تأثیر جایگزینی جو با تفاله خشک مرکبات در جیره گاوهای شیری هلشتاین بر عملکرد آنها

Abstract

In order to determine the effects of substitution of barley grain with dried citrus pulp (DCP) on eight lactating Holstein cows with average body weight of 550 ± 50 kg and 75 ± 15 days in milk were allocated to 4 dietary treatments, which were diet; the control with 0% dried citrus pulp (DCP) and 15% barley grain, diet 2, 3 and 4 containing 5, 10 and 15% DCP and 10, 5 and 0% barley grain respectively. Each period lasted for 21 days including 14 days adaptation and 7 days sample collection. Dry matter intake (DMI) body was not affected by DCP substitution, although, the DMI tended to decrease with increasing level of DCP. Results showed that increasing levels of DCP in diets had no significant effect on apparent digestibility, blood urea N and glucose, milk yield and composition and ruminal N-NH3, but ruminal pH was significantly lower for cows fed T1 and T2 compare to T3 and T4. The ruminal N-NH3 of diets 1, 2, 3 and 4 were 20.08, 19.96, 19.53 and 19.01 mg/dl and the ruminal pH 6.45, 6.52, 6.69 and 6.71 respectively. The time spent eating; ruminating and total chewing activities were not influenced different treatments. It was concluded that DCP can be substituted by barley grain up to 15% without any alters affects on dairy cow production performances