Utilisation of white clover silage fed alone or with maize silage by lactating dairy cows

Abstract

Six lactating dairy cows in mid lactation were fed either white clover silage or a mixture of white clover and maize silages (70 : 30, dry matter basis). Milk yields (about 20 L/day) and compositions were similar when cows were fed either diet. Although the mixed diet was less digestible and provided less energy and crude protein than white clover, rumen fermentation may have been improved relative to that when white clover silage was fed alone. Flow rates of fluid from the rumen were faster, pH values for rumen liquor were higher and concentrations of ammonia in rumen liquor were lower when cows were fed the mixed diet than white clover silage. Concentrations of total volatile fatty acids and the proportions of the major volatile fatty acids in rumen liquor were similar for both diets. The efficiency of utilisation of dietary nitrogen for liveweight gain and milk production also appeared to be similar for both diets. Plasma concentrations of key metabolites were consistent with the cows being well nourished when fed both diets. Overall, it was evident that white clover silage may be used effectively in combination with lower quality maize silage to meet the nutrient requirements of cows with reasonably high yields of milk during mid lactation.