Howard G. Bateman II | 10/4/2004 4:25:46 AM
Vitamin E plays a vital role in the reproduction processes of dairy cattle. Vitamin E deficiency has been linked to embryonic death, testicular atrophy, and ovarian failure.
Normal reproduction is dependent upon proper circulating levels of estrogen and progesterone. These steroid hormones are synthesized from cholesterol by the ovaries through a series of biochemical conversions. Normal respiration produces reactive oxygen based molecules that can interfere with these conversions. The reactive molecules selectively block some pathways while enhancing others resulting in decreased production of estrogen and progesterone in favor of production of cortisol and aldersterone. This shift in production of hormones can interfere with normal reproductive processes.
This hormone shift can also produce another undesirable effect of increasing the potential for edema since elevated plasma aldersterone is associated with fluid retention in the body. Research data has shown that vitamin E supplementation reduces the number of days until first observed estrous and interacts with Se to reduce the number of days open. Although cow numbers were limited, researchers also have suggested that vitamin E and Se may reduce the number of days until first breeding and the number of services per conception. Indirect evidence in the scientific literature suggests that the attachments of the placenta to the uterine wall may have an increased requirement for vitamin E and Se as compared to other reproductive tissues. In situations where vitamin E is marginal, supplementation during the dry period may help these tissues to be ready for detachment after calving.
The area of lactating cow supplementation with vitamin E that has received the most research attention is mastitis. Vitamin E is known to stimulate the immune system of cows. Mastitis is the clinical response of the mammary gland to a bacterial challenge. Therefore, vitamin E may enhance the mammary response to a bacterial challenge. Research has shown that cows with clinical mastitis have lower concentrations of vitamin E in their plasma and milk when compared to healthy herd mates. Vitamin E supplementation will enhance the activity of nutrophils, which are one of the types of cells in somatic cells. Vitamin E supplementation enhances immunogolubin production. Addition of vitamin E to vaccines (such as the J5 vaccine for E. coli mastitis) may enhance the acquired immunity levels gained from that vaccination.Vitamin E for Dairy Cattle