Mean values and the range of values for alkaline phosphatase activity in serum (expressed in units) were: - calves 909 (413-1445), bulls 325 (179-543) and cattle 131 (72 to 162). Differences between these groups were statistically significant. Values for bile were: - calves 416 (116-882), cattle 546 (145-1203), bulls 738 (108-1438) enzyme units; here there were no significant differences. Activity of the enzyme in urine was very low, mean values being 0.77 in calves, 0.39 in cattle and 1.69 in bulls; the differences between groups were statistically significant.