Comparison of two sampling tools for diagnosis of Tritrichomonas foetus in bulls and clinical interpretation of culture results.
OBJECTIVE
To compare sensitivity for diagnosing Tritrichomonas foetus infection in bulls using 2 sampling tools and to calculate negative predictive values for infection.


METHODS
Randomized clinical trial.


METHODS
30 Bos taurus bulls naturally or experimentally infected with T foetus.


METHODS
Preputial scrapings were obtained once/wk for 6 weeks using an artificial insemination pipette and a metal brush; which tool was used first for each bull was randomly determined. Samples were collected first from the left side of the prepuce and then from the right side and placed in commercially available transport media chi 2 Values and confidence limits were adjusted for effect of clustering of results by bull.


RESULTS
Significant differences in sensitivity of results were not found between samples collected using the brush or pipette. Using the pipette, sensitivity was estimated to be 91.6% (95% confidence interval, 84.3 to 95.7%); negative predictive values ranged from 41 to 99% for prevalence of infection of 90 to 5%, respectively. Sensitivity was 88.8% for first sample obtained and 96.1% for second sample obtained.


CONCLUSIONS
Collection of preputial scrapings with an artificial insemination pipette or a metal brush and use of a commercially available culture system can provide a sensitive diagnostic test for T foetus infection in bulls. Calculated negative predictive values indicated that 1 or 2 tests would suffice in most clinical situations. For bulls from herds in which T foetus is endemic, 2 to 4 tests/bull may be required to ensure that each bull is not infected.
Department of Herd Medicine and Theriogenology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Canada.
S
S
Parker
J
J
Campbell
C
C
Ribble
A
A
Gajadhar
D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000175:diagnosis*; D005188:False Negative Reactions; D008297:Male; D010413:Penis / Q000469:parasitology; D011237:Predictive Value of Tests; D011528:Protozoan Infections / Q000175:diagnosis; D011529:Protozoan Infections, Animal; D012680:Sensitivity and Specificity; D016037:Single-Blind Method; D013048:Specimen Handling / Q000662:veterinary; D016835:Tritrichomonas foetus / Q000302:isolation & purification*