It was the month of October when Kieran had a major problem with abortions.
He lost about ten foetuses in four days.
The resultant tests revealed salmonella as the cause of the outbreak.
He was devastated by his loss.
We are living in an age where we are all aware of the potential for animal diseases to change and seriously affect the human population.
Covid started as a virus of bats, and look how things have suddenly changed to affect the whole human race.
Salmonella is another zoonotic disease (meaning a disease of animals that can have severe effects on human health) and is becoming a growing concern for farmers and for veterinary surgeons, from a public health perspective.
Animals that become infected often become carriers of this disease.
Once the animals have recovered from the disease, the salmonella bacteria can hide away in the lymph glands and organs of the body, waiting for the animal to be knocked off balance by a moment of stress such as a change in the weather, feeding conditions, or the arrival of another disease.
It is at moments like this that the carrier begins to shed salmonella in vast numbers and becomes a serious threat to all its companions.
It has been shown that apparently healthy animals can still shed salmonella for up to 18 months after they have recovered from the disease. In any given herd, it has been shown that up to 5% of seemingly normal healthy cows can be shedding the bacteria, and up to 25% of cows on the cull list can also be shedding.
These are serious figures.
The most common route of infection is through the faecal–oral route. This means that, in the management of the farm, hygiene is extremely important.
Faecal contamination is involved in the spread of a lot of other diseases, like Johnes etc.
This is why it is vital to keep feed areas and water troughs as clean as possible.
They should be continuously checked for contamination, not just every now and again.
When an animal is suffering from diarrhoea, one of the causes that you have to rule out is Salmonella.
We often take a faecal sample and send it to the lab for culture.
If the disease is showing itself up as an abortion storm, then we send the foetus to the lab, and take blood samples to check for antibodies.
As a general barometer, some co-ops test bulk tank samples on a regular basis for levels of salmonella being shed in the milk.
Controlling this disease has all the same hallmarks as controlling most other diseases.
We can start with keeping a closed herd.
If we feel that we have no other alternative but to buy in, then the new arrivals should be quarantined for four weeks, and blood tested on arrival. Fencing should be maintained to prevent the chance of any break-ins or break-outs occurring.
Since this disease is most commonly spread through faeces, then particular care should be taken with slurry.
Faeces from any clinical case should be kept separate from the normal storage facilities.
That is why isolation units were called for on every farm.
Salmonella can survive for up to 300 days on soil, so if we can prevent spreading it out on grazing ground, we should do so.
Finally, mention has to be made of the vaccination of herds as a preventative measure.
The best time to start a vaccination programme is with calves.
A smaller dose is required for animals under six months, and this helps make it economically viable to begin vaccination at the calf stage. Thereafter, you will need to vaccinate once a year, and the timing of that is usually at this time of the year. Your vet will be delighted to answer any questions you might have in this regard.
Paul Redmond, MVB, MRCVS, Cert DHH, Duntahane Veterinary Clinic, Fermoy
