Comparison of diagnostic methods for detection of active infection with Tritrichomonas foetus in beef heifers.
OBJECTIVE
To compare sensitivity of a generic trypticase-yeast extract-maltose (TYM) medium versus a commercial nutrient medium in the diagnosis of Tritrichomonas foetus infection in heifers and to assess sensitivity when incubation of samples inoculated into commercial medium pouches is delayed overnight.


METHODS
Prospective study.


METHODS
30 virgin beef heifers.


METHODS
20 heifers vaccinated with a trichomonad antigen and 10 unvaccinated control heifers were exposed at synchronized estrus by intravaginal instillation of 10(6) T foetus organisms. Cervicovaginal mucus samples were collected every other week for 10 weeks from controls and once (10 weeks after exposure) from vaccinated heifers. Samples were inoculated into both media and immediately incubated at 37 C (98.6 F). A duplicate inoculation from controls was made into commercial medium, and the pouch was shipped overnight to a diagnostic laboratory without prior incubation.


RESULTS
For 40 of 50 samples from control heifers, there was agreement on diagnoses between media. There was agreement on a positive diagnosis for 3 of 20 samples from vaccinated heifers and on a negative diagnosis for 15 of these 20 samples. For samples shipped overnight before incubation, there were 10% fewer positive diagnoses, compared with samples incubated immediately in commercial medium and 10% more positive diagnoses, compared with samples immediately incubated in TYM.


CONCLUSIONS
Use of the commercial medium is a more sensitive indicator of current infection in heifers than use of generic TYM medium. In herds where infection prevalence is high, this method is likely to identify more infected females, an important consideration when control programs include culling of infected cows.
Kittel
D R
DR
Department of Population Health and Reproduction, School of Veterinary Medicine, University of California, Davis 95616, USA.
Campero
C
C
Van Hoosear
K A
KA
Rhyan
J C
JC
BonDurant
R H
RH
D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000175:diagnosis* / Q000469:parasitology / Q000517:prevention & control; D002582:Cervix Mucus / Q000469:parasitology; D003470:Culture Media; D005260:Female; D011446:Prospective Studies; D011528:Protozoan Infections / Q000175:diagnosis / Q000469:parasitology; D011529:Protozoan Infections, Animal; D012680:Sensitivity and Specificity; D013048:Specimen Handling / Q000662:veterinary; D016835:Tritrichomonas foetus / Q000302:isolation & purification*; D014611:Vaccination / Q000662:veterinary; D014621:Vagina / Q000469:parasitology
D003470:Culture Media