Najari Sghaier ⁽¹⁾, Atoui Ahlem*⁽¹⁾ and Abdennebi Moldi ⁽¹⁾

(1). Institute of Arid Regions, Médenine. 4119. Tunisia. Faculty of sciences (F.S.G) Gabés, University of Gabés, Tunisia.

(* Corresponding author: Dr. Atoui ahlem , E-mail : ahlematoui@gmail.com)

Received date: 8/03/2021                      Acceptance date: 11/04/2021

Abstract

The growth of kids represents an important production phenotype for the local goat population in pastoral areas. Thus, daily gain is a component of the selection criteria in genetic improvement plans for the local population. The study aims to estimate the genetic parameters for the average daily gains of the local kids by fitting four random regression models including or ignoring permanent maternal or environmental genetic effects. The genetic parameters and the (co) variance components were estimated from the data of 945 kids (531 males and 414 females), from 19 bucks and 285 goats collected between 1998 and 2014. The genetic parameters were estimated for five phenotypes: ADG (1-30), ADG (31- 60), ADG (61-90), ADG (91-120), ADG (121-150). Mother’s age, mother’s weight at kidding, the interaction sex × mode of birth, and year × month of birth were included, as fixed factors, in the mixed model. The direct and maternal heritability estimates of mean daily gains vary respectively from 0.10 to 0.39 and 0.09 to 0.24 The ADG (1-30), which estimates the growth of the goat during the first month of life, had the lowest estimates of maternal and direct heritability among other age groups. The maternal component of the estimated variance is larger than the direct variance at early ages, indicating the importance of the maternal capacity of this adapted local population. The results help to develop the genetic improvement plans adapted to the production and adaptation potential of the local goat, and to the characteristics of its arid environment.

Keywords : Local kids , Mixed models Environmental effects, Average daily gains, genetic evaluation.

Full paper in Arabic: pdf