| Titles |
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English :
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Relationships of first lactation with lifetime production and longevity traits of holstein-friesian cows in Egypt
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Arabic :
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علاقات صفات الموسم الاول بصفات انتاج اللبن خلال الحياة الانتاجية و صفات طول الحياة الانتاجية لابقار الهولشتين- فريزيان في مصر
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| Abstract |
Genetic and phenotypic correlations of first lactation traits (age at first calving, 305-day milk yield. lactation period and calving interval) with lifetime production traits (lifetime 305-day milk. lifetime total milk. yield and lifetime lactation period) and longevity traits (number of lactation completed, herd life and productive life) were estimated from 5642 records of 887 cows raised in Egypt, daughters of 94 Holstein bulls using the mixed model and multi-trait animal model technique to fit animals with their relationships as a random effect and year-season of birth as a fixed effect. The correlations among breeding values and among their ranks offirst lactation traits along with lifetime production traits and longevity traits for all animals were also estimated.
A complete negative genetic correlation was found between age at first calving and lifetime days in milk. Genetic correlations between age at first calving and lifetime milk yield (305-day and total) and longevity traits were high and negative (ranged from-0.70 to-0.98) as well as between first calving interval and lifetime production and longevity traits (ranged from -0.45 to -0.66). Genetic correlations between the first lactation 305-day milk yield and lifetime milk yield was positive and moderately high (0.57 - 0.67). High negative genetic correlations between age at first calving and first calving interval with both lifetime production and longevity traits were obtained. These correlations ranging between -0.65 and -1.00 suggest that first lactation traits (AGF or ClF) could be used in indirect selection for high lifetime production and long longevity traits. A reduction in age at first calving and calving interval of first lactation will minimize the rearing cost of the heifers. shorten the generation interval and/or maximize the number of lactations given per cow and all lifetime traits.
Keywords: Lifetime production, longevity, First lactation, Holstein-Friesian, Egypt
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| Publication year |
2004
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| Pages |
61-70
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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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| Country |
Egypt
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| City |
Moshtohor
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| serial title |
Annals of Agricultural Science
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| Volume |
42
. 1
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| Department |
Cattle Breeding Research Department
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| Author(s) from ARC |
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| Agris Categories |
Animal husbandry
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AGROVOC
TERMS |
Cows.
Egypt.
Lactation.
Longevity.
Production.
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| Proposed Agrovoc |
Lifetime production;First lactation;
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| Publication Type |
Journal
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