Tanzania Journal of Agricultural Sciences 2002, Vol.5(1) : 71-76The effects of dietary supplementation with dicalcium phosphate containing 10 g calcium and 8 g phosphorus on plasma total calcium inorganic phosphate, body condition score and milk yield were studied for 42 days, during the dry season of 1997 in forty grazing, lactating Zebu cows, in lringa region, Tanzania. The animals were allocated to two groups: one control group (T1) comprising off fifteen cows and a supplementation groUp (T2) comprising of twenty five cows. Dicalcium phosphate supplementation was done twice per week. Blood samples were collected before supplementation and at the engd of experimental period. Total milk yield and body condition of the animals were also recorded. Supplemented cows had higher (P< 0.001) mean plasma calcium and inorganic phosphate (1.30 mmol/Ca and 2. 08 mmol P/l) than the control cows (1.08 mmol/Ca and 1.58 mmol P/l). Supplemented cows, had a better (P<0. 0001) body condition score and produced more milk (3. 10 BCS and 181 kg) than control cows (2.63 BCS and 149 kg) and total 42 days milk yield (149 vs 181 kg). It is concluded that low plasma calcium and inorganic phosphate may be a problem to Zebu cows and that decalcium phosphate can provide a boost to plasma Ca and Pi ,during the dry season