Video 20 Neospora the facts
There can be many causes of abortion in cattle but one agent that has become more common is the parasite Neospora Caniumn.
This small parasite is said to be responsible for close to 10% of abortions in beef and dairy cattle identified in Irish labs. The big challenge with this parasite once an animal becomes infected they can become infected for life. They may not abort each year but they can produce healthy calves that may also be infected.
This means you can have Neospora infections lingering in your herd through generations causing abortion. When Neospora is identified it must be tackled and controlled.
How can it spread
There are two main presentations for Neospora abortion.
- Abortion storms in a naive herd where you get a large number of abortions. The parasite is spread in the feces of dogs (the host) and possibly foxes. Where you get large abortion storms it usually indicates feed or water has been contaminated with dog feces with oocysts in it.
One case I heard of was, where grass clippings from a lawn were fed to cattle that were contaminated with dog feces.
Another farm I worked on, we identified a potential spread was greyhounds were being walked through an out block.
It raises the concern of people going through farmland with dogs and the risk that poses for stock.
These cases are certainly rarer with about 10% of cases being spread like this
- The bigger spread occurs slowly with sporadic abortions. This is where several cows are infected and may or may not abort. Their newborn calves can be healthy but also can have the parasite and be infected for life. This is the main way neospora spreads in a herd in the womb from the dam to daughter,
This next generation will then again spread the parasite slowly through their offspring.
Dogs are the host for the parasite with it rarely affecting them. They can pick up the parasite most likely from eating the placenta (afterbirth) or any fetal materials from infected animals.
They then shed the oocysts in their feces with the potential to infect cattle. The dog becomes immune quite quickly and stop shedding. When abortions are detected the family pet or farm dog is no longer shedding.
Young dogs are more at risk.
The bottom line is to keep any dogs on a farm away fro any foetal material.
What will we see on the farm
- Abortions close to term at around 5-7 months
- We can see healthy calves being born from positive dams
- There can be early losses often seen as cows repeating after 2 – 3 months. There will often be no fetus discovered
- Very rarely infected calves can be born with neurological symptoms
How can we diagnose it
One thing that often frustrates farmers is the number of negative results from abortion workup. This doesn’t mean we should stop checking as knowing our cause or not is very important.
We still need to investigate all these. No test is perfect but to give ourselves the best chance to make a diagnosis submit the fetus, placenta, and blood to your local regional lab.
We can also use bloods and milk samples for routine screening. My preference would be blood tests. We are measuring antibodies (evidence of exposure) using blood or also milk. They can vary at different times of the reproductive cycle. They will be highest in the 4-8 weeks before calving.
This is an important fact when we are screening for the disease.
Anyone buying in replacements should be considering Neospora as one of the diseases worth screening for! The limitations of the test mean they may need to be tested in that window before calving again for peace of mind.
There are no treatments and no licensed vaccine in Europe. Thankfully it causes no disease in humans, unlike its close relation toxoplasma.
So it is all about prevention
If dog feces is a risk we must ensure no link between that and cattle feed or water.
This includes where any meal or feed is being supplied on a farm. It is a question people should be asking. Anyone who has experienced the disease would find it an easy question to ask in hindsight.
Where people are walking dogs on farmland at a minimum signage should be in place to warn them of the risk they may be causing to the cattle on your farm.
On a lot of farms, this can be difficult especially near built-up urban areas.
Dealing with an outbreak
Once you have diagnosed Neospora on-farm in your cattle. Letting it linger can be the wrong approach.
Unfortunately, testing and time are the main solutions.
Any animal positive, all her future generations on the farm should be at least tested. The best option is to begin testing the breeding herd over two years. Timing this again close to calving allows for better antibody responses.
With low numbers of positives culling and a red tag is the best option. Where high numbers are present careful decisions around not breeding replacements from them.
A Neopsora positive animal should of course never be sold on to another farm or the market.
Conclusion
Where abortion occurs they must be investigated. Where cows come back with Neosproa work with your vet to follow the infections through the herd. Be patient and begin testing to track positive animals and their progeny.
Thought for the day
Your health is your wealth
Huge thanks to Nettex for their support in making this video series happen.
Happy safe farming