This week, I met with two different farmers both with the same concern. This was a problem with a small parasite called Neospora Canium.

One farm had experienced an abortion storm in replacement heifers last year. The other had just sent samples to his vet from two recent abortions and was also concerned it could be this parasite.

The first farmer was now undertaking a comprehensive control plan with his vet. They had the heifers on rented land beside a greyhound kennels and I will explain why dogs can play a role in the spread of this parasite.

How does it spread?

Neospora is a small protozoan parasite that can cause abortion but not every time in every animal.

There are two main ways it is spread and the canine plays an important role in this but the main spread is from dam to foetus in the womb (90% of spread).

The dog plays a role in spread when eating an infected animal’s placenta or, more rarely, eating an infected animal and then shedding it in its faeces.

The cow can become infected when it eats feed contaminated with this dog’s faeces. The infected dog is thought to only shed for a couple of weeks, so often when the problem is diagnosed the dog that may be involved is no longer spreading the disease.

There is also a strong suspicion that foxes may be involved in the cycle.

The main method of propagation of the disease is from cow to foetus. So the most likely way this can be brought into the herd is with bought-in animals that are positive.

Dogs can also become infected by eating wild animals (again more rarely)that have been infected with neospora. For example, a deer that has been infected and eaten by the dog could be another source of the disease.

In group calving pens, it is also important to stop spread by ensuring cows aren’t eating each other’s placentas, although this risk is thought to be very low.

What happens when animals are infected?

When cows ingest infected faeces, if the ingested parasite passes the placenta (thought to be linked in some way to immune status of the animal at the time) they will often do a number of things.

Some will abort, often between five and seven months of pregnancy. They also might go full-term, producing weak calves (very rare), have normal calves or they might have calves born normal but positive for neospora for life. These are the calves that in later life may abort and also help spread the disease within the herd or between herds.

How can we diagnose it on our farms?

One of the challenges with neospora is cows can abort the foetus without many symptoms and just show up bulling at six to eight months after breeding.

Like any cow that has aborted, it is so important if we have the foetus and the placenta (where possible) to submit it for sampling along with blood samples from the dam.

It is very hard to test dogs for the disease. This is where the first farmer is now – he is investigating the recent abortions.

When screening a herd like the second farmer (who has an ongoing issue), the best time is in the last 10 to four weeks of pregnancy by blood-testing. This is when antibody levels are likely to be highest.

Some dairy farmers can monitor neospora on bulk milk tests but it is not very accurate as it requires a high number of positive animals often to show up a positive test.

How can we stop neospora spreading?

I think because there are some wildlife factors involved in the spread of this disease it is hard to completely eliminate the risk.

There are, however, things we can do on farm to greatly reduce the risk.

We know infected dogs can shed this parasite in their faeces (for 14 to 21 days) so ensuring dogs don’t have access to cows’ feed to defecate on is really important. It is also important dogs are not allowed eat placentas and that placentas, especially from infected animals, are burned or disposed of.

One big challenge for farmers is dogs not under their direct control. Because any dog can potentially pick up this infection through eating raw meat. Most dogs have the potential to get infected and shed neospora.

The first farmer beside the greyhound kennels is a good example of this. Also, with so many dogs being walked on farms near urban areas, the risk is small but the numbers of dogs with access to farmland is high.

It is interesting that in the UK there have been some campaigns targeted at dog owners to highlight the risk for cattle but also neospora can cause a meningitis in canines.

When neospora is found in a herd it is advisable to begin a control programme. There are no treatments or licensed vaccine in Europe, so the best thing we can do is test and remove animals that are positive over time.

When you find low levels it is advisable to remove them. When higher levels are positive in a herd, a decision must be made to cull some and also to manage the rest to reduce the spread within the herd. Animals that test positive for neospora should not have their progeny kept as replacements.

My experience of neospora is that this control programme takes planning and commitment to decrease the risk.

How can I keep it out?

If you’re free of neospora and maintaining a closed herd then managing canines on farm is important.

This may be complicated as I said earlier by those canines and potentially foxes (conclusive evidence about the latter is still not there but there are strong suspicions) as potential spreaders of this disease.

This herd with greyhound kennels beside rented land shows the difficulty of managing this risk.

Any farm buying in breeding cattle must consider screening for neospora. Remember the best time to test is in the last months of pregnancy, which complicates the situation.

So one negative test never gives a 100% accuracy but still must be highly recommended.

Unfortunately the cases of neospora as a cause of abortions now seem to be sl0wly rising in Irish herds (at around 10% of all abortions submitted last year). I would encourage farmers to be mindful of the risks and always submit any abortions for sampling.

Highlights of CAVI annual conference

This past weekend I attended Veterinary Ireland’s annual cattle conference in Mullingar. It was a reasonably well attended event, with probably a majority of older vets in attendance, although that varied with two little baby boys Fiadh and Jerimiah bucking that trend.

On the Friday, the discussion focused on industry challenges around the vet’s role in sustainability and antibiotic resistance. The highlight for me was the presentation by Professor Martin Cormican on antibiotic resistance. The need for us all to take individual responsibility to reduce our usage of antibiotics is about “holding the tide”. This just might be the biggest public health challenge of this century unless we act now.

On Saturday morning it was calf health. Consultant Martin Kavanagh gave a superb overview of calf health and system management. He told us about work he is doing in Sweden and how important it is to manage bottlenecks on the calves’ journey into the herd.

Case studies

Cork vet Hazel Mullins gave an insight into some practical examples of case studies she had encountered. One of my many take-home messages was the importance of hygiene in managing calf scour.

In the afternoon, we had two excellent nutritionists speaking on managing feed for the suckler herd. They emphasised the importance of using our senses, knowing what we have to feed this winter. Plan plan plan…

There was also a debate around corporate ownership of veterinary practices and the positives and neg- atives of this for the industry. I left this session more confused about the future of practice ownership than anything.

On the Sunday morning, there were two excellent presentations on surgery and the value of post-mortems.

This conference gives vets a chance to get up to date CPD (continuous professional development) but also importantly check in with and meet colleges. There were two great social events on both nights, always a good reminder for myself that I’m not as young as I used to be.

Well done to the CAVI committee for organising the event.