The aim of this study was to evaluate the effect on the productive performance, apparent digestibility
of DM, serum phosphorus and phosphorus balance in Holstein calves which received a high concentrate
diet with different doses of exogenous phytase for a period of 60d. The experiment was conducted with
a completely randomized design with three treatments of eight calves each, the treatment included dietary
supplementation of exogenous phytase at 0, 12 and 24 g/ton. Phytase inclusion increased (P<0.05) average
daily gain when phytase was supplemented at 24 (850g) as compared to 0 (816g) or 12 (809g) g/ton.
However, it had no effect (P>0.05) on DM intake, feed conversion and DM digestibility. Adding phytase
in the diet decreased phosphorus excretion in faeces (P<0.05) showing a significant linear increase with
increasing level of supplementation (the values being 9.96, 9.14 and 8.13 g/d) which, in turn, increased
the P retention (4.69, 5.37 and 6.45 g/d, resectively, for the three groups). In conclusion, supplementation
of phytase could improve the growth performance of calves without any discernible effects on feed intake
or digestibility of nutrients
