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Biomedical subjects

D Mitchell

Publications and source records attributed to D Mitchell.

At least 379 records · Page 21Linked to original sources
PubMed1968

Some effects of experimental Vibrio fetus (venerealis) infection on cattle inoculated with a commercial bacterin.

Four groups of ten heifers were used to study the effect of a commercial Vibrio fetus bacterin on the development of vaginal mucus agglutination (VMA) reactions and subsequent reproductive performance in the presence of active V. fetus infection. Two groups were vaccinated and one of these was infected one month later. The other two groups were not vaccinated and one of these was infected. It was found that in the absence of infection the bacterin did not produce diagnostically significant VMA reactions but in the presence of infection reactions comparable with the control group were detected. The infected control group required 4.9 services per conception, the first service-conception interval was 126.9 days and 50 per cent of the animals aborted. The corresponding figures in the infected vaccinates were 3.5 services, 68.9 days and 12.5 per cent abortions. It was concluded that although this bacterin has a beneficial effect on reproductive performance in the presence of genital vibrosis, maximum breeding efficiency will not be obtained unless V. fetus infection is eliminated. Persistent local reactions appeared at the site of inoculation in the majority of the vaccinated animals.

Animals↗
PubMed1967

The incidence and significance of bovine herpesvirus (infectious bovine rhinotracheitis) antibodies in the sera of aborting cattle.

The results of bovine herpesvirus (IBR-IPV) neutralization tests conducted on the sera of 463 animals with a prior history of undiagnosed abortion and 331 control animals with no history of abortion are reported. One hundred and thirty-one (28.3 per cent) of the aborting and 105 (31.7 per cent) of the control animals, were found to harbour antibody to this virus. No significant seasonal or gestational incidence could be determined but some variation in the annual incidence was apparent. On the basis of these results it appears unlikely that this virus is responsible for a significant proportion of the undiagnosed cases of bovine abortion in Quebec and Ontario, where the animals tested were located. The problems involved in substantiating a diagnosis of abortion due to bovine herpesvirus are briefly discussed.

Abortion, Veterinary↗