AT the end of January new veterinary medicines regulations will change the landscape for how we treat horses in Ireland. Medicines and measures that help prevent disease will increasingly be favoured. This is particularly so for infectious disease that affects populations – building resilience and ‘herd immunity’ (as popularised by Covid-conversations) is the way forward.

Infectious disease often spikes in winter as we and our horses are housed more, often in groups; contact is increased, ventilation is reduced; defences may be down. How can we, and our horses, defence ourselves better against disease-causing organisms (pathogens) – the minority of viruses, bacteria and parasites that do real harm? By supporting natural defence mechanisms and by bolstering these where possible.

The first and most critical barrier we have against attack is a physical one – skin and mucous membrane. In the layers of skin and mucous membrane reside a plethora of defence cells – that rush to police the barricade, physically digesting microbes, secreting chemical agents, producing antibodies and laying down memory to foster resistance against future attack. Once breached wounds become infected, pathogens potentially gain entry to deeper organs of the body. We can assist in building general resistance to disease –

  • breed robust, inherently healthy horses
  • ensure foals get plenty of quality colostrum, early – a good start is half the battle!
  • expose youngstock to moderate immune challenge, training it as it matures
  • provide an excellent diet, specifically quality protein, attuned to their age, stage and individual needs
  • supplement, if necessary, with essential vitamins and minerals, such as copper
  • use pre, pro and post-biotics to promote a healthy ‘microbiota’ on and in the body – these are the good guys!
  • employ anti-biotics in a targeted manner – especially avoid unnecessary use of broad-spectrum agents
  • consider vet-administered plasma, rich in relevant antibodies
  • employ immune-stimulants, some based on cell-wall extract or anti-parasitic agents – these tune-up the system to be more ready to respond to challenge
  • minimise stress (as cortisol is counterproductive), for example eliminating bullying at shared feed troughs.

    • Then add in the specific concept of vaccination: administer an antigen and healthy horses (should) mount an immune response that is self-protective. Produced commercially to prevent disease caused by a specific pathogen, some additionally believe in a broader benefit; and a study of passports shows some with vaccine entries more frequent than horse-sport regulators require.

    So one of the most valuable ways we can bolster our horses’ health is to stimulate their immune system with commercial vaccines, notably

  • Tetanus (a clostridial bacterium causing a horrible disease - lock-jaw)
  • Strangles (a streps bacterium forming abscesses especially around the throat)
  • Influenza (an ever mutating pneumonia virus)
  • Herpes virus (it comes in respiratory, reproductive and neurological forms)
  • EVA (vaccination reserved for stallions, a venereally transmitted virus)
  • Rabies virus (thankfully not found in these islands)
  • West Nile Virus and Equine Viral Encephalitis (caused by various viruses and insect vectors currently exotic to us, but cue climate change!)

    • Bacterial disease is generally more easily prevented by vaccination than is viral. Parasitic is more difficult still; you’ll not see any in the list above; we can still encourage natural immunity by allowing our horses as they age to carry a manageable burden. In individual horses, we can take specific but also more holistic measures, enhancing, supporting and boosting their defence mechanisms. In groups, we should look to promote an active immune response that helps confer protection on the whole herd.