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- Title
Non-linear model analysis of categorical traits related to female reproduction efficiency in beef cattle.
- Authors
Rust, T.; Schoeman, S. J.; van der Westhuizen, J.; van Wyk, J. B.
- Abstract
The utilization of non-linear threshold models and linear animal models to estimate variance components for categorical reproductive traits in beef cattle was investigated. Three traits, retention (RET), stayability (STAY) and calf tempo (CT) were defined. The data set consisted of 36 880 Afrikaner beef cattle measurements recorded over a period of 10 years. After editing, the records of 7 746 females from 473 sires were available for the genetic parameter estimation for RET. The corresponding number of records for STAY and CT were 3 018 (243 sires) and 7 653 (465 sires), respectively. Using GFCAT, sire variances for RET, STAY and CT were estimated as 0.202, 0.072 and 0.114, respectively. With error variances pre-set to one, the heritability estimates on the underlying scale were calculated as 0.67, 0.27 and 0.41 for RET, STAY and CT, respectively. From the three traits analyzed in this study CT probably reflects the true fertility of the bull's female progeny best.
- Subjects
BEEF cattle reproduction; ANIMAL reproduction; ANIMAL breeding; CATTLE breeding; HERITABILITY; NONLINEAR statistical models
- Publication
South African Journal of Animal Science, 2009, Vol 39, Issue 4, p260
- ISSN
0375-1589
- Publication type
Article