Jeon Seoyoung, Jeong Sinyong, Lee Mingyung, Seo Jakyeom, Kam Dong Keun, Kim Jeong Hoon, Park Jaehwa, Seo Seongwon
Division of Animal and Dairy Sciences, Chungnam National University, Daejeon 34134, Korea.
Life and Industry Convergence Research Institute, Department of Animal Science, Pusan National University, Miryang 50463, Korea.
Asian-Australas J Anim Sci. 2019 Nov;32(11):1705-1714. doi: 10.5713/ajas.19.0269. Epub 2019 Aug 26.
Reducing roughage feeding without negatively affecting rumen health is of interest in ruminant nutrition. We investigated the effects of roughage sources and concentrate types on growth performance, ruminal fermentation, and blood metabolite levels in growing cattle.
In this 24-week trial, 24 Hanwoo cattle (224±24.7 kg) were fed similar nitrous and energy levels of total mixed ration formulated using two kinds of roughage (timothy hay and ryegrass straw) and two types of concentrate mixes (high starch [HS] and high fiber [HF]). The treatments were arranged in a 2×2 factorial, consisting of 32% timothy-68% HS, 24% timothy-76% HF, 24% ryegrass-76% HS, and 17% ryegrass-83% HF. Daily feed intakes were measured. Every four weeks, blood were sampled, and body weight was measured before morning feeding. Every eight weeks, rumen fluid was collected using a stomach tube over five consecutive days.
The mean dry matter intake (7.33 kg) and average daily gain (1,033 g) did not differ among treatments. However, significant interactions between roughage source and concentrate type were observed for the rumen and blood parameters (p<0.05). Total volatile fatty acid concentration was highest (p<0.05) in timothy-HF-fed calves. With ryegrass as the roughage source, decreasing the roughage inclusion rate increased the molar proportion of propionate and decreased the acetate-to-propionate ratio; the opposite was observed with timothy as the roughage source. Similarly, the effects of concentrate types on plasma total protein, alanine transaminase, Ca, inorganic P, total cholesterol, triglycerides, and creatinine concentrations differed with roughage source (p<0.05).
Decreasing the dietary roughage inclusion rate by replacing forage neutral detergent fiber with that from non-roughage fiber source might be a feasible feeding practice in growing cattle. A combination of low-quality roughage with a high fiber concentrate might be economically beneficial.
在反刍动物营养中，减少粗饲料投喂量同时又不负面影响瘤胃健康是备受关注的问题。我们研究了粗饲料来源和精料类型对生长牛生长性能、瘤胃发酵及血液代谢物水平的影响。
在这项为期24周的试验中，24头韩牛（224±24.7千克）被投喂使用两种粗饲料（猫尾草干草和黑麦草秸秆）和两种精料混合料（高淀粉[HS]和高纤维[HF]）配制的营养水平相近的总混合日粮。试验处理采用2×2析因设计，包括32%猫尾草-68%HS、24%猫尾草-76%HF、24%黑麦草-76%HS和17%黑麦草-83%HF。测定每日采食量。每四周采集一次血液样本，并在晨饲前测量体重。每八周连续五天使用胃管收集瘤胃液。
各处理间平均干物质采食量（7.33千克）和平均日增重（1033克）无差异。然而，在瘤胃和血液参数方面观察到粗饲料来源和精料类型之间存在显著交互作用（p<0.05）。饲喂猫尾草-HF的犊牛总挥发性脂肪酸浓度最高（p<0.05）。以黑麦草为粗饲料来源时，降低粗饲料添加比例会增加丙酸的摩尔比例并降低乙酸与丙酸的比例；以猫尾草为粗饲料来源时则观察到相反的情况。同样，精料类型对血浆总蛋白、谷丙转氨酶、钙、无机磷、总胆固醇、甘油三酯和肌酐浓度的影响因粗饲料来源而异（p<0.05）。
用非粗饲料纤维源替代饲草中性洗涤纤维来降低日粮中粗饲料添加比例，对于生长牛来说可能是一种可行的饲养方式。低质量粗饲料与高纤维精料的组合可能在经济上有益。
