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English :
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Genetic analysis for some productive traits in pure bred and graded dairy cattle under the Egyptian conditions
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Arabic :
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تحليل وراثي لبعض الصفات الإنتاجية في ماشية اللبن الأصيلة و المدرجة تحت الظروف المصرية
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| Abstract |
There trials of upgrading Egyptian Domiati cows with Friesian (Friesian trial), Dairy Shorthorn (Shorthorn trail) and jersey (jersey trail) bulls were carried out in three experimental stations. of the Animal Production Reseaech Institute These three up-grading trials were used to quantify the heterotic components of direct additive effect (GI), mateJl1al additive effect (GM), direct heterosis (HI), maternal heterosis (HM), direct recombination effect (RI) and matemal recombiantion effect (RM) for milk production traits and reproductive intervals in these trials. Records were collected over a period of 26 consecutive years started from 1950. The traits included were initial 90-day milk yield (M90), 305-day milk yield (M305), total milk yield (TMY), lactation period (LP), dry period (DP), calving interval (CI), 305-day milk yield divided by calving interval (MC11), total milk yield divided by calving interval (MCI2) and age at first (ACI) and second (AC2) calving. Results obtained could be summarized as follow:
II. Direct(G 1) and maternal additive (GM( effects
For milk production traits, foreign breeds (Friesian, Shorthorn and Jersey) always surpassed Domiati breed in their direct (G1) and maternal (GM) additive effects.
III. Individual (H1 ) and maternal (H M) heterosis
In the three trials, direct heterotic superiority (H1) of crossbred cows over their purebred parents are evidenced. Positive estimates of H1 for milk production traits ranged from 1.2 to 13.30/0 in Friesian trial, 1.0 to 260/0 in Shorthorn trial and 0.3 to 47.4% in Jersey trial.
IV. Individual (R1) and maternal (R M) recombination effect
Estimates of R1and RM for milk production traits were positive and significant and indicating that crossbred dams mothered heifers with higher milking ability than did purebred Friesian dams where both groups were mated to the same purebred Friesian bulls. Insignificant negative estimates of R1 for DP were observed, while insignificant positive estin1ates were recorded for CI, AC1 and AC2.
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| Publication year |
1996
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| Pages |
150p.
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| Availability location |
مكتبة معهد بحوث الانتاج الحيوانى- شارع نادى الصيد- الدقى - الجيزة
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| Availability number |
532
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| Organization Name |
Animal Production Research Institute (APRI)
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| Country |
Egypt
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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 |
Breeds (animals).
Dairy cattle.
Egypt.
Genetic variation.
Production factors.
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| Publication Type |
PhD Thesis
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