Effects of pre-slaughter
practice on performance and behaviour of commercial pigs
M-J. Turgeon
Laval University, Sainte-Foy,
Quebec, Canada
Three batches of 256 pigs were raised in 16 pens and randomly allotted to one of 16 treatments (2X2X4 factorial design) 3 weeks before the start of shipping to the abattoir. Shipping took place at a rate of 4 pigs per pen per week. Factors were: feeding method (floor or trough); slaughter time (10h00 or 22h00); and fasting (16 hours) method (FM) prior to shipping (FM 1: 4 pigs were fasted in a separate expedition pen; FM 2: all pigs remained in their home pen and were fasted; FM 3: 4 pigs were fasted in their home pen by isolating them from others with a barrier; FM 4 (control): pigs were not fasted). Feeding mode had an effect on the average daily gain (ADG: 0.77 kg/d for trough-fed VS 0.72 kg/d for floor –fed pigs). Average proportions of pigs sitting, lying and standing, measured every 9 minutes over the last 12 hours before shipping, were significantly affected by treatments. A higher proportion of pigs (21.4%) that were slaughtered at night (fasted during the day), were observed standing, compared to pigs slaughtered in the morning (6.1%). Floor-fed pigs were also standing more than trough-fed pigs (15.6% VS 11.9%). Fasted pigs were found lying down less often than control pigs (84.0% VS 86.2%). Among fasted pigs, mixing (FM 1) and repeated fasting (FM 2) decreased the activity level of the animals. Slaughtering at night and mixing unfamiliar pigs during fasting (FM 1) negativiely affected the total amount and severity of aggression among pigs. The ease of manipulation, measured by the speed of loading and the number of electric goad hits, was not affected by fasting. The number of electric goad hits was higher for FM 3 compared to FM 1, but this difference did not lead to a faster speed of loading.
This study demonstrates that a 16-h fast before slaughter does not affect ADG and the ease of manipulation of pigs but has an effect on their behaviour. In addition, fasting method and slaughtering time can affect the activity level and the aggression of pigs.