Level of Leucaena leucocephala silage feeding on intake, rumen fermentation, and nutrient digestibility in dairy steers.

The objective of this experiment was to determine effects of Leucaena silage (LS) feeding on feed intake, nutrient digestibility, and rumen fermentation in dairy steers. Four rumen fistulated dairy steers, 167 ± 12 kg body weight (BW), were randomly assigned to receive dietary treatments according to a 4 × 4 Latin square design. Treatments were as follows: T1 = 100 % untreated rice straw (RS), T2 = 70 % RS + 30 % LS, T3 = 40 % RS + 60 % LS, and T4 = 100 % LS, respectively. All animals were fed rice straw and LS ad libitum with concentrate mixture supplemented at 0.2 % BW. The results found that dry matter intake and nutrient digestibility were the highest in dairy steers fed 60 % LS (P < 0.05). Ruminal temperature and pH were not affected by LS feeding (P > 0.05) while ruminal ammonia nitrogen and blood urea nitrogen concentration were linearly increased with increasing levels of LS feeding (P < 0.01). On the other hand, total volatile fatty acids and propionate (C3) were improved by LS feeding especially in steers fed 60 % LS (P < 0.05) whereas acetate (C2) production and C2/C3 ratio were decreased. Moreover, methane production was reduced together with increasing LS feeding level (P < 0.05). Based on this study, it could be concluded that 60 % LS feeding could enhance feed intake, digestibility, and rumen fermentation end-product while reducing methane production in dairy steers. This study suggested that LS could be used as high-quality roughage for ruminant feeding in the tropical region.