Makkar H P, Singh B
J Dairy Sci. 1987 Jun;70(6):1313-7. doi: 10.3168/jds.S0022-0302(87)80147-9.
Chaffed wheat straw treated with urea (5% wt/wt) alone or with rumen liquor, a source of urease (EC 3.5.1.5), was stored in polythene bags at 4, 22, and 37 degrees C up to 60 d. Moisture concentration was adjusted to 40%. Urea remaining in the straw and ammonia concentrations in the bags were measured on 2, 4, 8, 12, 16, 25, 40 and 60 d. Urea hydrolysis increased exponentially with time. Hydrolysis of urea was highest at 22 degrees C followed by 37 and 4 degrees C. Addition of rumen liquor substantially increased rate of urea hydrolysis at all temperatures studied, suggesting that treatment time can be reduced by addition of rumen liquor. Rates of ammonia binding at different temperatures were in the order 22 degrees C greater than 37 degrees C greater than 4 degrees C. No hydrolysis of urea was observed up to 7 d of storage at 22 and 37 degrees C when straw was autoclaved and the treatment was carried out under aseptic conditions.
单独用尿素（5%重量/重量）或与瘤胃液（一种脲酶来源，EC 3.5.1.5）处理的麦秸，在4、22和37摄氏度下储存在聚乙烯袋中长达60天。将水分浓度调整至40%。在第2、4、8、12、16、25、40和60天测量麦秸中残留的尿素以及袋中的氨浓度。尿素水解随时间呈指数增加。尿素水解在22摄氏度时最高，其次是37摄氏度和4摄氏度。在所有研究温度下，添加瘤胃液显著提高了尿素水解速率，这表明添加瘤胃液可缩短处理时间。不同温度下氨结合速率的顺序为22摄氏度大于37摄氏度大于4摄氏度。当麦秸经过高压灭菌且处理在无菌条件下进行时，在22和37摄氏度下储存长达7天未观察到尿素水解。
