24 May 1996

Fatter gilts fare better

SCOPE exists for producers to improve productivity by ensuring gilts carry sufficient fat at service.

Meat and Livestock Commission pig scientist Pinder Gill said most modern gilts were over lean at mating. "They fail to carry sufficient fat to see them through repetitive breeding cycles," he said. Producers are only capturing half sows potential prolificacy – with each averaging only four to five litters when eight or more was achievable. "Pig producers must encourage gilts to build up fat reserves from the 30kg to first mating stage," said Dr Gill.

He advised targeting P2 measurements of 17mm at 135kg liveweight.

Early evidence from work at the MLCs Stotfold Pig development unit suggests the required changes in body composition can be achieved nutritionally.

The MLC levy-funded research, using genotypes supplied by all the major UK breeding companies, has examined restricting lean growth, and encouraging fat deposition, by limiting lysine in the diet.

Levels were reduced to 0.6% over the 30-50kg stage and to 0.5% from 50kg to mating.

This compares with conventional diets which include about 1.2% and 1% at each stage to promote lean growth. "Were controlling size and body composition by keeping a ceiling on lean growth," said Dr Gill. "Smaller sows are also cheaper to feed and easier to handle."