Gunun Nirawan, Phimda Randorn, Piamphon Nonthasak, Kaewwongsa Walailuck, Puangbut Darunee, Kaewpila Chatchai, Khota Waroon, Cherdthong Anusorn, Gunun Pongsatorn
Department of Animal Science, Faculty of Technology, Udon Thani Rajabhat University, Udon Thani 41000, Thailand.
Department of Animal Science, Faculty of Natural Resources, Rajamangala University of Technology Isan, Sakon Nakhon Campus, Phangkhon, Sakon Nakhon 47160, Thailand.
Anim Biosci. 2024 Oct;37(10):1751-1758. doi: 10.5713/ab.24.0076. Epub 2024 Aug 16.
This experiment aimed to evaluate the effects of replacing concentrates with cassava root-top silage (CARTOS) on feed intake, digestibility, rumen fermentation, blood parameters, and growth performance of beef cattle.
Twenty crossbred bulls with a body weight (BW) of 226±56 kg were randomly assigned to one of five treatments for 90 d in a randomized complete block design having four blocks based on BW. The concentrates were replaced by CARTOS at levels of 0%, 25%, 50%, 75%, and 100% dry matter (DM). Animals were fed dietary treatments at 1.8% BW, with rice straw offered ad libitum.
The DM and crude protein (CP) intake were decreased (p<0.01, p = 0.04) when the diet's CARTOS level was increased. The digestibility of DM, OM, and CP were not different among treatments, while fiber digestibility was increased with the inclusion of CARTOS (p = 0.03). The addition of CARTOS to replace concentrates did not change ruminal pH or volatile fatty acid proportions except for acetic acid, which increased with the addition of CARTOS (p = 0.03). The ruminal ammonia-nitrogen (NH3-N) was decreased (p<0.01) with increasing levels of CARTOS. The blood glucose and blood urea nitrogen decreased (p = 0.01) with the addition of CARTOS at 100%, whereas total protein and hematological parameters did not change with increasing levels of CARTOS. The use of CARTOS to substitute concentrates at 75% and 100% decreased average daily gain (ADG) and gain to feed ratio (G:F) (p<0.01); therefore, the addition of CARTOS up to 50% maintained ADG and G:F in beef cattle.
CARTOS can replace concentrates up to 50% in beef cattle diets without adversely affecting feed intake, nutrient digestibility, rumen fermentation characteristics, blood parameters, or growth performance of beef cattle.
本试验旨在评估用木薯茎叶青贮料（CARTOS）替代精料对肉牛采食量、消化率、瘤胃发酵、血液参数和生长性能的影响。
将20头体重为226±56千克的杂交公牛，按照随机完全区组设计，根据体重分为四个区组，随机分配到五种处理之一，为期90天。精料分别用干物质（DM）含量为0%、25%、50%、75%和100%的CARTOS替代。按体重的1.8%给动物投喂日粮，随意提供稻草。
日粮中CARTOS水平升高时，干物质（DM）和粗蛋白（CP）摄入量降低（p<0.01，p = 0.04）。各处理间DM、有机物（OM）和CP的消化率无差异，而纤维消化率随CARTOS添加量增加而提高（p = 0.03）。添加CARTOS替代精料对瘤胃pH值或挥发性脂肪酸比例无影响，但乙酸比例随CARTOS添加量增加而升高（p = 0.03）。瘤胃氨氮（NH3-N）随CARTOS水平升高而降低（p<0.01）。添加100%的CARTOS时，血糖和血尿素氮降低（p = 0.01），而总蛋白和血液学参数随CARTOS水平升高无变化。用CARTOS替代75%和100%的精料时，平均日增重（ADG）和增重耗料比（G:F）降低（p<0.01）；因此，添加高达50%的CARTOS可维持肉牛的ADG和G:F。
在肉牛日粮中，CARTOS替代精料的比例高达50%时，不会对肉牛的采食量、养分消化率、瘤胃发酵特性、血液参数或生长性能产生不利影响。
