Crude glycerin combined with food additives in feeding beef cattle

ABSTRACT The objective of this study was to evaluate the effects of adding crude glycerin with food additives (sodium monensin or essential oils) to the diets of beef cattle on feed intake, ruminal parameters, in vitro digestibility, and production of greenhouse gases. Five ruminally cannulated Nellore steers were randomly assigned in a 5×5 Latin square design. The treatments were: control, without crude glycerin and additives; with essential oils and without crude glycerin; with sodium monensin and without crude glycerin; with essential oils and crude glycerin; and with sodium monensin and crude glycerin. The addition of crude glycerin caused a reduction in dry matter (DM) intake, increase in vitro dry matter digestibility, and decrease in vitro crude protein digestibility, regardless of the food additive. All treatments were effective in maintaining the rumen environment with pH values above 6.2 and ammonia nitrogen concentrations above 10 mg dL−1. No difference was observed in the production and quality of protozoal and bacterial fractions. The addition of crude glycerin at 200 g kg−1 DM in the total diet can partially replace corn grain and soybean hulls and be combined with either sodium monensin or essential oil without impairing the rumen fermentation, being effective in reducing gas methane production and, when combined with sodium monensin, enables more efficient utilization of the diet by the animal. Therefore, feedlot experiments at large scales of production should be evaluated to prove these positive results.

摘要 本研究旨在评估向肉牛日粮中添加搭配食品添加剂（莫能菌素钠或精油）的粗甘油，对其采食量、瘤胃参数、体外消化率及温室气体排放的影响。试验采用5×5拉丁方设计，选取5头安装瘤胃瘘管的内洛尔阉牛（Nellore）进行随机分组。试验设置5种处理组：对照组（不添加粗甘油与食品添加剂）、仅添加精油（无粗甘油）、仅添加莫能菌素钠（无粗甘油）、添加精油与粗甘油、添加莫能菌素钠与粗甘油。无论搭配何种食品添加剂，添加粗甘油均可降低干物质（DM）采食量，提升体外干物质消化率，但会降低体外粗蛋白消化率。所有处理组均可有效维持瘤胃内环境，使pH值高于6.2，氨氮浓度高于10 mg·dL⁻¹。瘤原虫与细菌组分的产量及品质均无显著差异。在全日粮中以200 g·kg⁻¹ DM的比例添加粗甘油，可部分替代玉米籽粒与大豆皮，且可与莫能菌素钠或精油复配使用而不会损害瘤胃发酵；该添加方式可有效减少甲烷排放，且与莫能菌素钠复配时可提升动物对日粮的利用效率。因此，需开展大规模育肥场试验以验证上述积极效果。