Identification of genomic regions associated with reproductive longevity in the Rubia Gallega beef cattle breed using a censored threshold model

Abstract

In beef cattle, the economic viability of farms is heavily influenced by the cow's ability to survive subsequent pregnancies. To understand the genetic basis of reproductive longevity in Rubia Gallega beef cattle breed, a ssGWAS was performed by back-solving the output of ssGBLUP under a censored threshold model. It considers the number of parities each cow reaches during its productive life as a phenotypic trait. The results of the study showed that the main source of variation of reproductive longevity is the herd. However, the posterior mean of the heritability of reproductive longevity was 0.173, indicating the potential for an appropriate genetic response to selection. Furthermore, it is shown that four genomic regions in chromosomes 2, 11 and 29 explain a large proportion of the additive genetic variance. The most important signal was detected on chromosome 2 in the vicinity of the MSTN (myostatin) gene that is associated with double muscling, and that it is segregating in the Rubia Gallega population. Some other interesting genes located within these regions encoded for several PAGs (Pregnancy-associated glycoprotein), LHCGR (luteinizing hormone/choriogonadotropin receptor), FSHR (follicle stimulating hormone receptor), PROKR1 (prokineticin receptor 1) and EHD3 (Eps15 homology domain-containing protein 3). This confirms the relevance of the reproductive performance in the reproductive longevity of cows. These findings provide valuable insights for the Rubia Gallega breeding program, as they can be used to define future selection strategies to improve reproductive longevity of the breed.