Milk Production in High Producing Dairy Cows as Influenced by Corn Silage Quality

Abstract

Greater milk production is the promised outcome for selecting corn hybrids with various traits that impact forage quality. Our objective was to select a set of hybrids most likely to exhibit differences in forage quality and evaluate milk production of cows fed a high forage diet. Four hybrids were selected for the feeding trial: a leafy hybrid (Mycogen TMF 100®; Mycogen Seeds, Indianapolis, IN), a brown midrib (BMR) hybrid (Mycogen BMR F407®), and two conventional hybrids varying in fiber digestibility (Pioneer 36B08® [Conventional 1 {CONV1}] and Pioneer 35P12® [Conventional 2 {CONV2}]; Pioneer Hybrid International, Inc., Des Moines, IA). Diets were formulated to provide 1.0% BW as forage NDF (approximately 32% NDF) and were balanced to meet or exceed NRC requirements. Fifty-six cows were fed for 56 d. The DMI of cows fed the BMR and the leafy hybrid total mixed rations (TMR) were greater than those of cows fed the other hybrids. Differences in milk production reflected the differences in intake. Cows fed the BMR (41.7 kg/d) and leafy hybrid (42.1 kg/d) TMR were not different from each other in milk production, but had greater (P<0.05) milk production than cows fed CONV1 (39.0 kg/d) or CONV2 (39.2 kg/d) hybrids. Greater intake by cows fed the BMR TMR than by cows fed the CONV1 or CONV2 TMR is likely the result of greater digestibility. Although the leafy hybrid TMR tended to be greater in digestibility than CONV1 or CONV2 TMR, it is likely that a lesser forage-to-concentrate ratio of the leafy hybrid TMR compared with the other TMR also contributed to its greater intake. Ruminal concentrations of propionate were greater in cows fed BMR than in those fed other hybrids, which could also result in greater milk production. Corn silage hybrids selected for improved forage quality can result in greater milk production by cows fed the improved hybrids in high forage diets.