Selenium and vitamin E and incidence of retained placenta in parturient dairy cows.

In a 2 X 2 X 2 factorial experiment, protein intake, selenium supplementation, and intake of phosphorus were related to the incidence of retained placenta in cows fed varying concentrations of these nutrients during the dry period. The population incidence of 38% retained placenta in 26 control cows was independent of phosphorus intake which ranged between 39 and 95 g per day. When a protein supplement was included in the concentrate as soybean meal, the incidence of retained placenta was reduced to 20% for supplemented animals from 50% for the animals that received no soybean meal. This increased protein in the ration was reflective of a mean increase from .02 ppm of selenium to .06 ppm of selenium in the ration. By increasing the mean daily intake of selenium at least 3 wk prepartum from .23 mg to .92 mg daily, overall incidence of retained placenta was reduced from 38% to 0%. A positive prophylactic effect was achieved regardless of whether alpha tocopherol was supplemented as well. These mature dairy cows were deficient in selenium, and supplementation of selenium reduced the incidence of retained placenta.