Rosendal S, Martin S W
Can J Vet Res. 1986 Apr;50(2):179-83.
Calves from five Ontario feedlots were bled on arrival and approximately 28 days later. Calves treated during this interval for undifferentiated respiratory disease were classified as cases and untreated calves were classified as controls. Serum was titrated blindly for antibodies to Mycoplasma bovis and Mycoplasma dispar. Indirect hemagglutination titers of 1:20 or more were assumed to reflect recent or current exposure, whereas 1:10 or less were not. The titers to M. bovis increased in all feedlots indicating active infection. The initial titers to M. dispar were higher than the titers against M. bovis, yet they increased in all feedlots except one, suggesting widespread infection with this organism. There was an increased risk (although not statistically significant) of being treated if the titer against M. bovis rose during the period. Calves with low M. dispar titers on arrival were at increased risk of being treated and titer increases were strongly associated with treatment (statistically significant). Thus, the serological results indicate high prevalence of M. bovis and M. dispar in the feedlot calves and that calves with increasing titers in particular to M. dispar are at increased risk of being treated for respiratory disease.
来自安大略省五个饲养场的犊牛在抵达时和大约28天后采血。在此期间因未分化呼吸道疾病接受治疗的犊牛被归类为病例，未接受治疗的犊牛被归类为对照。血清被盲目滴定牛支原体和副支原体抗体。间接血凝滴度为1:20或更高被认为反映近期或当前暴露，而1:10或更低则不是。所有饲养场中牛支原体的滴度都有所增加，表明存在活跃感染。副支原体的初始滴度高于牛支原体的滴度，但除一个饲养场外，所有饲养场中的副支原体滴度都有所增加，表明该病原体广泛感染。如果在此期间牛支原体滴度上升，则接受治疗的风险增加（尽管无统计学意义）。抵达时副支原体滴度低的犊牛接受治疗的风险增加，滴度增加与治疗密切相关（具有统计学意义）。因此，血清学结果表明饲养场犊牛中牛支原体和副支原体的患病率很高，尤其是副支原体滴度升高的犊牛患呼吸道疾病接受治疗的风险增加。
