Recovery and culture of ova from Brucella abortus infected cows.

One hundred and ninety-two ova were collected from 12 mixed-breed beef and dairy cows that had been artificially infected with Brucella abortus Biotype 1 Strain 2308. Each donor cow was treated for superovulation, and nonsurgical collections were performed on one, two or three occasions. A total of 27 nonsurgical collections on Days 6 through 12 (estrus = Day 0) resulted in the recovery of an average of 7.1 ova (4.4 fertilized and 2.7 nonfertilized). Ova were washed ten times in groups of not more than 10 and cultured for the isolation of B. abortus. A portion of the recovery medium, including sedimented uterine debris from each collection, was also cultured for isolation of the organism. Brucella abortus was not detected in any sample of the recovery medium or in any group of ova.

The effects of superovulation on Brucella abortus infection in the bovine uterus.

Uterine flushings were collected three times at predetermined intervals from 11 mixed-breed beef cows and cultured for Brucella abortus . Prior to sampling, all cows had aborted fetuses from which brucellae had been isolated. Initial collections were made between 21 and 34 days following abortion. The second flushing was conducted at the onset of injections used for inducing superovulation and the third flushing was conducted 6 to 8 days after the ensuing estrus. The latter two flushes were conducted between 60 and 120 days following abortion. Brucellae were isolated from uterine flushings collected from 6 of the 11 cows on the initial round of sampling. Cultures of all subsequent uterine flushings collected before and after injections for superovulation were negative. It was concluded that the superovulatory treatment is not likely to reactivate the release of brucellae into the uterine lumen during the period when embryos are normally collected.

Experimental infection of gray foxes (Urocyon cinereoargenteus) with Brucella abortus.

Ten gray foxes, eight principals that were fed approximately 4.4 X 10(10) colony forming units of Brucella abortus strain 2308 and two controls, were examined for serologic responses and tissue distribution of the organisms. Blood sera from each fox were tested on the day of exposure and at seven weekly intervals for antibodies to B. abortus, using the brucellosis card, standard tube agglutination, 2-mercaptoethanol and rivanol tests. Control foxes were serologically negative for all tests throughout the study and the principals were negative prior to exposure. On days 14, 21 and 28, the eight principals had positive card reactions and greater than or equal to 1:100 tube agglutination titers. After 28 days, the titers receded; and by day 49, three principals had negative card reactions and one of these was negative for all tests. Brucella abortus was isolated from one or more lymph nodes from seven of eight principals including the one which was seronegative. The bacterium was not isolated from lungs, livers, spleens, kidneys, uteri or testicles.

Culture of uterine flushings, cervical mucus, and udder secretions collected post-abortion from heifers artificially exposed to Brucella abortus.

Uterine flushings, cervical mucus swabs and udder secretions collected at weekly intervals from five mixed breed beef cows (four Brucella abortus strain 19 vaccinates, and 1 non-vaccinate) were cultured for Brucella abortus . Prior to sampling, four of the five had aborted 7-to 8-month-old fetuses and one gave brith to a weak calf. The fetuses and/or udder secretions from the cows were culture positive for B. abortus at the time of parturition. Three of the cows developed persistent udder infections. Two of these cows were also shown to have brucellae in their cervical mucus for 10 and 20 days and in their uterine flushings for 17 and 41 days after parturition, respectively. One other cow had brucellae in the cervical mucus for 16 days and in the uterine flushings for up to 36 days post-abortion. All attempts to isolate the organism from this cow's udder secretions in culture were negative. In two cows with culture-positive uterine flushings, isolations of brucellae were made subsequent to normal postpabortion return to estrus.