TMR silage with sugarcane bagasse and urea: effects on intake, digestibility, and feeding behavior in dairy heifers
State University of Southwest of Bahia, BR45700-000, Itapetinga, Bahia, Brazil
*Correspondence: amanda.s.ri@hotmail.com
Abstract:
This study evaluated the effects of total mixed ration (TMR) silage containing two levels of sugarcane bagasse (40% and 50% of dry matter), with or without urea inclusion (2.5%), on intake, nutrient digestibility, nitrogen balance, microbial protein synthesis, and feeding behavior of dairy heifers. Eight crossbred heifers were assigned to two simultaneous 4×4 Latin squares in a 2×2 factorial arrangement. Urea inclusion reduced (P < 0.05) dry matter and neutral detergent fiber intake but improved dry matter and crude protein digestibility. Increasing bagasse level to 50% reduced (P < 0.05) intake and digestibility of nutrients, reflecting the higher fiber content and lower energy density of the diets. Nitrogen balance and microbial protein synthesis were not affected by treatments. Higher bagasse levels increased rumination time per unit of NDF and the number of ruminal boli, indicating greater physical demand for fiber processing. Overall, TMR silage containing 40% sugarcane bagasse without urea provided the best balance between intake and nutrient utilization. These results highlight the importance of optimizing fiber levels and nitrogen sources in TMR silage to improve efficiency in dairy heifer feeding systems under tropical conditions.
Key words:
bagasse, digestibility, feeding behavior, nitrogen balance, TMR silage