Effects of silage crop and dietary crude protein levels on digestibility, ruminal fermentation, nitrogen use efficiency, and performance of finishing beef cattle

• Published in: Animal feed science and technology 2016-10, Vol.220, p.22-33
• Main Authors: da Silva, L.D., Pereira, O.G., da Silva, T.C., Valadares Filho, S.C., Ribeiro, K.G.
• Format: Article
• Language: English
• Subjects: Corn silage; Feedlot; Legume silage; Stylosanthes
• ISSN: 0377-8401; 1873-2216
• DOI: 10.1016/j.anifeedsci.2016.07.008

•Diets containing Stylosanthes silage showed lower digestibility but higher intake than diets containing corn silage.•Diets containing Stylosanthes silage as well as the level of 110g CP/kg diet did not compromise the feedlot performance of Nellore.•Stylosanthes silage-based diets tended to decrease feed efficiency in comparison to corn silage-based diets. Two trials were conducted to evaluate the effects of silage crop and levels of dietary crude protein (CP) in Nellore beef cattle. The experimental diets consisted of Stylosanthes (StS) or corn silage (CS) with two levels of dietary CP, 110 and 130g CP/kg diet on a dry matter (DM) basis. The forage to concentrate ratio was 50:50 on a DM basis. In Experiment 1, the four bulls that were used had an average initial body weight (BW) of 450±37.9kg, and were surgically cannulated in the rumen and abomasum. The bulls were assigned to a 4×4 Latin square with a 2×2 factorial design of treatments, and four 16-d periods. During this experiment, we collected ruminal fluid, abomasal digesta, feces, urine, and blood. In addition, the kinetic parameters of DM, CP, and neutral detergent fiber (NDF) degradation were estimated. In Experiment 2, 40 bulls with an average initial BW of 374±16.5kg were distributed into a 2×2 factorial in a randomized design with ten replicates. The trial lasted for 99 d and was divided into a 15-d period for adaptation and an 84-d period for data collection. The intake and digestibility of nutrients as well as animal performance were evaluated in Experiment 2. The potentially degradable fractions of DM, CP, and NDF of StS were lower than CS (P