Calf Talk

March, 2005

Volume 11, No. 3

NEW APPROACH TO SALMONELLA

By: Russ Schnepper, DVM

Salmonella outbreaks have been devastating . There are over 2400 different serotypes of salmonella bacteria. S. typhimurium usually hits the first couple of weeks and is spread by the oral fecal route. Immunoboost does well at treating this salmonella. Endovac-Bovi causes the calf to develop antibodies against the Gram negative endotoxins that are produced by Salmonella typhimurium, E. coli, Pasteurella multocida, and Pasteurella haemolytica. Very little immunity is evident until the second dose. Salmonella dublin is another situation. It has hit our producers between four and eighteen weeks, and is primarily a respiratory problem. Recent cases have hit hard. The salmonella organism has been resistant to the sulfas and all the antibiotics except Excenel. I used to feel salmonella was strictly an opportunist and would strike when the calf’s selenium level was low, or another stressor set the calf up for the disaster. With those cases an injection of selenium and vitamin E solved the problem. However, recent cases have taken place when the calf had adequate levels of selenium.

We now have access to a new and very promising technology to use against salmonella. It is SRP Technology. Currently it is a USDA conditionally licenced Salmonella Newport Bacterial Extract vaccine. The antibodies created in response to the ARP antigens lock on to the cell wall of the salmonella and prevent it from absorbing iron and the bacteria starves and dies. The vaccine has been well tested for efficacy and safety in animals over six months of age. As usual, we are on our own when it comes to using it in calves less than six months of age. However, it appears that a 1 ml dose (half the regular dose) may be effective in a baby calf. The label calls for a booster dose in two to four weeks. When we are in trouble in a calf barn, we do not have two weeks to wait. My suggestion is that if rapid immunity is critical, inject 1 ml of Immunoboost at the same time as the SRP. (There were studies a couple years ago, in which injecting Immunoboost to horses at the same time as vaccinating with West Nile Virus, the horse produced immunity if a few days.) If you want to give a second dose of SRP vaccine rather than the Immunoboost, I feel you would need to wait at least a week, otherwise you do not get an amnestic response to the second dose. The body merely treats it as more of the first dose and we do not get the increased immunity we want.

Currently many dairy herds are having problems with salmonella, so it is obvious the calves originating in those herds are likely to have salmonella infections also. Each calf raiser is going to have to access his risk and decide what to do. There will be more data in the future, but for now we have to figure it out. I would appreciate your letting me know how you used SRP and what the outcome was. We may be able to develop a lot of info in a short time, to the benefit of everyone. Calf raisers using the SRP currently are using it as an additional vaccine and not to replace Endovac bovi. Knowing how the salmonella is so dependent upon iron, I would not feed extra iron during a salmonella outbreak.

Contact information for ordering information and questions about our products:

Schnepper International, Inc.

3210 County B, Platteville, WI 53818

608-348-6141, Fax: 608-348-6146