Impeller mowing conditioners are commonly used to speed up the drying process on the field, making forage preservation (haying, ensiling) less dependent on weather conditions. However, the effects of this technique on the nutritive value of the forage and dairy cows' responses have not been investigated yet. Each half of two fields of grass-dominated swards, first regrowth, was cut either with or without the use of an impeller mowing conditioner (experimental hay and control hay, respectively). Ceteris paribus conditions were guaranteed by the same cutting and wilting times (roughly 48 h), number of teddings, field pickup technique and barn-drying method. At the beginning of the feeding trial, 19 lactating Holstein cows were allocated to one of two groups, one control (nine cows) and one experimental group (10 cows) and were fed the respective forage plus a fixed amount of concentrate [3.6 kg d−1; dry matter (DM) basis]. After a 14-d adaptation period, data were collected over 21 consecutive days. Covariate data of cows were collected prior to the experimental feeding period, over a time span of 9 d, and included in the statistical model. Results revealed that control and experimental hay showed significant (P < 0.05) differences in the nutrient profile. However, the magnitude of these differences was not enough to affect intakes of hay (18.4 ± 0.29 kg DM d−1), total dietary energy or chewing activity, but did lead to a decreased intake of water-soluble carbohydrates and an increased crude protein intake, thus affecting ruminal nitrogen balance (P < 0.01). This resulted in a higher milk urea content [23.3 vs 17.9 mg (100 mL)−1; P < 0.01] in cows fed the experimental hay, whereas other milk performance parameters remained unaffected. In conclusion, the use of the impeller mowing conditioner did not affect the overall forage utilization by cows when the diet contained about 16% concentrate (DM basis). As this is the first study dealing with the effects of an impeller mowing conditioner on cows' responses, future research should consider investigating the effects of mowing conditioners when cows are fed only forage or diets with lower concentrate amounts.

中文翻译：

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在干草制作过程中使用叶轮割草调节器对有机奶牛的采食行为、采食量或生产性能没有影响

叶轮割草调节器通常用于加速田间的干燥过程，从而减少草料保存（干草、青贮）对天气条件的依赖。然而，尚未研究该技术对草料的营养价值和奶牛反应的影响。在使用或不使用叶轮割草调节器（分别为实验干草和对照干草）的情况下，切割两片以草为主的草皮，首先是再生草的每一半。其他条件不变条件由相同的切割和萎蔫时间（大约 48 小时）、薹数量、田间拾取技术和谷仓干燥方法来保证。在饲喂试验开始时，将 19 头泌乳荷斯坦奶牛分配到两组中的一组，一组对照组（9 头奶牛）和一组实验组（10 头奶牛），分别饲喂各自的草料和固定量的精料 [3.6 kg d-1; 干物质（DM）基础]。经过 14 天的适应期后，连续 21 天收集数据。奶牛的协变量数据在实验喂养期之前收集，超过 9 天的时间跨度，并包含在统计模型中。结果表明，对照和实验干草显示显着（磷< 0.05) 营养成分的差异。然而，这些差异的大小不足以影响干草的摄入量（18.4 ± 0.29 kg DM d-1），总日粮能量或咀嚼活动，但确实导致水溶性碳水化合物的摄入量减少和粗蛋白摄入量增加，从而影响瘤胃氮平衡（磷< 0.01)。这导致更高的牛奶尿素含量 [23.3对比17.9 毫克（100 毫升）-1;磷< 0.01] 在饲喂实验干草的奶牛中，其他牛奶性能参数不受影响。总之，当日粮中含有约 16% 的精料（基于干物质）时，使用叶轮割草调节剂不会影响奶牛的整体草料利用率。由于这是第一项研究叶轮割草调节剂对奶牛反应的影响，未来的研究应该考虑调查割草调节剂在奶牛只喂饲草料或低精饲料时的影响。