ZINC SULFATE SUPPLEMENTATION TO RUMINANT RATIONS AND ITS EFFECTS ON DIGESTIBILITY IN LAMBS; GROWTH, RECTAL TEMPERATURE AND SOME BLOOD CONSTITUENTS IN BUFFALO CALVES UNDER HEAT STRESS

Document Type : Research article

Authors

Dept. of Animal Production, Fac. of Agriculture, Assiut Univ., Assiut, Egypt.

Abstract

Two different studies were carried out to test the effect of zinc sulfate addition to ruminant rations on digestibility, growth performance, rectal temperature and some blood constituents under stress of hot climatic conditions. Six Saidi rams were used at the first study to test the effect of zinc sulfate on digestibility. In the second study, which lasted for 180 days during hot climatic conditions, three groups of buffalo calves (3 males and 3 females) with 129 $ 3.77 kg average initial body weight were used to investigate the influence of dietary zinc sulfate supplementation on performance, rectal temperature, and metabolic status of buffalo calves. The experimental animals were fed a basal diet (control) or supplemented with 50 mg (T1) or 100 mg per kg diet (T2) ZnSO4.7H20. Animals were housed indoor during hot summer conditions. The results indicated that the nutrient digestibilities and feeding values were improved due to addition of zinc sulfate. The digestibilities of OM, CP and NFE increased (P<0.01) in treated lambs while CF increased (P<0.01) only in T2 group compared with those fed control ration. Zinc supplementation during the 6-month growth trial increased ADG in Ti (P<0.01) and T2 (P<0.05) than the control calves. Meanwhile, mean rectal temperature decreased in both Ti (p < 0.01) and T2 (P<0.05) calves compared to the controls indicating that the highest daily gain coinciding with the lowest rectal temperature. Dietary zinc sulfate resulted in an increase (P<0.01) in zinc concentration in blood serum, Vit.A, beta-carotene, total protein and total globulin while serum
 
glucose and SAST elevated significantly (P<0.05). Numerical increase in serum albumin, total cholesterol, triglycerides and SALT was noticed while concentrations of BUN and calcium decreased significantly (P<0.01). Inorganic phosphorus was not affected by zinc supplementation. Dietary zinc sulfate may improve growth performance, nutrient digestibilities, feeding values and selected blood serum metabolities in tested animals. In addition, fed zinc may regulate thermal mechanism of animals to adapt under heat stress, by reducing their rectal temperature, especially in upper Egypt conditions.

Keywords

Main Subjects