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English :
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Genetic and non-genetic factors affecting total milk yield, days open, number of service per conception and age at first calving of friesian cows in Egypt.
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Arabic :
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العوامل الو راثية والغير وراثية المؤثرة على إنتاج اللبن الكلى والأيام المفتوحة (فترة التلقيح) وعدد التلقيحات اللازمة للإخصاب والعمر عند أول ولادة فى أبقار الفريزيان فى مصر
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| Abstract |
Total of 1394 normal records of Friesian cows in first lactation sired by 146 bulls collected from Sakha Farm, Ministry of Agriculture, Egypt during the period from 1970 to 1993 were used in this study. The data were used to estimate: the effects of non-genetic and genetic (sire) factors on total milk yield (TMY) and some reproductive traits namely days open (DO), number of service per conception (NSPC) and age at first calving (AFC), and to estimate genetic and phenotypic parameters for the previous traits. Data were analyzed using linear mixed model of Harvey's (1990). The results obtained could be summarized as follows:-
1. The actual means of TMY, DO, NSPC and AFC were 3391.9 kg, 190.7 days, 2.2 service and 31.8 month, respectively. Coefficients of variation of TMY and some reproductive traits (DO, NSPC and AFC) were 42.8% and (34.7%, 59.3% and 16.8%), respectively.
2. Month of calving had significant (P< 0.05) effect on days open, while, non significant effects on number of service per conception, age at first calving and total milk yield.
3. Year of calving had highly significant (P< 0.01) effect on total milk yield and of reproductive traits under the present investigation.
4. The sire had highly significant (P< 0.01) effects on total milk yield and days open and only significant (P< 0.01) effects on number of service per conception. While, non significant effect on age at first calving. The sire variance component (s2s) were 3.62%, 6.13%, 2.43% and 1.30% for TMY, DO, NSPC and AFC, respectively.
5. The estimates of heritability of total milk yield and reproductive traits of the cows at their first parity (based on parental half-sibs methods) were 0.15, 0.25, 0.10 and 0.05 for TMY, DO, NSPC and AFC, respectively.
6. Genetic correlations between reproductive traits studied were positive and significant (P< 0.01), except NSPC with AFC it was negative and significant (P< 0.01).
7. Phenotypic correlations between some reproductive studied traits were showed positive and significant (P< 0.01) values.
Environmental correlation between reproductive traits studied were positive and highly significant (P< 0.01).
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| Publication year |
2004
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| Pages |
6843-6851
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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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| City |
المنصورة
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| serial title |
Journal of Agricultural Science Mansoura University
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| ISSN |
1110-0346
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| Author(s) from ARC |
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| Agris Categories |
Animal husbandry
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AGROVOC
TERMS |
Cows.
Egypt.
Genetic parameters.
Milk yield.
Reproductive performance.
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| Publication Type |
Journal
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