Before a mare can go to a stud, she needs to be tested for several diseases, each of which is notifiable to Defra (Department for Environmental, Food, and Rural Affairs). These diseases are Contagious Equine Metritis (CEM), Equine Infectious Anaemia (EIA) and Equine Viral Arteritis (EVA). Lets look at each in a little more detail…

Contagious Equine Metritis (CEM)

CEM is caused by a bacterium called  Taylorella equigenitalis and it is very difficult to treat. 10-14 days after breeding with an infected stallion, the mare may begin to show symptoms if infection is acute. These signs manifest as grey to creamy vulvar discharge which mats the hair of the buttocks and tail, however, she may also show no symptoms. Stallions show no signs, the first and only symptom is that mares he services fail to become pregnant. The disease causes sub-fertility (cannot carry foal to term)  and infertility in mares. She may spontaneously recover, however, will probably be a carrier for life.

Treatment

The uterus may be infused with antibiotics such as penicillin and the external part of the reproductive tract cleaned with chlorhexidine solution, and nitrofurazone cream. In the stallion the penis, when extended fully may be washed with chlorhexidine solution, and dried, then nitrofurazone cream applied.

Equine Viral Arteritis (EVA)

This is caused by an RNA virus of the  Arterivirus genus.

Symptoms manifest as 

  • depression
  • oedema (abnormal fluid filled swelling)
  • fever
  • nasal discharge
  • genital welling in both genders
  • conjunctivitis
  • and, extremely unhelpfully (at a stud) all pregnant mares abort the foetuses!
EVA passes from horse to horse very fast, and an ”abortion storm” can take place in studs where there are many pregnant mares! If a stallion contracts EVA he will be a carrier and shedder for life, passing the disease in his semen. Defra states he must be euthanized (put to sleep).
Equine Infectious Anaemia (EIA)
This is caused by a  retrovirus and transmitted by bloodsucking insects. In laymans terms, it is also known as swamp fever.
EIA is infectious for life, and horses are either quarantined for life or euthanized.
Symptoms
Acute:
  • sudden death
  • weak and/or irregular heartbeat
  • fever
  • abdominal and limb swelling

Subacute:

  • enlarged spleen
  • recurrent anaemia
  • reccurrent fever
  • penile enlargement in the stallion
  • swelling of chest and legs

Chronic

  • Horses tire easily and cannot work
  • recurrent fever and or anaemia
  • may suffer acute or subacute relapses

Pregnant mares may abort, however may hold pregnancy to term. Foal may or may not be infected.

Diagnosis: Coggins test

Treatment: Euthanasia or quarantine for life

Prevention: Vacccine

 

As you have seen, all these diseases are quite grim. Therefore, if your mare, or indeed stallion, is going to stud, have her (or him!) tested for these diseases, as calling the vet out to carry out a few tests saves potential heartbreak in the future.

 


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