Silvestre T, Martins L F, Cueva S F, Wasson D E, Stepanchenko N, Räisänen S E, Sommai S, Hile M L, Hristov A N
Department of Animal Science, The Pennsylvania State University, University Park, PA 16802.
Department of Animal Science, Khon Kaen University, Thailand 40002.
J Dairy Sci. 2023 Nov;106(11):7661-7674. doi: 10.3168/jds.2022-23181. Epub 2023 Aug 23.
The objective of this experiment was to investigate the effects of an essential oil (EO) blend on lactational performance, rumen fermentation, nutrient utilization, blood variables, enteric methane emissions and manure greenhouse gas-emitting potential in dairy cows. A randomized complete block design experiment was conducted with 26 primiparous and 22 multiparous Holstein cows. A 2-wk covariate and a 2-wk adaptation periods preceded a 10-wk experimental period used for data and sample collection. Treatments were: (1) basal diet supplemented with placebo (CON); and (2) basal diet supplemented with a blend of EO containing eugenol and geranyl acetate as main compounds. Supplementation with EO did not affect dry matter intake, milk and energy-corrected milk yields, and feed efficiency of cows, compared with CON. Milk fat and lactose concentrations were increased, and milk total solids (TS) concentration and milk fat yield tended to be increased by EO. Multiparous cows supplemented with EO tended to have slightly decreased dry matter and crude protein digestibility compared with CON multiparous cows. There was a tendency for increased ruminal pH by EO, whereas other rumen fermentation variables did not differ between treatments. Daily methane emission was not affected by EO supplementation, but methane emission intensity per kg of milk fat was decreased by 8.5% by EO. Methane emission intensity per kg of milk lactose and milk TS were decreased and methane emission intensity per kg of milk yield tended to be decreased by up to 10% in EO multiparous cows, but not in primiparous cows. The greenhouse gas-emitting potential of manure was not affected by EO supplementation. Compared with CON, fecal nitrogen excretion was increased by EO supplementation in multiparous, but not in primiparous cows, and milk nitrogen secretion (as a % of nitrogen intake) tended to be increased in EO supplemented cows. Blood variables were not affected by EO supplementation in the current study. Overall, dietary supplementation of EO did not affect lactational performance of the cows, although milk fat and lactose concentrations were increased. Most enteric methane emission metrics were not affected, but EO decreased methane intensity per kg of milk fat by 8.5%, compared with the control.
本实验的目的是研究一种精油（EO）混合物对奶牛泌乳性能、瘤胃发酵、养分利用、血液指标、肠道甲烷排放以及粪便温室气体排放潜力的影响。采用随机完全区组设计实验，选用26头初产和22头经产荷斯坦奶牛。在为期10周的数据和样本收集实验期之前，有2周的协变量期和2周的适应期。处理方式为：（1）基础日粮添加安慰剂（CON）；（2）基础日粮添加以丁香酚和乙酸香叶酯为主要成分的EO混合物。与CON组相比，添加EO对奶牛的干物质摄入量、牛奶和能量校正乳产量以及饲料效率没有影响。EO使牛奶脂肪和乳糖浓度升高，牛奶总固体（TS）浓度和牛奶脂肪产量有升高趋势。与CON组经产奶牛相比，添加EO的经产奶牛干物质和粗蛋白消化率有略微下降趋势。EO使瘤胃pH有升高趋势，而其他瘤胃发酵变量在各处理间无差异。每日甲烷排放不受添加EO的影响，但EO使每千克牛奶脂肪的甲烷排放强度降低了8.5%。添加EO的经产奶牛每千克牛奶乳糖和牛奶TS的甲烷排放强度降低，每千克牛奶产量的甲烷排放强度有降低趋势，最高可达10%，但初产奶牛无此现象。添加EO对粪便温室气体排放潜力没有影响。与CON组相比，添加EO使经产奶牛粪便氮排泄增加，但初产奶牛无此现象，添加EO的奶牛牛奶氮分泌（占氮摄入量的百分比）有升高趋势。在本研究中，血液指标不受添加EO的影响。总体而言，日粮添加EO虽使牛奶脂肪和乳糖浓度升高，但对奶牛泌乳性能没有影响。大多数肠道甲烷排放指标不受影响，但与对照组相比，EO使每千克牛奶脂肪的甲烷强度降低了8.5%。
