There is a growing public concern on the use of antibiotics and ionophores in livestock and emerging antimicrobial resistance. Plant extracts and essential oils are natural alternatives having antimicrobial and antioxidant properties. This study evaluated the effects of a mixture of baccharis (Baccharis dracunculifolia) leaves and stems, tamarind (Tamarindus indica L.) seed, cashew (Anacardium occidentale) nut shell liquid, and clove (Syzygium aromaticum) essential oil on animal performance, feed intake, feed efficiency, apparent digestibility, molar concentration of volatile fatty acids and feeding behavior of bulls finished in the feedlot and fed high-grain diets. A total of 32 bulls (½ Angus vs. ½ Nellore) with a mean age of 24 ± 2.0 months and a mean body weight of 418 ± 4.51 kg were distributed in a completely randomized design with four diets and eight replications per diet. The four experimental diets were as follows: CONT – basal diet; MIX2 – basal diet and 2 g/animal/d of extracts from baccharis, tamarind, cashew nut shell liquid, and clove; MIX4 – basal diet and 4 g/animal/d of extracts from baccharis, tamarind, cashew nut shell liquid, and clove; MIX6 – basal diet and 6 g/animal/d of extracts from baccharis, tamarind, cashew nut liquid shell liquid and clove. Animal performance, dry matter, and other nutrients intake were similar among diets. Dry matter, neutral detergent fiber, and organic matter digestibilities were greater for the MIX2 when compared to other diets. There was an increase in propionate and a decrease in the acetate/propionate ratio when MIX6 was used. A similar effect was observed when orthogonal contrasts comparing the CONT diets with the addition of MIX was used. Feeding behavior was similar among the four diets. Our findings indicated that supplementation of baccharis, tamarind, cashew nut shell liquid, and clove oil (2, 4, and 6 g/animal/d) may be fed to beef cattle once it showed no adverse effects on feed intake and nutrient digestibility. Moreover, it was observed a higher concentration of propionate, a reduction in acetate/propionate ratio, and a greater digestibility of dry matter, neutral detergent fiber, and organic matter. However, more studies should be carried out to determine the effect of higher levels of MIX aiming to use it as a feed additive to improve animal performance and ruminal fermentation in beef cattle finished in feedlot.

公众越来越关注在牲畜中使用抗生素和离子载体以及新出现的抗菌素耐药性。植物提取物和香精油是具有抗菌和抗氧化特性的天然替代品。本研究评估baccharis（的混合物的效果Baccharis dracunculifolia）叶和茎，罗望子（酸豆L.）种子，腰果（腰果）果壳液，和丁香（丁香动物性能）精油，饲料摄取量，饲料效率，表观消化率，挥发性脂肪酸的摩尔浓度以及在饲养场和饲喂高谷物日粮中完成的公牛的饲喂行为。一共有32头公牛（½安格斯vs.平均年龄为24±2.0个月，平均体重为418±4.51 kg的Nellore（½Nellore）采用完全随机设计分配，每组饮食有四种饮食，每组重复八次。四种实验饮食如下：CONT –基础饮食；MIX2 –基础饮食和2 g /动物/天的杆菌，罗望子，腰果壳液和丁香提取物；MIX4 –基础饮食和4 g /动物/天的杆菌，罗望子，腰果壳液和丁香提取物；MIX6 –基础饮食和6 g /动物/天的杆菌，罗望子，腰果壳液和丁香提取物。饮食之间的动物性能，干物质和其他营养摄入相似。与其他饮食相比，MIX2的干物质，中性洗涤剂纤维和有机物质消化率更高。使用MIX6时，丙酸根增加，乙酸根/丙酸根比率降低。当使用CONT日粮和添加MIX的正交对比进行比较时，观察到相似的效果。四种饮食之间的喂养行为相似。我们的研究结果表明，一旦对肉牛没有饲料，营养成分的消化不良的影响，就可以补充牛油，罗望子，腰果壳液和丁香油（2、4和6 g /动物/天）。此外，观察到较高的丙酸盐浓度，乙酸盐/丙酸盐比率的降低以及干物质，中性洗涤剂纤维和有机物质的更大的消化率。然而，