¿Qué enfermedad causa el aborto en el ganado??

Los abortos bovinos son una preocupación importante en la producción ganadera, especialmente en rebaños comerciales de leche y carne de vacuno. When a cow aborts—defined as the loss of a fetus between day 42 and day 260 of gestation—it can lead to considerable economic loss and often signals an underlying herd health issue. Understanding what diseases cause abortion in cattle is essential for effective prevention and management.

Abortion in cattle is multifactorial, but infectious agents are the most common cause, particularly in herd outbreaks. These infections may be bacterial, viral, protozoal, or fungal in origin. Below, we’ll explore the most prevalent diseases that lead to bovine abortion, how they’re transmitted, diagnosed, and managed, as well as prevention strategies used on farms.

A visual diagram of bovine reproductive tract and gestational stages

1. Brucellosis (Brucella abortus)

Brucellosis is a contagious bacterial disease that primarily affects the reproductive system. It is transmitted through direct contact with aborted fetuses, placentas, or uterine discharges. Once a cow is infected, the bacteria localize in the uterus, leading to placentitis and ultimately abortion, usually in the second half of gestation.

Control involves strict biosecurity, test-and-slaughter programs, and vaccination where permitted. Brucellosis is also zoonotic, meaning it can infect humans, making control efforts doubly important.

2. Neosporosis (Neospora caninum)

Neosporosis is currently one of the most frequently diagnosed causes of abortion in cattle worldwide[1]. The disease is caused by a protozoan parasite, Neospora caninum, which uses dogs as a definitive host. Cattle become infected via ingestion of feed or water contaminated with oocysts shed in dog feces.

Abortions typically occur between 3 y 7 months of gestation, and cows can transmit the parasite to their calves transplacentally. Control strategies include minimizing dog-cattle interaction and culling persistently infected cows.

3. Bovine Viral Diarrhea Virus (BVDV)

BVDV is a pestivirus that can cause abortions, stillbirths, and congenital defects. Infection during early pregnancy often leads to embryo resorption or abortion, while infection later in gestation may produce persistently infected calves.

BVD is transmitted through direct contact, contaminated equipment, and body fluids. Diagnostic screening, culling of persistently infected animals, and vaccination are the cornerstones of control programs.

4. Infectious Bovine Rhinotracheitis (IBR)

Caused by bovine herpesvirus-1 (BoHV-1), IBR primarily affects the respiratory tract but can also induce abortions, especially in naïve or unvaccinated cows. The virus may cause abortion storms weeks after infection, even in the absence of respiratory symptoms.

Control measures include vaccination and biosecurity protocols to prevent viral spread between herds.

5. Leptospirosis

Leptospira bacteria infect cattle via contaminated water or contact with infected urine. Once inside the bloodstream, the bacteria localize in the uterus and placenta, resulting in abortions, often during the last trimester.

Infected animals may also become chronic carriers, intermittently shedding the organism. Vaccination and rodent control are critical components of prevention.

6. Campylobacteriosis and Trichomoniasis

These two diseases are venereal infections, passed through natural service or contaminated semen. Campylobacter fetus and Tritrichomonas foetus colonize the reproductive tract, causing early embryonic death and sporadic abortion.

Control typically involves testing bulls, using artificial insemination, and culling infected animals.

7. Listeriosis

Listeria monocytogenes is an environmental bacterium that thrives in silage, especially poorly fermented batches. Pregnant cows ingest the pathogen, which can invade the uterus and cause abortion, often without other systemic signs.

Improving feed hygiene and silage fermentation quality is crucial for prevention.

Microscopic images of pathogens that cause abortion in cattle

8. Fungal Infections

Fungal abortion in cattle is generally sporadic and often results from moldy feed, especially in wet or humid environments. Aspergillus species are most commonly involved. These infections can result in thickened, leathery placentas and dead fetuses expelled in late pregnancy.

Ensuring proper storage of feed and avoiding mold contamination are the best preventive measures.

Diagnosis and Use of Ultrasound

Ecografía veterinaria plays a critical role in diagnosing reproductive issues and monitoring fetal development. While it cannot directly identify pathogens, it can detect signs of fetal death, placental abnormalities, and abnormal uterine contents, allowing for timely intervention and laboratory sampling for confirmation.

Prevention and Biosecurity

The foundation of preventing abortion in cattle is robust herd health management. This includes:

• Biosecurity measures to prevent the introduction of pathogens

• Testing and quarantine of new animals

• Vaccination schedules tailored to local disease risk

• Regular reproductive exams, including ultrasound

• Nutritional management to support maternal immunity

• Rodent and pest control

Conclusión

Abortion in cattle is rarely random and often signals an underlying infectious process. Diseases like neosporosis, brucellosis, BVD, IBR, and leptospirosis top the list of causes worldwide. Veterinarians and producers must collaborate to diagnose cases accurately, identify trends, and implement effective herd health plans that reduce the risk of abortion, ensuring economic stability and Bienestar animal.

Citations:

[1] Dubey, J. P. (2003). Review of Neospora caninum and neosporosis in animals. The Korean Journal of Parasitology. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2732525/

[2] Radostits, O. M. et al. (2006). Veterinary Medicine: A Textbook of the Diseases of Cattle, Caballos, Oveja, Pigs and Goats. 10th ed. Saunders Ltd.

[3] USDA APHIS. (2022). Brucellosis Factsheet. https://www.aphis.usda.gov/publications/animal_health/2022/fs_brucellosis.pdf

[4] Iowa State University Extension. Leptospirosis in Cattle. https://vetmed.iastate.edu/vdpam/extension/disease-topics/leptospirosis

[5] University of Wisconsin-Madison. Bovine Viral Diarrhea. https://datcp.wi.gov/Pages/Programs_Services/BovineViralDiarrhea.aspx