Estimation of Genetic Growth Parameters of Lambs of Ouled Djellal Algerian Sheep Breed

Background: The sheep population in Algeria is composed of several breeds including the Ouled Djellal breed, numerically the most important in the national herd. The Ouled Djellal sheep breed suffers from a lack of genetic studies carried out on it. This is why its genetic capacities remain unknown. In this regard, the success of any selection program is based on knowledge of the estimation of genetic parameters and especially the parameters of growth. Methods: The genetic parameters of growth of lambs of the Algerian breed Ouled Djellal were estimated for five variables: birth weight (BW), weight at 10 days (W10), weight at 30 days (W30), weight at 70 days (W70) and weaning weight (W90). The data base used in this study consists of 817 records of birth weight (BW), 817 records of weight at 10 days (W10), 805 records of weight at 1 month (W30), 803 records of weight at seventy days (W70) and 800 records of weight at ninety days (W90). The year, ewe age, month of birth (September, October, November), sex (male or female) and birth type (single or double) were tested as factors with fixed effects. The direct genetic effects and the permanent environmental effects of the ewe were considered as random factors. Result: The use of the direct genetic effect model in this study gives heritability coefficients (h2a) of 0.17 (BW), 0.07 (W10), 0.07 (W30), 0.20 (W70) and 0.10 (W90). Thus, the values of the maternal heritability coefficient (h2m) vary around 0.20 (BW), 0.11 (W10), 0.04 (W30), 0.04 (W70) and 0.07 (W90).The heritability coefficients obtained were low overall, due to the influence of the environment and the non-normal mode expression of these variables.