Although milk substitutes attract a large subsidy from the EEC provided they contain at least 600 g skim milk solids/kg, several cheaper whey-based products have been Introduced commercially in recent years. Nevertheless, information on the nutritive value of such products is lacking. Since the calf is vulnerable to digestive upsets especially during the first month of life, an experiment was made to assess the effect on health and performance of replacing some or all of the skim milk solids with a mixture of whey powder and whey protein concentrate.

Experimental Thirty-two Friesian bull calves in a randomised block experiment were given one of four milk substitute diets containing 200 g fat and 260 g crude protein/kg DM from 2 to 64 days of age. The reconstituted diets (1 powder:6 water, w/w) were offered to appetite twice daily by bucket at 38°C. The quantities of skim milk solids in each formulation were (g/kg DM): none (diet WP1), 200 (diet WP2). 400 (diet WP3) and 600 (diet WP4), as shown in Table 1. In vitro tests showed that coagulation with rennin did not occur with diets WP1 and WP2 and the clot formed with diet WP3 was much softer than that with diet WP4.