Digestibility and performance of dairy bulls fed corn and grass silages with various sequences and levels of barley

Abstract

of dairy bulls fed corn and grass silages with various sequences and levels of barley. Can and feed efficiency by 55% (P:0.0062) compared to inclusion of barley in the silage mixtures during the first period. Feed efficiency improved with concentrate supplementation of both silages (P<0.0001), but the improvement with grass silage was greater than with corn silage (P:0.0041). Dry matter and energy digestibilities were not affected by feed sequences (P:0.1025, P:0.0833, respectively), but they were higher for mixed diets than fbr pure silage (P:0.0186, P:0.0218, respectively). Dry matter intake was 0.81 kg d-' higher (P<0.0001) when concentrate was added to the diet. These results suggest that energffeeds suih as 6arley are more efficiently used in the last part ofgrowth. This experiment demonstrates the feasibility of switching grain-fed calves to roughage diets.