Trichomoniasis in cattle: Causes, Signs, Diagnosis and Treatment

Trichomoniasis in cattle is a venereally transmitted disease caused by the protozoan parasite Tritrichomonas foetus (T. foetus). While it’s more commonly associated with infections in cats and cattle, it can also affect other mammals, including humans. In cattle, trichomoniasis primarily affects the reproductive tract, leading to infertility, abortions, and economic losses in affected herds.

Causes of Trichomoniasis in Cattle

Trichomoniasis in cattle is primarily caused by the protozoan parasite Tritrichomonas foetus (T. foetus). This single-celled protozoan parasite is the primary causative agent of trichomoniasis in cattle. T. foetus primarily infects the reproductive tract of cattle, including the uterus and prepuce.

Epidemiology of Trichomoniasis in Cattle

The epidemiology of trichomoniasis in cattle involves the study of the distribution, determinants, and dynamics of the disease within cattle populations. Here are some significant points regarding the epidemiology of trichomoniasis in cattle:

1. Prevalence: Trichomoniasis is widespread in many cattle-producing regions worldwide. However, the prevalence can differ significantly between regions and even within individual herds. Factors such as population size, management practices, and biosecurity measures influence the prevalence of trichomoniasis.
2. Seasonality: Trichomoniasis often exhibits seasonal patterns. In regions with distinct breeding seasons, such as temperate climates, the disease may peak during the breeding season when cattle are more actively mating. However, in regions with year-round breeding, trichomoniasis may occur consistently throughout the year.
3. Herd Dynamics: Trichomoniasis can persist within cattle herds due to the presence of carrier bulls and asymptomatic cows. Once introduced into a herd, the parasite can spread rapidly through mating, leading to endemicity within the population. Herd size, turnover rate, and contact patterns between animals influence the dynamics of trichomoniasis within herds.
4. Transmission: Sexual transmission is the primary transmission mode of trichomoniasis in cattle. Infected bulls serve as parasite reservoirs and can transmit it to susceptible cows during mating. Once infected, cows can harbor the parasite and pass it to other bulls during subsequent matings. Movement of infected animals between herds can also contribute to the spread of the disease.
5. Risk Factors: Several risk factors contribute to the epidemiology of trichomoniasis in cattle. These include inadequate biosecurity measures, introducing infected animals, mixing bulls between herds, and failing to implement testing and culling protocols. Factors such as high bull-to-cow ratios and extensive grazing practices can also increase the likelihood of transmission.
6. Diagnostic Challenges: Diagnosing trichomoniasis in cattle can be challenging due to the parasite’s intermittent shedding and the carrier animals’ presence. PCR (polymerase chain reaction) testing of preputial washings or vaginal mucus is commonly used for accurate detection of T. foetus DNA. However, false-negative results can occur, particularly during the transient phase of infection.

Clinical Signs of Trichomoniasis in Cattle

Trichomoniasis in cattle can manifest with various clinical signs, though it’s important to note that some infected animals may not exhibit any symptoms. Here are the typical clinical signs associated with trichomoniasis in cattle:

1. Infertility: Trichomoniasis can reduce fertility in both cows and bulls. Infected cows may experience prolonged calving intervals, meaning they take longer to become pregnant after birth or being bred. Bulls infected with trichomoniasis may have decreased fertility, resulting in a lower conception rate in cows.
2. Early Embryonic Death: Infected cows may experience early embryonic death, where embryos fail to develop or are reabsorbed shortly after conception. This can lead to repeat breeding or prolonged periods of infertility in affected cows.
3. Abortion: Trichomoniasis is a common cause of abortion in cattle. Infected cows may abort their fetuses at various stages of gestation, leading to economic losses for cattle producers. Aborted fetuses may show signs of fetal death, such as maceration or decomposition.
4. Pyometra: In some cases, trichomoniasis can lead to pyometra, a condition characterized by the accumulation of pus within the uterus. Pyometra typically occurs in non-pregnant cows and can result in infertility or reproductive problems if left untreated.
5. Extended Calving Intervals: Cows infected with trichomoniasis may have extended calving intervals, meaning they take longer to conceive and give birth to calves. This can result in reduced reproductive efficiency and decreased productivity in affected herds.
6. Subclinical Infections: It’s important to note that some infected animals may not show any clinical signs of trichomoniasis. These animals, known as carriers, can harbor the parasite without exhibiting outward symptoms. However, they can still transmit the infection to other animals during breeding.
7. Chronic Infections: Trichomoniasis in cattle can sometimes lead to chronic infections, where animals continue to shed the parasite intermittently over an extended period. Chronic infections can contribute to the persistence and spread of the disease within cattle herds.

