High Oil Corn as Silage or Grain for Dairy Cows During an Entire Lactation

Forty-five multiparous Holstein cows were used to compare the effects of diets that contained high oil corn grain, high oil corn silage, or a combination of both. At wk 4 after calving, cows were assigned to one of four treatments in a 2 (silage type) × 2 (grain type) factorial arrangement: 1) control silage and control grain, 2) high oil silage and control grain, 3) control silage and high oil grain, or 4) high oil silage and high oil grain. Diets contained haylage, corn silage, and concentrate (25:25:50, DM basis); corn grain was 27% of dietary DM. Data were analyzed for wk 4 to 17 and wk 4 to 43 of lactation and adjusted for covariate measurements made during wk 3. During wk 4 to 43, DMI increased when high oil grain was included in the diet, but was unaffected by type of silage. During wk 4 to 43 of lactation, yields of milk, CP, and fat; percentages and yields of N components in milk; body condition score; BW, and concentrations of NEFA, glucose, BHBA, and urea N in plasma were not affected by type of silage or corn grain fed. Results were similar for wk 4 to 17, except that milk yield tended to be higher for cows fed the high oil grain, and CP content of milk was lower when high oil corn silage was in the diet. Compared with corn grain from typical hybrids, high oil grain may improve DMI and milk yield of dairy cows during early lactation.