Ounces of Prevention

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The disease you are suspicious of—Bovine Viral Diarrhea—is caused by a virus that invades the dam by entering the respiratory or gastrointestinal tract. The placenta is then invaded and exhibits a mild to severe inflammatory response which then infects the fetus. Most BVD abortions occur in the first trimester, although infection of the dam in the second trimester may also lead to abortion, severe nervous system or ocular signs in the calf, or resorption of the fetus. Serology, or blood testing, may be helpful in diagnosing the disease; however, BVD virus is frequently present in fetuses that have been aborted because of infection with other organisms.

BVD virus is the cause of sporadic abortions, so before you attempt to rid your herd of the disease, I suggest narrowing down the many causes of the abortions by careful examination of herd history and consultation with your veterinarian.

I have had several calves die very early in life. We own a small farm (10 Holstein cows), and the neighbors also had thishappen a couple of years ago. They suspected a selenium deficiency. Is this likely?

-Barry Robinson
Park City, UT

It is indeed a likely possibility, as nutritional causes of neonatal death are extremely common depending on the area of the country you are located in. Nutritional deficiencies in dairy cattle are more commonly associated with infertility and neonatal calf mortality than with abortion.

Multiple deficiencies result in acute, severe starvation for the calf. Protein deficiencies result in prematurity, dystocia (difficult delivery), neonatal mortality, and weak calf syndrome. Vitamin A is responsible for maintenance of the lining of gastrointestinal and respiratory tracts, as well as skin, ocular, and bone growth. Deficiency of vitamin A in the herd usually results in late-term abortion or birth of weak, uncoordinated, or blind calves. Iodine deficiency can cause thyroid problems manifested as hairless, timid, weak calves. Likewise, phosphorus, magnesium, and copper deficiencies may also produce weak, nonviable calves.

Selenium is responsible for upkeep of a very important enzyme in the body known as glutathione peroxidase. This enzyme prevents the formation of peroxides, which damage cell membranes. If selenium is deficient in the soil where the animals forage, this enzyme cannot function correctly and skeletal and cardiac (heart) muscle cell membranes degenerate. This condition is known as white muscle disease. Vitamin E and vitamin C deficiency result in similar problems, especially in young, rapidly growing animals. Degeneration of the heart muscle is responsible for the death of most calves with this disease.

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