Genetic analysis for sow stayability at different parities in purebred Landrace and Large White pigs

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, horizontal ellipsis , 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.

Automated summary

Genetic parameters for sow stayability were estimated from farrowing records of Landrace and Large White sows, showing differences in heritability and genetic correlations among parities between breeds and models. The study also found that selection for number born alive does not necessarily reduce sow stayability, with results possibly influenced by culling decisions made by farmers.