14 January 2000

Low-protein diets wrong approach

INCREASING fat depth in breeding gilts by feeding high energy/low protein diets before mating to improve reproductive performance is not appropriate for modern lean genotypes.

MLC pig technical manager, Pinder Gill, told delegates that advice to aim for a fat depth of 19mm in gilts at first mating to maximise litter size was inappropriate.

"Many feed companies are still producing protein restricted diets for gilts containing 0.65-0.7% lysine. These diets restrict lean growth rate which can have adverse consequences for reproductive performance."

Dr Gill advised offering a standard finisher diet containing 14MJ ME and 0.85-0.9% lysine to gilts from 90kg until mating. "This ration will ensure rapid weight gain in preparation for mating at third oestrus.

"It should increase first and second litter performance by about one pig a litter."

But watching out for lameness is necessary where animals are gaining weight rapidly, warned Dr Gill. "Culling for lameness has increased recently and rapidly growing animals are susceptible. A long-term genetic solution is needed."