Diagnosing Trichomoniasis Poses Challenges

June 20, 2013 | Barbara Duckworth | The Western Producer

Trichomoniasis is a venereal disease of cattle that has been detected in Alberta with serious consequences.

When a veterinary practice at High River, Alta., diagnosed it in cattle that had occupied two grazing reserves in southern Alberta, patrons were forced to take serious steps to get rid of it. It is a protozoan organism that lives in the sheath of bulls and is transmitted with sexual contact.

As a newly licensed vet, Jordan Holt was sent to pregnancy check cows that spent the summer on a grazing reserve. 
Much to his surprise, 70 percent of the 80 cows were not pregnant. The owner asked if he knew what he was doing, but when they were checked again the diagnosis was confirmed. 
He described the situation at the University of Calgary veterinary school’s beef cattle conference held in Calgary June 20-21.

The bulls appear healthy when this organism is present, but cows suffer early abortions and may cycle again at the end of the breeding period. It can also be passed back and forth among breeding animals. 
The bulls were tested, and two of the five bulls on the site were positive. No one is sure where they picked up the disease, but a meeting has been held with patrons to discuss controls. The reserve did not have firm health rules before 2012.

A second reserve had 34 clients with four to six patrons sharing one of eight paddocks. Patrons supplied their own bulls with a 60 day breeding period. 
They had requirements for testing and the bulls were ruled negative before they entered. 
However, the pregnancy checks discovered that one-third of the cows were open on one of the breeding paddocks. 
One positive bull was eventually diagnosed, but no firm evidence was found as to where it picked up the disease.

“There is a possibility a bull tested negative in April was missed,” said Holt. “Our sensitivity with one test is only about 85 percent.”
 He said trichomoniasis can devastate a cow herd so community pastures need to take prevention seriously with firm biosecurity control measures.

“Rules are good but if rules are not enforced, they are useless,” he said.

As well, producers who suspect they have trichomoniasis in their herds need to clear it up to avoid pregnancy losses not only in their cattle but also in other producers’ herds. 
Do not underestimate a bull’s ability to break loose, he added.

“Just because the cows are on the other side of the river doesn’t mean that they are going to be OK,” he said.

  • Use only virgin bulls and heifers as replacements; use as many home-raised heifers as possible.
  • Buy confirmed pregnant heifers only if outside replacements are needed.
  • Maintain a limited tight breeding season.
  • Keep the average bull age as young as possible.
  • Test all mature bulls for trichomoniasis at least three times at weekly intervals before introducing them into the herd.
  • Community pastures should test all bulls for trichomoniasis at least three times before the beginning of the breeding season.
  • Only allow cows with their calves at foot or virgin heifers in the grazing reserve to eliminate the risk of introducing infected cows.
  • Perform breeding soundness exams of all bulls before turnout.
  • Monitor the breeding period to detect signs of excessive repeat breeding.
  • Control other reproductive diseases such as campylobacteriosis with appropriate vaccinations.
  • Perform breeding soundness exam of all bulls before turnout.
  • Cull open cows at pregnancy check and test cows that have recently aborted.
  • Do not buy open cows from auction markets.
  • Avoid using and sharing bulls from herds with unknown histories.
  • Consider implementing an artificial insemination program in the herd.
  • Maintain proper fencing of pastures to avoid mixing of animals from herds with unknown status.

 

 Source:  http://www.producer.com/2013/06/diagnosing-trichomoniasis-poses-challenges/#.UdNFOrgjHV4.wordpress