Salmonella vaccination a vital investment for Co. Waterford farmer

Salmonella is a significant disease on Irish dairy farms and can greatly impact on herd productivity and profitability. The implications include high abortion rates, high calf mortality, reduced growth rates and depressed fertility in animals that do overcome the infection. It is also a zoonotic disease, which means it can be transferred easily from animals to humans.

Tom Power, Dairy Farmer, Waterford

One farmer who doesn’t take any risks when it comes to Salmonella is Waterford farmer, Tom Power. Farming in Drumhills, Dungarvan, Co. Waterford, Tom is milking a herd of 300 cows in a spring-calving system.

In the video below, Tom outlines the importance of Salmonella control on his farm and why vaccinating with Bovilis® Bovivac® S has become a critical component of his herd management programme.

“The herd is at a size now, where we can’t take any chances with their health and that’s why we vaccinate against Salmonella. Like most farmers do, we put a huge amount of time and effort into getting the cows into calf, so keeping them in calf is our number one priority,” says Tom.   

No farm is risk free

According to Tom’s local Veterinary Practitioner, Declan Gilchrist from Deise Vets in Dungarvan, Co. Waterford, “no farm is risk free. Just because you haven’t had Salmonella on your farm before, doesn’t mean you are protected from it.”

Vaccination against Salmonella

Currently in Ireland, Bovilis® Bovivac® S is the only vaccine available for the control of salmonellosis in cattle. Healthy calves from approximately three weeks of age can receive the primary vaccination course of two 2ml injections separated by an interval of 14 to 21 days.

Calves over six months of age and adult cattle should receive two 5ml injections 21 days apart. All cattle vaccinated with the primary vaccination course of Bovilis® Bovivac® S should receive a 5ml injection at least two weeks prior to each period of risk or at intervals of no more than 12 months thereafter.

Tom concludes: “We try to give each animal a chance and by vaccinating against Salmonella every year, we are reducing the risk of illness and ensuring the cow’s health and performance is not impacted. As it is a zoonotic disease, vaccination also possibly lowers the risk to anyone working here on the farm.”

Reasons to control Salmonella 

There are two strains of Salmonella to be aware of for your herd. Salmonella dublin (S dublin) is the most common type associated with abortion in cattle in Ireland and has a high carrier status. Salmonella typhimurium is more commonly associated with diarrhoea outbreaks but can be a cause of abortions.

As well as causing abortions, clinical signs can vary from very mild diarrhoea to those which show obvious signs of fever, dehydration, and profuse diarrhoea, followed by death in a few days.

Clinical outbreaks in young calves can often resemble pneumonia. Acute infections can become chronic and may result in poor thrive, chronic diarrhoea, and terminal dry gangrene.

Salmonella is a significant disease on Irish dairy farms. It can survive for up to two years in the right conditions and the disease is shed mostly in faeces.

In many cases, cows that are infected with Salmonella will often appear clinically normal and Salmonella can survive for up to two years in the right conditions and the disease is shed mostly in faeces. In many cases, cows that are infected with

Salmonella will often appear clinically normal and healthy. It is common when these animals become stressed that they begin shedding the bacteria, infecting other cows, or getting sick themselves. 

Hygiene and biosecurity to control Salmonella

Vaccination is critical; however, to maximise animal immunity and minimise exposure, it must coincide with the strict management measures outlined below.

  • Maintain a closed herd.
  • If buying in, quarantine arrivals for a period of four weeks minimum.
  • Strict biosecurity should be particularly maintained around cases.
  • Faecal material from clinical cases must not enter the slurry tank.
  • A disinfection point should be in place for everyone who enters and leaves the farm to use.
  • A rodent and bird control plan should be in place, especially regarding access to feed stores.
  • Hygiene of buildings between batches of animals is also critical.

For more information about controlling Bovine Salmonellosis in your herd talk to your vet or visit Salmonella – Bovilis – MSD Animal Health

Salmonella – The notorious bacterial disease that no-one wants on their farm

Introduction

Salmonella infection is one of the most well-known diseases affecting cattle in Ireland. Samonella infections is a serious drain on the profitability and productivity of the Irish dairy herd. In addition, there is the added risk of being a zoonotic disease, meaning infection can be transmitted to humans from animals. Infection in the dairy herd has the potential to cost up to €112 per cow, per year. Research has shown that herds which include vaccination as part of a control plan record superior profits in comparison to unvaccinated, positive herds to a value of €11,800 based on a 100-cow herd.

