Optimizing Gilt Body Weight At First Insemination, By Graeme McDermid South West Ontario Veterinary Services

Gilts often account for 18 to 20 % or more of the breeding herd. Gilt reproductive performance therefore has a significant effect on overall sow herd productivity. Gilt management factors can affect reproductive performance and longevity in subsequent parities. Gilt age, body weight, backfat thickness, and loin muscle depth are some of the more common factors that are believed to have an effect on reproductive success. A number of researchers have looked at the effect of age and body weight at first insemination in various genetic programs. These Spanish researchers wanted to assess the effect of body weight (BW) at first service on sow performance during first parity and overall lifetime reproductive efficiency. In this particular study, a total of 360 DanBred gilts were categorized into three groups according to their BW at first insemination: (1) Small sows (< 135 kg BW; n = 108); (2) Medium sows (135-150 kg BW; n = 155); (3) Large sows (> 150 kg BW; n = 63). Gilts were studied from first insemination to first weaning and then reproductive parameters were monitored until culling. Sow body status, litter size and weight, farrowing rate, weaning-to-conception interval, and lifetime performance were recorded.