Gould D H, Cummings B A, Hamar D W
Department of Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins 80523, USA.
J Vet Diagn Invest. 1997 Jan;9(1):72-6. doi: 10.1177/104063879700900113.
Two groups of 3 120-160-kg Holstein steers were fed a diet high in carbohydrate and low in long fiber and either with or without added sodium sulfate. Prior to and during the course of feeding the experimental diet, the concentrations of rumen hydrogen sulfide gas and rumen fluid sulfide were determined by a simple sulfide detector tube method and by sulfide-selective electrode, respectively. Other measurements included rumen fluid pH, blood creatine kinase, and blood sulfhemoglobin. Two of the 3 steers fed the high-sulfate diet developed signs and lesions of polioencephalomalacia. Clinical signs included episodic ataxia and blunted or absent menace reaction. Increased ruminal H2S gas concentrations occurred in all 3 steers consuming the diet with added sulfate. The onset of clinical signs coincided with the onset of elevated H2S concentrations. These increases were 40-60 times the values measured in the steers consuming the diet without added sulfate. In contrast, increases in rumen fluid sulfide concentrations usually rose to 4 times that of control steers. The steers fed an identical diet but without added sulfate exhibited no signs or lesions of polioencephalomalacia and no elevations of sulfide in rumen gas or fluid. All steers had a modest decrease in rumen fluid pH associated with the transition to the concentrate diet. No significant changes were observed in any of the blood measurements of any of the steers. An additional pair of steers was fed the experimental diet with or without added sulfate to compare the ruminal H2S gas concentrations estimated by H2S detector tubes with those estimated by a different method of analysis utilizing charcoal trapping of H2S, conversion to sulfate, and measurement of the sulfate. Both methods yielded comparable estimates of H2S concentration. Overall, these data indicate that changes in rumen gas cap H2S concentrations are larger than changes in rumen fluid sulfide concentration and the estimation of rumen gas cap H2S concentration may be a practical approach to detecting pathologic increases in ruminal H2S gas. This simple, rapid, minimally invasive method should be useful for estimating the H2S content of ruminal gas under field conditions.
两组体重120 - 160千克的荷斯坦公牛，被喂食高碳水化合物、低长纤维的日粮，一组添加硫酸钠，另一组不添加。在喂食实验日粮之前和过程中，分别通过简单的硫化物检测管法和硫化物选择性电极测定瘤胃硫化氢气体浓度和瘤胃液硫化物浓度。其他测量指标包括瘤胃液pH值、血液肌酸激酶和血液硫血红蛋白。喂食高硫酸盐日粮的3头公牛中有2头发病，出现脑灰质软化的症状和病变。临床症状包括间歇性共济失调以及威胁反应迟钝或消失。所有3头食用添加硫酸盐日粮的公牛瘤胃硫化氢气体浓度均升高。临床症状的出现与硫化氢浓度升高同步。这些升高幅度是食用未添加硫酸盐日粮的公牛所测值的40 - 60倍。相比之下，瘤胃液硫化物浓度通常升至对照公牛的4倍。喂食相同日粮但未添加硫酸盐的公牛未出现脑灰质软化的症状或病变，瘤胃气体或液体中的硫化物也未升高。所有公牛在过渡到精料日粮时瘤胃液pH值均有适度下降。所有公牛的任何血液测量指标均未观察到显著变化。另外一对公牛被喂食添加或不添加硫酸盐的实验日粮，以比较用硫化氢检测管估计的瘤胃硫化氢气体浓度与用另一种分析方法估计的浓度，后者利用活性炭捕集硫化氢、转化为硫酸盐并测量硫酸盐。两种方法得出的硫化氢浓度估计值相当。总体而言，这些数据表明瘤胃气体顶空硫化氢浓度的变化大于瘤胃液硫化物浓度的变化，估计瘤胃气体顶空硫化氢浓度可能是检测瘤胃硫化氢气体病理性升高的一种实用方法。这种简单、快速、微创的方法应有助于在现场条件下估计瘤胃气体中的硫化氢含量。
