Friendship R M, Metzger K R, Robinson N P, Doig G S
Can Vet J. 1990 Oct;31(10):697-9.
The purpose of this study was to examine the litter size and stillbirth rate associated with cesarean-derived litters and to examine the relationship between the number of previous cesarean sections a sow had experienced and litter size. The records of 856 cesarean sections during a ten-year period from 1978 to 1988 were examined. The mean litter size was 10.6 +/- 3.2 and the mean number of stillborn pigs per litter was 0.2 +/- 0.8. The low level of stillbirth observed in this study provides supportive evidence to many earlier publications suggesting that the majority of stillborn pigs die during the birth process itself.A negative correlation between the number of previous cesarean sections a sow had experienced and litter size (r(2) = 0.015, p < 0.001) was observed. The slope of the regression line was -0.55, suggesting that litter size is reduced by approximately one-half a piglet for each cesarean section the sow has previously experienced. There are many factors which influence the variation in litter size. The small correlation coefficient (r(2) = 0.015) observed in this study indicates that only 1.5% of the variation in litter size can be explained by the number of previous cesarean sections that the sow has experienced.
本研究的目的是检查剖腹产仔猪的窝产仔数和死产率，并研究母猪既往剖腹产次数与窝产仔数之间的关系。对1978年至1988年十年间856例剖腹产记录进行了检查。平均窝产仔数为10.6±3.2，每窝死产仔猪的平均数量为0.2±0.8。本研究中观察到的低死产率为许多早期出版物提供了支持性证据，这些出版物表明，大多数死产仔猪在分娩过程中死亡。观察到母猪既往剖腹产次数与窝产仔数之间存在负相关（r² = 0.015，p < 0.001）。回归线的斜率为-0.55，这表明母猪每经历一次剖腹产，窝产仔数大约减少半头仔猪。有许多因素会影响窝产仔数的变化。本研究中观察到的小相关系数（r² = 0.015）表明，窝产仔数变化中只有1.5%可由母猪既往剖腹产次数来解释。
