STUDIES ON MILK PRODUCTION AND GROWTH OF FRIESIAN × BUNAJI CROSSES: II. GROWTH TO YEARLING AGE

The data analysed consisted of body weight records at birth, and at 3, 6, 9 and 12 months of age of 549 half Friesian $\times$ Bunaji crossbred heifers collected over a twenty-five year period (1965-1989). Least squares $means{\pm}s.e$. of body weights at birth, 3, 6, 9 and 12 months of age were $26.7{\pm}1.3$, $72.4{\pm}4.5$, $112.9{\pm}6.9$, $147.2{\pm}9.2$ and $182.1{\pm}11.1kg$, respectively. Year of birth was highly significant (p < 0.01) in affecting body weights at all ages, while the effect of month of birth was not. Seasonal influence on birth weight and body weights at 3 and 6 months of age was significant (p < 0.05). Phenotypic correlations between body weights at all ages were positive and highly significant (p < 0.01), ranging from 0.30 to 0.79. The results of this study showed that the beneficial effect of crossbreeding Friesian with Bunaji cattle was reflected in the growth performance of the $F_1$ crosses, since they grew faster than the indigenous Bunaji from brith to yearling age. The study also indicated that heifer selection for yearling body weight can be done early on the basis of weights at 3 and 6 months of age.