Plant secondary compounds (PSC) are prevalent in many woody, temperate-climate plant species and play a crucial role in dietary attempts to mitigate methane emissions in ruminants. However, their application requires sufficient palatability and feeding value. In the present study, leaves from silver birch (Betula pendula), hazel (Corylus avellana), blackcurrant (Ribes nigrum), green grape vine (Vitis vinifera) and the herbs rosebay willow (Epilobium angustifolium) and wood avens (Geum urbanum) were tested in various doses with the Hohenheim gas test method in vitro and their short-term palatability in dairy cows. For the palatability experiment, the plants were pelleted with lucerne in different proportions to obtain the same phenol content, but realised contents differed from expected contents. The pellets were provided separately from a mixed basal ration (0.4 : 0.6) to each cow, in a randomised order, for 3 days per plant. All plants mitigated in vitro methane and ammonia formation, often in a linear dose response. These levels of effects differed among plants. Significant effects were observed at 100 (hazel, rosebay willow) to 400 g/kg of plant material. The test plants had a lower feeding value than the high-quality basal diet. This was indicated by in vitro organic matter digestibility, short-chain fatty acid formation and calculated contents of net energy of lactation. Simultaneously, the linear depression of ammonia formation indicated a dose-dependent increase of utilisable CP. Only blackcurrant and birch were less preferred to lucerne. However, this aversion subsided on day 3 of offer. The rosebay willow pellets had the highest phenol content but were not the least palatable. Accordingly, PSC may not be the main determinants of palatability for the plants tested. Plants did not differ significantly in their short-term effects on milk yield and composition, and all of the plants substantially reduced milk urea content. Overall, the results suggest that hazel and vine leaves, and rosebay willow and wood avens herbs should be tested for their potential to mitigate methane and N emissions in vivo.

中文翻译：

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木本和草料饲用植物对体外瘤胃甲烷和氨气形成的剂量反应效应，以及它们在泌乳母牛中的短期适口性。

植物次生化合物（PSC）在许多木本，温带气候的植物物种中普遍存在，并且在膳食尝试中减少反刍动物甲烷排放的过程中起着至关重要的作用。然而，它们的应用需要足够的适口性和饲喂价值。在本研究中，分别是白桦（Betula pendula），榛（Corylus avellana），黑加仑（Ribes nigrum），绿葡萄树（Vitis vinifera）和草药玫瑰湾柳树（Epilobium angustifolium）和木avens（Geum urbanum）的叶子。用Hohenheim气体测试方法在体外以各种剂量进行测试，以及它们在奶牛中的短期适口性。为了进行适口性实验，将植物与卢塞恩按不同比例进行制粒，以获得相同的苯酚含量，但实际含量与预期含量不同。将颗粒与混合基础日粮（0.4：0.6）分开以随机顺序分别提供给每头母牛，每株3天。所有植物通常以线性剂量响应减轻体外甲烷和氨的形成。这些效应水平在植物之间有所不同。在100（榛树，玫瑰湾柳）至400 g / kg的植物材料中观察到了显着的影响。受试植物的饲喂价值低于优质基础饮食。体外有机物的消化率，短链脂肪酸的形成和泌乳净能量的计算值表明了这一点。同时，氨形成的线性下降表明可利用CP的剂量依赖性增加。仅黑加仑和桦树比卢塞恩更不受欢迎。但是，这种厌恶情绪在报价的第3天就平息了。玫瑰湾柳颗粒的苯酚含量最高，但味道也不差。因此，PSC可能不是测试植物适口性的主要决定因素。植物对牛奶产量和组成的短期影响没有显着差异，所有植物都大大降低了牛奶尿素含量。总体而言，研究结果表明，应测试榛树和藤本植物的叶子，玫瑰湾柳树和木本植物的药草在体内缓解甲烷和氮排放的潜力。