In vitro degradability of forage legumes using the Ankom^RF gas technique

The AnkomRF gas production technique was used to assess rumen degradability of Mucuna pruriens (velvet bean), Vigna unguiculata Walp (L) (cowpea) and Desmodium uncinatum (silverleaf desmodium) forage legumes. Forage samples of 1.0 g/DM were placed into 250ml glass jar and incubated at 39˚C over 72 hours. Rumen liquor that was taken from 2 fistulated Friesian cows on a dairy ration was mixed with saliva in the ratio of 4:1. Most but not all of the gas in the three legume forages was produced within the first 48 hours post-incubation. The volumes of gases produced ranged from 61.38 to 70.37 ml, with an average of 64.16ml, whilst the fractional rate of gas production varied between 4.6 and 5.6%/h with a mean of 5%/h. Cowpea produced the highest amount of gas followed by velvet bean.