Estimation of heritabilities, genetic correlations, phenotypic correlations and genetic trends for production and reproduction traits of Holstein-Friesian dairy cattle using sire model
Mohamed Osman,Khairy M. El-Bayomi,Sherif A. Moawed +2 more
- Vol. 18, Iss: 1, pp 115-128
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TLDR
Generally, the current results showed genetic improvement of most of traits that reflect the efficiency of selection programs.Abstract:
A total of 3460 lactation records that represented 1059 dairy Holstein-Friesian cows were used in the present study that aimed to estimate genetic parameters such as heritability, genetic correlations, phenotypic correlations and genetic trends for some productive and reproductive traits. Studied traits were total milk yield, days in milk, fat %, protein %, dry period, age at first calving, number of services per conception, days open and calving interval. Data were collected from Egyptian Copenhagen Company in Alexandria-Cairo desert road for cows calved from 1998 to 2010. Least square analysis of mixed sire model was used in analysis using Harvey (1990) program. Heritability estimates were high for all traits and very high for fat and protein % that exceeded 0.83 in two lactations. Genetic correlations were higher than phenotypic correlations and were high especially among production traits. Regression coefficients of genetic trends were positive for all studied traits except for days in milk and days open (in second lactation) and age at first calving. Generally, the current results showed genetic improvement of most of traits that reflect the efficiency of selection programs.read more
Citations
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Effects of season and age at first calving on genetic and phenotypic characteristics of lactation curve parameters in Holstein cows
TL;DR: In this article, the effect of age at first and season of calving on parameters of the Wood lactation curve was analyzed to determine the effect on milk yield in primiparous Holstein cows.
Journal ArticleDOI
Genetic and non-genetic analysis for milk production and reproductive traits in Holstein cattle in Egypt
TL;DR: Moderate heritability estimates and positive genetic correlation for most of traits studied suggested that genetic improvement of these traits would be achieved via multi-trait selection.
Journal ArticleDOI
Multi-trait and multi-source selection indices for milk production and reproductive traits in a herd of Holstein cattle in Egypt
TL;DR: It could be suggested using the higher indexes of Rih (I 1 (RE=100) ) to improve milk production and reproductive traits in Holstein cattle under own-performance strategy and using I 16 under multi-source strategy to get high accuracy and higher expected genetic changes per generation compare to general index.
Journal ArticleDOI
Estimate of Direct and Maternal Genetic Parameters for some Production and Reproduction Traits in Friesian COWS through Sire and Animal Models
H. El–Awady,I. Abu El-Naser +1 more
TL;DR: High estimates of genetic correlations between MY, LP and reproductive traits (DO and CI) that offer the possibility genetic improvement if selection for MY avaiable are presented, indicating that genetic improvement should be preferable realized through cows which the minimum of acurrecy was highest comparing to sires or dams.
Journal ArticleDOI
Genetic Parameters, Breeding Values and Genetic Trends for Some Productive and Reproductive Traits of Holstein Cows in Egypt
TL;DR: Positive genetic trends for 305-day milk yield, age at first calving, fat%, fat yield and protein% indicated that there was a genetic improvement in these traits in desirable direction, but negative genetic Trends for days open and protein yield indicated a decrease in mean breeding value for these traits over the study period.
References
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Genetic Parameters for Clinical Mastitis, Somatic Cell Score, and Production in the First Three Lactations of Swedish Holstein Cows
TL;DR: Using a mixed linear animal model, genetic parameters were estimated for clinical mastitis, lactation average somatic cell score, and milk production traits in the first 3 lactations of more than 200,000 Swedish Holstein cows with first calving from 1995 to 2000, implying that selection for low LSCS will reduce the incidence of mastitis.
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Genetic Aspects of Milk Yield and Reproductive Performance
TL;DR: Genetic correlations between reproductive performance and 60-day, 180- day, and 305-day fat-corrected-milk-yields were positive, indicating that higher producing cows were bred later, took longer to conceive, and required more services per conception.
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Genetic parameters and evaluations from single- and multiple-trait analysis of dairy cow fertility and milk production
TL;DR: Two-trait analysis of fertility and milk yield was investigated as a method to estimate fertility breeding values when culling or selection based on milk yield in early lactation determines presence or absence of fertility observations in later lactations.
Journal ArticleDOI
Genetic parameters for yield and reproductive traits of Holstein and Jersey cattle in Florida.
TL;DR: Estimates of genetic parameters and correlated responses in this subtropical environment did not differ appreciably from those that occur in temperate dairy areas.