REPRODUCTIVE PERFORMANCE OVER FOUR PARITIES OF GILTS STIMULATED TO EARLY ESTRUS AND MATED AT FIRST, SECOND OR THIRD OBSERVED ESTRUS

Abstract

One hundred and eighty-seven gilts that were moved, regrouped and exposed to a mature boar at approximately 140 ± 3 d of age and subsequently farrowed to assigned mating at first, second, or third observed estrus as gilts were used to evaluate reproductive performance over four parities. Over the four parities, the average number of litters per initial sow (3.22–3.25); the average litter size 21 d postfarrow (8.3 to 8.6); the average total number of piglets weaned per initial sow (26.9 – 27.7); the number of sows completing four parities (37–40); the average litter weight at 21 d postfarrow (146–148 kg) were similar for each mating group. The age difference of 36.8 d at first mating between those mated on first or third estrus as gilts was maintained until 28 d postfarrowing after the fourth parity (37.1 d). Overall, reproductive performance after four parities was similar for gilts mated at first, second or third observed estrus. Key words: Pigs, reproduction, mating, longevity