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

This Article 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 Buddenberg, B. J. Articles by Peterson, H. P. Search for Related Content PubMed PubMed Citation Articles by Buddenberg, B. J. Articles by Peterson, H. P.

Heritability Estimates of Pregnancy Rate in Beef Cows under Natural Mating¹

University of Arkansas, Fayetteville 72701

Abstract

Observations of 3,029 matings over 17 yr on an Ozark upland range were used to estimate heritability of pregnancy rate in Angus, Hereford and Polled Hereford cows. Pregnancy rate, the percentage of cows exposed that produced a live calf in the spring, was transformed using the empirical logit transformation and then analyzed for each breed separately by weighted least squares using a mixed model procedure. A numerator relationship matrix for sires of cows was incorporated into the sire model to account for relationships among sires. Variation among years significantly affected pregnancy rate in all three breeds. Age of dam significantly affected pregnancy rate in the Angus and Hereford groups. Paternal half-sib estimates of heritability from the observed binary data (h²_b) for pregnancy rate were calculated on first-calf heifers and mature cows for each breed. Respective h²_b estimates for heifers and mature cows were .17 and .09 in the Angus group, .04 and .01 in the Hereford group and .05 and .05 in the Polled Hereford group. The heritability estimates when binary records were transformed to the probit scale (h²) were .04 ± .003 and .02 ± .001 for Angus, .01 ± .002 and 0 for Hereford and .01 ± .001 and .02 ± .001 for Polled Hereford for heifers and mature cows, respectively. Heritability estimates in this study are in agreement with the literature, indicating little opportunity for improvement in pregnancy rate by selection within a breed.

¹ Published with the approval of the Director of the Univ. of Arkansas Agric. Exp. Sta.

² Dept. of Anim. Sci., Univ. of Arkansas.

³ Dept. of Mathematical Sci., Univ. of Arkansas.

This article has been cited by other articles:

				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]