Latack Brooke C, Carvalho Pedro H V, Zinn Richard A
Cooperative Extension, Division of Agriculture and Natural Resources, University of California, Holtville, Holtville, CA, United States.
Department of Animal Science, University of California, Davis, Davis, CA, United States.
Front Vet Sci. 2022 Dec 1;9:1032532. doi: 10.3389/fvets.2022.1032532. eCollection 2022.
Bans on the use of ionophores in several regions of the world has led to a need to identify alternative feed additivies to be added in cattle diets. Essential oil blends have been identified as a potential alternative to ionophores in feedlot diets. The objective of this study was to evaluate the effects of a supplemental a blend of essential oils and 25-hydroxyvitamin D3 on growth performance, energetic efficiency, and carcass characteristics in calf-fed Holstein steers. Ninety Holstein steer calves (123 ± 7 kg; 4 months old) were randomly assigned to 18 pens (5 steers/pen; 6 pens/treatment). Dietary treatments consisted of a steam-flaked corn-based diet supplemented with (DM basis): (1) no additives (CON); (2) 30 mg/kg DM of monensin (MON); (3) 200 mg/kg DM of a mixture of essential oils plus 25-hydroxyvitamin D3 (EO+HYD). There were no treatment effects ( > 0.05) on initial, intermediate and final cattle live weight; moreover, cattle had similar ( > 0.05) average daily gain (ADG) and dry matter intake (DMI) among dietary treatments. However, during the first 112 days of feed, calf-fed Holstein steers supplemented with EO+HYD had a greater ( ≤ 0.05) gain to feed ratio (G/F) than cattle fed the control diet but similar ( > 0.05) G/F to cattle supplemented with MON. However, there was no effect ( > 0.05) of dietary treatments on 112 to 286 d and the overall G/F ratio of calf-fed Holstein steers. Calf-fed Holstein steers supplemented with EO+HYD had greater ( ≤ 0.05) estimated net energy for maintenance (NEm) and net energy for gain (NEg) based on cattle growth performance than cattle fed the CON diet. Cattle supplemented with MON had an intermediate and similar ( > 0.05) NEm and NEg compared to the other two dietary treatments. However, when observed vs. expected NEm and NEg were calculated, cattle supplemented with MON and EO+HYD had greater efficiency of dietary energy utilization than cattle fed the CON diet. Calf-fed Holstein steers supplemented with MON had greater ( < 0.05) fat thickness than EO+HYD supplemented steers, and both were intermediate ( ≥ 0.05) to that of cattle fed the CON diet. There were no other effects ( > 0.05) on kidney, pelvic and heart fat, longissimus area, marbling score, and retail yield. The health status of cattle and liver abscesses or liver scars at slaughter were similar ( > 0.05). We conclude that supplementing calf-fed Holstein steers with MON or EO+HYD for over 285 days increased dietary net energy utilization for maintenance and gain of the diet by 3 and 4%, respectively, compared to non-supplemented steers.
世界上几个地区对离子载体使用的禁令导致需要确定可添加到牛日粮中的替代饲料添加剂。精油混合物已被确定为育肥牛日粮中离子载体的一种潜在替代品。本研究的目的是评估补充精油和25-羟基维生素D3混合物对犊牛饲养的荷斯坦公牛生长性能、能量效率和胴体特性的影响。九十头荷斯坦公牛犊（123±7千克；4月龄）被随机分配到18个围栏（每围栏5头牛；每个处理6个围栏）。日粮处理包括以蒸汽压片玉米为基础的日粮，并补充（以干物质计）：（1）不添加任何添加剂（对照）；（2）30毫克/千克干物质的莫能菌素（莫能菌素组）；（3）200毫克/千克干物质的精油与25-羟基维生素D3的混合物（精油+25-羟基维生素D3组）。日粮处理对牛的初始、中期和最终体重没有影响（P>0.05）；此外，不同日粮处理间牛的平均日增重（ADG）和干物质采食量（DMI）相似（P>0.05）。然而，在饲喂的前112天，补充精油+25-羟基维生素D3的犊牛饲养的荷斯坦公牛的料重比（G/F）高于饲喂对照日粮的牛（P≤0.05），但与补充莫能菌素的牛的料重比相似（P>0.05）。然而，日粮处理对112至286天以及犊牛饲养的荷斯坦公牛的总体料重比没有影响（P>0.05）。基于牛的生长性能，补充精油+25-羟基维生素D3的犊牛饲养的荷斯坦公牛的维持净能（NEm）和增重净能（NEg）估计值高于饲喂对照日粮的牛（P≤0.05）。补充莫能菌素的牛的NEm和NEg处于中间水平，与其他两种日粮处理相似（P>0.05）。然而，当计算观察到的与预期的NEm和NEg时，补充莫能菌素和精油+25-羟基维生素D3的牛的日粮能量利用效率高于饲喂对照日粮的牛。补充莫能菌素的犊牛饲养的荷斯坦公牛的脂肪厚度高于补充精油+25-羟基维生素D3的公牛（P<0.05），且两者均处于饲喂对照日粮的牛的中间水平（P≥0.05）。对肾脏、盆腔和心脏脂肪、背最长肌面积、大理石花纹评分和零售产量没有其他影响（P>0.05）。屠宰时牛的健康状况以及肝脏脓肿或肝瘢痕相似（P>0.05）。我们得出结论，与未补充的公牛相比，给犊牛饲养的荷斯坦公牛补充莫能菌素或精油+25-羟基维生素D3超过285天，日粮用于维持和增重的净能量利用率分别提高了3%和4%。
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