a trichy problem - department of animal...

A Trichy Problem

Getting a handle on trichomoniasis in beef herds in Florida

LIZ Y STEELE DVM

Do you have trich?

Background –Bovine Trichomoniasis

Venereal disease of cattle caused by protozoan parasite Tritrichomonas foetus that causes increased abortion loss (>25%)

Bulls are super spreaders able to infect multiple cows during coitus

Electron micrograph of Tritrichomonas foetus. Image credit Parkinson TJ, England GCW, Arthur GH, Arthur's Veterinary Reproduction and Obstetrics, Saunders, 2001

Classic Management of Trich Identifying/Suspecting an infestation

– Unacceptable Numbers, Pyometra, “late” calf crop, or routine BSE – PCR vs. Culture

Culling Positive Bulls Vaccination of Cows & Bulls Culling Repetitively Open Cows Careful Purchase of Bulls and Cows Yearly Surveillance with your Veterinarian through BSE’s Florida does not yet regulate intrastate movement of bulls in regards to Trich

Why is Trich a “hot topic”? • Auburn University discovery of the pseudocyst • Stumbling upon positive bulls converting to negative status • Variability between interstate testing requirements • Variation in pregnancy/calving/weaning percentages in Trich

infested herds • Variability in types tests and subsequent results

Dr. Hilary Swain

Executive Director

Gene Lollis

Ranch Manager

Dr. Raoul Boughton Rangeland Scientist

Dr. Betsey Boughton Director of Research

Florida Beef Producers

Providing opportunities to

supply unvaccinated trich positive bulls

Team of Veterinarians

Dr. John Yelvington Dr. John Crews Dr. Liz Steele Dr. Robert Gukich Dr. Kerry McGehee Dr. Owen Rae Dr. Mark Davis Dr. Max Ursik

InPouch™

• October 2012 annual bull breeding soundness exam – 9/108 Bulls with Positive

Trichomonad Cultures • No PCR done on initial cultures

• All Bulls have been vaccinated for T. foetus for at least 4 years – Initial vaccination + booster at least 4

yrs previous to this event, then single annual booster

– TrichGuard® (BI) vaccine used

• 2500+ Adult Cows-No cows vaccinated for T. foetus

CASE STUDY – WHAT DID I STUMBLE UPON?

• Second Test - ~3 weeks later – 104 Bulls cultured – 1 Positive Culture on a bull that was culture negative on 1st

test. – Sample sent for PCR Confirmation – Positive – 9 previously culture positive T. foetus bulls are now culture

negative

CASE STUDY

• Third Test – 107 Bulls – All Culture Negative

• Fourth Test – 7 Previous Positive Cultures all negative on culture (3 of the original 10

bulls were out with a group of 78 cows)

• Fifth Test – 10 Previous Culture positive bulls plus 5 cull bulls were tested - all

culture negative

• 14 of these bulls are being tested monthly and have remained Culture and PCR negative

Case Study - Bulls

• Group of 78 cows were commingled with the only PCR

positive bull and two other Culture Positive bulls for ~60 days

• February 2013 – all 78 were ultrasounded for

pregnancy – 52 Pregnant – 26 Opens (66% Bred) – 1 cow presented with uterine discharge that was culture

positive for T. foetus and PCR confirmed

Case Study - Cows

• March 2013 – 57 pregnant – 21 open (73% Bred) – Cultured cows previously pregnant but open or if pregnant and had signs

of inflammation – 2 culture positives and 4 PCR T. foetus positives at Colorado of 9 sent for

testing.

• April 2013 – 53 pregnant – 25 open (68 %) – Cultured cows previously pregnant but now open or if pregnant and had

signs of inflammation – Culture test all negative. PCR negative. – May 2013 – 53 pregnant – 25 Open 68% Bred – Cultured 78 cows – All Culture Negative – PCR negative.

Case Study - Cows

• Temporal pattern of trich infection in cows – repeated sampling of 78 head exposed to trich bulls.

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BullsOut

Feb March April May Jun Jul Aug Sep Oct Nov

# Pregnant% loss% Found Infected

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Summary • 10 Trich bulls became test NEGATIVE after vaccination and have remained that way for 11 months

• Evidence suggests these so called NEGATIVE bulls resulted in Trich being recovered from open cows they were exposed to.

• Do we continue to cull positive bulls?

• Does the Trichgard vaccine clear infection in bulls?

• Does the vaccine mask a carrier status?

• If it does mask a carrier status, how does this impact state import/export rules?

• Does trich live further up the reproductive tract?

• Which single test should we recommend a producer use to screen his herd for trich?

• Do cows play a larger role in disease prevalence and persistence with in a herd?

THE TRICH PROJECT 1. Does vaccination of a T. foetus positive bull reduce the ability

to successfully identify infection in a bull via culture or PCR? 2. If vaccination reduces the ability to successfully identify

positive bulls, how long does their test negative status persist? 3. If the positive bull is vaccinated and becomes test negative,

does the infection persist in the reproductive tract resulting in continued infection of the cow herd?

4. Observe the systemic IgG antibody titers to T. foetus

Trich Project Update • Started on March 3rd with

splitting the group and giving 1st immunization

• Booster immunization on March 24th

• 1st collection April 21st • 2nd collection May 19th and

monthly thereafter Dr. John Crews

Studying Trich in Cows Is difficult because 1. Hard to recover

organisms even in heavily infected cows

2. # of other factors involved in pregnancy rate and loss (nutrition, mineral status, other infectious diseases, weather, ect.)

I LOOK FORWARD TO GIVING A BETTER UPDATE IN MARCO!

What is going to change? • Identifying/Suspecting an infestation

– Unacceptable Numbers, Pyometra, “late” calf crop, or routine BSE – PCR vs. Culture

• Culling Positive Bulls • Vaccination of Cows & Bulls • Culling Repetitively Open Cows • Careful Purchase of Bulls and Cows • Yearly Surveillance with your Veterinarian through BSE’s • Florida does not yet regulate intrastate movement of bulls in regards

to Trich (THIS IS ABOUT TO CHANGE COUNTRYWIDE)

More dificult

New testing methods

QUESTIONS?