This study was carried out to study the effect of zinc or zinc plus vitamin A supplementation on nutrients digestibility of adult rams (61 kg in average) and on milk production of seven lactating Friesian crossbred cows (447 kg in average) using “Swing Over" method to evaluate the following experimental rations: Control ration (C)   : Concentrate feed mixture (C.F.M.) + Rice straw (R. S.). 1^st tested ration (T₁) : C.F.M. + 50 mg Zn/kg DM (as zinc sulphate) + R. S. 2^nd tested ration (T₂): C.F.M. + 50 mg Zn/kg DM + 10000 IU vitamin A/100 kg body                                    weight + R.S.                 The main results showed that the DM and OM digestibility of sheep fed ration (T₂) were significantly (P<0.05) higher than rations (T₁) and control (C). Also, the previous items of T₁ ration were significantly (P<0.05) higher than ration C. The total digestible nutrients (TDN) and starch equivalent  (SE) of the three tested rations were responded simillary as that of DM and OM digestibility.                 The differences in daily DM intake of cows fed C, T₁ and T₂ rations were not significant. The daily milk yield as fat corrected milk (FCM) was higher by 10.08 and 15.57% in cows fed T₁ and T₂ than the control ration. Also, fat yield was higher by 11.23 and 16.05 % in cows fed T₁ and T₂ than C ration.                 Total solid and lactose of milk of lactating cows fed ration T₁ and T₂ were significantly (P<0.05) higher than control ration. Additionally, feed efficiencies (as kg TDN and SE/kg FCM) were better (P<0.05) of cows fed ration T₂ than others.                 The economical efficiencies and return/kg FCM were the best for cows fed the rations supplemented zinc with or without vitamin A.