Department of Animal and Poultry Science, College of Agricultural and Bioresources, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5A8, Canada.
Lethbridge Research and Development Center, Agriculture and Agri-Food Canada, Lethbridge, Alberta T1J 4B1, Canada.
J Dairy Sci. 2018 Sep;101(9):7971-7979. doi: 10.3168/jds.2017-14203. Epub 2018 Jun 28.
The objectives of this study were to evaluate the effects of pretreating dairy cow rations with a fibrolytic enzyme derived from Trichoderma reesei (FETR; mixture of xylanase and cellulase; AB Vista, Wiltshire, UK) on lactation performance, digestibility, and feeding behavior in response to feeding a barley silage-based diet. Before starting the dairy trial, in vitro incubations were conducted to determine whether the addition of FETR would have an effect on these animal performance characteristics when applied to a barley silage-based diet for dairy cows. The dairy trial was performed using 8 Holstein dairy cows. The cows were blocked by parity and assigned randomly to 1 of 4 treatments: 0, 0.5, 0.75, and 1 mL of FETR/kg of dry matter (DM) diet in a replicated Latin square design. The pretreatment was applied to the complete diet during the mixing process. The experimental period continued for 22 d, with each experimental period consisting of a 16-d adaptation period and a 6-d sampling period. The daily feed intake of each individual cow was monitored using Insentec feed bins (RIC system, Insentec, Marknesse, the Netherlands). Feeding behavior characteristics were measured during the entire sampling period using the feed bin attendance data. Milk samples were collected in the last 3 d of each experimental period. The addition of FETR linearly increased the in vitro DM digestibility and tended to improve the in vitro digestibility of barley silage. There was a cubic effect of the enzyme levels on the total-tract DM and neutral detergent fiber digestibility. Maximal digestibility was reached at 0.75 mL of FETR/kg of TMR. The milk fat yield, fat-corrected milk, and energy-corrected milk quadratically responded to the incremental levels of FETR. The milk protein percentage linearly improved in response to FETR. Increasing FETR levels resulted in a quadratic effect on feed efficiency. There was no effect of FETR level on feeding behavior. In conclusion, pretreating dairy cow barley silage-based diet with 0.75 mL of FETR/kg of TMR increased the milk production efficiency of dairy cows fed diet containing 34% barley silage (DM basis). The positive effect of adding FETR could benefit the dairy industry in western Canada, where barley silage-based diets are common.
本研究的目的是评估用源自里氏木霉（Trichoderma reesei）的纤维分解酶（FETR；木聚糖酶和纤维素酶混合物；AB Vista，威尔特郡，英国）预处理奶牛日粮对泌乳性能、消化率和采食行为的影响，以响应饲喂大麦青贮日粮。在开始奶牛试验之前，进行了体外孵育，以确定当将 FETR 添加到用于奶牛的大麦青贮日粮中时，它是否会对这些动物性能特征产生影响。奶牛试验使用 8 头荷斯坦奶牛进行。根据胎次将奶牛分组，并随机分配到 4 种处理中的 1 种：0、0.5、0.75 和 1 毫升 FETR/千克干物质（DM）日粮，采用重复拉丁方设计。在混合过程中对预处理进行了应用。试验期持续 22 天，每个试验期包括 16 天的适应期和 6 天的采样期。使用 Insentec 饲料仓（RIC 系统，Insentec，Marknesse，荷兰）监测每头奶牛的每日采食量。在整个采样期间，使用饲料仓出勤数据测量采食行为特征。在每个试验期的最后 3 天收集牛奶样品。添加 FETR 线性增加了体外 DM 消化率，并倾向于提高大麦青贮的体外消化率。酶水平对全肠道 DM 和中性洗涤剂纤维消化率有立方效应。在 0.75 毫升 FETR/千克 TMR 达到最大消化率。乳脂产量、校正乳和校正能量乳对 FETR 的递增水平呈二次响应。牛奶蛋白百分比线性提高，对 FETR 有反应。增加 FETR 水平会对饲料效率产生二次影响。FETR 水平对采食行为没有影响。总之，用 0.75 毫升 FETR/千克 TMR 预处理奶牛的大麦青贮日粮提高了饲喂含 34%大麦青贮（DM 基础）日粮的奶牛的牛奶生产效率。在加拿大西部，添加 FETR 的积极影响可能有益于以大麦青贮为基础的日粮常见的奶牛养殖业。
