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 本研究旨在评估在肉牛日粮中添加含食品添加剂（莫能菌素钠（sodium monensin）或精油（essential oils））的粗甘油（crude glycerin）对其采食量、瘤胃参数、体外消化率及温室气体产生量的影响。本试验选取5头瘤胃插管的内洛尔阉牛，采用5×5拉丁方试验设计进行随机分组。试验处理组设置如下：对照组（无粗甘油与添加剂）、仅添加精油组（无粗甘油）、仅添加莫能菌素钠组（无粗甘油）、添加精油与粗甘油组、添加莫能菌素钠与粗甘油组。无论添加何种食品添加剂，粗甘油的添加均会降低肉牛干物质（DM）采食量，提升体外干物质消化率，同时降低体外粗蛋白消化率。所有处理组均可有效维持瘤胃环境，使pH值维持在6.2以上，氨氮浓度维持在10 mg dL⁻¹以上。各试验组的瘤胃原虫与细菌组分的产量及质量均无显著差异。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，且与莫能菌素钠或精油联用均不会损害瘤胃发酵，同时可有效减少甲烷气体产生；当与莫能菌素钠联用时，还可提升动物对日粮的利用效率。因此，需开展大规模育肥场生产试验以验证上述积极效果。