PRODUCTIVE PEFORMANCE, NUTRIENTS DIGESTIBILITY AND SOME SERUM METABOLIC INDICES AS AFFECTED BY DIEATARY SUPPLEMENTATION OF COPPER AND ZINC IN EGYPTIAN BUFFALO CALVES

This study was designed to evaluate the effects of dietary supplementation of copper (Cu) and zinc (Zn) on productive performance, nutrients digestibility and some serum metabolic indices in Egyptian buffalo calves. A total number of 32 calves averaged 278.8 ± 5.40 kg and 18 months old were divided into four equal groups (8 calves / each). Animals were fed on basal diet containing 4.38 mg Cu and 6.30 mg Zn/kg DM (control) supplemented with 10 mg Cu (T1), 30 mg Zn (T2) and 10  mg Cu plus 30 mg Zn (T3) /kg DM for 120 days. Digestibility of DM, NDF and ADF was higher (P<0.05) for calves fed T2 and T3 vs. T1 or control. The OM digestibility increased (P<0.05) for calves fed T1, T2 and T3 vs. control. Calves fed on T1, T2 and T3 had higher (P<0.05) digestibility of CP and CF than those fed control. Digestibility of CP and CF increased (P<0.05) with feeding T3 ration vs. each of T1 or T2 alone. The digestibility of EE increased (P<0.05) for calves fed T3 vs. those fed T1 or control rations. The digestible crude protein values were greater (P<0.05) with feeding T1, T2 and T3 than control. The total digestible nutrients values increased (P<0.05) for calved fed on T3 when compared to control or T1. Results showed significant (P<0.05) increasing in final body weight for calves fed T2 and T3 vs. control or T1. The averages daily gain (ADG) increased (P<0.05) for calves fed T1, T2 and T3 vs. control. Also, ADG improved (P<0.05) for calves fed T3 vs. those of T1 and T2. In the same time, no significant changes were noticed in feed intakes (rice straw,concentrate feed mixture and total dry matter) among treatments vs. control, while digestible crude protein intake increased (P<0.05) for calves fed T1, T2 and T3 vs. control. The total digestible nutrients intake increased (P<0.05) with T3 compared to control. Feed conversion was improved (P<0.05) for calves fed T2 and T3 vs. control. The T2 and T3 recorded higher (P<0.05) levels of serum total protein, albumin and globulin vs. control or T1. Serum globulin levels increased (P<0.05) in calves fed T1 vs. control. Feeding T1 decreased (P<0.05) serum cholesterol, but increased (P<0.05) HDL-cholesterol concentrations vs. control. The differences in serum glucose and triglycerides concentrations were not significant among calves in T1, T2 and T3 vs. control. The present study indicated that dietary supplemental Cu plus Zn showed beneficial additive effects to improve nutritive values, productive performance and blood metabolic indices in buffalo calves.