Genomic evaluation of reproductive disorders in Czech Holstein cattle
Genomic breeding values were estimated for reproductive disorders in Czech Holstein cattle. Evaluated traits were defined as binary with no case (0) or at least 1 case (1) of retained placenta (RP), metritis (MET) or cystic ovaries disease (CYS) during lactation. Dataset included 91 368 lactations of 57 788 Holstein cows calved between July 2017 and February 2022 in 95 herds for RP; 135 361 lactations of 83 564 Holstein cows calved in 116 herds for MET and 82 724 lactations of 49 130 Holstein cows calved in 71 herds for CYS. The lactation incidence was 5.46% for RP, 12.68% for MET and 9.16% for CYS. The model equation included the fixed effects of herd-year-season of calving, parity of the cow, sex of the calf (for RP and MET), the random additive genetic effect of the animal, the random permanent environment of the cow, and the random residual effects. Pedigree involved from 111 858 (CYS) to 185 874 (MET) animals. The reference population for the single-step GBLUP method was defined as genotyped (Illumina BovineSNP50 BeadChip) bulls and cows that were present in the pedigree of animals with reproductive disorders records. Estimated heritabilities were 0.02 for all traits. Resistance to RP and MET were moderately genetically correlated (0.61), while the genetic correlation of both traits with CYS did not statistically differ from 0. Estimated breeding values were normally distributed with a mean of 0.00 and SD ranging between 0.11 and 0.17. Their mean reliabilities were low due to data structure and a relatively short period of recording. The results were expressed as relative breeding values RBV (mean = 100, SD = 12, for base bulls) and reversed in the sign which means that higher RBV are connected with better resistance to partial disorder. The correlations of RBV with other routinely evaluated traits showed, that CYS and MET were favourably correlated with fertility and longevity traits. MET was also favourably correlated with milk, fat and protein yield. Correlations with type traits showed an association of MET with udder traits and CYS with locomotion, bone quality and stature.
Authors who publish with this journal agree to the following terms:
- Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.
- Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.
- Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).