| Titles |
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English :
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Genetic parameter estimates of lifetime performance traits for Holstein-Friesian cattle raised in Egypt
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Arabic :
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تقدير المقاييس الوراثية لصفات اداء مدى الحياة لماشية الهولشتين فريزيان المرباة في مصر
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| Abstract |
A total of 5662 lactation records for 1029 Holstein-Friesian cows sired by 139 bulls raised in three commercial herds was used in the present study to estimate genetic parameters of total and partial lifetime traits with a multiple trait animal model. The study took into account four lifespan traits (lifetime, productive life, lifetime days in milk and lifetime score), lifetime milk yield and two reproductive traits (age at first calving and calving interval). Milk yield was calculated per day of lifetime, productive life and lifetime days in milk. Partial lifetime traits were considered for the first three parities.
The model of analysis included herd, season of birth and year of birth as fixed effects and animal as a random effect. Milk/d of lifetime days in milk was added to the model as a covariate for lifespan traits only. Year of birth contributed significantly to variation in all traits. Herd showed significant effect on all the traits except for milk per-day of productive life and milk per-day of lifetime days in milk season of birth showed a significant effect on all lifespan traits. Heritability estimates for lifespan traits were low (0.05 to 0.12), indicating few possibilities for direct genetic selection. All estimates of genetic correlations (0.97 - 0. 98) between lifespan traits were high and very proximate to their corresponding phenotypic correlations. Heritability estimates for partial lifetime performance traits increased notably when more parities were included. Genetic and phenotypic correlations between partial lifetime trails and their corresponding total lifetime traits also increased gradually when more information was considered. These results may indicate that early indirect selection to improve total lifetime could be achieved.
Keywords: Genetic parameters, lifetime traits, Holstein-Friesian, Egypt
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| Publication year |
2008
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| Pages |
21-31
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| Availability location |
معهد بحوث الانتاج الحيوانى- شارع نادى الصيد- الدقى - الجيزة
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| Availability number |
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| Organization Name |
Animal Production Research Institute (APRI)
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| serial title |
Egyptian Journal Animal Production
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| Author(s) from ARC |
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| External authors (outside ARC) |
حارث عمر الحماد
جامعة القاهرة
محمد عبد العزير محمد ابراهيم
جامعة القاهرة
على عطية نجم
جامعة القاهرة
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| Agris Categories |
Animal husbandry
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AGROVOC
TERMS |
Animal models.
Bulls.
Cattle.
Egypt.
Genetic parameters.
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| Proposed Agrovoc |
lifetime traits;Holstein-Friesian;
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| Publication Type |
Journal
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