Effect of gilt development diet on the reproductive performance of primiparous sows

The objective of this study was to evaluate the effect of development diet on first-parity reproductive performance across different genetic types of females. Gilts (n = 708) 8 to 15 d of age from five genetic lines were asse mbled using a segregated early weaning protocol. Genetic types represented industry variation for reproductive capacity and lean growth potential. Sam pling procedures were not designed to evaluate performance differences amon g the genetic lines. When the gilts weighed approximately 20 kg, they were moved from the nursery facilities to a slotted-floor, environmentally contr olled facility, and seven to eight animals within a genetic type were penne d together. When the gilts weighed approximately 40 kg, they were moved to a modified open-front facility. Nineteen gilts were allotted to each pen (. 92 m(2) per pig). Gilts were assigned to one of three development diets at 120 d of age. Diet 1 (high energy, 18% CP) and Diet 2 thigh energy, 13% CP) were provided for ad libitum consumption to the assigned gilts until they weighed approximately 113 kg. Gilts receiving Diet 3 (23% CP) were fed 1.8 kg/d from 82 kg until they reached 180 d of age (approximately 100 kg). Gil ts were fed 2 kg daily of a gestation diet from 180 d to 200 d of age and 2 .7 kg daily from 200 d until mating. To stimulate the estrus cycle, gilts w ere commingled and exposed to vasectomized boars beginning at 180 d of age. Gilts that were in estrus and 210 d of age or older were artificially inse minated with commercial semen. Gilts not detected in estrus within the firs t 50 d of observation were injected with PG600 and estrus detection continu ed for 30 additional days. Of the 657 gilts entering breeding pens, 422 far rowed. Bred gilts were distributed to 10 cooperator facilities before farro wing. Mixed model procedures were used to analyze the data. Significant (P < .05) genetic type x gilt development diet interactions were found for num ber of pigs born, number of pigs born alive, total litter birth weight, and litter birth weight of pigs born alive. Significant interactions consisten tly involved one genetic line and gilt development Diets 1 and 2. Gilts fro m this genetic line-diet subclass had poorer farrowing performance (P < .05 ) than gilts from the same line fed development Diet 3. Only two other sign ificant genetic line x gilt development diet interactions were found. Gilt development diet had little influence on first-parity reproductive performa nce.