Is Trich Cutting Into Your Profits?

April, 2012
by Bridget Carlisle, Polk County Livestock Extension Agent

Trichomoniasis, or “trich,” is a sexually transmitted disease of cattle caused by a protozoan parasite, Tritichomonas foetus.  It is estimated that the economic losses to the U.S. beef industry from reduced conception rates, lowered weaning weights and increased culling due to this disease exceed $100 million annually.  Bulls infected by T. foetus show no outward signs of infection.  Bulls act as a reservoir for this organism and are the primary transmitter of the disease.  The trich organism interferes with an infected cow or heifer’s ability to stay bred and, therefore, is responsible for varying degrees of reproductive inefficiency.  Because there are no outward signs of the illness, it often goes undetected for a great length of time resulting in further spread of the infection.  The effects of the disease are seen in devastating losses due to poor calf crops and prolonged calving seasons. 


For example, in infected herds with a short defined breeding season, the calf crop can be decreased by 50%.  Herds with longer breeding seasons will experience even longer calving seasons resulting in a reduced calf crop and reduced weaning weights. 


T. foetus lives in the reproductive tract of the cow and in the sheath of the bull’s penis.  The typical means of transmission is an infected bull exposing unexposed cows.  But the disease can also spread through the purchase of infected, open cows and mixing of clean herds with infected cattle through broken fences.  The infection does not interfere with conception but rather results in death of the embryo in the first half of gestation (fifteen to eighty days).   Cows may remain infertile and may build up immunity (for two to six months) but immunity is usually short lived.  While rare, some cows that are infected may carry the fetus to full term and deliver a normal calf.  These cows are of concern because they can serve as a source of infection to bulls during subsequent breeding seasons. 


Typically the only detectable symptom of trich in the herd is an increase in open or “late” cows at pregnancy checking.  Other signs are reduced calving rates and a calf crop that is extended over three to six months.  Bulls will not show symptoms.


Diagnosis is made through sampling of the preputial fluid taken from the sheath of the bull’s penis or uterine/vaginal fluid from the cow.  The organism may be observed by direct microscopic examination of the fresh samples, by examination of culture media inoculated with infected material, or by the detection of T. foetus DNA through the PCR (Polymerase Chain Reaction) test method.  Microscopic examination and culture tests are only mildly to moderately accurate.  The PCR test is considered to be the most accurate and is required by some states as the method of testing.  At this time, there is not an approved treatment or vaccination to use on bulls.    Identification of infected bulls is critical.  Control and prevention involves testing and then culling and replacing infected bulls.


A vaccine is available to help cows clean up faster from an infection and rebreed, but it doesn’t prevent trich from infecting the herd.  Often it’s the open and late cows that are carrying the disease, so they, too, need to be culled and replaced.


The most effective way to control Trich is to prevent the introduction of the organism into a herd.  Prevention is essential in managing trichomoniasis infections.  Measures include:

  • Testing all new bulls prior to entry into the herd.
  • Preventing unwanted bulls from entering through damaged fence lines.
  • Keeping young bulls rather than older ones.
  • Testing all bulls prior to each breeding season.   
  • Purchase only virgin bulls.
  • Do not share or lease bulls.
  • Do not purchase older cows and add them to your herd, without the necessary precautions.
  • Cull open cows.
  • Maintain a defined breeding season to identify reproductive problems.
  • Pregnancy test all cows and heifers 120 days after the breeding season and cull open females.
  • Vaccination, but vaccine alone will not prevent the disease from getting into the herd.
  • If you are shipping bulls out-of-state contact your veterinarian to find out the policy for shipping bulls to the particular state.  As many states have changed or adopted new rules on the movement of bulls into their state due to Trichomoniasis.  This is necessary even if the bulls are to be used on your females residing, or operations belonging to you, in another state.    

The cost of prevention is far more affordable than the losses caused by this devastating disease.  Contact your veterinarian or Extension office for more information.

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