CSI-Dairy: Wild turkeys and the case of Salmonella
Numerous ‘culprits’ exist on dairy farms, robbing herd performance and injuring the dairy’s bottom line. Identifying and arresting the offender isn’t always easy, and often requires a full investigation, gathering and analyzing evidence on the farm and in the lab. Uncovering the source of a Salmonella outbreak can be a difficult challenge.
By Corey Caraway
Andrea was at the end of her rope when she called. As the calf manager on a 1,200-cow dairy, she had a mess on her hands and wasn’t sure what to do. Calves were dying, pneumonia and scours rates were soaring and growth of calves at weaning was terrible. Worse yet, the dairy just had built a new calf facility, and instead of seeing improvement, they were facing a crisis.
The herd veterinarian necropsied a few calves and found high levels of Salmonella. What was odd about this discovery was that the dairy was using a Salmonella vaccine and thought it had the problem under control.
Was the vaccine failing? Were other diseases at play? What else could be going on?
I pulled together a response team to investigate. The team included Dr. Larry Slinden, a technical services veterinarian with Epitopix Inc.
Getting the facts straight
Dr. Slinden and I headed to North Dakota to help. When faced with a dire situation like this, it’s difficult to fight the urge to just start treating every animal in the hopes something will help. But before trying to fix things with a needle, we had to make sure we had all the facts straight.
• We confirmed through blood work the disease was Salmonella.
• We pulled total proteins on newborns to evaluate colostrum management and passive transfer.
• We measured Salmonella antibody levels in young calves to evaluate product compliance.
• We completed a facility walk-through to review environmental risks for the disease.
After our walk-through, it was clear calves were struggling. Weaned calves were the same size as newborns, and pneumonia rates were high. The calf pens were clean and the barn had adequate ventilation, but there were bird feces everywhere, including in the starter cart. The fields around the dairy were filled with wild turkeys, and Salmonella was ripping through the facility like a plague, so we had plenty of reason to suspect birds were a source of the disease.
Blood work confirmed several major issues. Total proteins on the calves were very low, indicating a colostrum management problem. Also, there were no titers for the Salmonella antibodies; it looked as if the vaccine wasn’t being used at all.
Dr. Slinden and I discussed the results with Andrea and discovered the Salmonella vaccine was being used off-label. Calves were being given a half dosage of the vaccine, and the vaccine is not labeled to be used in animals prior to 6 months of age. Instead of helping prevent Salmonella Newport, stress from vaccination was pushing subclinical cases over the edge into clinical symptoms. The dairy also was not revaccinating in a timely manner. We discussed how important it is to give a second dose at the appropriate time to help build a strong immune response. The first correction was to stop off-label use.
Salmonella starts in the fresh pen
Now that we knew what we were up against, we needed to break the disease cycle. Salmonella attacks the most susceptible animals on the dairy. Our protection efforts started in the fresh pen, to help reduce shedding of the bacteria after calving and increase Salmonella Newport antibody levels in the colostrum.
We got back to the basics of colostrum management. The dairy purchased a colostrometer to test colostrum quality, and we showed them how to draw blood and test total proteins in calves to evaluate passive transfer. We implemented an on-label vaccination program. All dry cows and springing heifers were vaccinated, followed by a booster four weeks later, which follows the vaccine’s label.
It worked, but ...
One month later we had broken the disease cycle. Deaths had stopped, but calves were still struggling – pneumonia remained an issue and total proteins weren’t up to par.
We dug deeper and uncovered that the new colostrum pasteurizer had been set to run at 150° F for 20 minutes. Instead of just killing bacteria, we were essentially baking the colostrum and destroying all of the valuable immunoglobulins. A problem easy to fix, the pasteurizer was reset to run at 145° F for 30 minutes.
I saw Andrea several months later at the Central Plains Dairy Expo and was happy to hear her calves were doing well. The Salmonella Newport control program had experienced no hiccups since. This is the kind of conversation we like to have!
• Corey Caraway is a territory manager for Pfizer Animal Health. He works with producers and veterinarians in Minnesota and the Dakotas to help improve on-farm dairy wellness.
• To learn more about your dairy’s risk for Salmonella, use the new online risk tool at www.SalmonellaRisk.com.
Each month, DairyBusiness Communications will check the case files of lead dairy ‘investigators’ to uncover another ‘CSI-Dairy’ mystery. Episodes are archived at www.dairybusiness.com.