Full Lactation Response of Cows Fed Diets with Different Sources and Amounts of Fiber and Ruminal Degradable Protein

¹ Department of Dairy Science, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster 44691

Twenty Holstein cows were fed diets based on a mix of haycrop silage (immature orchardgrass or immature alfalfa) and corn silage with a conventional concentrate (primarily ground ear corn and soybean meal) or a concentrate based on by-products (primarily soyhulls, fish meal, and corn gluten meal). Diets for periods 1 (7 to 134 DIM), 2 (135 to 234 DIM), and 3 (235 to 305 DIM) were 40: 10:50, 40:20:40, and 4030:30 haycrop si1age:corn si1age:concentrate (DM basis), respectively. Dietary NDF ranged from 33 to 45%. The species of haycrop forage fed in combination with corn silage did not greatly affect milk production (mean = 28 kg/d), milk composition, nutrient digestibility, or DMI (expressed on a BW basis). Cows fed alfalfa gained more BW than those fed orchardgrass (.18 vs. .03 kg/d). Cows fed by-products produced similar amounts of milk, more milk fat (1.1 vs. .9 kg/d), and had higher DMI (21.4 vs. 19.6 kg/d) but lower BW gains (.03 vs. .18 kg/d) than those fed conventional concentrate. These data showed that a mix of high quality orchardgrass and corn silage is acceptable for dairy cows and that supplementation strategies are similar for diets based on orchardgrass and those based on alfalfa.

Key Words: alfalfa • orchardgrass • neutral • detergent fiber • by-products

Submitted on October 14, 1994
Accepted on April 11, 1995

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