Effects of post-weaning altrenogest treatment in primiparous sows

Abstract

Major losses of body weight and fat reserves during the first lactation are a cause of unsatisfying reproductive performances in primiparous sows. This study, conducted in three commercial sow herds, investigated whether weaning the sows three days earlier together with administering altrenogest was effective for improving reproductive performance (weaning-to-estrus interval, pregnancy rate after first insemination, total litter size and number of live born piglets in the second litter) and body condition. In the herds suffering from the second litter syndrome, a non-significant improvement of the second litter size was found with on average 1.9 extra piglets born. During the treatment period, the treated sows gained on average 1.4 mm back fat, while the control sows lost 0.4 mm back fat. In conclusion, the treatment is useful for putting the sows in better condition at the moment of insemination and it may possibly improve reproductive performance in farms with the second litter syndrome.