RELATIONSHIPS BETWEEN OVULATION RATE, PRENATAL SURVIVAL AND LITTER SIZE IN FRENCH LARGE WHITE PIGS

摘要

The relationship between total number born (TNB), ovulation rate (CL) and prenatal survival was analysed in a French Large White population. The left ovary had a significantly (P < 0.01) higher ovulation rate (7.9) than the right ovary (6.9). Prenatal survival showed an ovum wastage of 35 or 37% depending on whether referred to total number born or number born alive. No differences between parities were found in these traits. There was a negative relationship between ovulation rate at both sides (r = -0.34). There was a negative relationship between CL and prenatal survival (r = -0.37), a low correlation between CL and TNB (r = 0.19), and a high positive correlation between prenatal survival and TNB (r = 0.82). Litter size showed a quadratic relationship with ovulation rate, and the individual variation for each class of ovulation rate was found to be high. The relationship between prenatal survival and ovulation rate was found to be linear, and a high individual variation for each class of litter size was also found. The relationships between prenatal survival and litter size were quadratic, but depended much less on individual variation.