. Compared with GH, RH increased climbing, slipping and turning around behaviours during unloading, and climbing on the way to stunning. RH also reduced drinking behaviour during lairage. Pigs kept in large groups were observed more often standing and fighting than pigs kept in small groups, but, in contrast, had a slightly lower level of urinary cortisol at slaughter. Stomach weight and microbial contamination at slaughter were not affected by treatments. RH tended to increase skin bruise score on the carcass and produced more exudative meat. In conclusion, the response of pigs to the two specific stressors applied prior to slaughter in this study did not seem to contribute to stomach weight variation at slaughter, but it did influence pork quality.

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