Effect of some trace mineral-vitamin supplements on thyroid hormones and blood metabolites of high production Holstein cows during summer season
This study was conducted to evaluate the effects of some nutritional and injectable mineral-vitamin supplements on thyroid hormones (T3 and T4) and blood metabolites in transition dairy cows. One hundred multiparous Holstein cows were randomly assigned to four groups. The treatments were consisted of: (1) control, (2) injection of Se- vitamin E supplement, (3) Feed minerals- vitamins bolus supplement, and (4) injection and feed mineral-vitamin supplements. The injectable supplement was contained vitamin E and Se and the dietary bolus was contained Cu, Co, Se, Mn, I, Zn, and vitamins A, E and D3. The data showed nutritional bolus or injectable supplement had no effect on concentration T3 and T4 hormans. Nutritional bolus increased (P<0.05) total blood protein at parturition time. The group supplemented with injectable vitamin E-Se along nutritional bolus had higher triglyceride in the first month of lactation (P<0.05). The treatments had no effect on blood urea nitrogen. It was concluded that the nutritional bolus had positive effects on some of blood metabolic profile.
Keywords: Mineral- vitamin supplements, Dairy cow, Blood metabolites, Thyroid hormones