Agriculture and Agri-Food Canada, Sherbrooke Research and Development Centre, 2000 College Street, Sherbrooke, QC, Canada J1M 0C8.
Agriculture and Agri-Food Canada, Sherbrooke Research and Development Centre, 2000 College Street, Sherbrooke, QC, Canada J1M 0C8.
J Dairy Sci. 2019 Dec;102(12):11766-11776. doi: 10.3168/jds.2018-16014. Epub 2019 Oct 3.
The objective of this study was to investigate the effects of forage source (red clover silage: RCS vs. corn silage: CS) and diet supplementation with linseed oil (LO) on CH emissions of manure from dairy cows. For this purpose, 12 lactating cows were used in a 2 × 2 factorial arrangement of treatments. Cows were fed (ad libitum) RCS- or CS-based diets (forage:concentrate ratio 60:40; dry matter basis) without or with LO addition (4% dry matter). Feces and urine were collected from each cow and mixed with residual sludge obtained from a manure storage structure. Manure was incubated for 17 wk at 20°C under anaerobic conditions (O-free N) in 500-mL glass bottles. Methane emissions and changes in chemical composition of the manure were monitored during the entire incubation period. The total amount of feces and urine excreted by cows was not affected by dietary treatments and averaged 6.6 kg/d of volatile solids (VS). Compared with manure from cows fed RCS-based diets, maximum CH production potential of manure from cows fed CS-based diets was 54% higher (182 vs. 118 L/kg of VS) throughout the incubation period. Maximum CH production potential from manure also increased (by 17%) when cows were fed LO-supplemented diets compared with those fed nonsupplemented diets. Similar to maximum CH production potential, VS degraded during incubation (i.e., VS loss) was higher from manure from cows fed CS-based diets versus cows fed RCS-based diets (30.6 vs. 22.5%), and increased (+3 percentage units, on average) with the addition of LO to the diets. Ammonia concentration in manure was higher when cows were fed CS-based diets compared with RCS-based diets, and declined with LO supplementation to CS and RCS diets. It is concluded that both dietary forage source and fat supplementation affect maximum CH production potential from manure and this should be taken into account when such dietary options are recommended to mitigate enteric CH emissions from dairy cows.
本研究旨在探讨饲粮中不同饲草来源（红三叶草青贮料：RCS 与玉米青贮料：CS）和添加亚麻籽油（LO）对奶牛粪便 CH 排放的影响。为此，采用 2×2 完全交叉试验设计，选用 12 头泌乳奶牛，分为 4 个处理组，每组 3 个重复。奶牛自由采食以 RCS 或 CS 为基础的饲粮（饲草：精料比为 60:40；干物质基础），饲粮中添加或不添加 LO（占干物质的 4%）。从每头奶牛收集粪便和尿液，与从粪肥储存结构中获得的剩余污泥混合。在 20°C、厌氧条件（无氧氮）下，在 500-mL 玻璃瓶中孵育粪便 17 周。在整个孵育期间监测甲烷排放和粪便化学成分的变化。奶牛的粪便和尿液排泄总量不受饲粮处理的影响，平均每天排泄挥发性固体（VS）6.6kg。与 RCS 基础饲粮组奶牛的粪便相比，CS 基础饲粮组奶牛的粪便在整个孵育期间的最大 CH 产生潜力高 54%（182 比 118L/kgVS）。与不添加 LO 的饲粮相比，当奶牛饲喂添加 LO 的饲粮时，粪便的最大 CH 产生潜力也增加了（17%）。与最大 CH 产生潜力一样，在孵育过程中 VS 降解（即 VS 损失）也更高，CS 基础饲粮组奶牛的粪便比 RCS 基础饲粮组高（30.6 比 22.5%），并且当 LO 添加到 CS 和 RCS 饲粮中时，会平均增加（3 个百分点）。与 RCS 基础饲粮相比，CS 基础饲粮组奶牛的粪便中氨浓度更高，并且随着 LO 对 CS 和 RCS 饲粮的添加而降低。综上所述，饲粮的饲草来源和脂肪添加均影响粪便的最大 CH 产生潜力，在推荐这些饲粮选择以减少奶牛肠道 CH 排放时应考虑到这一点。
