YAKUBU A.
Abstract
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 signifi cantly
correlated with heart girth (HG), fore right teat length (FRTL), fore left teat length (FLTL), rear right teat length (RRTL),
rear left teat length (RLTL) and udder circumference (UC) (r = 0.538-0.766; P < 0.01). However, the phenotypic
correlation between milk yield and udder height (UH) was negative (r = -0.420; P < 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 statistically signifi cant direct effects on milk yield
(path coeffi cients = 0.446 and -0.254; P < 0.01 for UC and UH and 0.100; P < 0.05 for HG, respectively). The effects of
the other body parameters 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 coeffi cient
of determination (R2) of 0.665 and determination coeffi cient of error of 0.335. This model could be useful in predicting
milk yield of Bunaji cows on-farm and for selection purposes.
Key words:
milk yield; biometric traits; white fulani cows; path analysis