Salmonella Infection in Calves

 D. E. Larsen, DVM

Larry was waiting at the barn when I pulled off Old Holley Road. I parked in front of the barn, stepped out of the trunk, and shook Larry’s hand.

“What do you have going on today, Larry?” I asked as I opened the back of the truck.

“Doc, I have been buying all the bull calves from a dairy over by Shedd,” Larry said. “I was up to twenty-four of them the first of the week. I got them for a good price, and I was figuring I would make a bundle on them. Then, this week, I have lost six calves. Two of them just this morning. I guess I want to know what’s going on with them.”

“Let’s look at what you have set up before I get anything out of the truck,” I said.

We walked through the barn door, and Larry had the two dead calves laid out in the straw by the door. They were thin, skinny would be a better description, and their rear ends were soiled from diarrhea.

“When this started, I just thought it was a case of scours,” Larry said. “So I picked up these scour pills from the feed store. But they haven’t helped at all.”

Larry handed me a package of scour pills, Aureomycin, a tetracycline pill. Looking at the calves in the pen, they were all thin, and most of them were showing some signs of diarrhea. They were well bedded in straw, but it looked like new straw was laid down over older straw when it became soiled.

“If you have lost six calves this week, you need to load these two dead calves up and take them over to the diagnostic lab at Oregon State,” I said. “This is not just a simple case of scours.”

“I figured that out when two of them were dead this morning,” Larry said. “Do you think these pills are okay?”

“No, I don’t use tetracycline in nursing calves,” I said. “Some of the drug might be bound up with the calcium in the milk, and you need a stronger antibiotic anyway. I will leave you some trimeth/sulfa until we get the results from the diagnostic lab. I also want you to turn these calves out on pasture, if that is possible. This setup is okay, but when we have a lot of diarrhea, pasture just gives these calves a cleaner environment.”

“I was thinking of turning them out anyway,” Larry said. “The pasture is really starting to grow with the warmer weather. And Doc, could you give me a prescription for those pills from the pharmacy. I need to save as much as possible with this many calves.”

“Okay, and call if you see any calves not eating or with watery diarrhea,” I said. “They will need some fluids, and if we start early, we can use oral fluids. Those are a lot cheaper than giving IV fluids.”

“Will the lab know I’m coming?” Larry asked.

“Yes, I will call over there and try to build a fire under them so they will put these calves at the head of the line,” I said. “We will need to get early results if we can.”

Larry was loading the dead calves into the back of his pickup as I pulled out of the driveway. I called Dr. Snyder at the diagnostic lab when I returned to the office.

“Stan, I am sending a client over this morning with a couple of dead calves,” I said. “He has a bunch of calves that he gets from a dairy, and he has lost six out of twenty-four calves this week. I guess I’m asking for some special treatment if that is possible.”

“We see some nasty bugs in some of the dairies around the valley here,” Dr. Snyder said. “I will take the case when he gets here. We will have the gross necropsies done this afternoon. But, as you know, any culture will take a day or two.”

The initial results of the necropsy had Dr. Snyder thinking we were dealing with one of the virus diseases, probably bovine virus diarrhea, but the following morning he was on the phone again.

“Dave, the initial culture results look like we are dealing with a Salmonella bacteria,” Dr. Snyder said. “That’s really preliminary, and it will take another day to put an accurate name on the bug, but we will start a sensitivity test right away, so you should have those results in the morning. You need to caution Larry about this bug. It is definitely zoonotic. If any of his kids have been working with these calves or anyone with any immune suppression, they should be checked by a doctor if they have any problems.”

“Okay, I was going to stop by his place this afternoon anyway,” I said. “Thanks for the special attention in this case. I know you guys are busy over there most of the time.”

When I stopped at Larry’s place, he seemed all smiles. 

“These calves are looking better already with that new antibiotic,” Larry said. “Most of the stools I see are looking almost normal.”

“Initially, Dr. Snyder thought we had some virus problems, but this morning it looks like they have a positive culture for salmonella,” I said. “If the stools are looking better, I maybe made a lucky guess on the antibiotic. We also need to worry about any infection in you or your family. Salmonella bacteria is a serious infection, and looking at your dead calves, it can be life-threatening. It can definitely cause disease in people.”

“My son has had some diarrhea the last couple of days,” Larry said. “We didn’t worry much about it. It’s just one of those things kids have at times.”

“This is nothing to play around with, Larry,” I said. “You need to have him checked by your doctor. I can send him the culture results tomorrow when I get the report, but you should get your son to the doctor today.”

When the culture results came in, they listed a heavy growth for Salmonella species, type D, cultured from the lungs of both calves. The sensitivity showed resistance to many antibiotics. Just by the luck of the draw, the bug was sensitive to trimeth/sulfa.

The remaining calves continued to improve and thrived on the pasture. When I stopped for a quick look the following week, you couldn’t tell they had ever had a problem.

Larry’s son went to the doctor and was started on antibiotics. I never heard any results, but the two of them were in later in the summer talking about fishing the canyons of the upper Santiam River, so I would guess his problems resolved just fine.

Photo by Evgen Slavin on Unsplash.