부산대학교 도서관

This study was conducted to investigate the effects of parity, season and year of farrowing on the preweaning traits of swine based on the data obtained from 1,370 litters of Duroc, Hampshire, Landrace and Yorkshire breeds. The sows were raised at the Swine Breeding Station of National Livestock Cooperatives Federation in Yeong Kwang from 1983 through 1986. Least squares means were computed within breed and the results are summarized as follows: 1. Overall least squares means for litter size alive were superior in Landrace (9.35 head) to those in other breeds. 2. For the litter sizes at 21 and 42 weaning days of age, Landrace showed best and was followed by Yorkshire, Duroc and Hampshire in order. 3. Percentages of weaned pigs were 93.5 in Landrace 90.0 in Yorkshire which showed about 1(1% higher than those in the other two breeds. 4. Sows furrowed at 3rd or 4th parity showed better performances for most of the traits studied. 5. Pigs born in spring or fall were superior to those born in summer or winter. The year 1984 in general seemed to be better than any other years included in this analysis.