Kongphitee Kanokwan, Sommart Kritapon, Phonbumrung Thamrongsak, Gunha Thidarat, Suzuki Tomoyuki
Department of Animal Science, Faculty of Agriculture, Khon Kaen University, Khon Kaen 40002, Thailand.
Bureau of Animal Nutrition Development, Department of Livestock Development, Ratchathewi, Bangkok 10400, Thailand.
Asian-Australas J Anim Sci. 2018 Sep;31(9):1431-1441. doi: 10.5713/ajas.17.0759. Epub 2018 Mar 13.
This study was conducted to assess the effects of replacing rice straw with different proportions of cassava pulp on growth performance, feed intake, digestibility, rumen microbial population, energy partitioning and efficiency of metabolizable energy utilization in beef cattle.
Eighteen yearling Thai native beef cattle (Bos indicus) with an average initial body weight (BW) of 98.3±12.8 kg were allocated to one of three dietary treatments and fed ad libitum for 149 days in a randomized complete block design. Three dietary treatments using different proportions of cassava pulp (100, 300, and 500 g/kg dry matter basis) instead of rice straw as a base in a fermented total mixed ration were applied. Animals were placed in a metabolic pen equipped with a ventilated head box respiration system to determine total digestibility and energy balance.
The average daily weight gain, digestible intake and apparent digestibility of dry matter, organic matter and non-fiber carbohydrate, total protozoa, energy intake, energy retention and energy efficiency increased linearly (p<0.05) with an increasing proportion of cassava pulp in the diet, whereas the three main types of fibrolytic bacteria and energy excretion in the urine (p<0.05) decreased. The metabolizable energy requirement for the maintenance of yearling Thai native cattle, determined by a linear regression analysis, was 399 kJ/kg BW0.75, with an efficiency of metabolizable energy utilization for growth of 0.86.
Our results demonstrated that increasing the proportion of cassava pulp up to 500 g/kg of dry matter as a base in a fermented total mixed ration is an effective strategy for improving productivity in zebu cattle.
本研究旨在评估用不同比例的木薯浆替代稻草对肉牛生长性能、采食量、消化率、瘤胃微生物种群、能量分配及可代谢能量利用效率的影响。
将18头平均初始体重（BW）为98.3±12.8 kg的一岁泰国本地肉牛（印度牛），按照随机完全区组设计，分配到三种日粮处理之一，自由采食149天。采用三种日粮处理，在发酵全混合日粮中使用不同比例（以干物质计为100、300和500 g/kg）的木薯浆替代稻草作为基础日粮。将动物置于配备通风头箱呼吸系统的代谢笼中，以测定总消化率和能量平衡。
随着日粮中木薯浆比例的增加，平均日增重、干物质、有机物、非纤维碳水化合物的可消化采食量和表观消化率、总原生动物、能量摄入量、能量保留和能量效率呈线性增加（p<0.05），而三种主要类型的纤维分解菌和尿中能量排泄量（p<0.05）下降。通过线性回归分析确定，一岁泰国本地牛维持所需的可代谢能量为399 kJ/kg BW0.75，生长的可代谢能量利用效率为0.86。
我们的结果表明，在发酵全混合日粮中，将木薯浆作为基础日粮的比例提高至500 g/kg干物质是提高瘤牛生产力的有效策略。
