Genetic parameters for sow stayability were estimated from farrowing records of 10,295 Landrace sows and 8192 Large White sows. The record for sow stayability from parity k to parity k + 1 (k = 1, …, 6) was 0 when a sow had a farrowing record at parity k but not at parity k + 1, and 1 when a sow had both records. Heritability was estimated by using single-trait linear and threshold animal models. Genetic correlations among parities were estimated by using two-trait linear–linear and single-trait random regression linear animal models. Genetic correlations with litter traits at birth were estimated by using a two-trait linear–linear animal model. Heritability estimates by linear model analysis were low (0.065–0.119 in Landrace & 0.061–0.157 in Large White); those by threshold model analysis were higher (0.136–0.200 & 0.110–0.283). Genetic correlations among parities differed between breeds and models. Genetic correlation between sow stayability and number born alive was positive in many cases, implying that selection for number born alive does not reduce sow stayability. The results seem to be affected by decisions on culling made by farmers.

中文翻译：

---

纯种长白猪和大白猪不同胎次母猪存活率的遗传分析

根据 10,295 头长白母猪和 8192 头大白母猪的分娩记录估算了母猪存活率的遗传参数。当母猪在第 k胎时有分娩记录但在第 k 胎时没有分娩记录时，从第k胎次到第k  + 1 胎次（k  = 1, …, 6）的母猪存活率记录为0 + 1，当母猪有这两项记录时为 1。通过使用单性状线性和阈值动物模型估计遗传力。通过使用双性状线性-线性和单性状随机回归线性动物模型估计胎次之间的遗传相关性。通过使用双性状线性-线性动物模型估计出生时与窝性状的遗传相关性。通过线性模型分析估计的遗传力较低（长白为 0.065-0.119，大白为 0.061-0.157）；通过阈值模型分析的那些更高（0.136-0.200和0.110-0.283）。品种和模型之间的胎次之间的遗传相关性不同。在许多情况下，母猪的存活率与活产数之间的遗传相关性呈正相关，这意味着选择活产数不会降低母猪的存活率。