Instituto de Ciências Agrárias e Ambientais, Universidade Federal de Mato Grosso, Campus Sinop, Sinop, MT 78557-267, Brazil; Department of Animal Sciences, University of Florida, Gainesville 32611.
Department of Animal Sciences, University of Florida, Gainesville 32611; Department of Food Quality and Safety, Agricultural Research Organization, The Volcani Center, Bet Dagan 50250, Israel.
J Dairy Sci. 2017 Jun;100(6):4587-4603. doi: 10.3168/jds.2016-11815. Epub 2017 Mar 23.
Forages are usually inoculated with homofermentative and facultative heterofermentative lactic acid bacteria (LAB) to enhance lactic acid fermentation of forages, but effects of such inoculants on silage quality and the performance of dairy cows are unclear. Therefore, we conducted a meta-analysis to examine the effects of LAB inoculation on silage quality and preservation and the performance of dairy cows. A second objective was to examine the factors affecting the response to silage inoculation with LAB. The studies that met the selection criteria included 130 articles that examined the effects of LAB inoculation on silage quality and 31 articles that investigated dairy cow performance responses. The magnitude of the effect (effect size) was evaluated using raw mean differences (RMD) between inoculated and uninoculated treatments. Heterogeneity was explored by meta-regression and subgroup analysis using forage type, LAB species, LAB application rate, and silo scale (laboratory or farm-scale) as covariates for the silage quality response and forage type, LAB species, diet type [total mixed ration (TMR) or non-TMR], and the level of milk yield of the control cows as covariates for the performance responses. Inoculation with LAB (≥10 cfu/g as fed) markedly increased silage fermentation and dry matter recovery in temperate and tropical grasses, alfalfa, and other legumes. However, inoculation did not improve the fermentation of corn, sorghum, or sugarcane silages. Inoculation with LAB reduced clostridia and mold growth, butyric acid production, and ammonia-nitrogen in all silages, but it had no effect on aerobic stability. Silage inoculation (≥10 cfu/g as fed) increased milk yield and the response had low heterogeneity. However, inoculation had no effect on diet digestibility and feed efficiency. Inoculation with LAB improved the fermentation of grass and legume silages and the performance of dairy cows but did not affect the fermentation of corn, sorghum, and sugar cane silages or the aerobic stability of any silage. Further research is needed to elucidate how silage inoculated with homofermentative and facultative heterofermentative LAB improves the performance of dairy cows.
饲料通常接种同型发酵和兼性异型发酵乳酸菌（LAB），以增强饲料的乳酸发酵，但这种接种剂对青贮质量和奶牛性能的影响尚不清楚。因此，我们进行了荟萃分析，以检查 LAB 接种对青贮质量和青贮保存以及奶牛性能的影响。第二个目的是检查影响 LAB 接种青贮的响应的因素。符合选择标准的研究包括 130 篇检查 LAB 接种对青贮质量影响的文章和 31 篇研究奶牛性能响应的文章。使用接种和未接种处理之间的原始平均差异（RMD）评估效应大小。通过元回归和亚组分析探索异质性，使用饲料类型、LAB 种类、LAB 应用率和青贮窖规模（实验室或农场规模）作为青贮质量响应的协变量，以及饲料类型、LAB 种类、日粮类型[全混合日粮（TMR）或非-TMR]和对照奶牛的产奶量水平作为性能响应的协变量。接种 LAB（≥10 cfu/g 进料）显著提高了温带和热带草、紫花苜蓿和其他豆类的青贮发酵和干物质回收。然而，接种不能改善玉米、高粱或甘蔗青贮的发酵。接种 LAB 减少了梭菌和霉菌的生长、丁酸的产生和所有青贮中的氨氮，但对有氧稳定性没有影响。接种 LAB（≥10 cfu/g 进料）增加了牛奶产量，且响应的异质性较低。然而，接种对日粮消化率和饲料效率没有影响。接种 LAB 改善了草和豆科青贮的发酵和奶牛的性能，但对玉米、高粱和甘蔗青贮的发酵或任何青贮的有氧稳定性没有影响。需要进一步的研究来阐明同型发酵和兼性异型发酵 LAB 接种如何改善奶牛的性能。
