Comparison of the voluntary intake by lactating cows of two maize silages with different in situ dry matter degradability

The relationship between dry matter degradability of two maize silages meas ured in situ and dry matter intake, mill, yield, milk composition and weigh t gain was studied in a changeover experiment with 20 dairy cows. The anima ls were fed a balanced diet based on maize silage and concentrate with the same quantities of concentrate given with both silages. The two maize silag es had equal levels of dry matter but were different in their neutral deter gent fibre (NDF) levels (473 and 414 g.kg(-1)) and dry matter degradability values measured in situ over 48 h (53.9 and 57.6 %). The dry matter intake of the low-NDF, highly degradable silage was significantly higher than tha t of the high-NDF, low degradable material (12.8 vs. 13.5 kg DM.d(-1)) but no significant difference was observed for milli yield, far protein and lac tose milli content, milk lactose or weight gain between the two silages (23 .7 vs. 23.4 kg.d(-1), 41.2 vs. 41.4 g.kg(-1), 31.6 vs. 31.6 g.kg(-1), 46.5 vs. 46.2 g.kg(-1) and 498 vs. 515 g.d(-1) for, respectively, high- and low- NDF content maize silage). Although higher intake was linked to better dry matter degradability of maize silage, there was no effect on production, pr obably because of the late stage of lactation of the cows used in this expe riment. ((C) Elsevier / Inra).