Document Detail

Growth curves of crossbred cows sired by Hereford, Angus, Belgian Blue, Brahman, Boran, and Tuli bulls, and the fraction of mature weight and height at puberty.
MedLine Citation:
PMID:  21531851     Owner:  NLM     Status:  Publisher    
The objective of this study was to evaluate the growth curves of females to determine if mature size and relative rates of maturing amongst breeds differed. Body weight and hip height data were fitted to the nonlinear function: BW = f(t) = A - Be(k × age), where A is an estimate of mature BW and k determines the rate that BW or height moves from B to A. Cows represented progeny from 28 Hereford, 38 Angus, 25 Belgian Blue, 34 Brahman, 8 Boran, and 9 Tuli sires. Bulls from these breeds were mated by artificial insemination to Angus, Hereford, and MARC III composite (&frac14; Angus, &frac14; Hereford, &frac14; Red Poll, and &frac14; Pinzgauer) cows to produce calves in 1992, 1993, and 1994. These matings resulted in 516 mature cows whose growth curves were subsequently evaluated. Hereford-sired cows tended to have heavier mature weight as estimated by parameter A than Angus- (P = 0.09) and Brahman-sired cows (P = 0.06), and were heavier than the other breeds (P < 0.001). Angus-sired cows were heavier than Boran- (P < 0.001) and Tuli-sired cows (P < 0.001), and tended to be heavier than Belgian Blue-sired cows (P = 0.097). Angus-sired cows did not differ from Brahman- (P = 0.94) sired cows. Brahman-sired cows had a heavier mature BW than Boran- (P < 0.001), Tuli- (P < 0.001), and Belgian Blue-sired cows (P < 0.04). Angus-sired cows matured faster (k) than cows sired by Hereford (P = 0.03), Brahman (P < 0.001), Boran (P = 0.03), and Tuli (P < 0.001) sires, but did not differ from Belgian Blue-sired (P = 0.13) cows. Brahman-sired cows took longer to mature than Boran- (P = 0.03) or Belgian Blue-sired cows (P = 0.003). Belgian Blue-sired cows were faster maturing than Tuli-sired cows (P = 0.02). Brahman-sired cows had reached a greater proportion of their mature BW at puberty than Hereford- (P < 0.001), Tuli- (P = 0.003), and Belgian Blue-sired cows (P = 0.001). Boran-sired cows tended to have reached a greater proportion of their mature BW at puberty than Angus-sired cows (P = 0.09), and had reached a greater proportion of their mature BW at puberty than Hereford- (P < 0.001), Tuli- (P < 0.001), and Belgian Blue-sired cows (P < 0.001). Within species of cattle, the relative range in proportion of mature BW at puberty (Bos taurus 0.56 through 0.58 and Bos indicus 0.60) was highly conserved, suggesting that proportion of mature BW is a more robust predictor of age at puberty across breeds than absolute weight or age.
H C Freetly; L A Kuehn; L V Cundiff
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2011-4-29
Journal Detail:
Title:  Journal of animal science     Volume:  -     ISSN:  1525-3163     ISO Abbreviation:  -     Publication Date:  2011 Apr 
Date Detail:
Created Date:  2011-5-2     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8003002     Medline TA:  J Anim Sci     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
USDA, ARS, U.S. Meat Animal Research Center, Clay Center, NE 68933.
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