The effects of Ureplasma diversum inoculated into the amniotic cavity in cows

Ureaplasma diversum was inoculated into the amniotic cavity in four cows. Two calves were aborted and two were born alive. One of the latter died shortly after birth and the other was killed. The cows remained clinically normal except that three retained their placenta. On microscopic examination there was a severe placentitis and an alveolitis was present in the lungs of all calves. Ureaplasma was recovered from four placentas and three lungs. Cows remained infected for a maximum of 132 days following inoculation and the organism was recovered in urine and vulvar swabs for a maximum of 17 and 60 days respectively following expulsion of the calf. Ureaplasma diversum has been isolated from natural cases of abortion with similar lesions. This experiment strongly supports a causal relationship between abortion, birth of calves with pneumonia and U. diversum infection.