In the 1980s and 1990s, administering supplemental injections of selenium and vitamin E to dairy calves shortly after birth was widely performed. Many beef cow-calf producers still employ the practice today.
Many dairies have discontinued selenium supplementation, crediting better dry-cow nutrition and colostrum quality with adequate selenium delivery to the calf. But a study by researchers at the University of Guelph involving 1,500 newborn dairy heifer calves from 14 Ontario herds classified one-third of newborn calves as selenium deficient.
The Ontario researchers also studied the effects of administering supplemental selenium and vitamin E injections to newborn calves. As soon as possible after birth, 835 calves were injected with either 1.0 mL of a combined selenium/vitamin E product, or a placebo control. Weekly blood samples, fecal samples, disease incidence and treatment records; and growth records were evaluated until weaning at about 7 weeks of age.
They found that calves that received the selenium/vitamin E supplementation had higher blood selenium levels in the first week of life. The untreated calves, on the other hand, were more likely to test positive for rotavirus and were 1.6 times more likely to be treated for diarrhea. However, selenium supplementation had no significant impact on Cryptosporidium parvum infections, and did not enhance the absorption of immunoglobulins, or improve rates of successful passive transfer of immunity.
The researchers concluded that the inexpensive practice of routinely administering selenium/vitamin E to newborn calves could be beneficial, especially for herds challenged by rotavirus; heifer calves raised in commercial rearing facilities; and bull calves entering veal operations.
A full report of the injection study can be read here.