Models to Describe Growth Curve of Egyptian Damascus Goat Kids

Abstract

This study was conducted to describe the growth curves of Damascus kids reared in Egypt, using some linear and nonlinear models to provide a specific shape of the growth curve for that breed. A total of 855 records belonging to 47 kids’ progeny of 30 Damascus does between parities 1 and 5 kept in the Experimental Station of Alexandria University, Egypt, were used in this study. Kids were weighed immediately after birth and weekly thereafter till weaning at four months of age. All weights, except birth`s, were recorded early in the morning after 12 h fasting period. The effects of parity and type of birth on birth and weaning weights and on averages daily weight gains were evaluated. Also, the associations between age and weight within parities and types of birth were described using linear, quadratic and four modified nonlinear growth functions. Parity had no significant effects on birth and weaning weights. However, kids born in fourth parity had the greatest daily gain, while the second and fifth parities born kids had the lowest. Type of birth affected all studied traits. Single born kid had the highest birth and weaning weight and the highest daily weight gain compared to twice or triple born kids. Single kids born from does in third parity had the highest weights at birth and weaning and had the highest daily weight gain. Quadratic model exhibited the best goodness of fit for all kids.