Effects of extra feeding during mid-pregnancy on gilts productive and reproductive performance

The effects of a supplemental feeding strategy during mid-gestation on lean gilts body reserves, productive and reproductive performance were assessed. A total of 90 gilts were allocated into two treatments (Control, C, and Supplemented, S). Control sows (n = 43) were fed according to the level routinely used on farm (2.5-3.0 kg d-1, 2.9 Mcal metabolizable energy kg-1 feed and 0.6% of lysine) throughout gestation, and S sows (n = 47) received 50% more feed from day 45 to day 85 of gestation. Body weight (BW) and sows body condition [backfat (BF), loin depth and body condition score] were recorded on days 40 and 80 of gestation, at farrowing and at weaning. Litter performance at birth and on day 18 ± 1 of lactation was registered at first and second parities. Although no differences in backfat levels were found at weaning, a higher proportion of S sows stayed within the target backfat interval both at farrowing (17-21 mm) and at weaning (> 14 mm). No differences were found in BW and body reserves losses during lactation between treatment groups. Litter weight at birth tended to be higher in the S group of sows, consistently, in the first and second parities (P 14 mm). No se encontraron diferencias entre tratamientos en las pérdidas de BW y reservas corporales en lactación. El peso medio de camada al nacimiento resultó mayor en las cerdas S (P < 0,10) en los dos partos estudiados. En conclusión, un aporte extra de alimento durante la gestación media resultó en beneficios sobre las reservas grasas de cerdas nulíparas al destete, y en un ligero pero positivo efecto en los rendimientos productivos, aunque éstos difícilmente compensan el aporte extra de alimento