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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 #99791
Title: USE OF RECORDS OF BOVINE SOMATOTROPIN TREATED COWS IN GENETIC EVALUATION

Author
item TSURUTA, S. - UNIV. OF GEORGIA, ATHENS
item KEOWN, JEFFREY - UNIV. OF NEBRASKA-LINCOLN
item Van Vleck, Lloyd
item MISZTAL, I. - UNIV. OF GEORGIA, ATHENS

Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 3/1/1999
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Records from the North Carolina State Dairy Records Processing Center were used to estimate effects of bovine somatotropin (bST) treatment and (co)variance components and to predict breeding values on milk production traits. The data comprised 5,245 test-day (TD) records of bST treated cows and 126,223 TD records of untreated cows in first lactation for milk, fat, and protein yields. Fixed effects of bST by days in milk (DIM) interaction and (co)variance components of random effects (animal, permanent environment, random regressions, and residual) were estimated from TD animal models with herd-year (HY) effects on herd-test-date (HTD) effects using the REMLF90 program. To assess the potential for bias in genetic evaluations when some and not all cows are treated with bST, breeding values predicted by the animal models with and without effects of bST treatment were compared for cows and sires. Random regressions for additive egenetic and permanent environmental effects were included in the models. I the model with HY effects, responses to bST treatment for milk yield increased with DIM, suggesting interaction between effects of bST and DIM. However, in the model with HTD effects, the interaction between effects of bST and DIM was small. Percentages of increase due to bST treatment were ranging from 5 to 8% for TD milk, fat, and protein yields. Correlations between breeding values predicted from the models with and without effects of bST treatment were greater than .99. These results suggest that bias in genetic evaluation due to ignoring bST treatment may be small or that responses to bST and breeding values may be highly correlated.