酵母培养物添加及季节推进对大平原北部混合草草原放牧阉牛的影响：II. 瘤胃发酵、消化部位及微生物效率

Influence of yeast culture supplementation and advancing season on steers grazing mixed-grass prairie in the northern Great Plains: II. Ruminal fermentation, site of digestion, and microbial efficiency.

作者信息

Olson K C, Caton J S, Kirby D R, Norton P L

机构信息

Department of Animal and Range Sciences, North Dakota State University, Fargo 58105.

出版信息

J Anim Sci. 1994 Aug;72(8):2158-70. doi: 10.2527/1994.7282158x.

DOI:10.2527/1994.7282158x

PMID:7982847

Abstract

Twelve ruminally and duodenally cannulated beef steers (initial BW 368 +/- 25.3 kg) and four ruminally cannulated beef heifers (initial BW 559 +/- 79.5 kg) were used to evaluate the effects of yeast culture (YC) and advancing season on ruminal fermentation, microbial protein synthesis, ruminal fluid kinetics, and site of digestion. Treatments were control and YC supplementation (28.4 g.steer-1.d-1 dosed ruminally). Steers grazed from late June to early November 1991 on mixed-grass prairie. Ruminal pH decreased (P < .10) from late July to early October. Fluid dilution rate decreased (P < .10) as the grazing season advanced, whereas ruminal fluid volume and flow rate increased (P < .10) from late July to early October. Ruminal ammonia concentration (milligrams/deciliter) was lower (P < .10) during late July and late August than during late June and early October at 4, 8, 12, and 16 h after sunrise in YC-supplemented steers. Molar proportions of propionate and butyrate were greater (P < .10) in control than in YC-supplemented steers at 0, 4, 12, and 24 h and 0, 4, and 12 h after sunrise, respectively, during late July. Acetate (mol/100 mol) was greater (P < .10) during late July and late August than in late June and early October for YC-supplemented steers at 0, 4, and 8 h after sunrise. True ruminal OM digestion was greatest (P < .10) in late June, intermediate in late July and late August, and least in early October. Supplementation with YC increased (P < .04) true ruminal OM digestion in late June and late July. Steers receiving YC had greater (P < .07) duodenal bacterial N flow in late July. These data indicate that yeast culture supplementation can increase true OM digestibility early in the grazing season. Advancing season seems to result in increased ruminal fluid volume, lower true ruminal OM digestion, and greater microbial efficiency.

摘要

选用12头安装了瘤胃和十二指肠瘘管的肉用公牛（初始体重368±25.3千克）和4头安装了瘤胃瘘管的肉用小母牛（初始体重559±79.5千克），以评估酵母培养物（YC）和季节推进对瘤胃发酵、微生物蛋白合成、瘤胃液动力学及消化部位的影响。处理方式为对照组和补充YC组（每头公牛每天瘤胃内投给28.4克）。公牛于1991年6月下旬至11月初在混合草场上放牧。从7月下旬到10月初瘤胃pH值下降（P<0.10）。随着放牧季节推进，液体稀释率下降（P<0.10），而瘤胃液体积和流速从7月下旬到10月初增加（P<0.10）。在补充YC的公牛中，7月下旬和8月下旬日出后4、8、12和16小时的瘤胃氨浓度（毫克/分升）低于6月下旬和10月初。在7月下旬，对照组在日出后0、4、12和24小时以及0、4和12小时的丙酸和丁酸摩尔比例分别高于补充YC的公牛（P<0.10）。在7月下旬和8月下旬，补充YC的公牛在日出后0、4和8小时的乙酸（摩尔/100摩尔）高于6月下旬和10月初（P<0.10）。真瘤胃有机物消化率在6月下旬最高（P<0.10），7月下旬和8月下旬居中，10月初最低。补充YC可提高6月下旬和7月下旬的真瘤胃有机物消化率（P<0.04）。7月下旬，接受YC的公牛十二指肠细菌氮流量更高（P<0.07）。这些数据表明，在放牧季节早期补充酵母培养物可提高真有机物消化率。季节推进似乎会导致瘤胃液体积增加、真瘤胃有机物消化率降低以及微生物效率提高。