Effects of Dry or Ensiled Feeds and Protein Percent on Milk Production and Nitrogen Utilization by Lactating Cow

In two 2 x 2 factorial experiments, 28 cows in first and later lactation (TriaI 1) and 28 cows in second and later lactation (Trial 2) were fed rations containing either dry (low nitrogen solubility) or ensiled (high nitrogen solubility) feeds with low (14%) or high (16%) concentrations of crude protein. Rations were formulated with hay or hay crop silage and dry shelled corn or high moisture shelled corn in a 50:50 ratio (Trial 1) or 40:60 ratio (Trial 2) of forage to concentrate in the dry matter. Soybean meal was used to alter the protein content.