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Genomic evaluation of heifer livability.

M. Neupane




Genomic evaluation of heifer livability.
M. Neupane*, C. P. Van Tassell, P. M. VanRaden. Animal Genomics and Improvement Laboratory, Agricultural Research Service, USDA, Beltsville, MD .

Differences in breeds and sire lines suggest the presence of a genetic component for heifer livability (HLIV). Genomic evaluation of this trait can increase profitability and improve animal health and welfare. Evaluations for HLIV were examined from 3,360,847 calf data records for heifers of all breeds born from the year 2009—2016. Data were obtained from the national cooperator database maintained by the Council on Dairy Cattle Breeding, USA. The total number of deaths reported was 134,804 (4.01%), which includes the herds with death loss between 1 and 25%. Total death rate from >2 d of age until the heifer left the herd or until a maximum of 18 mo of age was evaluated, but records were not included until 3 years after the birthdate so that live status of contemporaries could be confirmed by a calving date. Deaths observed until 2 d after birth were included in stillbirth rather than HLIV. The scale used for analysis of HLIV was 0 (died) or 100 (live) and the heritability estimate was 0.4% based on sire model REML. Genomic predicted transmitting abilities (GPTA) for Holstein range from −1.5% to +1.5% with a standard deviation of 0.5% and GPTAs for Jersey range from −0.8% to +0.8% with SD of 0.2% compared with means of about 4% death loss. Reliabilities of genomic predictions for young animals averaged 46% for Holsteins and 30% for Jerseys while corresponding traditional parent average reliabilities averaged 16% and 12%. Correlations of HLIV were 0.44 with productive life, 0.34 to 0.36 with yield traits, 0.37 with calving trait dollars, and 0.36 with early first calving on proven Holstein bulls. The HLIV trait had a favorable genetic trend in recent years, likely because of selection for the correlated traits. The trait HLIV could get 1% of emphasis on net merit index making economic progress of $0.05 million per year. By encouraging more recordings on calf mortality, the reliabilities of evaluations can increase significantly.

Keywords: heifer livability, genomic evaluation, animal welfare.