Abstract
This study was conducted in the animal farm college of agriculture and forestry/ Mosul university by using three multiparous Friesian dairy cows in the 95 ± 12 of DIM, average body weight 399.67 kg, using latin square design (3 × 3) with three period each was lasted 21 days. The cows was placed in individual pen and fed with three rations; first one was control consist of barley, wheat bran, soybean meal and contained 10% rumen degradable protein as dry matter base (T1), second ration was similar to the control with addition 35 g / cow per day of yeast (Saccharomyces Cerevisiae) T2, while in the third, rumen degradable protein was increased to 12% of dry matter by urea with addition 35 g / cow per day (T3). Cows were fed with 7.5 kg of concentrate and 2.25 kg wheat straw ,with grazing for 5 – 6 hr daily. Results showed no significant increase in milk yield in T2 and T3 11.109 and 11.029 kg/ day, fat corrected milk 4% 9.365 and 9.795 kg/ day as compared with T1 9.826 and 8.402 kg/ day respectively. Also it was noted no significant differences in milk fat 3.05, 2.96, 3.20%, protein 2.85, 2.78, 2.81%, lactose 4.25, 4.15, 4.20% and energy 605, 589, 616 kcal/ kg. It was noted that the differences was not significant in blood parameters.
