Effects of polymer coated slow-release urea on ruminal fermentation and nutrient total tract digestion of beef steers

Revista Brasileira de Zootecnia

Rennó, Francisco Palma²  Calomeni, Gustavo Delfino²  Gandra, Jefferson Rodrigues¹  Freitas Júnior, José Esler de⁴  Takiya, Caio Seiti²  Gardinal, Rodrigo²  Souza, Heraldo Namorato de³  Vendramini, Thiago Henrique Annibale² 

[1] Universidade Federal da Grande Dourados, Dourados, Brazil;Universidade de São Paulo, Pirassununga, Brazil;Petrobras, Rio de Janeiro, Brasil;Universidade Federal da Bahia, Salvador, Brazil

关键词:  ammonia;    digestibility;    microbial protein;    Nellore;    non-protein nitrogen;    soybeanIntroductionUrea is the most common source of non-protein nitrogen (NPN) and is widely used in ruminant feeding because of its lower cost compared with true protein sources (e;   

DOI  :  10.1590/S1806-92902016000200004

学科分类：兽医学

来源: Universidade Federal de Vicosa

【 摘 要 】

The objective of this study was to evaluate the effects of polymer coated slow-release urea (SRU) in high-forage diets of beef steers on nutrient intake and digestibility, ruminal fermentation, microbial protein synthesis, and energy balance. Eight 24-mo-old rumen-fistulated castrated Nellore steers (average body weight = 418.0±40.0 kg) were used in a replicated 4 × 4 Latin square design. Animals were randomly distributed to receive one of the following diets: no urea inclusion; 1.0% inclusion of feed grade urea in the diet (dry matter [DM] basis); 1.0% inclusion of slow-release urea 1 in the diet (DM basis); and 1.0% inclusion of slow-release urea 2 in the diet (DM basis). Slow-release urea 2 had a similar composition to that of slow-release urea 1 and differed in that it contained 2.95% sulfur. A high-forage diet was provided (75% of total DM) and corn silage was used as the forage source. Diets with urea had increased crude protein (CP) intake, and CP and total digestible nutrients total tract digestion. Urea sources increased ruminal concentrations of ammonia nitrogen and acetate, and decreased butyrate concentrations. The polymer coated urea did not alter ruminal fermentation when compared with feed grade urea. Diets did not affect the energy balance of steers. Feed grade urea presented greater microbial protein synthesis than polymer coated slow-release urea. The partial replacement of soybean meal by 1% slow-release urea in a diet with 75% forage does not improve ruminal fermentation and microbial protein synthesis, and shows similar results as feeding feed grade urea to beef steers.

【 授权许可】

Unknown