Article (Scientific journals)
Development of a genetic evaluation for body condition score for Canadian Holsteins
Loker, S.; Bastin, Catherine; Miglior, F. et al.
2013In Journal of Dairy Science, 96, p. 3994-4004
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Keywords :
Body condition score; Genetic evaluation; Type trait; Random regression model
Abstract :
[en] Valacta (Sainte-Anne-de-Bellevue, Québec, Canada) is the Canadian Dairy Herd Improvement organization responsible for milk recording in Québec and Atlantic provinces. Up to 14 first-lactation body condition score (BCS) records were collected per cow (average of 2.5 records per cow), allowing the trait to be described by a random regression animal model so that animals could be ranked by the shape of their BCS curve. However, Valacta’s BCS are available from Québec herds only and the long-term objective of this research is to develop a nationwide genetic evaluation of sires and cows for BCS. Alternatively, Holstein Canada (Brantford, Ontario, Canada) collects type trait records nationwide, primarily for first-lactation cows. Holstein Canada typically collects a single record per trait, so that selection for Holstein Canada BCS would be based on overall BCS level rather than the shape of the BCS curve. Several different methods of genetically evaluating Valacta’s BCS were investigated, including consideration of average BCS level across lactation, the amount of fluctuation in the BCS curve during lactation, and combinations of BCS level and BCS fluctuation. Sires with ≥25 daughters were compared (as opposed to comparing cows) because their BCS estimated breeding values (EBV) are based on more information, and so should be more reliable. Of the different methods of calculating Valacta BCS EBV, ranking bulls based on overall BCS level gave the best results in that their daughter phenotypic BCS curves showed limited loss in early lactation BCS and replenished condition by the end of lactation. Whereas Valacta’s BCS were analyzed using a random regression animal model, Holstein Canada only needs to collect 1 BCS record per cow at classification and the resulting BCS EBV was strongly correlated with Valacta’s BCS EBV. Furthermore, because Holstein Canada’s BCS are collected nationally and Valacta’s BCS are not, a national genetic evaluation for Holstein Canada’s BCS is more convenient. The results of this study do not eliminate the possibility of a genetic evaluation of BCS as a longitudinal trait, but indicate that other methods of calculating Valacta BCS EBV should be explored. Until that time, genetically evaluating Holstein Canada’s BCS is simple, easily implemented, and may be effective in altering the level and shape of the genetic BCS curve.
Disciplines :
Genetics & genetic processes
Animal production & animal husbandry
Author, co-author :
Loker, S.;  University of Guelph > Department of Animal & Poultry Science > Centre for Genetic Improvement of Livestock
Bastin, Catherine ;  Université de Liège - ULiège > Sciences agronomiques > Zootechnie
Miglior, F.;  Agriculture and Agri-Food Canada > Guelph Food Research Centre
Sewalem, A.;  Agriculture and Agri-Food Canada > Guelph Food Research Centre
Schaeffer, L.R.;  University of Guelph > Department of Animal & Poultry Science > Centre for Genetic Improvement of Livestock
Jamrozik, J.;  University of Guelph > Department of Animal & Poultry Science > Centre for Genetic Improvement of Livestock
Osborne, V.;  University of Guelph > Centre for Nutrition Modelling
Ali, A.;  University of Guelph > Department of Mathematics and Statistics
Language :
English
Title :
Development of a genetic evaluation for body condition score for Canadian Holsteins
Publication date :
2013
Journal title :
Journal of Dairy Science
ISSN :
0022-0302
eISSN :
1525-3198
Publisher :
American Dairy Science Association, Champaign, United States - Illinois
Volume :
96
Pages :
3994-4004
Peer reviewed :
Peer Reviewed verified by ORBi
Available on ORBi :
since 30 January 2014

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