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English :
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Genetic evaluation for some productive traits in rabbits
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Arabic :
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التقييم الوراثى لبعض الصفات الانتاجية في الارانب
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| Abstract |
Fourteen different genetic groups of rabbits. Data of growth traits and litter traits were recorded during the experimental period, conducted for five consecutive production years.
For post-weaning growth traits (body weight, daily body gain and livability):
The purebreds G had higher body weight at 4, 8 and 12 weeks of age than the N. the crossbred genetic group contained 75% of G breed was the highest in body weights at 4, 8 and 12 weeks of age. Analysis of variance revealed that the differences between averages of daily body gain during the period 4-8, due to breed effect was significant. The differences between means of post-weaning livability during the period from 4-8 weeks of age for purebred N and G were non-significant, while during the period from 8-12 weeks were significant. The percentages of direct additive genetic variance for post-weaning body weight were moderate at 4 weeks and decreased thereafter at 8 weeks up to 12 weeks of age. Estimates of heritabilities using Animal model for body weight were higher at 4 weeks than at 8 and 12 weeks. Estimates of heritabilites for post-weaning daily gains, during the periods from 4-8 and 8-12 weeks were very low. Estimates of heritabilities for livability at 8 weeks (L8) was markedly lower than L12. Estimates of crossbreeding effects: (a) using sub-models of Dickerson and Hill Model. The additive (direct genetic) effects were almost negative and significant in all four sub-models and the negative absolute values.
2. Litter traits:
The differences between means of litter size and weight of both NZW and Gabali at birth and at weaning were non-significant. The percentages of direct genetic variance estimates were somewhat low or moderate. Heritabilities estimates were low. The coefficients of each of genetic correlation, common correlation and environmental and phenotypic correlations among these traits were positive and moderate to high in values. Estimates of crossbreeding effects for LSB, LSW, LWB and LWW were:-a) Using Hill sub-models: The additive (direct genetic effect), the dominance effect, the epistatic, the maternal and paternal effects were non-significant. B) Using Dickerson sub-models: With respect to LSB, the additive (direct genetic) effect was significant (P<0.01) and the % of low negative
3. Fur traits:
The means of hair length, medulla diameter and % of medulla diameter of down hair of Gabali breed was significantly higher than NZW breed. While with respect of means of hair length, hair diameter, medulla diameter and % of medulla diameter of guard hair in NZW breed were higher than Gabali breed also mean of hair diameter of down hair of NZW was significantly higher than Gabali breed.The percentages of direct additive genetic variance for hair length of down and guard hair were high. A genetic relationship of hair length was positive and at a medium and high levels. Estimates of crossbreeding effects for hair physical characteristics of down and guard hair of crossbred NZW and Gabali at 12 weeks of age.
4. Minerals content in rabbit hair and blood:
4.1.In rabbit hair: Iron, cobalt and copper contents in hair of NZW rabbits were significantly higher than these mineral contents in hair of Gabali rabbit. Zinc, magnesium contents also were higher in NZW but the differences were non-significant. The percentages of direct additive genetic variance for the six trace elements were in high levels except with respect to Zn. The were also in the same levels.
4.2. In serum of rabbit blood:
The difference between values of cobalt, magnesium and iron, contents in blood serum of NZW and Gabali were non-significant. The percentages of direct additive genetic variance for six trace elements were almost in high levels except percentage Zn in medium level. The coefficients of genetic correlation between each of the six minerals, in blood and hair of rabbits, were in low values.
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| Publication year |
2005
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| Pages |
429p.
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| Availability location |
مكتبة معهد بحوث الانتاج الحيوانى- شارع نادى الصيد - الدقى - الجيزة
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| Availability number |
934
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| Organization Name |
Animal Production Research Institute (APRI)
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| Country |
Egypt
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| Department |
Rabbit, Turkey and Water Fowl Research Department
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| Author(s) from ARC |
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| Agris Categories |
Animal husbandry
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AGROVOC
TERMS |
Crossbreds.
Genetic parameters.
Production.
Rabbits.
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| Publication Type |
PhD Thesis
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