Energy and Nitrogen Balance in Lactating Cows Fed Diets Containing Dry or High Moisture Corn in Either Rolled or Ground Form

The effects of harvesting and processing methods on the value of net energy for lactation of corn grain were investigated. Lactating Holstein cows were used in a replicated Latin square design with a 2 x 2 factorial arrangement of treatments. Treatments were different methods for the storage (dry or high moisture) and processing (rolled or ground) of corn grains. Alfalfa silage was the forage source in the diets. Indirect calorimetry was conducted using a 6-d nutrient balance protocol; respiration measurements were made at 24-h intervals. Dry matter intake did not differ among treatments and averaged 24.2 kg/d. Milk yield was 2.0 kg/d greater for cows fed diets containing high moisture corn than for cows fed diets containing dry corn and was 2.2 kg/d greater for cows fed diets containing ground corn than for cows fed diets containing rolled corn. Apparent digestibilities of nonfiber carbohydrates, crude protein, and dry matter were greater for cows fed diets containing high moisture corn than for cows fed diets containing dry corn. Metabolizable energy and heat production were greater for diets containing high moisture corn than for diets containing dry corn and were greater for diets containing ground corn than for diets containing rolled corn. Net energy for lactation was greater for diets containing high moisture corn than for diets containing dry corn (1.78 vs. 1.64 Mcal/kg of dry matter).