Jagos P, Bouda J, Skrivánek M
Vet Med (Praha). 1986 Mar;31(3):141-7.
The influence of an increasing intake of urea in feed rations for calves on its levels in blood plasma and urine, development of health condition, weight gains and on other biochemical characteristics in the blood of calves was studied. The experimental group (n = 4) received urea in feed ration from the 17th day of age, at the beginning in the preparation Syrur, later on (from the 66th day) in the synthetic form only. The feed ration of the control group (n = 3) differed only in the zero content of urea. Over the period of ten weeks the blood was sampled for biochemical examination twice a week, since the 52nd day of age urine was also taken at the same intervals. Starting the 24th day of age, the levels of urea in the blood plasma of experimental animals were significantly higher (P less than 0.05). The concentrations of urea in the urine of the animals belonging to the experimental group were also higher, however, the differences in the average values were not significant. In both groups of animals under study no significant differences in the content of vitamin A, concentration of total protein, glucose, bilirubin, activities of aspartate aminotransferase (AST), gammaglutamyl transferase (GMT) and lactate dehydrogenase (LD) were observed. The average daily weight gains were higher in the calves of the control group, however, the differences were not significant. Over the whole experimental period the health condition of both groups of calves was good.
研究了犊牛日粮中尿素摄入量增加对其血浆和尿液中尿素水平、健康状况发展、体重增加以及犊牛血液中其他生化特性的影响。实验组（n = 4）从17日龄开始在日粮中添加尿素，开始时使用Syrur制剂，后来（从66日龄起）仅使用合成形式的尿素。对照组（n = 3）的日粮仅在尿素含量为零方面有所不同。在十周的时间里，从52日龄开始，每周对血液进行两次生化检查，同时从该日龄起，每隔相同时间采集尿液。从24日龄开始，实验组动物血浆中的尿素水平显著更高（P小于0.05）。实验组动物尿液中的尿素浓度也更高，然而，平均值的差异不显著。在研究的两组动物中，未观察到维生素A含量、总蛋白浓度、葡萄糖、胆红素、天冬氨酸转氨酶（AST）、γ-谷氨酰转移酶（GMT）和乳酸脱氢酶（LD）活性有显著差异。对照组犊牛的平均日增重更高，然而，差异不显著。在整个实验期间，两组犊牛的健康状况良好。
