Estimates of phenotypic and genetic parameters for birth weight of Brown Swiss calves in Turkey using an animal model |
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Authors: | A Sahin Z Ulutas A Yilmaz Adkinson R W Adkinson |
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Institution: | (1) Department of Animal Science, Faculty of Agriculture, Gaziosmanpasa University, 60250 Tokat, Turkey;(2) Department of Animal Science, Faculty of Agriculture, Erciyes University, 38039 Kayseri, Turkey |
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Abstract: | A study was conducted to assess the influence of genetic and environmental factors on Brown Swiss calf birth weight, and to
estimate variance components, genetic parameters, and breeding values. Data were collected on 1,761 Brown Swiss calves born
from 1990 to 2005 in the Konuklar State Farm in Turkey. Mean birth weight for all calves was 39.3 ± 0.09 kg. Least squares
mean birth weights for male and female Brown Swiss calves were 40.3 ± 0.02 and 39.0 ± 0.02 kg, respectively. Variance components,
genetic parameters, and breeding values for birth weight in Brown Swiss calves were estimated by restricted error maximum
likelihood (REML)–best linear unbiased prediction(BLUP) procedures using an MTDFREML (multiple trait derivative free restricted
maximum likelihood) program employing an animal model. Direct heritability (h
d2), maternal heritability (h
m2), total heritability (h
T2), r
am and c
am estimates were 0.12, 0.09, 0.23, −0.58, and −0.06, respectively. The estimated maternal permanent environmental variance
expressed as a proportion of the phenotypic variance (c
2) was 0.05. Breeding values were estimated for the trait and used to evaluate genetic trends across the time period investigated.
The genetic trend linear regression was not different from zero. No genetic trend for birth weight was expected, since there
had been no direct selection pressure on the trait. Absence of a trend confirms that there was no change due to selection
pressure on correlated traits. Genetic and environmental parameter estimates were similar to literature values indicating
that effective selection methods used in more developed improvement programs would be effective in Turkey as well. |
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Keywords: | |
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