Genetic evaluation of Retained Placenta and Metritis and identification of risk factors associated with these traits in the first three parities of Iranian Holstein dairy cows

The objectives of this study were to estimate heritability and genetic, environmental and phenotypic correlations between retained placenta (RP) and metritis (MET) and also identification of risk factors associated with these traits in the first three parities of Iranian Holsteins. In the present investigation, data on RP and MET in Holstein dairy cows which were collected from 2008 to 2017 in 17 large dairy herds were used. Data across the first, second and third parties included records on 63039, 46265 and 30031 cows, respectively. A multivariate analysis under threshold models was considered for genetics evaluation. Multivariate Logistic regression models were used to identify the risk factors associated with MET and RP. The most important risk factor associated with RP and MET were stillbirth and Retained Placenta, respectively. Posterior means for heritability of RP were 0.06, 0.03, and 0.05 and those of MET were 0.03, 0.2, and 0.03 in the first, second, and third parity, respectively. Posterior means of genetic correlations across parities were moderate to high for RP (0.41-0.73) and MET (0.34-0.9). Genetic and phenotypic correlations between RP and / or between MET across the parities were lower than unity which implying RP and/or MET may be considered as distinct traits in different parities which is required to be considered in genetic evaluation of these traits in the Iranian Holstein cows.