A wet summer is never good for animal performance. Constantly eating low dry matter grass, as has been the case for the last two months, leads to poorer than expected thrive in livestock and milk production in dairy cows.

Parasites, however, seem to thrive in wet conditions and so the disease burden in cattle is greater after a period of wet weather.

Because animal performance is already compromised, the risk of picking up disease from parasites is even greater.

Like with everything, prevention is better than cure but with margins on dairy and beef farms squeezed, there is a temptation to skimp on some routine preventative measures.

Animal health costs on farms can be broken down into four areas: routine, eg dosing, testing and vaccinations, veterinary call-outs and treatment costs and, finally, costs associated with loss of production due to a diseases and parasites.

An effective animal health programme will reduce the costs associated with treatments and losses by having an adequate preventative programme involving routine dosing and vaccination.

Skimping on this will lead to higher risks of disease outbreaks and resultant treatment costs. OK, we can sometimes come across cases where the farmer vaccinates for little or nothing and animal health is still fine. The risk here though is that in the event of a disease outbreak, that herd is extremely exposed because it is naïve to the disease, not having been vaccinated.


Grazing weanlings and calves should have been treated for worms since mid-summer as they have no immunity to stomach worms.

It is only after exposure to worms that animals build up immunity.

Without dosing, the worm burden becomes too high and animal performance drops significantly.

Management of animals in their first year is finely balanced between having enough exposure to build up immunity and not being sick from worms.

Over- or under-dosing in the first year will affect subsequent immunity and may lead to resistance so it is important to use the correct dose rate per kilo of liveweight.

Most stomach wormers also treat for lungworms

Under-dosing, in which not enough product is used, is worse than overdosing because some worms will survive the dose and then build up resistance to it even if correctly dosed in the future.

Most stomach wormers also treat for lungworms. Lungworm (hoose) is looking like a big problem this year because of the wet summer.


The symptoms of hoose is a husky cough and difficulty in breathing. Immunity to lungworms only lasts for six months so adult cattle can get re-infected, especially if they are grazing high-risk pastures such as fields previously grazed by infected young stock. It’s one to watch out for in adult dairy cows as we move from autumn to winter.

Bulk tank milk sample

An ELISA test on a bulk tank milk sample (when all the herd is going into the tank) will confirm what the herd’s exposure is to ostertagia or stomach worms.

Faecal samples from cows are the ultimate test for stomach worms.

If there are over 500 eggs per gramme, you are recommended to dose.

Many farmers now routinely dose their cows for worms during the dry period but whether or not to dose should really be based on milk or faecal sample results.

Liver fluke

Most farmers will need to routinely treat their stock for liver fluke. Faecal samples will determine the presence and density of infection but it is normally only very dry farms, with no wet areas, that can get away without dosing.

For dairy stock, treatment without withholding milk is reserved for the dry period and even then only certain products are permitted for use.

The most important thing when treating for liver fluke is to understand the product that you are using.

Some products only treat adult fluke so a second dose about four weeks later will be required to kill the flukes that were immature at the first dose.

As all flukicides have a milk withdrawal period, it is really important that a good treatment programme is in place during the dry period to reduce the burden.

Rumen fluke

Most doses for liver fluke do not kill rumen fluke. Rumen fluke was identified as a big problem after the wet summers of 2009 and again in 2012 so it could be a problem again this year.

Most farmers shouldn’t have to routinely dose for rumen fluke. Doing so could cause resistance developing to the drug

The oxyclozanide range of flukicides, such as Rumenil, have been proven to kill rumen fluke but dosing should really only be used to treat clinical cases.

Most farmers shouldn’t have to routinely dose for rumen fluke. Doing so could cause resistance developing to the drug. In the event of an outbreak of rumen fluke, consult your vet for best treatment options.


Every year, there are cases of a salmonella outbreak in dairy herds resulting in multiple cases of abortions and sometimes sick cows.

In some cases, the herds are vaccinated but the vaccine wasn’t correctly administered or it was given too late. In some cases, the strain of the outbreak can be different to that vaccinated against.

The financial consequences can be traumatic.

In spring-calving herds, August and September are the best times to give the salmonella vaccine.

However, vaccinating at this time will only protect the cow from abortions. It will not reduce the risk of salmonella scour in calves.

Heifers getting their first vaccine will need two shots two to three weeks apart.

Pregnant cows can be vaccinated again three to four weeks before calving to help pass on immunity to their calves.

I’m hearing of a scarcity of salmonella vaccines this year, so order it early if possible to ensure it is available when needed.


IBR is a respiratory disease that can affect all bovine animals. It is a virus that can develop into pneumonia and can cause severe ill thrift and death. Most vaccination programmes are either annual or twice a year.

Some vaccines are live while others are inactive. Which vaccination programme to choose will depend on the veterinary advice for your farm.

  • This autumn could be a high-risk period for worms in youngstock and adult cattle on dairy and beef farms.
  • Bulk milk tank herd health screening and faecal samples will help to detect parasites.
  • Animals should not be dosed for rumen fluke unless there is a rumen fluke outbreak, which is affecting performance.