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ARS Home » Plains Area » Clay Center, Nebraska » U.S. Meat Animal Research Center » Genetics and Animal Breeding » Research » Publications at this Location » Publication #107726
Title: GENETIC PARAMETERS FOR COW WEIGHTS AT DIFFERENT AGES

Author
item RUMPH, JANICE - UNIV. OF NEBRASKA-LINCOLN
item KOCH, ROBERT - RETIRED-UNIV. OF NEBRASKA
item GREGORY, KEITH - ARS COLLABORATOR
item Cundiff, Larry
item Van Vleck, Lloyd

Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 1/14/2000
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Data were 14,419 weight records of Hereford cows taken from 1 to 8 years of age. Cows represented a control line and three lines selected for weaning weight, yearling weight, and an index of yearling weight and muscle score. Each record included a measurement of cow weight at the time of brand clipping (BC) and/or just before breeding (BB). Records included age of dam m(AD), year (Yr), age (Ag), line (Ln), pregnancy status (Pg), birth and method of rearing (BMR), and calf disposal code (DSP). Fixed effects in model were AD and Yr x Ag x Ln, Pg x Ln, BMR x Ln, and DSP x Ln subclass effects. Random effects were direct genetic, direct permanent environment, uncorrelated dam maternal, and residual. Interval between calving and weigh date was a covariate. Estimates by REML of genetic parameters were obtained. For BC and BB weights, estimates over all ages of fractions of variance (SE) were .67 (.03) and .63 (.03) for direct genetic, .00 (.03) and .00 (.02) for direct permanent environment, and .07 (.02) and .11 (.01 for dam maternal effects. For BC weights (no yearling data) with bivariate analyses at different ages, estimates of heritability ranged from .42 to .72, genetic correlations between ages ranged from .86 to 1.00, and correlations between maternal effects of dams ranged from .00 to .05. For BB weights, heritability ranged from .21 to .36 for yearling weights and .47 to .71 for older weights, and genetic correlations between ages ranged from .79 to 1.00. Genetic correlations with weights at older ages increased from yearling weights to weights at three years of age and were near unity for weights taken at four years and older. The results indicate that measurements of cow weights at two to four years of age could be used to select for desired mature weight.