4 April 1997

Gilts benefit from high protein diet

FEEDING young gilts a high protein diet at ovulation after a period of restricted protein feeding improves fertility and could increase longevity.

SAC nutritionist Sandra Edwards explained at the BSAS meeting that modern gilts may be apportioning more protein from feed to lean tissue growth than to laying down fat and reproductive functions.

"This results in poorer fertility and higher replacement rates because with less backfat available for milk production the gilt loses more condition," said Dr Edwards.

In an initial trial carried out at SAC young gilts were fed low protein diets to restrict their frame and lean growth so that their size was limited and a greater proportion of backfat laid down.

"This resulted in a far lower culling rate in these pigs. But the restricted protein also caused low ovulation rates and we, therefore, tried to boost protein levels at ovulation to increase the number of eggs shed in a second trial," she said.

"Using ultrasound we were able to establish that the number of eggs produced increased when protein intake was increased at ovulation.

"We then fed sows with high protein at ovulation and found that even in older sows boosting protein led to improved ovulation rates and hence to larger litters," she added.

Sandra Edwards: Feeding gilts a high protein diet at ovulation to boost fertility.