Intake, digestibility, rumen characteristics and microbial protein synthesis efficiency in bovine and bubaline fed sugar cane silage with additives

Intake and total and ruminal digestibility, ruminal characteristics and microbial synthesis efficiency in bovine and bubaline fed sugar cane silages treated with microbial additive Lactobacillus buchneri (inoculate) and the addition of: cassava byproduct meal at 250 g/kg; soybean hulls at 250 g/kg; and urea at 33 g/kg, in natural matter were evaluated. The forage:concentrate ratio was 600:400 g/kg. Bubaline body weight (BW) was 403±49 kg and bovine BW was 492±10 kg. The experimental design consisted of two 4 × 4 Latin squares in a 4 × 2 factorial arrangement. The average DM intake did not differ between species, and the diet with urea showed lowest intake (13 g/kg BW). Among the diets, the one with soybean hulls addition increased the total digestibility of DM, organic matter (OM) and neutral detergent fiber (NDF), while addition of urea reduced the DM, OM and non-fibrous carbohydrates (NFC) total digestibility in both species. Bovines have higher ruminal digestibility of NFC in the diet with addition of inoculate, inoculate + soybean meal and inoculate + urea diets than bubaline. Ruminal liquid pH was higher for bubaline (6.61) than bovines (6.48). Diets with addition of cassava byproduct and soybean hulls presented higher ruminal short chain fatty acids concentrations. Ruminal ammonia concentration (N-NH3) did not differ between species and the treatment with urea presented the highest value of N-NH3 (17.25 mg/100 mL). Liquid passage rate was higher for bubaline (12.9%/h) than bovines (9.9%/h). Bubaline has higher microbial synthesis efficiency than bovine: 35.1 vs 24.6 g of N-microbial/kg OM of the total rumen digestibility, regardless of the diet.