A note on concentrate energy source for dairy cows in mid lactation

The forage: concentrate ratio in the diet is known to influence the fermentation characteristics in the rumen (Sudweeks, Ely, Mertens and Sisk, 1981). Increasing the proportion of concentrates in rations fed to dairy cows has been shown to narrow the acetate plus butyrate: propionate ratio in the rumen (Sutton, 1981) with an associated depression in milk fat concentration (Ørskov, Reid and McDonald, 1981). The magnitude of the effect, on milk yield and composition, of increasing the concentrate proportion in the ration has been shown to be dependent on feeding level (Sutton, 1981), and the number of meals of concentrate per day (Johnson, 1979) and also may be influenced by dietary protein level and source (Ørskov et al., 1981).