Mixing piglets at weaning is disruptive and reduces performance
Take Home Message: Keep litter mates together to reduce aggression and increase post-weaning weight gain.
There are no negative consequences of mixing unacquainted piglets on the initiation of feeding post weaning. But trial results do suggest a post weaning growth benefit when piglets remained with their litter mates, indicating that mixing piglets at weaning is disruptive.
“Mixing piglets at weaning increases stress and aggression, which would decrease FCR efficiency and reduce weight gain post weaning,” Leeds University’s Fiona Reynolds told delegates at the 2009 British Society of Animal Science’s annual conference.
“But mixing litters post weaning is common practice in the pig industry in order to ‘size’ pigs for easier management. So consideration should be given to alternative mixing strategies at weaning in order to improve piglet welfare and performance during this critical period.”
Her team’s experiment was part of a larger investigation into the voluntary feed intake of the piglet in the immediate post weaning period. Miss Reynolds investigated the difference between mixed litter origin or sibling groups on latency to initiate feeding and performance to day six post weaning.
A total of 76 Large White x Landrace piglets were weaned at 8.0kg and around 28 days old and sorted into 18 mixed sex groups with four or five pigs per pen. Piglets were housed in fully slatted weaner pens and allocated to either mixed (each individual from a different litter) or litter pens (siblings), balanced for weight and gender.
Feeding behaviour was monitored 24 hours a day using a multi-spaced feed intake recording system in each pen. Piglets were identified using an individual transponder ear tag. Each pen of piglets was offered ad-lib access to one feed (16.45MJDE/kg, 1.6g lysine/kg). Piglets were weighed at weaning and six days post weaning.
The time in minutes between entering the pen and being actively present at the trough for a feeding bout of more than 30 seconds was defined as the latency to first meal.
“And we found that there was no significant difference between the latency to first meal between mixed or litter treatments, with a mean latency of 379 minutes,” said Miss Reynolds. “However, piglets in litter pens tended to have higher average daily weight gains than piglets in mixed pens – 197g/d and 77g/d respectively.”
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