Multitrait Estimation of Genetic Parameters of Lactation Curves in Holstein Heifers
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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The efficient dairy production depends greatly on proper decisions made at different production stages. Numerous genetic and environmental factors that influence animals performance could complicate decisions making, therefore, some toolkit for facilitation of breeding and management decisions on dairy farm is required. Lactation curves, that are mathematical formulas that describe flow of milk...
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to estimate the genetic parameters for production and reproduction traits in holstein cows, information from 15 herds recorded by animal breeding center of iran during 1980 – 2004, were employed. estimations were made using restricted maximum likelihood method under an animal model ranging df-reml and matvec software. estimates of heritabilities for yield traits were moderate and ranged from 0....
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Early lactation parameters are difficult to estimate from commercial dairy records due to the small number of records available before the peak of production. A biological model of lactation was used with weekly milk records from a single Holstein herd to estimate these early lactation parameters and the secretion rate of milk from the average cell throughout lactation. A genetic analysis of th...
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Variance components of the covariance function coefficients in a random regression test-day model were estimated by Legendre polynomials up to a fifth order for first-parity records of Dutch dairy cows using Gibbs sampling. Two Legendre polynomials of equal order were used to model the random part of the lactation curve, one for the genetic component and one for permanent environment. Test-day ...
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ژورنال
عنوان ژورنال: Journal of Dairy Science
سال: 1987
ISSN: 0022-0302
DOI: 10.3168/jds.s0022-0302(87)80260-6