Effect of some Genetic and Non Genetic factors on the weights of many genotype lambs at different age stages.

	Effect of some Genetic and Non Genetic factors on the weights of many genotype lambs at different age stages.
Kufa Journal for Agricultural Science
Article 1, Volume 3, Issue 1, 2011, Pages 265-272
Abstract
Abstract This study was conducted at Al-Radwaniyah Station for Sheep Breeding ‚ Iraqi state Board for Agricultural Research .The objective of the study was to analyze the research data taken in 1999 and 2000 on the sheep hard belonging to that station and consisting of the following breeding groups : Local Awassi ‚ Assaf ‚ 50% Assaf × 50% Local Awassi (AL)‚ 25% Hamadani× 25% D’man × 25% Turkish Awassi × 25% Local Awassi (HDTL) and 25% Hamadani × 25% D’man × 25% Assaf ×25% Local Awassi (HDAL) .The data included 2025‚ 1623 ‚ 1354 ‚ 1136 and 901 records on animal weights at birth weaning ‚ 6 months ‚ 9 months and 12 months of age ‚ respectively . The study aimed to determine the effect of genetic and non-genetic factors on the weights of lambs at different age stages .The results show that the genotype had a significant effect (p<0.01) on all traits involved in the study. Also‚ the non genetic factors including lamb sex ‚ type of birth ‚ Age of dam and lambing year ‚ had the same significant effect (P<0.01) on all studied traits excluding the effect of birth type on the weight at age of 12 months and effect of lambing year on weaning weight ‚ Some of the genetic parameters such as the heritability were estimated as well. This heritability of each trait was estimated by using the Paternal Half-Sibs method. It’s values of weight reached 0.23 ‚ 0.31 ‚ 0.30 ‚ 0.38 and 0.41 at birth ‚ weaning ‚ 6 months ‚ 9 months and 12 months of age ‚ respectively . The genotypic and phenotypic correlation among traits studies were positive and ranged from moderate to high and significant (P<0.01).

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