Effect of feeding silages from corn hybrids selected for leafiness or grain to lactating dairy cattle.

Three corn hybrids were harvested as silage and fed to lactating dairy cows to determine performance and digestibility differences between hybrids. Corn hybrids were a grain type, a generic blend, and a leafy type. Starch content of the grain, blend, and leafy silage hybrids was 26.1, 23.8, and 23.5%, respectively. In vitro digestible dry matter of the leafy hybrid silage (69.2%) was higher than the grain (66.8%) or blend (66.7%) hybrid silage. Sixty-two Holstein cows (39 primiparous and 23 multiparous) were fed diets containing (dry matter basis) 40.6% of one of the corn silages, 10.2% alfalfa haylage, 23.5% corn grain, 7.4% whole-fuzzy cotton-seed, 13.8% protein concentrate, and 4.5% vitamin and mineral mix. Cows were assigned to their silage treatment diet 3 d after parturition and remained on the diet until wk 22 of lactation. Dry matter intake, milk yield, and milk components did not differ for cows fed the grain, leafy, or generic blend silage diets for either parity group. Digestibilities of dry matter, organic matter, and neutral detergent fiber, and rate of passage were not different across the silage diets for either parity. Multiparous cows receiving the blend silage diet lost more weight throughout the 22-wk study than did cows on the leafy or grain silage diets. Primiparous cows receiving the blend silage diet spent more time eating than cows on either the grain or leafy silage diet. Time spent chewing did not differ among hybrids. Corn hybrid at 40% of dietary dry matter as silage did not have a major impact on dairy cattle performance in this trial.