HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Riley, D. G. Articles by Hammond, A. C. Search for Related Content PubMed PubMed Citation Articles by Riley, D. G. Articles by Hammond, A. C.

Genetic and nongenetic influences on vigor at birth and preweaning mortality of purebred and high percentage Brahman calves^1,2,3

D. G. Riley^*,4, C. C. Chase, Jr.^*, T. A. Olson, S. W. Coleman^* and A. C. Hammond^*

^* ARS, USDA, Subtropical Agricultural Research Station, Brooksville, FL 34601 and and University of Florida, Gainesville 32611

⁴ Correspondence: 22271 Chinsegut Hill Rd. (phone: 352-796-3385; fax: 352-796-2930; e-mail dgriley{at}mail.ifas.ufl.edu).

Abstract

The objectives of this study were to assess the risk associated with proportion Brahman inheritance, cow age, dystocia, and birth date weather conditions on calf vigor at birth (n = 3,253) and preweaning mortality (n = 3,631), and to estimate heritabilities for these traits. Calves that had poor vigor at birth and calves that died before weaning were coded 1, and those that had adequate birth vigor or survived to weaning were coded 0. Traits were analyzed using GLM. Year (1951 to 2002), cow age, calf gender, minimum temperature on date of birth (two levels: 5.6°C; or >5.6°C), and occurrence of dystocia were main effects in models. The proportion of Brahman inheritance in calves was modeled as a covariate. Males had greater odds of poor birth vigor (odds ratio = 1.44, 95% confidence interval = 1.14 to 1.82). The odds of death before weaning for steers relative to heifers approached significance (P = 0.07; odds ratio 1.41, 95% confidence interval 0.97 to 2.04). Calves born to young (3-yr-old) or very old (13 yr or older) cows had greater (P < 0.05) odds of poor vigor and death before weaning than calves of 5-yr-old cows. Calves with difficult births had 2.59 times greater odds of poor birth vigor (95% confidence interval 1.40 to 4.79) and 12.9 times greater odds of death before weaning (95% confidence interval 8.14 to 20.39) than calves born with no dystocia. Calves born on days with minimum temperatures of 5.6°C or less had greater odds of poor vigor (odds ratio 1.97, 95% confidence interval 1.50 to 2.59) and of death before weaning (odds ratio 1.64, 95% confidence interval 1.27 to 2.13) than did calves born on days with higher minimums. The occurrence of rainfall on date of birth did not influence calf vigor at birth or preweaning mortality (P > 0.85). Purebred Brahman calves had 24.7 times greater odds (95% confidence interval 8.23 to 73.97) of poor vigor than Brahman calves. The regression coefficient estimate for fraction of Brahman inheritance approached significance (P = 0.07) for preweaning mortality. Estimates of direct and maternal heritability were 0.09 ± 0.05 and 0.10 ± 0.04 for birth vigor, and 0.06 ± 0.05 and 0.09 ± 0.04, respectively, for preweaning mortality. Some exploitable genetic variation exists for these traits, but management of other factors may yield more immediate improvement than selection.

Key Words: Brahman • Calves • Genetic Parameters • Mortality • Vigor

This article has been cited by other articles:

				D. G. Riley, C. C. Chase Jr., S. W. Coleman, and T. A. Olson Evaluation of birth and weaning traits of Romosinuano calves as purebreds and crosses with Brahman and Angus J Anim Sci, February 1, 2007; 85(2): 289 - 298. [Abstract] [Full Text] [PDF]

				J. L. L. Guerra, D. E. Franke, and D. C. Blouin Genetic parameters for calving rate and calf survival from linear, threshold, and logistic models in a multibreed beef cattle population J Anim Sci, December 1, 2006; 84(12): 3197 - 3203. [Abstract] [Full Text] [PDF]