Goat breeding structure and repeatability of litter size in smallholder goat herds in Kano, Nigeria

Abstract

One hundred and sixteen (116) does from 22 randomly selected smallholder herds in Kano and environs were surveyed to evaluate the goat breeding herd structure and to estimate the repeatability of litter size. The study revealed that the average herd size of smallholder goats in the study area is 15.5 goats. The average breeding male and female per herd buck to doe ratio and litter size per doe was 1.8, 6.5, 4.9 and 1.7 kids, respectively. These characteristics were highly variable (CV = 42 . 70%). The breeding does constituted the majority (78%) of the breeding herd, which increases with herd size. The average buck to doe ratio for the goat herd was 1:5. However, a buck to doe ratio of 1:10 was observed for herd size 21-30 goats, while for herd size . 10 and 11- 20 goats it was 1:3. The litter size of 1 and 2 was in the majority across the herd sizes. Litter size 4 was rare in the herds (0.3%). Herd size was significantly and positively correlated with the number of breeding males and females in the herd (P<0.01; r =0.40-0.80). The number of breeding males in the herd was significantly and positively correlated with breeding females (P<0.05; r = 0.25) but negatively correlated with mating ratio (P<0.01; r = -0.75). However, mating ratio was significantly and positively correlated with the number of breeding females (P<0.01; r=0.50). Litter size of the doe was not significantly correlated with the measured breeding herd characteristics (P>0.05; r= -0.05 to 0.04). The average repeatability in the herd was 0.41. However, repeatability of litter size decreases with increase in herd size; 0.71, 0.60 and 0.32 for . 10 goats, 11-20 goats and 21-30goats herd size, respectively. The high estimates for litter size obtained in this study suggests that Kano brown goat which is the predominant breed of goats reared in the study area is a highly prolific breed and the moderate repeatability estimate is an evidence that the prolificacy is probably influenced by a single major gene suggesting that an appreciable rate of genetic response in litter size could be achieved through selection.