Responses to different feeding levels during the first month post-insemination in highly prolific multiparous sows

Aim of study: To evaluate the impact of the feed level during the first month of gestation on body weight evolution, backfat and loin muscle depths and reproductive performances in highly prolific sows. Area of study: Galicia (Northwestern Spain). Material and methods: Thirty-six Danbred sows were assigned to three experimental groups (n=12) receiving, from day 1 to 30 of pregnancy, 2.5, 3.0 or 3.5 kg/d of a standard diet (8.83 MJ net energy and 138.5 g crude protein/kg). In each group, the number of sows in the second-, third-and fourth-cycle was the same. All animals received, of the same diet, 2.5 kg/d from day 31 to 90 and 3.0 kg/d from day 91 to 107. Seven days prior the parturition, sows were moved to the farrowing-lactating facilities where spent until weaning receiving a common standard lactation diet. At 24 h post-farrowing, litters were standardized to 13 piglets each by cross-fostering. Main results: The optimal feeding level during the first 30 days of gestation was 3.0 kg/d because a lower amount penalized their body weight gain and a higher amount did not improve their fatty reserves. It is worth considering that the increase from 2.5 to 3.5 kg/d generated advantages at birth (higher and more homogenous piglet weights) but also handicaps (lower litter size). The effects were similar irrespective of the cycle number. Research highlights: Different feeding levels during the early pregnancy were tested because it is a critical period. Suppling 3.0 kg/d carried out the best productive and reproductive implications