Case management of Ureaplasma diversum in a replacement dairy heifer operation and a commercial beef herd
Keywords:bovine, infertility, ureaplasma, abortion, beef bulls, beef cattle, beef cows, bulls, case reports, chlortetracycline, clinical aspects, conception rate, cows, dairy bulls, dairy cattle, dairy cows, diagnosis, disease transmission, lesions, tetracyclines, antibiotics
A herd of 18-month-old heifers from Kansas, USA with low pregnancy rates is reported. The heifers were exposed to Holstein bulls for 90 days and presented with clinical signs of abortion, failure to conceive, and had reddened vulvas with small blister-like lesions. Vaginal swabs of the lesions were positive for U. diversum using the polymerase chain reaction test. At the time of diagnosis, the Holstein bulls were housed with beef bulls used for the producer's commercial cow/calf operation. Preputial swabs confirmed that all dairy and beef bulls were positive for U. diversum. The dairy heifers and all bulls were sexually rested for 28 days and fed 350 mg chlortetracycline (CTC)/head/day. Eleven of the 12 bulls remained preputial swab-positive for U. diversum after 28 days of CTC treatment. Following the 28-day rest period, the Holstein bulls were returned to the dairy heifer pen. Out of the 250 dairy heifers, 238 were pregnant 90 days after the bulls were re-introduced. Additionally, the producer elected to use the Ureaplasma-positive beef bulls to breed his commercial beef cows and heifers. Upon rectal palpation, 282 of 285 beef cows and heifers were pregnant in the fall. These results indicate that feeding 350 mg CTC/head/day did not eliminate U. diversum from the prepuce of the bulls. Ureaplasma in this case was either non-pathogenic, or the beef cows and dairy heifers were immune due to prior exposure, which allowed Ureaplasma-positive bulls to breed both dairy and beef cattle and achieve high conception rates.