摘要
This study investigated the degradability of corn silage (CS) and Leymus chinensis silage (LS) in vitro, and evaluated the effect of various ratios on growth performance, digestion and serum parameters in beef cattle. A 72‐hr bath culture trial was performed to evaluate degradability and rumen fermentation characteristics of CS, LS and their combinations [67:33, 33:67, dry matter (DM) basis]. Forty Simmental steers, averaging 441.46 ± 4.45 kg of body weight (BW), were randomly allocated into four dietary treatments for 120‐d period. Diets were given as total mixed rations with a forage‐to‐concentrate ratio of 60:40 and CS:LS ratios of 100:0, 67:33, 33:67 and 0:100 (DM basis). The in vitro trial showed that DM and neutral detergent fibre (NDF) degradability decreased linearly as LS proportion increased, whereas CP degradability increased linearly. Additionally, increased acid detergent fibre (ADF) degradability was detected at 48 hr of incubation. Increasing the proportion of LS increased rumen liquor pH and decreased volatile fatty acid linearly including acetate, propionate and butyrate, whereas the ammonia‐N increased linearly at 12 and 72 hr of incubation. With increasing LS ratio, final BW, average daily gain and feed conversion ratio of steers decreased linearly, whereas DMI was not affected. Additionally, apparent digestibility of DM, organic matter, NDF and ADF linearly and quadratically decreased while ether extract apparent digestibility decreased linearly, and CP apparent digestibility was not affected. Serum glucose and urea nitrogen linearly and quadratically decreased while glutamic‐pyruvic transaminase activity linearly decreased as the proportion of LS increased. Other serum parameters including total triglycerides, total cholesterol, total protein, albumin and glutamic‐oxalacetic transaminease were not affected. Overall, enhancing ratio of LS caused inferior DM and NDF degradability but improved CP degradability in the combinations of LS and CS. A CS:LS ratio of 67:33 resulted in the best growth performance and nutrient utilization in steers.
摘要译文
本研究调查了玉米青贮饲料（CS）和羊草青贮饲料（LS）的体外降解性，并评价了不同比例对肉牛生长性能，消化和血清参数的影响。进行了72小时的浴培养试验，以评估CS，LS及其组合的可降解性和瘤胃发酵特性[67：33、33：67，以干物质（DM）为基础]。四十只西门塔尔牛公牛平均体重为441.46±4.45千克（BW），随机分配到四种饮食疗法中，持续120天。日粮以总混合饲料为基础，饲料与精料的比例为60：40，CS：LS的比例为100：0、67：33、33：67和0：100（以DM为基础）。体外试验表明，DM和中性洗涤剂纤维（NDF）的降解性随着LS比例的增加而线性降低，而CP降解性则线性增加。另外，在孵育48小时后发现酸性洗涤剂纤维（ADF）的降解性增加。 LS的比例增加会提高瘤胃液的pH值，而挥发性脂肪酸线性减少，包括乙酸盐，丙酸酯和丁酸盐，而氨氮在孵育12和72小时时呈线性增加。随着LS比率的增加，公猪的最终BW，平均日增重和饲料转化率线性下降，而DMI不受影响。此外，DM，有机物，NDF和ADF的表观消化率线性和二次下降，而醚提取物的表观消化率线性下降，而CP的表观消化率不受影响。随着LS比例的增加，血清葡萄糖和尿素氮呈线性和二次方下降，而谷氨酸丙酮酸转氨酶活性呈线性下降。其他血清参数，包括总甘油三酸酯，总胆固醇，总蛋白，白蛋白和谷氨酸-草酰乙酸转氨酶均不受影响。总体而言，LS的增加比例导致DM和NDF的降解性较差，但在LS和CS的组合中CP的降解性得到改善。 CS：LS比率为67:33可使ste牛的生长性能和养分利用率达到最佳。
Xianglun Zhang[1];Hongliang Wang[2];Wei You[1];Hongbo Zhao[1];Chen Wei[1];Qing Jin[1];Xiaomu Liu[1];Guifen Liu[1];Xiuwen Tan[1];Xingling Wang[1];Fachun Wan[1];Xiaoyu Sun[2]. In vitro degradability of corn silage and Leymus chinensis silage and evaluation of their mixed ratios on performance, digestion and serum parameters in beef cattle[J]. Journal of Animal Physiology and Animal Nutrition, 2020,104(6): 1628-1636