Periódicos Brasileiros em Medicina Veterinária e Zootecnia

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Effect of birth weight and litter size on the performance of landrace gilts until puberty

Almeida, MirianMari, Mari, Mari, MariPinheiro Motta, AlanaPandolfo Bortolozzo, FernandoWentz, Ivo

Background: The selection for larger litter size has resulted in reduction of average birth weight and in increase of withinlitter birth weight variation in pigs. Birth weight is one of the most important factors affecting the survival and performance of piglets until weaning. The aim of this study was to evaluate the effect of litter size into which gilts were born and their individual birth weight on mortality and culling rate until the time of selection, as well as on puberty onset.Materials, Methods & Results: Female Landrace piglets (n = 1525) were identifi ed and weighed within 18 h after birth. They were also weighed at weaning (n = 1379), and at the end of the nursery (n = 1198) and rearing phases (n = 940). Three classes of litter size were created: Small LS (7-11 piglets), Intermediate LS (12-13 piglets) and Large LS (14-19 piglets). Gilts were also separated in three classes according to their birth weight: Low BW (530-1200 g), Intermediate BW (1205-1600 g) and High BW (1605-2535 g). When compared to High BW gilts, the risk of death until weaning was greater (P 0.05) in Low BW gilts from Intermediate LS and Large LS litters, but not in Low BW gilts from Small LS litters. Within the Low BW class, the risk of mortality until weaning was greater or tended to be greater if gilts were born in Intermediate LS (P 0.05) or Large LS (P = 0.079) litters compared

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