Evaluations of milk yield, udder and teat morphometric traits of lactating goats reared in pastoral lowlands of the Bale zone, Ethiopia

Abstract

Udder and teat morphometrics provide a simple, low-cost tool to predict milk yield, showing positive correlations with yield and body condition, and serving as key selection criteria for improvement programs. Thus, the study was conducted to evaluate milk yield performances and udder and teat morphometric traits of lactating goats reared in the lowlands of the Bale Zone, Ethiopia. For this study, 270 clinically healthy lactating goats were selected from three districts highly inhabited by goats. Data on the daily milk yield (DMY), udder height (UH), udder width (UW), udder circumference (UC), udder depth (UD), teat depth (TD), teat length (TL), distance between the teats (DBT), teat circumference (TC), udder distance from ground (UDG), and udder volume (UV) of lactating does were measured early in the morning and evening before kids sucking among lactation stages, dam parity, birth type, and sex of kids. Data were analyzed using ANOVA, correlation, regression, and multivariate analysis. Results indicated that DMY, udder, and teat morphometric traits were significantly (p < 0.05) affected among the studied districts except UV. The lactation stage effect was significant (p < 0.0001) on DMY and UC; however, the effect was non-significant for UD, UDG, and TD. The doe parity effect was highly significant (p < 0.0001) on TD and DMY, while it was non-significant (p > 0.05) on UW, UD, UC, UDG, and UV. High milk yield in does enhanced the performance of second-parity, single-born, and male kids. UC, UV, and UW showed significant variations (p < 0.0001) and exhibited moderate to high correlations with DMY, indicating strong positive associations for predicting milk yield performance. Therefore, presence of wide variation among all measured udder and teat morphometric traits and DMY among studied goat populations were potentials for selections to initiate community based breeding programs in lowlands of the Bale zone, Ethiopia.