EFFECTS OF SEASON AND LITTER SIZE ON GESTATION LENGTH IN SWINE

Abstract

488 gestations (309 Large White and 179 Landrace) and the size of all litters resulting from services which occurred between January 1967 and March 1970 were analysed. The mean gestation length was 113.96 days for the Large White and 113.74 days for the Landrace while the mean values for the litter size were 9.14 and 9.58 respectively. There was a significant negative correlation between these two traits in both breeds (P 0.01). A slight and non-significant seasonal effect (P 0.10) was shown with the highest and lowest gestation lengths being recorded in July (114.38 days) and in January and February (113.40 days). Breed effect and interaction between breed and season were also not significant.