The use of vaccinations has become a cheap insurance policy, protecting the herd from the loss in production associated with a disease outbreak, according to progressive dairy farmer David Hannon.

Hannon told crowds at the Teagasc/Lakeland Dairies Dairy Farm Structures for Expansion open day, which took place on his farm, that disease outbreaks can have negative impacts on farm during expansion.

The Hannon farm has faced a number of challenges with infectious diseases during the process of expansion.

In recent years, a vaccination programme has been implemented to control disease outbreaks as the herd moves from 217 to 450 cows, he said.

The herd previously had issues with disease outbreaks including salmonella, IBR and cryptosporidium.

“Even though the cost of vaccination is quite expensive, saving one cow and her production will more than cover the cost of the vaccination program,” he said.

One of Ireland’s top vets Frank O’Sullivan was also speaking at the event.

According to O’Sullivan controlling diseases and proper health plans are essential to ensure the profitability of dairy herds.

The Co. Meath-based vet was on hand to highlight how these disease outbreaks impacted on the Hannon farm and he also discussed the impacts other disease outbreaks could possibly have.


David Hannon highlighted the impact a salmonella outbreak had on his farm. His cows started to abort just as they were being dried off.

According to Hannon, these cows were essentially no use after this disease outbreak and all were factory cases.

“We started a vaccination program since then and I would be afraid to stop now. The reality of a vaccination programme is that it is cheap insurance,” he said.

According to O’Sullivan, an animal can shed salmonella for a period of up to six months following first infection.

“This animal is a sub clinical shedder which could pose a problem to farmers who are purchasing animals to expand their herd.”


The Hannon farm has also had exposure to IBR, but there hasn’t been clinical issues in the last while.

According to O’Sullivan, IBR has the ability to sit in the animal’s nerve tissue until it becomes stressed and  this is when outbreaks occur.

Numerous factors can cause stress, these include weather, housing, nutritional or even calving stress. He added that the time to vaccinate these animals is before the stress happens.

However, O’Sullivan also said that many farmers have confused IBR with a lungworm infection this year.

“There have been problems with coughing cows during the summer. In our practice we have seen cases where the cow has dropped in milk and is panting heavily caused by heavy lungworm infections.

“Lungworm has become a problem in milking cows. It is one of the knock on effects of intensive grazing,” he said.

Johne’s disease

Johne’s disease warrants consideration by expanding dairy farmers, particularly those purchasing in stock from other herds, he said.

There are some herds with high rates of infection, but apart from the clinical wasting the disease will also result in a reduction in herd performance.

Johne’s disease has a long incubation period and can sit dormant in the animal for a period of five to seven years.

Therefore it is quite difficult to know an animal’s status when introducing these animals to the herd, added O’Sullivan.

Other important infectious diseases

Leptospirosis is another major infectious disease, said the Co. Meath-based vet. This bacteria is spread in the urine and can cause abortion and a milk drop. Approximately 60-70% of herds in the country have leptospirosis.

Another infectious disease which could have major implications for herd health and profitability is neospora, which is the most common cause of abortion in Ireland.

It is spread by dog faeces or through neospora sheders whose daughters will be more likely to abort in the future, he said.

Calf health

The expanding dairy farm has also had a few issues with calf health this year, particularly as a result of cryptosporidium.

“We had a few cases of cryptosporidium at the end of calving. Basically the houses are getting over used. It is just a fact that we have too many going through,” said Hannon.

According to the farm’s vet, cryptosporidium outbreaks often happen near the end of calving as the bug builds up over time as calving progresses.

Cost of disease in growing dairy herds
  • Lower milk sales
  • Increased culling rates
  • Poor herd fertility/calving pattern
  • Lower calf and cow sales value
  • Extra labour
  • Increased stress
  • Higher veterinary costs