Farm Ireland

Monday 26 February 2018

We're facing a surge in superbugs if we don't use antibiotics with care

I was out the other morning, walking through a field of cattle with a farmer client as we discussed the worming programme for the coming year.

The dew was heavy on the grass and the cattle looked as healthy as could be, away from the last of those winter bugs that prevail in the pens and houses of the winter farmyard.

The conversation came around to how little we need antibiotics with outdoor cattle, and how much we rely on them when our animals are indoors.

There's no doubt that all of our focus should be on minimising our dependence on anti-microbials and on producing good wholesome food with little or no exposure to antibiotics.

There's no such thing as a perfect world, so bacteria are an everyday challenge on modern farms, and antibiotics are here to stay, for the time being at least.

I say "for the time being" because, unless we practise good use of these drugs, they will become ineffective and redundant in the not too distant future.

In human medicine we've all heard of MRSA (Methicillin Resistant Stapphylococcus Aureus) and of hospital superbugs.

A more recently heard name is C difficile infections, which are a member of the clostridial family (the C stands for clostridia).

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That's the family that causes blackleg, tetanus and braxy and are well known in the farming world.

The MRSAs of the medical world resulted in horrific skin infections that could not be killed.

The patient suffered with a flesh-eating bacteria that knew no bounds or restraint. Images of leprosy sprang to mind and we all grew wary of staying any length of time in hospitals.

However, veterinary research has shown that MRSA and many other superbugs exist in the animal world also, and we are seeing more and more cases of infections that are not clearing up as quickly as they used to.

It is well recognised that every time we use an antibiotic, we are exposing all bacteria to that medicine.

The medicine will kill all the sensitive bugs but will also leave a colony of resistant bacteria.

Very quickly, those resistant bacteria multiply and colonise the immediate environment within that one animal only, or with continued use, we colonise an entire group of cattle with the resistant strain of that bacteria. It's a fine balance of good bugs and bad bugs, and the animal's own immune system, that keeps the battle of bacteria at bay. Every now and again that balance gets tipped in the favour of the disease-producing bacteria, and an animal begins to get sick. Of course, with modern farming, it's never just one animal. And often it is not just one disease.

And so, we get this ebb and flow of good health and ill-health in every batch of cattle on every farm. The battle is in the animal's favour when out on grass, such as they were the other morning. But the balance swings in the bacteria's favour when we speak about very young vulnerable stock, or when the animals go back indoors.

It's then that we need to prime the animal's immune system against the disease by use of correct vaccinations.

We also reduce the stress factors in our sheds that will lower the animal's immunity. Comfortable, clean and well-ventilated sheds become the order of the day with well-fed and well-adjusted groups in each pen.


It's only when all our preparations break down that we must turn to antibiotics to treat active bacterial infections.

What we must never do is use antibiotics as our first line of defence. They will quickly become redundant and ineffective if we begin to use them with any degree of frequency.

And we must remember that they are completely useless against any viral infections.

Antibiotics do not kill viruses. They only kill bacteria.

We can only make use of them to treat primary or secondary bacterial infections.

Primary bacterial infections are infections that are wholly and solely caused by bacteria.

Secondary bacteria are those that invade a sick animal once some other problem has caused the sickness.

What if the animal is suffering from a parasite problem, or a mineral deficiency or a viral infection?

And what if the single shot is of a medicine that requires a daily injection for three to five days to be in any way effective?

Let's all draw breath for a moment and remember to use antibiotics only when required.

They should only be used under the guidance of your vet, at the correct dose for the appropriate duration of treatment against a known bacterial infection.

I never want to hear anyone blame Irish farmers and vets for the development of superbugs.

We all need antibiotics in our armoury against bacteria, but let's use them with due care and only when truly required.

Peadar Ó Scanaill MVB is a veterinary practitioner in Ashbourne, Co Meath, and is a member of the Food Animal Group of Veterinary Ireland Tel: (01) 4577976

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