République Tunisienne  
Ministère de l'Agriculture, des Ressources Hydrauliques et de la Pêche

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Estimation of genetic parameters and adjustment factors for growth characters of barbarine high lambs in low input production systems>  Description

 
Date de publication 2018
Télécharger Estimation of genetic parameters and adjustment factors for growth characters of barbarine high lambs in low input production systems
Auteur  I. Ben Abdallah, A. Hamrouni, M. Djemali
Mots clés

sheep, Barbarine, growth, adjustment, heritability

Résumé

The Barbarine breed with big tail still requires interest although it has been the subject of several studies given its size and distribution in different geographical areas and production systems.
The objectives of this study were to: 1) Identify the main sources of variation in the different traits of breed growth, 2) Estimate the adjustment coefficients for dominant non-genetic effects, and 3) Estimate the genetic parameters of the trait traits growth in the breed. Records of a total of 191 371 lambs collected over 10 years (from 2004 to 2014) were used in this study. A linear model including the livestock sector (state or private), farm-herd-year of birth-lambing season, maternal age, and sex-mode of birth was used to identify the main sources of variation in the growth of Barbarine. Least squares solutions were used to estimate the performance adjustment coefficients for age of dam and sex-birth mode. The REML method was used for estimating heritability.
The main results showed that the average performance was 4,2 ± 0,42 kg; 5,37 ± 1,32 kg; 8,29 ± 2,11 kg ; 14,04 ± 3,46 kg; 16,21 ± 3,83 kg; 127 ± 56 g/day; 187 ± 49 g/day; 165 ± 61 g/day; 134 ± 45 g/day and 135 ± 42 g/day for BW, W10, W30, W70, W90, ADG030, ADG1030, ADG3070 and ADG3090, respectively.
The coefficients of determination R² varies between 36% and 48%. Sector, age of dam, sex-mode of birth, and farm-herd-year-in-season combination were found to be the major factors that significantly affect lamb growth from birth to weaning at 90 days.
The phenotypic correlations between different weights were positive and ranging from 0.122 to 0.99 between ADG030-ADG3090 and W30-ADG030, respectively. The estimated heritabilities ranged for the first group from 0.09 ± 0.31 to 0.409 ± 0.64 for the weights BW, W30, W70 and W90 and from 0.14 ± 0.37 to 0.468 ± 0.68 while the second group was 0.109 ± 0.33 to 0.251 ± 0.5 and 0.124 ± 0.35 to 0.444
± 0.66.

Lu 2611 fois Dernière modification le mardi, 19 juin 2018 13:16