FACTORS INFLUENCING, AND REPEATABILITY OF THE DURATION OF FARROWING IN YORKSHIRE SOWS

Abstract

The duration of farrowing was recorded for 92 sows farrowing 401 litters over a period of 16 yr. The data were analyzed to study the effects of parity, season of the year, time of the day, size of the litter, birth weight of the piglets and length of the gestation period, and to calculate the repeatability of the trait. The least-squares mean duration of farrowing was 3.9 h for litters adjusted to 1 1.2 piglets, 1.14 kg piglet weight and 114.6 days of gestation. The duration of farrowing increased significantly only with increase in the number of piglets born per litter and length of gestation period. All the factors studied accounted for only 18% of the total variation. The repeatabilities of the duration of farrowing, litter size and litter weight were 0.14, 0.10 and 0.21, respectively.