Rutten-Ramos Stephanie C, Deen John
Department of Veterinary Population Medicine, University of Minnesota, Saint Paul, MN 55108, USA.
J Am Vet Med Assoc. 2009 Mar 1;234(5):665-8. doi: 10.2460/javma.234.5.665.
To evaluate the success of removal and replacement decisions in commercial swine herds when sow removal was attributed to problems with fertility, fecundity, or old age.
Retrospective case-control study.
3,000 sows removed from 3 commercial swine herds (case sows), 3,000 matched control sows retained in the herds, and 3,000 replacement gilts.
Control sows were included to generate an estimate of reproductive performance that could have been expected had case sows been retained in the herds. Control sows and replacement gilts were followed up until the next farrowing or until removed from the herd, and reproductive performance, calculated as number of pigs born alive per mated female per year, was compared between groups.
In 2 of the 3 herds, reproductive performance was significantly higher for replacement gilts than for control sows matched with case sows removed for reasons of fertility, and in all 3 herds, reproductive performance was significantly higher for replacement gilts than for control sows matched with case sows removed for reasons of fecundity. In the 2 herds with case sows removed because of age, reproductive performance did not differ significantly between replacement gilts and control sows. The odds of greater performance among replacement gilts relative to control sows ranged from 1.305 to 1.955 for removals attributed to fertility, 1.305 to 1.955 for removals attributed to fecundity, and 1.000 to 3.999 for removals attributed to age.
Results suggested that performance-based removal and replacement programs in commercial swine herds may not yield the anticipated results.
当母猪因繁殖力、生育力问题或老龄而被淘汰时，评估商业猪群中淘汰和补充决策的成效。
回顾性病例对照研究。
从3个商业猪群中淘汰的3000头母猪（病例母猪）、猪群中保留的3000头匹配对照母猪以及3000头后备小母猪。
纳入对照母猪以估计若病例母猪保留在猪群中可能预期的繁殖性能。对对照母猪和后备小母猪进行随访，直至下次产仔或直至从猪群中淘汰，并比较各组间以每年每头配种母猪产活仔数计算的繁殖性能。
在3个猪群中的2个，后备小母猪的繁殖性能显著高于因繁殖力原因被淘汰的病例母猪所匹配的对照母猪；在所有3个猪群中，后备小母猪的繁殖性能显著高于因生育力原因被淘汰的病例母猪所匹配的对照母猪。在因老龄淘汰病例母猪的2个猪群中，后备小母猪和对照母猪的繁殖性能无显著差异。因繁殖力淘汰时，后备小母猪相对于对照母猪表现更优的几率为1.305至1.955；因生育力淘汰时为1.305至1.955；因老龄淘汰时为1.000至3.999。
结果表明，商业猪群中基于性能的淘汰和补充计划可能无法产生预期结果。
