Two trials were conducted to determine the effect of coagulation suppression of milk and milk replacers on apparent digestibility coefficients and body mass-gain of calves. In Experiment 1, two groups of five Holstein bull calves, two to four days of age, were given a milk replacer in which casein coagulation either was normal (CM), or was prevented by the precipitation of Ca++ with an oxalic acid – sodium hydroxide buffer (NCM). Apparent digestibility of dry matter, organic matter, crude protein and fat was 87 and 91 %, 88 and 92%, 75 and 84% and 83 and 87% for the NCM and CM treatments, respectively. Treatment means did not differ statistically, although there was a tendency towards lower crude protein digestibility for the NCM treatment. Owing to Ca++ precipitation in the one treatment, apparent ash and calcium digestibility (availability) coefficients were significantly lower for the NCM treatment than for the CM treatment, viz. 65 vs. 83% and 29 vs. 78%, respectively. In Experiment 2 (growth trial), four groups of seven Friesian bull calves, two to four days of age, were used. Whole milk (WM) and a commercial coagulable milk replacer (CM), were used either directly, or after treatment with oxalic acid (NWM and NCM). Body mass-gain (kg) and efficiency of feed conversion (kg dry matter intake/kg gain) over the 28-day experimental period were respectively 7,3 and 1,8 (WM); 7,3 and 1,8 (NWM); 4,3 and 3,9 (CM) and 4,9 and 2,9 (NCM). Both whole milk treatments were superior to milk replacer treatments, but prevention of coagulation per se had no significant effect on calf performance and on the occurrence of diarrhoea.