Heritability Estimates for some Measures of Reproduction in Hereford Heifers2

Abstract
Records on 491 Hereford cows were analyzed to estimate heritabilities of some measures of reproduction in the first calving. Estimates were obtained from paternal half-sibs by both analysis of variance (ANOVA) and chi-square (✕2)- Heritabilities estimated from ANOVA and from ✕2 for binary variables were corrected to a normal basis (ANOVA—C and ✕2 —C). For calving rate at 2 years of age the heritabilities were .01 ± .02 (ANOVA), .02 ± .04 (ANOVA-C), .13 ± .09 (✕2) and .22 ± .12 (✕2—C). When heifers that failed to calve at both 2 and 3 years of age (barren) were excluded from the data, estimated heritabilities were .21 ± .13 (ANOVA), .45 ± .19 (ANOVA-C), .22 ± .14 (✕2) and .48 ± .20 (✕2 —C). The heritability of barrenness was .0 ± .04 (ANOVA), .16 + .10 (✕2) and .33 ± .15 (✕2 —C). Analysis of perinatal survival evaluated as a characteristic of the dam yielded heritability estimates of .64 ± .21 (ANOVA), 1.25 ± .35 (ANOVA—C), .61 + .25 (✕2) and 1.19 ± .34 (✕2 —C). Heritability of services per conception for the first calving was estimated at .64 ± .29. Copyright © 1979. American Society of Animal Science . Copyright 1979 by American Society of Animal Science.

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