BSAS conference: Less variation at weaning increases profitability

Large variations in pig-growth rates can reduce profitability by as much as 11p/kg for carcass value, equating to £32,000 a year for a 1100-pig herd.

And with the normal growth rate variation within pigs being about 15%, there are significant losses in the industry, says Agri-Food and Biosciences Institutes’ Elizabeth Magowan.

“Genotype, disease, management and nutrition are all causes of variation. The aim of the current study was to try to reduce variation in growth rate between pigs by grouping them in either uniform or mixed-weight groups at weaning and offering them either a special or normal dietary regime,” she said.

Pigs at weaning were allocated into weight groups, two light (average 7.1kg), two medium (average 8.9kg), two heavy (average 10.4kg) and two mixed-size groups. During the post-weaning period each group was offered either a high-allowance starter diet, 4kg pig followed by 8kg/pig, or low-allowance diet (2kg/pig followed by 4kg/pig). At 10 weeks, each group was then split into two and then allocated a special diet with a digestible energy content of 14.5MJ/kg, or a normal diet of 13.5MJ/kg.

“Uniform grouping of pigs at weaning lowered the variation in weight between pigs at 11 weeks and 15 weeks of age and also at 20 weeks, demonstrating the value of grouping according to size. Also offering pigs a similar level of nutrition reduced variation in growth rate between pigs during the finishing period, compared with those receiving a mixture of levels of nutrition,” said Dr Magowan.