干旱区生态环境知识资源中心

Data issued from a weighing protocol of 722 kids during four years was analysed to establish the impacts of non-genetic factors upon kids’ weights at some standard ages. A Gompertz model was applied to estimate kids’ weights at some standard ages 1, 10, 30, 60, 90, 120, 150 and 180 days. A GLM procedure and a means comparison test (SNK, = 0.05) were applied to identify the statistical effects of some factors and their homogenous classes at several ages. The determination coefficient R-2 remains lower than 87% of all studied traits due to the observed data structure. All traits seem to be affected (P<0.001 or 0.05) by the factors related to the restrictions and the irregularities of the technical and natural environment of pastoral husbandry. The non-genetic factors impact increases with kids’ age and requirements. Growth traits varied depending to the natural and technical factors which illustrates the local population genetic response towards environmental resources in arid zone. The year and zone factors play an important role upon the kid’s weight and it evolution till 6 months age due to the large inter-annual variation of rainfall. Also the technical level of the herder seems affecting highly the kids’ performances. Therefore, arid environment affects both quantitatively and qualitatively individual kid’s growing behaviour and have to be considered for local goat rational genetic improvement modelling and planning.