Infertility and pregnancy loss in the mare and stallion

Why is infertility and pregnancy loss important?

• welfare

• financial

• time

How much does it cost to get a mare pregnant?

£5000

How many days is a mares pregnancy

336 days

UK horse industries

Horse racing

• restricted to throroughbreds

• multi billion pound industry (2.83 billion)

• breeding: 17,000 foals a year in GB

• training: 14,000 horses in training

• racing: 90,000 runners per year (9,000 races)

• betting- 10bn per year

Sports horses: dressage, show jumping, polo ect

Rare breeds: native ponies

Horse breeding finances

Stud fees: mare owners pay for stallions to inseminate their mares

Sales: horses at any stage of their training

Factors that impact fertility

Infectious:

• pathogens such as bacteria/ viruses

• some are “exotic” therefore notifiable to Defra

Non- infectious causes

Infectious disease control, including reproductive disease

HBLB (horserace betting levy boards) codes of practice

thoroughbred specific but sets standard for all horses

Viral pathogens

• Equid herpresvirus-1 (EHV-1)

• Equine arteritis virus (EAV/ EVA)

• Equine herpesvirus-3

Equid herpresvirus-1 (EHV-1)

Late gestation >/ 5m abortion

“red bag” placenta

neonatal foal death

endemic

infects white blood cells and endothelium

latency

Equine arteritis virus (EAV/ EVA)

Clinical signs: flu-like, conjunctivitis, limb oedema

Abortion: 3-10 months gestatin

Shed in semen

Symptomatic treatment and recovery over 1 month

Notifiable- exotic to UK

Equine Viral Arteritis (EVA) in stallions

30% stallions shed via semen for life

• virus harboured in accessory glands

Dissemination via venerata route

• mated mares develop respiratory tract infection

• virus is spread to other mates- can cause abortion

These stallions are always seropositive

There is no treatment for these stallions except castration

Difficult to differentiate serologically- infected vs vaccinated

• repeated semen collection and virus isolation required

Equine herpesvirus-3

Equine coital exanthema

Distal reproductive tract

Vesicles → ulcerated nodules (penis/ clitoris)

Sexually transmitted through reciprocal contact

Self- limiting

Susceptible to antibiotics (secondary bacterial infection)

Prevention and vacination

Biosecurity/ quarantine is crucial

Equine Viral Arteritis (inactivated virus)

Equine Herpes Virus 1 (inactivated virus)

Inspection negative for sings of Equine herpesvirus 3 (equine coital exanthema)

Bacterial Pathogens