D. E. Larsen, DVM
Floyd was waiting for me at his driveway on Liberty Road. Sitting in his old pickup, he woke with a start when I pulled in alongside his truck. Floyd was a big man, his hands spoke of a lifetime of hard work, and his gray hair told of his age.
“I am glad you could come this morning, Doc,” Floyd said. “I have a dead ewe in the upper pasture. She was fine last night.”
“You saw her last night?” I asked.
“Yes, I’m not up there every day, but last night I was up there bringing a feed rack back to the shop with the tractor. I figured I wouldn’t need it this spring and summer. The ewes were all there, and their lambs. This morning, she is lying near the gate, all blown up like she has been dead for several days.”
“That almost sounds like Blackleg or something,” I said. “I didn’t think we were supposed to have that stuff on this side of the mountains.”
“You can follow me up there,” Floyd said. “The road gets a little rough, but it looks like your truck can probably handle it okay.”
“Yes, you put 4-wheel drive on these trucks, and they go just about anywhere,” I said.
I followed Floyd up a well-graveled drive beside a cemetery. Floyd stopped and opened a gate to the dirt road to the upper pasture. I stopped and closed the gate as soon as I was through it.
“You can leave that open,” Floyd yelled back to me.
“Habit, Floyd,” I said. “My grandfather always said it was easier to close the gate than it is to wish you had closed it.”
“Smart man, your Grandfather,” Floyd said.
We continued up the badly rutted dirt road, finally crossing a cattle guard into the upper pasture. The ewe was right there beside the road. If Floyd had been up here last night, there is no way he would have missed seeing her.
This ewe was on her right side and blown up, not from rumen bloat, just blown up like a balloon. All four legs sticking straight out, there was some pinkish foam at her nostrils.
I got out of the truck and opened the vet box. After pulling on my coveralls and boots, I retrieved my necropsy knife, a bucket with some water, and a pair of gloves. As I approached the dead ewe, I noticed that she smelled like she had been dead for several days.
“You are sure she wasn’t here last night?” I asked Floyd.
“She was sort of a pet, you know,” Floyd said. “She was up butting me around when I was hooking up the feed rack. She was as normal as could be.”
With gloves on, I pressed my fingers into her skin over her back. She had a lot of air under the skin, subcutaneous emphysema. It felt and sounded like I was popping bubbles. The wool pulled out along with the outer layer of the skin. There was a blueish discoloration to both the skin on both rear legs and extending along her back. This was Blackleg.
“Floyd, I am not going to open her up at all,” I said. “This is probably Blackleg. It could be one of the other Clostridial diseases like Malignant Edema, but that is sort of academic. They are all diseases that cause sudden death; most are impossible to effectively medicate, even if you make the diagnosis early. Most of the time, you just find them dead. The vaccines are all combination vaccines that include the whole bunch in one shot.”
“I have not heard of Blackleg around here,” Floyd said.
“We saw a lot of it in Colorado,” I said. “Guys had to vaccinate for it, or they would have dead animals. I never saw a case in Enumclaw. I was always told it was rare on this side of the mountains. This might change my thinking on that aspect of the disease. I am going to aspirate a little fluid from under the skin. I can pretty much confirm the diagnosis when I get back to the clinic and get the sample under a microscope.”
“What should I do with her?” Floyd asked, pointing to the ewe.
“You should bury her deep if you have a backhoe or some grandkids,” I said. “Bury her right where she lays, don’t drag her anywhere. This disease is caused by spore-forming bacteria, and you would contaminate the pasture more. Or you could burn her if you have enough fuel. I don’t know if the rendering company would pick her up or not.”
“And what about the others?” Floyd asked.
“You need to get a vaccine into them,” I said. “I have both a 4-way and a 7-way vaccine at the office. You should do that yesterday, and they will need a booster vaccine this year, in 3 – 4 weeks. I would hedge on the short side, 3 weeks.”
“I can bury her with a backhoe,” Floyd said. “And I can get some guys to help me vaccinate the others, that might take a day or two.”
“I wouldn’t let it take too long, you might find some more like this one,” I said. “If you are going to work through the whole bunch, it might be a good time to worm them.”
“You are trying to make a sheep rancher out of me,” Floyd said.
Back at the clinic, I did a quick gram stain on a slide I made from the aspirate from the ewe. The slide was covered with large gram-positive rods that were characteristic of Clostridium organisms. That, coupled with the clinical signs of the ewe, was pretty much diagnostic for Blackleg.
I checked and made sure I had an adequate supply of vaccine for Floyd.
The next morning I thought I should call a couple of other veterinarians in Lebanon and Albany. I wanted to check to see if they saw any of the Clostridial diseases in this area. As I was considering those calls, the telephone rings.
“Doc, this is Walt up on Fern Ridge,” he said. “I went out this morning to look over the animals in the field. I check them morning and night. Everything was fine last night, this morning there are seven dead steers in the pasture. I sure hope you can tell what the heck is going on with that.”
“Give me a little time, Walt,” I said. “I can get up there in a little over an hour. Are they near the house?”
“No, they are down the road a ways,” Walt said. “I will be in my blue truck and will park at the gate. You should not have any problem, the field is right along the road.”
When I pulled up to the gate, I could see the seven dead steers scattered across the field. These steers were all at market weight. What a loss.
“I moved all the other stock out of this pasture,” Walt said. “What do you think is going on?”
“Let me get a look at them,” I said. “You said they were fine last night?”
“I was up here before dark last night,” Walt said. “They were all up and running around like nothing was wrong.”
All of these steers looked just like Floyd’s ewe. They lay on their sides, puffed up like a balloon, and all four legs were sticking out, straight and stiff. When I pushed on the skin, I could feel the air popping under the skin, not unlike pressing on some bubble wrap.
The carcasses were in an accelerated rate of decay, with a strong odor and hair easily slipped from the skin, especially in areas where the skin was discolored. These steers all died from Blackleg. I took a few aspirates and went to talk with Walt.
“Walt, this is Blackleg,” I said. “Everything fits, sudden death, rapid decay, subcutaneous emphysema, and discoloration of the skin and tissues. If you want a thorough diagnosis, you need to load one of these guys up and take them over the diagnostic lab at Oregon State.”
“What is the risk to the rest of the herd?” Walt asked.
“Clostridial organisms are spore-forming bacteria,” I explained. “Those spores last for many years. They have spores from soil collected in Kanas in the 1890s that are still infective. What causes an event like this is not really known. What is known is that vaccination is a very effective preventative. You need to vaccinate the rest of the herd yesterday.”
“Okay, I can get a crew together and do that chore this afternoon,” Walt said.
“If you have any animals that have not been vaccinated before, you need to booster the vaccine in 3 weeks,” I said.
“What do I do with these steers?” Walt asked.
“The rendering company can probably pick them up,” I said. “If not, you should bury them deep, right where they lay, no dragging them across the pasture.”
“Have you ever seen anything like this before, Doc?” Walt asked.
“In Colorado, the Clostridial diseases were common, and ranches who did not keep up on their vaccines always had problems,” I said. “There, I would see several animals at a time. In Enumclaw, I never saw a case. Had you talked to me last week, I would have recommended vaccinations for Blackleg, but I would not have worried too much if you failed to take my advice. After the last couple of days, vaccinations will be required in the herds I take care of regularly.”
“That sounds like you are a little strict, Doc,” Walt said.
“Better than checking seven dead steers in the pasture,” I said. “There are other veterinarians in the valley, people always have choices.”