Jones C D, Webster A J
Res Vet Sci. 1984 Sep;37(2):132-7.
Nasopharyngeal swabs were taken from four groups of veal calves at intervals throughout their growth and the aerobic bacteria cultivated from the swabs counted. The calves were kept under three different husbandry systems; naturally ventilated straw-yards, fan-ventilated crates and crates with a controlled climate. The numbers of bacteria isolated varied in a complex manner; however, in one group of calves a significant proportion (P less than 0.01) of the variation in weekly bacterial counts was associated with the changes in vapour pressure and temperature which took place between two and four days previously. In calves kept at a constant temperature of 16 degrees C, the bacterial populations in the nasopharynx were at a minimum between 65 and 75 per cent relative humidity and tended to rise at humidities outside this range. There was a temporal relationship between nasopharyngeal bacteria and lung lesions. In three groups the numbers of bacteria in calves at nine weeks old were positively correlated (P less than 0.05) with lung damage observable at 16 to 18 weeks old.
在四组犊牛的整个生长过程中，定期采集鼻咽拭子，并对从拭子中培养出的需氧菌进行计数。这些犊牛饲养在三种不同的饲养系统下：自然通风的稻草围栏、风扇通风的板条箱以及气候可控的板条箱。分离出的细菌数量变化复杂；然而，在一组犊牛中，每周细菌计数的显著比例（P小于0.01）的变化与前两天到四天之间发生的蒸汽压和温度变化有关。在保持在16摄氏度恒温的犊牛中，鼻咽部的细菌数量在相对湿度65%至75%之间时最少，在这个范围之外的湿度下往往会上升。鼻咽部细菌与肺部病变之间存在时间关系。在三组中，九周龄犊牛的细菌数量与16至18周龄时可观察到的肺部损伤呈正相关（P小于0.05）。
