ARS | Publication request: Orchardgrass hay equals alfalfa hay as grain replacement in UMN-St. Paul dairy trial

Submitted to: Forage Focus
Publication Type: Trade Journal
Publication Acceptance Date: December 21, 2010
Publication Date: December 27, 2010
Citation: Peterson, P., Raeth-Knight, M., Litherland, N., Linn, J., Paulson, J., Jung, H.G. 2010. Orchardgrass hay equals alfalfa hay as grain replacement in UMN-St. Paul dairy trial. Forage Focus. December 2010. p. 15-16.

Technical Abstract: In a recent feeding trial with 50 Holstein dairy cows, replacing corn and soybean meal with orchardgrass hay resulted in similar milk production compared to replacement with alfalfa hay. The orchardgrass hay had a similar rate and greater extent fiber digestion compared to the alfalfa hay. The feeding trial had 10 treatments including alfalfa hay fed at 15, 20, 25, 30, and 35% of diet DM; vs. orchardgrass hay fed at 10, 15, 20, 25, and 30% of diet DM. These variable hay types/amounts replaced corn grain and soybean meal in TMRs that included 35% corn silage. For alfalfa-based TMRs, ground corn was decreased from 21 to 8%, and soybean meal decreased from 7 to 0%, as hay inclusion increased from 15 to 35% of diet DM. For orchardgrass-based TMRs, ground corn was decreased from 21 to 6%, and soybean meal decreased from 10 to 6%, as hay inclusion increased from 10 to 30% of diet DM. Feed intake of the orchardgrass- vs. alfalfa-based TMRs behaved similarly, decreasing about 0.8 lb/cow/day as hay inclusion rate increased from 10 to 35% of diet DM. Milk production behaved similarly, decreasing about 0.6 lb/cow/day as hay DM increased from 10 to 35% of the diet. A striking difference between the hays was the relationship between milk production and diet NDF concentration. For the orchardgrass-based TMRs, milk production declined about 1 lb/cow/day as total-diet NDF increased from 30 to 40% NDF with increased hay inclusion. For the alfalfa-based TMRs, milk production declined about 2.7 lb/cow/day as total-diet NDF increased from 29 to 36% NDF with increased hay inclusion. The alfalfa-based TMRs also resulted in greater eating time and less chewing time than orchardgrass-based TMRs. Milk composition and body weight were unaffected by hay type and amount. These results support previous research indicating that good-quality grass forage is a viable dairy-cow feed.