The influence of season, parity, and duration of lactation on some performance traits of sows indigenous to Nigeria.

120 young sows of less than one year of age and 240 old sows indigenous to Nigeria were randomly subjected to a 2 X 2 X 2 factorial analysis of variance. The results showed that the factors season, parity, and lactation period had no influence on the gestation period and some weaning features, like the number of stillborn piglets per litter and pre-weaning deaths. More piglets were farrowed live by old sows than by the young sows. The litter birth weight, the number of piglets weaned per litter and the number of days to estrous following weaning depended on the season and the lactation length.