Limestone with different particle size and sodium bicarbonate to feedlot lambs fed high grain diets with or without monensin

作者：Gastaldello A L Jr; Pires A V^*; Susin I; Mendes C Q; Queiroz M A A; Amaral R C; Gentil R S; Ferreira E M; Mourao G B; Eastridge M L

来源：Small Ruminant Research, 2013, 114(1): 80-85.

DOI：10.1016/j.smallrumres.2013.05.009

• Buffers
• Feedlot
• Ionophores
• Lambs
• Rumen pH

The objectives of this study were to determine the effects of using different buffer sources and monensin on total tract apparent digestibility of nutrients and ruminal constituents of feedlot lambs fed high grain diets. Twenty-four lambs cannulated in the rumen were used in a randomized complete block design. Animals were fed diets containing 90% concentrate and 10% hay with addition of two limestone sources of different particle sizes and sodium bicarbonate, with or without monensin addition. Experimental treatments were arranged in a 2 x 3 factorial, with two monensin (0 or 30 mg/kg of diet) and three buffers: L = 1.3% limestone; FL = 1.3% filler limestone, and L + SB = 1.3% limestone + 1% sodium bicarbonate (DM basis). Dry matter, organic matter and crude protein digestibilities were higher (P %26lt; 0.05) for animals fed FL, when compared to other buffer treatments. Similarly, NDF digestibility was higher (P %26lt; 0.01) for treatments containing monensin compared to treatments without monensin. There were no differences in ruminal pH, water intake, ruminal acetate: propionate, and ruminal butyrate concentration. There was an interaction (P %26lt; 0.05) between FL and monensin addition for ruminal NH3-N, VFA, acetate, and propionate concentrations. Concentrations of these two VFA were lower (P %26lt; 0.05) when the ionophore was added. There was an interaction between the L + SB and monensin for total VFA (P %26lt; 0.01), acetate (P %26lt; 0.01), and propionate (P %26lt; 0.05) concentrations, with lower (P %26lt; 0.05) concentrations in treatments without monensin. The use of FL improved digestibility of DM, and it may be used in feedlot systems in which high concentrate diets are fed to lambs; however, the cost of this product in relation to limestone should be considered. Monensin increased NDF digestibility, as well as showed a positive interaction with FL and sodium bicarbonate; therefore, the use of monensin is recommended in high concentrate diets for finishing lambs.

• 出版日期2013-8