Effect of some mineral-vitamin supplements on lactation performance and colostrum quality of high yielding Holstein cows during summer season

This study was conducted to evaluate the effects of some nutritional and injectable mineral-vitamin supplements on milk and milk components and colostrum quality in transition dairy cows during the summer season. One hundred high yielding، multiparous Holstein cows were randomly assigned to four groups (25 cows per treatment). The treatments were consisted of: (1) control، (2) injection of Se- vitamin E supplement، (3) minerals and vitamins supplement bolus، and (4) combinations of treatments 2 and 3. 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 increased (P<0. 05) milk yield of cows. The group supplemented with injectable vitamin E-Se with nutritional bolus had higher (P<0. 05) milk protein yield (kg/d). The treatments affected milk solids nonfat and the control group had lower content (P<0. 05) than those others. The nutritional bolus decreased (P<0. 05) and injectable Se- vitamin E increased (P<0. 05) milk somatic cell score (SCS) compared with control group. The treatments just affected the colostrum fat content. It is concluded that the nutritive bolus with or without injectable supplement had positive effects on milk and milk components and colostrum composition.