Comparison of ‘Mott’ Dwarf Elephantgrass Silage and Corn Silage for Lactating Dairy Cows

Mott' dwarf elephantgrass (Pennisetum purpureum) is a tropical perennial bunchgrass growing to an undefoliated height of 1.5 m. Twelve lactating Holstein cows averaging 72 DlM were arranged in three replications of a 4 x 4 Latin square. Cows were fed a dietary forage to concentrate ratio of 48:52. Chopped alfalfa (Medicago sativa) hay made up 10% of DM. Dietary treatments were com (Zea mays) silage and dwarf elephantgrass silage fed at DM ratios of 38:0,20:18, 10:28, and 0:38. Dry matter intake responded in a quadratic fashion (19.1, 19.4, 18.9, and 17.2 kg/d for diets 38:0 to 0:38). Digestibility (determined with chromic oxide marker) of dietary NDF and ADF increased linearly with increasing concentration of elephantgrass in the diet. Milk and 4% FCM yields tended to decrease slightly with increasing dietary elephantgrass. Ruminal pH and molar percentage acetate increased linearly, whereas ammonia N declinc:<l linearly with increasing elephantgrass m the diet. In situ extents and rates of DM and cellulose digestion were higher for elephantgrass than for com silage. Dwarf elephantgrass silage appears ~o be of high quality with potential for high DMI. When substituted for com silage, it resulted in only a small decrease in milk yield.