Submitted to: American Dairy Science Association Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 6/1/1998
Publication Date: N/A
Technical Abstract: Relationship of current breed members were identified by calculating expected inbreeding percentages for future progeny. Reference populations of potential mates were chosen by randomly selecting 300 males and 300 females born in 1996. Smaller samples of 100 and 200 animals of each gender were examined to determine effect of reference population size. The tabular method was used to compute inbreeding percentage and relationships among members and ancestors of reference populations. Although nearly 2 GB of memory were required for the maximum of 13,508 animals included in this step, computing times were just a few minutes. Mean relationship of other animals to the reference population was computed as the mean for their parents. To-Mar Blackstar-ET and Pawnee Farm Arlinda Chief were most related to the Holstein breed with expected inbreeding of 8.4 and 8.0%, respectively. Corresponding Jersey bulls were Highland Magic Duncan and Soldierboy Boomer Sooner of CJF with expected inbreeding of 11.6 and 9.8%. Among bulls with >100 daughters, highest expected inbreeding was 11.5% for Selwood Betty's Commander, 8.2% for Forest Lawn Simon Jetway, 10.1% for Dutch Mill Telestars Fayette, and 7.6% for Sunny View Princess' Promise for Ayrshire, Brown Swiss, Guernsey, and Milking Shorthorn breeds. Some bulls had few daughters but high expected inbreeding percentages. Their pedigrees almost always included 1 or more of the bulls above. Expected inbreeding percentages and rank changed little when reference populations included fewer animals. Regression on inbreeding in the genetic evaluation procedure would remove effects of past inbreeding, and information on expected inbreeding of future progeny could allow predicted transmitting abilities to include expected future inbreeding depression.