Abstract
The present experiment was designed to study the effects of vitamin mixtures and exogenous enzymes ZADO (R) in alleviaties heat stress in ewes in summer temperatures (25-44 degrees C) compared with winter temperatures (8-22 degrees C). Fifty lactating Ossimi ewes were divided randomly into 5 treatment groups. In summer, the experiment included four treatments: (i) control i.e., normal summer conditions, no supplements (control 2), (ii) ewes supplemented with 10 g/head/day of ZADO (R) mixed in the concentrate, (iii) ewes supplemented with vitamin AD(3)E (250 mg/kg BW) and C (45 mg/kg BW) mixture, and (iv) ewes supplemented with ZADO (R) and vitamin mixture as above. In winter, the treatment comprised of assessments only under normal winter condition (8 to 22 degrees C) without any additives (control 1). Blood and milk samples from each ewe were collected biweekly throughout lactation. Results indicate that plasma total protein, total lipids and glucose, and milk production and composition were decreased (P<0.01) in summer compared with winter. Addition of ZADO (R) increased plasma total protein, glucose, milk production, protein and lactose as compared with summer control (control 2). Vitamin mixture increased (P<0.01) plasma total protein, milk production and milk protein, but had no effect on total lipids, glucose, milk fat and lactose. Combination of vitamin mixture with ZADO (R) addition increased the ability of lactating ewes to alleviate heat stress as evident by increased plasma parameters and milk production during the summer season.