Path analysis of conformation traits and milk yield of Bunaji cows in smallholder's herds in Nigeria
2011
Yakubu, A., Nasarawa State Univ., Keffi (Nigeria). Dept. of Animal Science
The aim of the present study was to determine the relationships between milk yield and conformation traits of Bunaji (White Fulani) cows using path analysis. The sampled populations were 267 cows in their 1st-3rd lactation order, extensively managed in northern Nigeria in the early to late dry season period. Milk yield positively and significantly correlated with heart girth (HG), fore right teat length, fore left teat length, rear right teat length, rear left teat length and udder circumference (UC) (r = 0.538-0.766; P less than 0.01). However, the phenotypic correlation between milk yield and udder height (UH) was negative (r = -0.420; P less than 0.01). This trend was reversed when the direct and indirect effects of these morphological traits on milk yield were considered. The path analysis showed that udder circumference, udder height and heart girth had significant direct effects on milk yield (path coefficients = 0.446 and -0.254; P less than 0.01 for UC and UH and 0.100; P less than 0.05 for HG, respectively). The effects of the other body traits on milk yield were indirectly realised via udder circumference as revealed by t-statistic. The optimum linear multiple regression model included udder circumference, udder height and heart girth with a coefficient of determination of 0.665 and determination coefficient of error of 0.335. This model could be useful in predicting milk yield of Bunaji cows on-farm and for selection purposes.
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