Estudo comparativo de parâmetros reprodutivos e produtivos de porca de raça Alentejana e porcas Large-White x Landrace

This study compared some reproductive (gestation and farrowing length; total born, born alive, stillbirths, mummified, post-natal mortality) and productive traits (piglet and litter weights at birth and at 21 days) between Alentejano swine breed (AL) and a conventional genotype (Large-White x Landrace - C). A total of 90 animals (45 per genotype) reared under 4 production environments were studied along farrowing and lactation (21 days) periods. The AL sows were managed under extensive outdoor whereas the C sows were managed under intensive indoor conditions. Alentejano sows had shorter gestations (P < 0.01) and farrowings (P < 0.01) compared with C sows. Conventional genotype sows farrowed more total and born alive piglets (P < 0.001). Lighter weights were observed both in AL litters and individual AL piglets at birth and d 21 (P < 0.001). Average daily gain from birth to 21 days, was higher in C piglets (P < 0.001). Mortality rates of born alive piglets (total and during the first 24h) were higher in AL litters (P < 0.001, for both). The piglets that died during the nursing period were lighter and gained less weight during the first 24h than the survivor littermates (P < 0.001). Overall the lower performance of the AL compared with the C genotype is due to its poorer reproductive and productive traits and a higher mortality rate during the nursing period. Possible explanations for the higher mortality in Al genotype are discussed