|PARKER GADDIS, KRISTEN - Council On Dairy Cattle Breeding|
|WRIGHT, JANICE - Former ARS Employee|
|MEGONIGAL, JOEL - Council On Dairy Cattle Breeding|
|CLAY, JOHN - Dairy Records Management Systems(DRMS)|
Submitted to: World Congress of Genetics Applied in Livestock Production
Publication Type: Proceedings
Publication Acceptance Date: 2/7/2018
Publication Date: 2/7/2018
Citation: Parker Gaddis, K.L., Tooker, M.E., Wright, J.R., Megonigal, J.H., Clay, J.S., Cole, J.B., Van Raden, P.M. 2018. Development of national genomic evaluations for health traits in U.S. Holsteins. World Congress of Genetics Applied in Livestock Production. Auckland, New Zealand, Feb. 11–16, Vol. Biol. & Species–Bovine (dairy) 1, p. 594.
Technical Abstract: The objective of this research was to develop genomic evaluation for resistance to six common health events reported in U.S. dairy herds. The diseases of interest were selected based on their frequency, severity, and economic impact. They included hypocalcemia (milk fever), displaced abomasum, ketosis, mastitis, metritis, and retained placenta. Dairy Records Management Systems (Raleigh, NC) provided producer-recorded data for these six health events. A total of 3.1 million records from 1.7 million Holsteins were available after data quality edits were applied. Genetic differences accounted for 0.6%, 1.1%, 1.2%, 3.1%, 1.4%, and 1.0% of the total observed variation for hypocalcemia, displaced abomasum, ketosis, mastitis, metritis, and retained placenta, respectively. Traditional evaluations were calculated for 63.1 million Holsteins using a linear animal model, and genomic evaluations included information from 60,671 DNA markers for 1.36 million Holsteins. Young animal reliabilities averaged 11-18% in the pedigree-based model versus 40-49% using genomic information. Average reliabilities for proven animals ranged from 20-33% in the pedigree-based model compared to 44-56% from genomic predictions. Direct costs for each health event ranged from $28 for ketosis up to $197 for displaced abomasum. The six health traits together will receive 2-3% of the total relative emphasis when included in the lifetime net merit selection index that is used by dairy farmers to rank animals and make selection decisions.