Navarrete Juan D, Montano Martin F, Raymundo Constantino, Salinas-Chavira Jaime, Torrentera Noemi, Zinn Richard A
Department of Nutrition and Biotechnology of Ruminants, Instituto de Investigaciones en Ciencias Veterinarias-UABC, Mexicali, Baja California 21100, México.
Department of Animal Nutrition, Facultad de Medicina Veterinaria y Zootecnia, Universidad Autónoma de Tamaulipas, Cd. Victoria, Tamaulipas 87000, México.
Asian-Australas J Anim Sci. 2017 Oct;30(10):1396-1404. doi: 10.5713/ajas.16.0826. Epub 2017 Mar 21.
This study was determined the influence of virginiamycin supplementation on growth-performance and characteristics of digestion of cattle with decreasing dietary net energy value of the diet for maintenance (NE) from 2.22 to 2.10 Mcal/kg.
Eighty crossbred beef steers (298.2±6.3 kg) were used in a 152-d performance evaluation consisting of a 28-d adaptation period followed by a 124-d growing-finishing period. During the 124-d period steers were fed either a lesser energy dense (LED, 2.10 Mcal/kg NE) or higher energy dense (HED, 2.22 Mcal/kg NE) diet. Diets were fed with or without 28 mg/kg (dry matter [DM] basis) virginiamycin in a 2×2 factorial arrangement. Four Holstein steers (170.4±5.6 kg) with cannulas in the rumen (3.8 cm internal diameter) and proximal duodenum were used in 4×4 Latin square experiment to study treatment effects on characteristics of digestion.
Neither diet energy density nor virginiamycin affected average daily gain (p>0.10). As expected, dry matter intake and gain efficiency were greater (p<0.01) for LED- than for HED-fed steers. Virginiamycin did not affect estimated net energy value of the LED diet. Virginiamycin increased estimated NE of the HED diet. During daylight hours when the temperature humidity index averaged 81.3±2.7, virginiamycin decreased (p<0.05) ruminal temperature. Virginiamycin did not influence (p>0.10) ruminal or total tract digestion. Ruminal (p = 0.02) and total tract digestion (p<0.01) of organic matter, and digestible energy (p<0.01) were greater for HED vs LED. Ruminal microbial efficiency was lower (p<0.01) for HED vs LED diets.
The positive effect of virginiamycin on growth performance of cattle is due to increased efficiency of energy utilization, as effects of virginiamycin on characteristics of digestion were not appreciable. Under conditions of high ambient temperature virginiamycin may reduce body temperature.
本研究旨在确定添加维吉尼亚霉素对日粮维持净能值（NE）从2.22兆卡/千克降至2.10兆卡/千克的肉牛生长性能和消化特性的影响。
选用80头杂交肉牛（体重298.2±6.3千克）进行为期152天的性能评估，其中包括28天的适应期，随后是124天的生长育肥期。在这124天期间，肉牛分别饲喂能量密度较低（LED，2.10兆卡/千克NE）或能量密度较高（HED，2.22兆卡/千克NE）的日粮。日粮按2×2析因设计分别添加或不添加28毫克/千克（基于干物质[DM]）的维吉尼亚霉素。选用4头装有瘤胃（内径3.8厘米）和十二指肠近端插管的荷斯坦肉牛（体重170.4±5.6千克）进行4×4拉丁方试验，以研究处理对消化特性的影响。
日粮能量密度和维吉尼亚霉素均未影响平均日增重（p>0.10）。正如预期的那样，LED组肉牛的干物质采食量和增重效率高于HED组（p<0.01）。维吉尼亚霉素对LED日粮的估计净能值没有影响。维吉尼亚霉素提高了HED日粮的估计净能值。在温度湿度指数平均为81.3±2.7的白天，维吉尼亚霉素降低了瘤胃温度（p<0.05）。维吉尼亚霉素对瘤胃或全消化道消化没有影响（p>0.10）。HED组的瘤胃（p = 0.02）和全消化道有机物消化率（p<0.01）以及可消化能量（p<0.01）均高于LED组。HED组的瘤胃微生物效率低于LED组（p<0.01）。
维吉尼亚霉素对肉牛生长性能的积极作用归因于能量利用效率的提高，因为维吉尼亚霉素对消化特性的影响不明显。在环境温度较高的条件下，维吉尼亚霉素可能会降低体温。
