Neospora; Abortion in your herd?

Published on: May 16, 2023

We wrapped up the series of Winter Discussion Groups at Pilton with a meeting on Neospora. It was great to have a mixed beef and dairy meeting at the Pilton club.

We had two guest speakers joining Alex. Liz Nabb from APHA Starcross explained to us the importance of abortion diagnoses at the Veterinary Investigation Centre. We were able to see recent data gathered from England and Wales showing the various diagnoses found when we send aborted carcass into the post mortem centres, and, compared this to the diagnoses met when we send only samples, e.g. blood/milk. It was very clear to see that by proportion we can see that submission of whole carcasses, preferably with placenta, leads to around 45% diagnostic rate compared to <10% from postal submissions.

In the data sets looked at, 2018-2022, Neospora ( 23%) and Salmonella ( 25%) were the most commonly diagnosed infectious cause of abortion in dairy herds whilst the most commonly identified infectious causes in suckler herds were Neospora 13% and the opportunistic invaders bacteria Bacillus, Trueperella and fungi ( combined 30%), but also a higher proportion of vaccinatable disease (IBR and BVD) caused abortion in suckler herds than dairy. Perhaps indicating the benefits of feeding suckler cows well preserved forage with no moulds and infectious disease screening, vaccinating for those diseases your herd maybe susceptible to.

Alex spoke about the disease Neospora, and explained how its complex life cycle with cows as an intermediate host needs the dog to complete its life cycle and it is in the dog that the protozoa then form the infective oocysts which are shed out in the dogs faeces. The dog needs to have eaten infected cattle material, so; aborted calf, birth materials, placenta, or carcass remains to become infected. So whilst public footpaths and dog walkers are an important risk factor to control, our own dogs on farms and hunt hounds are shown to be much more likely positive. Numerous scientific

studies have shown that the European fox in the UK ( Vulpes Vulpes) will not shed infective oocysts after eating infected cattle materials. They are genetically distinct from the dog family (Canis lupus) We also learnt that once it is on a farm the Cow to Calf route of transmission is incredibly efficient ( upto 90%) meaning whole family lines can become infected.

We learnt that there are no treatments nor vaccinations for Neospora and so we are advised to control the disease and the introduction of disease onto farm with on farm management practices.

Eamon Watson from NML spoke to us about herd surveillance using milk testing both bulk and individual. We can test the herd using blood sampling too, more appropriate for our beef herds.

So how do we best control Neospora…

• Dogs – All dogs must be prevented from having access to calving areas, carcase material and placentas. Access to pasture used for grazing and the production of forage should be kept to a minimum.
• Placentas – Placentas from still born calves and carcases of dead and aborted calves should be removed from the calving accommodation and paddocks as soon as possible to a secure location ready for removal by fallen stock contractors for incineration. This location should be inaccessible.
• The Public – and their dogs must not have access to paddocks used for calving.
• Feed Storage – Facilities including ‘straights’ and forage must be dog proof to prevent contamination by faeces. They should be vermin proof to prevent contamination by foxes, badgers, rats and mice.
• Feed supplies – Suppliers of feed/forage should provide assurances that measures are in place to prevent contamination of feed by faecal material from dogs.
• Added animals – If possible only buy animals which have been confirmed negative with two negative blood tests taken between 10 and 4 weeks before two calvings. This could include the pre-purchase blood sample.
• Identify positive cows – Whole herd or individual tests. Speak to your vet for the best fit for your farm and timing of testing.
• Cull infected cows – Expensive, depends on number, selective breeding do not breed replacements from these animals.
• Embryo transfer – Ensure recips are negative.