Submitted to: American Dairy Science Association Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: July 26, 2000
Publication Date: July 26, 2000
Citation: Van Tassell, C.P., Sattler, C.G. 2000. Characterization of data and proposed edits for the national calving ease genetic evaluation. American Dairy Science Association Proceedings. JOURNAL OF DAIRY SCIENCE, vol. 83 (Suppl. 1), pp. 61.
Distributions of scores for birth difficulty (BD) were examined for herds included in the national genetic evaluation for calving ease. BD scores ranged from 1, no problem, to 5, extreme difficulty. Data for this study were from the February 2000 genetic evaluation and included scores from 8,296,832 calvings in 45,243 herds. The fraction of BD scores 1 to 5 across herds were .65, .14, .14, .05, and .03 for first parity, and .82, .08, .06, .02, and .01 for second and later parities. Sires with extreme evaluations tended to have a large fraction of records in a herd with an unusual BD score distribution. To determine useful edits for BD score distributions, frequencies of scores were summarized by herd-size and parity. Frequencies of observed scores (OS) and cumulative scores (CS) (5, 4+, 3+, and 2+) were considered. Herds that exceeded the 95 to 99 percentiles were removed to test potential edits. Thresholds based on OS percentiles resulted in many fewer herds passing the edits than those based on the CS. Elimination of records without maternal grandsire (MGS) resulted in the loss of 46.1% of the data. For edits based on OS, 50.9% and 79.4% of the records were retained for 95- and 99-percentile cutoffs, respectively, when MGS was not required, and 24.6% and 40.6% when MGS was required. For edits based on CS, 82.4% and 92.6% of the records were retained for 95- and 99-percentile cutoffs when MGS was not required, and 42.5% and 49.1% when MGS was required. Comparison of genetic evaluations from these different subsets of data will be compared to assess the impact of these edits. Based on these results new edits will be proposed for the national evaluation system.