A Saturday Afternoon Outbreak

D. E. Larsen, DVM

It was almost a perfect Saturday afternoon. Late August in the Willamette Valley provides a short stretch of weather that acts as an interlude between the summer heat and the fall’s rains.

We were still getting settled into our newly purchased house. We had the kids outside, working in the garden, and playing in the grass. I started to consider setting up the garage to see patients for a couple of months while waiting for the clinic construction to be completed.

The afternoon’s calm was broken when the phone rang.

“Doc, I know this is Saturday evening,” Dave said while trying to catch his breath. “But Doc, I was just out in the pasture, and I have seven dead calves, all about 2 months old. They were healthy as could be yesterday. I have about 30 more out there. What do you think I have going on?”

“It sounds like we need to get a necropsy on one or two of those dead calves,” I said. “The Diagnostic Lab at OSU is closed for the weekend. I can do a necropsy, but any lab work would need to wait until Monday.”

“If seven of them died overnight, they might be all dead by Monday,” Dave said.

“I agree, Dave,” I said. “I have a pretty good background in pathology. I worked in the necropsy room at CSU the summer following my sophomore year in vet school. I can likely get a good diagnosis with a gross necropsy. I will collect samples, just in case we need them for Monday.”

Seven dead calves amounted to about 15% of his herd. That was probably the profit for the year, at least a good chunk of it. A dead animal usually was not an absolute emergency, unless it was a herd animal. Unless it was a bunch of animals that died in a short time.

Dave had all seven dead calves lined up at the pasture gate when I pulled in the driveway. 

What a waste. All seven calves were in good shape, looked good for a couple of months old. I surveyed the herd out in the pasture. Good pasture for August, and the herd looked like nothing was wrong.

“Where do they get their water?” I asked.

“There is a pond, just over the rise, at the far end. You can’t see it from here.”

I pulled on a pair of gloves and looked over all the calves. Jaundice was evident in each one.

“Let’s take the smallest one and pull him over here out of the pasture,” I said. “We don’t want to contaminate things any more than they are already.”

I laid the calf on his left side and quickly reflected his skin and right legs. Stretching them out over his back. I took a moment to remember Dr. Norrdin’s words, “Work with your mouth closed.” Then I opened the chest and abdomen. The chest was fine, but the liver was swollen and dark in color. The urine in his bladder colored with bile. This was an acute outbreak of Leptospirosis. 

Lepto was known to cause abortion ‘storms’ in pregnant cow herds. Acute outbreaks in young calves occurred only rarely. It always amazed me how I always seemed to see all the rare events in my first couple of years out of school.

I collected samples for the lab on Monday if we needed them, liver, kidney, spleen, gall bladder, urine, and blood. Then I roughly closed the animal up. 

“Dave, I think you have an unusual outbreak of Lepto in these young calves.”

“Is there anything we can do to stop it?” Dave asked.

“Have you had any cows abort this year?” I asked.

“We had one cow abort about a week ago. I never thought much about it. It is not unusual for us to have an abortion or two every year.”

“There is an antibiotic treatment that will stop an abortion storm in cows. The entire herd is treated with a single dose of Streptomycin. I don’t think anything is written about controlling an outbreak in young calves. But my guess is if it stops abortions in a herd, it will stop an outbreak in calves.”

“So where am I going to get enough streptomycin to treat a herd at this hour on Saturday evening?” Dave asked.

“You’re lucky enough that I ordered it on my initial stocking order. I didn’t think I would ever use it, but I wanted to have it on hand. So, I think I have you covered in that regard.”

“There are a couple of other items we need to cover,” I said. “Number one, this is contagious to people. And it can do the same thing to people that it does to these calves. I was just talking with Dr. Craig the other day, he worked a herd with another veterinarian, and they both got sick. Dr. Craig went to the doctor as soon as he noted some blood in his urine, he got well. The other veterinarian waited till the next morning, he died.”

“Number two is the pond. Lepto is usually spread via contaminated water sources. If you had a cow with a Lepto abortion, she sheds organisms in her urine for several weeks. If she pees in or near that pond, calves that drink out of the pond can end up here,” I said as I pointed to the dead calves.

“You need to fence that pond and put a water tank in the pasture,” I said. 

“Do you think I should inject these calves tonight?” Dave asked.

“If you’re up to it, that is what I would recommend,” I said. “You might wake up in the morning with another batch of dead calves.”

“I will get you enough Streptomycin and vaccine,” I said. “I would give both. Lepto vaccines have some limitations in that there are many strains of Lepto. The vaccine protects against three of the most common strains, but there are others, and there is not a lot of cross-protection. It is the best we can do at the moment.”

“What should I do with these calves?” Dave asked.

“Move them out of the pasture. If you will have the rendering truck pick them up, that is okay. Otherwise, bury them deep. And don’t let the dogs get into this calf that we opened. They can get this also.”

I fixed up Dave with the necessary antibiotic and dosages and left him enough vaccine for the entire herd. He had a crew coming to help him. When I left that evening, I left him with one last piece of advice.

“Dave, you make sure everyone works with their mouth closed tonight,” I said. “And make sure they shower before going to bed.”

“Thanks, Doc, wish me luck,” Dave said.

“There is very little luck in this business. That is why it is important to do things the best we can at all times,” I said. “I will give you a call in the morning.”

I spent a long time drinking my coffee in the morning, and Sandy noticed.

“What is wrong with you this morning?” she asked.

“I am dreading calling Dave,” I said. “I am hopeful that I solved his immediate problem last night, but if I didn’t, he might have a bigger problem this morning.”

“Dave, this is Doc. I was just checking in with you on how things went last night and how things look this morning,” I said.

“We got the herd done, had to get out some floodlights for the tail end of it, but they are done. Things look good so far this morning. I have a couple of guys stringing an electric fence around the pond this morning, and I have a small water tank in the pasture. I am getting ready to run to Albany and see if I can pick up a large tank. Can’t thank you enough, Doc. I will keep you posted.”

Dave never had another problem, and the lab confirmed the Lepto diagnosis on Monday. In the next forty years, I never saw another outbreak like this one. Go figure the odds.

Photo by Kat Jayne from Pexels