Lotus Corniculatus and Condensed Tannins – Effects on Milk Production by Dairy Cows

Birdsfoot trefoil (Lotus corniculatus) increases milk yield of dairy cows. An indoor feeding experiment using Friesian dairy cows in mid lactation was conducted to determine what proportions of the milk yield and composition changes were due to the condensed tannins (CT) in Lotus, and what proportions were due to factors associated with legumes (higher herbage intake and forage quality). Cows were fed either perennial ryegrass or Lotus, and were also drenched with either polyethylene glycol (PEG) to block the action of CT, or water. Milk yields (kg/cow/d) were higher on Lotus (21.24) than on Lotus+PEG (18.61), ryegrass (15.53) or ryegrass+PEG (15.49) indicating that CT contributed to 46% of the increased milk yield that resulted from feeding Lotus rather than ryegrass. CT had no effect on intake, but contributed to increased milk protein concentration, increased efficiency and decreased milk fat concentration.