Genomic evaluation of reproductive disorders in Czech Holstein cattle
Year | 2022 |
Cathegory | Entries in proceedings |
Internal link | 22156.pdf |
Abstract | 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. |
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