Document Type : Research Paper
M. Sc. Student in Ruminant Nutrition, College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran
Professor, College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran
Associate Professor, College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran
Sodour Ahrar Shargh Co., Tehran, Iran
The aim of this study was to investigate the effect of mineral supplementation and chelates of trace elements on production, milk composition and blood parameters of lactating Holstein cows. Lactating Holstein cows (n=24) were randomly assigned to one of the following four treatments; 1) the basic diet include inorganic trace minerals (C), 2) 55 mg of iron, 125 mg of copper, 360 mg of zinc, 3.5 mg of chromium, 200 mg of manganese, 2 mg of selenium and 12 mg of cobalt with daily feeding of 7 g of Bonzaplex7 chelated mineral supplement (B), 3) the same amount of zinc, manganese, copper and cobalt was supplied with 7 gr of organic trace mineral supplement Availa4 (A), 4) feeding 7 gr of Availa 4 plus 3.5 gr of Availa-Cr, 2 gr of Availa-Se, 1gr of Availa-Fe (A+3). This study lasted 35 days. Daily feed intake and milk production (3X) were recorded. In spite of more numerical increase in milk yield in treatment B, no effect was observed on the production of milk, milk composition, dry matter intake and rumen metabolites. Plasma glucose concentration in treatments tended to decrease (P=0.07). Plasma triglyceride concentration decreased significantly in treatments (A), (B), (A+3) compared to group (C), present results could be related to increase bioavailability of trace minerals in chelated form specially chromium and copper in present study.