Comparison of body weight changes between sexes and among differences in litter composition during suckling period in kids of Tokara native goats

Data on body weight changes in kids of Tokara native goats were collected from 68 kids (13 male singles, 11 female singles, 10 sets of male twins, 4 sets of female twins and 8 sets of male-female twins) during the 10-week suckling period. Each kid or set of twins was housed with corresponding mother and kid(s)-mother pairs were housed separately each other. Kids were weighed from the birth of life to 10 weeks of age at two-week intervals. The body weight of male kids was significantly higher than that of female kids during the period. In male kids, the body weight of the male in male-female twins was the highest from the birth to the 6th week of age, but male singles showed the highest body weight after the 8th week and male twins tended to show the lowest body weight during the period. In female kids, the body weight of the female in male-female twins was the highest and that in female tu;ins were the lowest during the period. It was suggested that (1) male kids showed slightly higher growth rate than female kids and this was due to higher activity in the milk sucking, and (2) the male sib accelerated the growth rate of the female in male-female twins through stimulating the milk sucking.