Weiss W P, Conrad H R, Martin C M, Cross R F, Shockey W L
J Anim Sci. 1986 Aug;63(2):525-32. doi: 10.2527/jas1986.632525x.
Some animals consuming hay treated with anhydrous ammonia have developed neurological signs including hyperexcitability, circling and convulsions. A series of experiments was conducted to identify tentatively the toxin and determine its mode of action. Three out of four sheep fed ammoniated orchardgrass hay (approximately 4% ammonia on a dry basis) developed convulsions. Two of the three sheep died within 18 h of the onset of signs. The concentrations of blood lactate and pyruvate were elevated in the symptomatic sheep (P less than .05). A proposed toxin, 4-methyl imidazole, did not induce the syndrome when 750 mg/d (approximately 10 times the dietary amount) were administered orally. Four out of five calves that received milk from cows fed ammoniated oat hay (approximately 5% ammonia on dry basis) displayed hyperexcitability and circling. Concentrations of blood lactate and pyruvate were also elevated in the calves. The crude alkaloid fraction of the toxic milk produced neurological signs similar to those of the calves when injected into mice. A fluorescent compound was found in the alkaloid fraction of toxic milk and ammoniated hay, but not in control milk or untreated hay. The fluorescent compound was quite labile; hence, characterization has been unsuccessful thus far.
一些食用了用无水氨处理过的干草的动物出现了神经症状，包括过度兴奋、转圈和抽搐。进行了一系列实验来初步鉴定毒素并确定其作用方式。四只喂食氨化果园草干草（干基含氨约4%）的绵羊中有三只出现了抽搐。三只绵羊中有两只在症状出现后的18小时内死亡。有症状绵羊的血液乳酸和丙酮酸浓度升高（P小于0.05）。一种推测的毒素4-甲基咪唑，当以750毫克/天（约为日粮量的10倍）口服时，并未诱发该综合征。五只从喂食氨化燕麦干草（干基含氨约5%）的奶牛获取牛奶的小牛中有四只表现出过度兴奋和转圈。小牛的血液乳酸和丙酮酸浓度也升高了。将有毒牛奶的粗生物碱部分注射到小鼠体内时，产生了与小牛相似的神经症状。在有毒牛奶和氨化干草的生物碱部分中发现了一种荧光化合物，但在对照牛奶或未处理的干草中未发现。这种荧光化合物相当不稳定；因此，到目前为止对其进行表征的尝试尚未成功。
