This study, conducted at the São Paulo State University feedlot, Dracena campus, Brazil, was designed as a completely randomized block with 2 × 2 factorial arrangement of treatments to evaluate the effects of adding functional oils (FO) or sodium monensin (MON) on feedlot performance, carcass traits, feeding behaviour and rumen morphometrics of Nellore cattle. Ninety-six 20-mo-old Nellore bulls (365.52 ± 39.19 kg) were randomly allocated to 24 pens (n = 4/pen), which were assigned to the treatments: (1) Control (no feed additives); (2) FO (500 ppm); (3) MON (27 ppm); and (4) MON + FO (27 + 500 ppm, respectively). Each treatment was replicated 6 times, and cattle were fed for 105 days. From 0 to 28 days on feed, cattle fed FO had lower dry matter intake (DMI) variation, sorted for medium particles and presented smaller papillae width. The feeding of FO did not negatively impact feedlot performance overall. When MON was added to the diet, cattle had lower DMI overall and 12th rib fat daily gain, and improved gain to feed ratio. The addition of MON to diets improved feedlot performance but reduced the rate of carcass fat deposition. The few effects observed when FO was added to diets were not sufficient to impact feedlot performance.

中文翻译：

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在高浓度日粮中添加功能性油或莫能菌素钠对育成 Nellore 牛的生产性能、采食行为和瘤胃形态的影响

这项研究在巴西 Dracena 校区的圣保罗州立大学饲养场进行，被设计为一个完全随机的区组，采用 2 × 2 的因子排列处理，以评估添加功能性油 (FO) 或莫能菌素钠 (MON) Nellore 牛的饲养场性能、胴体性状、摄食行为和瘤胃形态测量。96 头 20 个月大的 Nellore 公牛（365.52 ± 39.19 kg）被随机分配到 24 个围栏中（n= 4/栏），分配给以下处理：（1）对照（无饲料添加剂）；(2) FO (500 ppm)；(3) 星期一（27 ppm）；(4) MON + FO（分别为 27 + 500 ppm）。每个处理重复6次，饲养牛105天。从饲喂 0 到 28 天，饲喂 FO 的牛具有较低的干物质摄入量 (DMI) 变化，分选为中等颗粒并呈现较小的乳突宽度。FO 的饲喂并未对饲养场的整体性能产生负面影响。在日粮中添加 MON 后，牛的总体 DMI 较低，日增重为 12 肋，并提高了增重比。在日粮中添加 MON 提高了饲养场的性能，但降低了胴体脂肪沉积率。在日粮中添加 FO 时观察到的少量影响不足以影响饲养场的性能。