Salmonella is considered endemic in Ireland and can be commonly found in herds throughout the country. The majority of salmonella infections in Irish cattle are caused by one of the following serotypes: Salmonella typhimurium or Salmonella dublin, with abortion outbreaks typically associated with Salmonella dublin. Other clinical signs such as pneumonia, meningitis, arthritis, osteomyelitis and sloughing of extremities are also seen. Salmonella is primarily shed in the dung of infected cattle and infection is usually picked up by oral ingestion. Once an animal is infected, they can become carriers of the infection for life. This is known as latency and it is an important component in maintaining infection within a herd. Carrier cattle will often shed the bacteria during times of stress such as around calving or changes in management, acting as a source of infection to the rest of the herd. As many dairy herds have expanded in recent years, there has been a heightened risk of introduction of the disease through the buying-in of these carrier animals.

Diagnosis

              As with any disease outbreak it is important to involve your attending veterinary practitioner to assist with diagnosing the exact cause of disease and to formulate an effective control plan. Diagnosis of infection by post mortem investigation is considered gold standard. Any aborted foetuses should go to the local regional veterinary laboratory as soon as possible. In a scour outbreak, multiple dung samples can be used to help identify bacteria while paired blood samples can be taken can be taken to demonstrate a rising level of immunity to the infection. The first sample is taken during the active phase of infection while the second sample is taken four weeks later.

Bulk milk antibody testing can be a useful surveillance tool for dairy herds too. Although results might not indicate active infection within herd at the time of sampling, monitoring results can give an idea of the level of exposure within the herd and potential trends of infection. Recent research has shown exposure of Irish dairy herds to salmonella is very common, with 49% of bulk milk tanks testing positive for salmonella antibodies, indicating cattle in these herds had come into contact with the bacteria at some point in the preceding months.

Control

As the disease is notoriously difficult to eliminate from farms, vaccination and strict management measures must be implemented to reduce the spread of infection. These can include –

  • Maintaining a closed herd/purchase from herds of known disease status – If buying in, quarantine arrivals for a period of 4 weeks minimum.
  • Strict biosecurity – Cows which have aborted should be isolated for one month and any abortion materials should be disposed of in a hygienic manner. Ensure fencing is stock proof to avoid break-in infection from neighbouring herds.  
  • Management of slurry – Salmonella bacteria can survive for prolonged periods in slurry tanks and for up to 300 days on soil. Faecal material from clinical cases must be prevented from entering the slurry tank.
  • Strict hygiene – A disinfection point should be in place for everyone who enters and leaves farm to use. Hygiene of buildings between batches of animals is critical while personal hygiene should also be maintained as a result of the zoonotic risk.
  • Rodent and bird control – As pests can spread disease, a plan should be in place for rigorous control, especially with regard to access to feed stores.

Vaccination

            Bovivac S is the only vaccine available for Salmonella dublin and Salmonella typhimurium in Ireland. For best herd control of salmonellosis, it is advisable to vaccinate all animals in the herd. Healthy calves from approximately three weeks of age can receive the primary vaccination course of two 2ml injections separated by an interval of 14-21 days.  Calves over six months of age and adult cattle should receive two 5ml injections 21 days apart. Depending on the level of infection circulating in the herd, one annual vaccination should maintain a sufficient level of immunity in the herd. Although not licensed for the control of abortion, research has reported that the proportion of Salmonella dublin positive abortions from vaccinated herds was significantly lower than in herds which were not vaccinating. To determine the most appropriate time to vaccinate your herd, please consult with your attending veterinary practitioner.

In conclusion, the implications of a salmonella outbreak can be severe and result in significant financial, production and welfare costs. Not to mention the stress of its potential zoonotic risk. Vaccination can form the cornerstone of control along with good management, strict hygiene protocols and high biosecurity standards.