Genomic evaluation of late-term abortion in cows recorded through Dairy Herd Improvement test plans

Late-term abortions cause significant economic loss and are of great concern for dairy herds. >152 d <251 gestation that terminate a lactation or initiate new have long been recorded by Dairy Herd Improvement (DHI). For 24.8 million DHI lactations, the average incidence late-term across all years (2001–2018) was 1.2%. However, 1.3% reported in 2012 has declined to <1.0% since 2015. Small adjustments were applied 82 daughter pregnancy rate (DPR), 29 cow conception (CCR), 9 heifer (HCR) records account more accurately. Fertility credits CCR HCR changed treat last breeding as failure instead success if next calving coded abortion. Similarly, when computing DPR, days open is now set maximum value 250 an The test these changes showed very small standard deviation high correlations (0.997) adjusted predicted transmitting abilities (PTA) with official PTA from about 20,000 Holstein bulls born 2000 >50% reliability. abortion trait, estimated heritability only 0.001 had 0.1% recent sires reliability (>75%). Young animal genomic near 50% but range −0.5 +0.4 because low heritability. Genetic trend slightly favorable correlated favorably 0.27 net merit, 0.49 productive life, 0.33 livability, 0.23 CCR, 0.20 HCR, 0.26 −0.31 somatic cell score, −0.24 stillbirth, −0.26 dystocia. Thus, should not be needed separate fertility trait minor edit suffice. would add little national evaluations current traits already those losses.