Diagnosis of Trichomoniasis in Cattle

Diagnosing trichomoniasis in cattle typically involves testing for the presence of the protozoan parasite Tritrichomonas fetus (T. fetus) in reproductive tract samples. Here are the main diagnostic methods used for detecting trichomoniasis in cattle:

1. Preputial/Genital Swabs: In bulls, preputial or genital swabs are commonly used to collect samples for T. foetus detection. A swab is inserted into the preputial cavity or the urethra to collect mucus and cellular material. These samples can then be examined microscopically for the presence of T. foetus organisms, although this method has limitations due to the parasite’s intermittent shedding.
2. PCR (Polymerase Chain Reaction) Testing: PCR testing is an empathetic and specific method for detecting T. foetus DNA in preputial or genital swab samples. This molecular technique amplifies and detects specific DNA sequences of the parasite, providing accurate and reliable results. PCR testing is considered the gold standard for diagnosing trichomoniasis in cattle.
3. Vaginal Swabs: In cows, vaginal swabs can be used to collect samples for T. foetus detection. Swabs are inserted into the vagina to collect mucus and cellular material, which are then examined microscopically or tested using PCR for the presence of the parasite. Vaginal swabs are handy for diagnosing trichomoniasis in cows suspected of being infected.
4. Culture: Culturing samples collected from bulls or cows can also be used to isolate and identify T. foetus organisms. However, culturing can be time-consuming and less sensitive than PCR testing, making it less commonly used for diagnosing trichomoniasis in cattle.
5. Serological Testing: Serological tests, such as ELISA (enzyme-linked immunosorbent assay), have been developed to detect antibodies against T. foetus in cattle blood samples. While serological testing can indicate exposure to the parasite, it is not helpful for diagnosing active infections or identifying carrier animals.
6. Post-Mortem Examination: In cases of abortion or reproductive tract pathology, post-mortem examination of aborted fetuses or reproductive tissues can be performed to identify lesions consistent with trichomoniasis. Histopathological examination and PCR testing of tissue samples can confirm the presence of T. foetus.

Treatment of Trichomoniasis in Cattle

Trichomoniasis in cattle can be challenging to treat, as there are limited options for effective medication against the causative agent, Tritrichomonas fetus (T. fetus). Unlike other bacterial or parasitic infections in cattle, no widely accepted treatments reliably eliminate T. foetus from infected animals. Here’s why:

1. Limited Drug Efficacy: Many of the drugs used to treat parasitic infections in cattle are ineffective against T. foetus. The protozoan parasite has developed resistance or tolerance to several antimicrobial agents, making it difficult to eradicate from infected animals.
2. Inaccessibility to the Infection Site: T. foetus primarily inhabits the reproductive tract of cattle, including the uterus in females and the preputial cavity in males. Systemic medications can make these areas difficult to access, limiting the effectiveness of treatment.
3. Carrier State: Infected animals, particularly bulls, can serve as carriers of T. foetus without showing clinical signs of disease. These carrier animals can continue to shed the parasite and transmit the infection to other animals, even after treatment with antimicrobial agents.
4. Risk of Selecting Resistant Strains: In addition to the challenges of treating individual animals, there is concern that widespread use of antimicrobial agents could lead to the selection of resistant strains of T. foetus, further complicating control efforts.

Prevention of Trichomoniasis in Cattle

Preventing trichomoniasis in cattle involves implementing management practices, biosecurity measures, and testing protocols to minimize the risk of introducing and spreading Tritrichomonas foetus within cattle herds. Here are key strategies for preventing trichomoniasis in cattle:

1. Bull Testing: Regular testing of breeding bulls for T. foetus infection is crucial for preventing the spread of trichomoniasis within cattle herds. Bulls should be tested before the breeding season and periodically after that, using methods such as PCR testing of preputial or genital swab samples. Infected bulls should be promptly identified and culled from the herd to prevent further parasite transmission.
2. Closed Herds: Maintaining closed herds, where no new animals are introduced from outside sources, can help prevent the introduction of T. foetus into cattle populations. If new animals must be brought into the herd, they should be tested for trichomoniasis and quarantined before being introduced to prevent the spread of the disease.
3. Segregation of Bulls: Segregating bulls based on their reproductive status can help prevent the spread of trichomoniasis within cattle herds. Infected bulls should be kept separate from uninfected bulls to reduce the risk of transmission during mating.
4. Biosecurity Measures: Implementing strict biosecurity measures, such as limiting contact between bulls from different herds, preventing nose-to-nose contact between animals, and practicing good hygiene and sanitation protocols, can help reduce the risk of introducing and spreading T. foetus within cattle populations.
5. Artificial Insemination: Artificial insemination (AI) instead of natural mating can eliminate the risk of T. foetus transmission between animals. AI allows for controlled cattle breeding without direct contact between bulls and cows, reducing the risk of sexually transmitted diseases like trichomoniasis.
6. Testing of Cows: While testing bulls is the primary focus for trichomoniasis prevention, testing of cows can also be beneficial, particularly in herds with a high disease prevalence. Testing cows for T. foetus infection can help identify carriers and prevent them from transmitting the parasite to uninfected bulls during mating.
7. Education and Training: Educating cattle producers, herd managers, and veterinary professionals about the risks and consequences of trichomoniasis, as well as the importance of testing and prevention measures, can help raise awareness and promote proactive management practices.

Concluding Remarks on Trichomoniasis in Cattle

In conclusion, trichomoniasis in cattle is a sexually transmitted disease caused by the protozoan parasite Tritrichomonas fetus (T. foetus). This disease poses significant challenges to cattle producers due to its impact on reproductive health and productivity within herds. Trichomoniasis is a significant concern for cattle producers worldwide, and proactive management strategies are necessary to minimize its impact on cattle reproductive health and herd productivity. By implementing preventive measures and working closely with veterinarians, cattle producers can reduce the risk of trichomoniasis introduction and transmission within their herds, ultimately improving overall herd health and profitability.