Effects of different sources of selenium on some hematological parameters and antioxidant response in Holstein dairy cows

Selenium has a special place in the natural antioxidants and prevents the oxidation of cell structures.
This experiment was conducted in order to investigate the effects of different sources of selenium on blood parameters and antioxidant response in Holstein dairy cows fed fat rich diets.
Twelve Holstein cows with average milk production of 40±4kg were used in merged incomplete Latin squares design with 4 treatments and 3 repeats in each treatment. The experiment was designed and conducted in 3 periods of 28 days and 4 treatments including; group 1 (basal diet containing 20% cottonseed meal, without selenium supplement), group 2 (basal diet 0.3 ppm inorganic selenium, as sodium selenite), group 3 (basal diet.3 ppm organic selenium, as selenised yeast) and group 4 (basal diet.3 ppm selenium, as nano selenium). At the first and last days of each period, blood samples were collected and milk production was also recorded.
The results showed that however adding different selenium sources to the diets had no effect on dry mater intake; it increased milk and 4% FCM production. Selenium supplementation did not affect blood glucose concentration, urinary nitrogen, ceratenin, total protein, albumin and globulin concentrations of dairy cows. Selenium supplementaition, specialy organic and nano selenium, significantly decreased concentration of serum fat metabolites and activity of Alkaline phosphatase and Aspartate Amino Transferase activity (p Overall results of the present study showed that supplementation of 0.3 ppm selenium to the diet containing high level of unsaturated fat decreased concentration of serum harmful fats and increased antioxidant capacity of serum which is reflected in improved milk production of the cows.