Affiliation:
1. Department of Animal Science, McGill University, Macdonald Campus, 21,111 Lakeshore Road, Ste Anne de Bellevue, Québec, Canada H9X 3V9
2. Department of Research and Development, Valacta, Centre d'Expertise en Production Laitière, 555 boul. Des Anciens Combattants, Ste Anne de Bellevue, Québec, Canada H9X 3R4
3. Département des sciences animales, Université Laval, Québec, Canada G1V 0A6
4. Agriculture and Agri-Food Canada, British Columbia V0M 1AZ
Abstract
Cue, R. I., Pietersma, D., Lefebvre, D., Lacroix, R., Wade, K., Pellerin, D., de Passillé, A-M. and Rushen, J. 2012. Growth modeling of dairy heifers in Québec based on random regression. Can. J. Anim. Sci. 92: 33–47. A total of 144 006 weight (calculated from tape girth measurements) and height data records from Québec dairy heifers were analyzed using random regression to estimate growth curve parameters of Ayrshires, Brown Swiss and Holstein animals to permit prediction of individual heifer growth from 0 to 32 mo. There were, on average, 5.15 records per heifer (minimum 3 records, maximum 25 records). The body weight data were analyzed using linear and quadratic fixed and random regressions, with a power-of-the-mean (POM) function to model the residual variance. The POM was 1.2 for Holstein and Ayrshire and slightly less than 1 for Brown Swiss. Estimated body weight at 24 mo was 507, 564, 624 kg, for Ayrshires, Brown Swiss and Holstein, respectively. The height data were analyzed with a Brody, monomolecular non-linear growth curve model. Mature height was estimated to be 148 cm in both Holstein and Ayrshires, and 150 cm in Brown Swiss. Random regression models were shown to be able to predict individual growth, and can be incorporated in decision-support tools to help producers reducing the average age at first calving.
Publisher
Canadian Science Publishing
Subject
Animal Science and Zoology,Food Animals
Cited by
11 articles.
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