Including ramie (Boehmeria nivea L. Gaud) in the diet of dairy cows: effects on production performance, milk composition, rumen fermentation, and nutrient digestion

This experiment was conducted to examine the effects of substituting mixed silage (fresh ramie: dry rice straw = 80: 20; kg: kg) composed of fresh forage ramie, also known as 'China grass', Boehmeria nivea L. Gaud (a nettle native to Asia) and rice straw for corn silage and alfalfa hay on the production performance, milk components, rumen fermentation parameters, and nutrient digestion in dairy cows. Thirty multiparous Chinese Holstein cows (629 +/- 59.2 kg of BW, 25 +/- 4.7 kg of milk yield, and 100 +/- 18 DIM; mean +/- SD) were randomly divided into three groups. The experimental treatments containing three diets, each consisting of differing proportions of mixed silage (0%, 10%, and 20%, designated as CON, MS1, and MS2, respectively) as a substitution for corn silage and alfalfa hay. There were no effects of mixed silage diets on dry matter intake (DMI), 3.5% fat-corrected milk (FCM) yield, milk protein percentage, milk somatic cell count, and milk urea nitrogen (MUN), but linearly increased total solids (p = .03) and milk fat percentage (p = .001) in cows fed the MS1 and MS2 diets. Feeding mixed silage diets linearly reduced milk yield (p = .01) and milk lactose percentage (p = .01), and had linearly increased rumen pH values (p = .01). There were no observable differences in other rumen fermentation parameters between the mixed silage and control diets. Mixed silage diets exhibited increased DM digestibility (linearly, p = .04; quadratically, p = .017) and linearly decreased crude protein digestibility (p = .05), but we observed no differences in the apparent total-tract digestibility of EE, NDF, and ADF between the control and mixed silage diets. In conclusion, using ramie and rice straw mixed silage proved beneficial by increasing milk fat percentage, milk solids, and DM digestibility, ramie could be used as a potential forage resource in dairy cow diets.