Model Comparisons and Genetic Parameters Estimates of Productive Traits in Holstein Cows
نویسندگان
چکیده
منابع مشابه
Estimation of Genetic Parameters for Lactation Curve Traits in Holstein Dairy Cows in Iran
The objectives were to estimate (co)variance components and genetic parameters for lactation curve traits in Holstein dairy cows in Iran. The used data were records on Holstein cows collected during January 2003 to December 2012 by the Animal Breeding Center of Iran (Karaj, Iran). In order to describe the lactation curve, an incomplete gamma function was fitted to 691200 test-day records on 962...
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Genetic parameters were estimated with restricted maximum likelihood for individual test-day milk, fat, and protein yields and somatic cell scores with a random regression cubic spline model. Test-day records of Holstein cows that calved from 1994 through early 1999 were obtained from Dairy Records Management Systems in Raleigh, North Carolina, for the analysis. Estimates of heritability for in...
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in the present study, to estimate genetic parameters and genetic and phenotypic trends in holstein dairy cows in the north of iran, the records from first lactation of 11398 collected from 1989 to 2006 were used. records were collected from 290 herds. productive traits were 305 day-2x adjusted milk and fat yield and reproductive traits were age at first calving, calving interval and dry days. g...
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To satisfy the growing demand of the human population for milk, the Moroccan government set up a plan in 1975 to increase milk production. The most important genetic strategies were the introduction of improved dairy cattle, the institution of milk recording, and the extension of artificial insemination (AI). Thus, more than 10,000 Holstein and Friesian heifers were purchased annually from Euro...
متن کاملgenetic parameters estimation of age at first calving and its effect on productive traits of holstein dairy cows
the aim of this study was to estimate genetic parameters of age at first calving and its relationship with productive traits of holstein dairy cows. a total of 24491 first lactation records (2x 305d) which were collected from 1995 to 2009 were used. the general linear model (glm) procedure was applied to determine effective factors on studied traits. herd-year-season (hys) and age at first calv...
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ژورنال
عنوان ژورنال: Journal of Applied Sciences
سال: 2016
ISSN: 1812-5654
DOI: 10.3923/jas.2016.380.387