<div style="text-align:justify">The present investigation included the data of 29,879 birds pertaining to 8 generations, from 2010 to 2018 on growth line (PB1) of IBL-80 broiler. The mean estimates of growth and fertility traits were BWT0 (39.97&plusmn;0.05 gms), BWT5 (1189.17&plusmn;1.45 gms), BWT10 (1723.59&plusmn;6.26 gms), BWT15 (2165.71&plusmn;7.90 gms), BWT20 (2611.23&plusmn;4.10 gms), ADG5 (32.36&plusmn;0.07 gms/day), ADG10 (13.09&plusmn;0.14 gms/day), ADG15 (12.38&plusmn;0.13 gms/day), ADG20 (12.65&plusmn;0.13 gms/day), AFE (171.80&plusmn;0.21 days) and ENO40 (62.47&plusmn;0.25) which indicated higher growth performance of PB1 affected its fertility performance. ADG5 had highest estimate indicating higher growth during chick stage. Least squares analysis indicated that effect of gender, month of hatch and generation were significant (p&lt;0.01) for all growth and fertility traits. AIREML heritability estimates indicated appreciable additive variance in BWT0 (0.50), BWT5 (0.54) and ADG5 (0.20). Other growth and fertility traits had lower heritability which was due to stage wise selection in breeder flock. Phenotypic and genetic correlation estimate indicated negative association between growth and fertility traits.</div>

<div style="text-align: justify;">AIREML estimation of genetic parameters and study of factors affecting growth and fertility performance of sire line of IBL-80 broiler chicken</div>

<p><strong>Background:</strong> For this study, information was gathered on 6785 Chokla sheep at the Central Sheep and Wool Research Institute in Bikaner, Rajasthan, India and documented between 1974 and 2020.&nbsp;<br />
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<strong>Methods:</strong> (Co)variance components and genetic parameters of weight at birth (BW), weaning (WW), 6, 9 and 12 months of age (6W,9W and YW, respectively) of Chokla sheep, were estimated by average algorithm restricted maximum likelihood (AIREML), fitting six different animal models with various combinations of direct and maternal effects.<br />
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<p><strong>Result:</strong> The direct heritability estimates increased from birth to twelve months of age and values for all the body weight traits except birth weight (0.170) were moderate (0.30-0.50). The maternal influence diminished as age increases and maternal genetic effect (m<sup>2</sup>) was found to be important and sizeable at weaning stage (0.181). Maternal permanent environmental variance was found to influence the early body weight traits. Negative and high estimate of covariance between direct and maternal effects, resulted in highly inflated values of additive heritability. In this condition, it is more useful to use the total heritability (h<sup>2</sup>t) for evaluation of the response for selection based on phenotypic values to prevent the use of biased estimates of additive heritability. Genetic and phenotypic correlations among body weights at different ages were positive and ranged from medium to high.</p>


AIREML estimation of genetic parameters and study of factors affecting growth and fertility performance of sire line of IBL-80 broiler chicken

Estimates of Maternal Effect and (co)Variance Components for BodyWeight at Different Ages by Animal Model in Chokla Sheep