


Ivan Leyva-Baca, DVM, PhD

Animal Health Product Applications at Thermo Fisher Scientific

What is Tritrichomonas foetus (Trich)?

Tritrichomonas foetus, also known as Trich, is a protozoan that is pear-shaped and single-celled. It has three flagella on the anterior side and has a single flagellum on the posterior. This can make disease diagnosis using microscopy difficult because there are similar protozoa that are closely related but not pathogenic such as Tritrichomonas foetus.

What is Tritrichomonas foetus (Trich)?

The genome of Tritrichomonas is large - it has five haploid chromosomes that have been sequenced. It includes many repetitive sequences, making it a complicated genome.

What are the clinical signs of Tritrichomonas foetus?

Identify low calving rates or those that have dropped considerably from one season to another. For example, if your calving rate is normally about 80% to 90%, and the next season your calving rate drops to 50% that would be an indicator that Trich has entered the herd, especially if you're not managing and monitoring the Trich status of bulls entering the herd.

Clinical Signs at Herd Level

  • Negative impact on female reproductive efficiency through increased numbers of non-pregnant cows
    • Increased pyometras
    • Increased abortions
    • Cows pregnant but with a later-than-normal expected calving date
  • The early return to estrus is the main clinical sight of Trich infection during the breeding period
  • Low calving rates (30% to 60%)
  • Longer calving intervals (?100 days than non-infected herds)

In bulls, there are no specific clinical signs that can be visually identified, and transmission of the disease can easily occur by natural breeding. Trich is a venereal disease that becomes encrypted in the herd from the bull to the cows in the herd.


  • Don’t exhibit any pathogenic lesions
  • Immune response is limited

For cows, clinically the symptoms include a higher than normal amount of open cows. These cows will become infected and generate pyometras. They will abort their calf and keep cycling. However, they usually become infertile for many months until they can clear out the disease. Producers should watch out for a cow’s failure to get bred.


  • Early return to estrus (most common sign)
  • Pyometras (usually at day 50 post-infection) with prolonged infections
  • Purulent debris in the uterine lumen
  • Early embryonic death
  • Fetal maceration detected by palpation
  • Abortion (by the 5th month of gestation)
  • Temporary infertility (2-6 months)


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