The objective of this study was to investigate parenteral
vitamin E for the prevention of peripartum disease
in dairy cows. A randomized clinical trial was
conducted in 21 commercial dairy herds. Cows (n =
1142) were randomly assigned to receive either a single
subcutaneous injection of 3000 IU of vitamin E,
or placebo, 1 wk before expected calving. Serum α-
tocopherol was significantly increased in treated cows
at 7 and 14 d, but not at 21 d after injection. Overall,
there were no significant differences between treatment
groups in the incidence of retained placenta, clinical
mastitis, metritis, endometritis, ketosis, displaced
abomasum, or lameness. However, there was a conditional
benefit of treatment for reduction of the incidence
of retained placenta. Cows with marginal pretreatment
vitamin E status (serum α-tocopherol to
cholesterol mass ratio < 2.5 × 10-3) that received an
injection of vitamin E tended to have reduced risk of
retained placenta. However, in cows with adequate
serum vitamin E, there was no reduction in the incidence
of any disease. For clinical application, primiparous
animals were most likely to benefit from prepartum
injection of vitamin E.