In Wednesday’s blog, I admitted that my lamb flock currently has a mysterious illness. Most of the biggest and strongest lambs have a rash all around their mouths, some with blisters; and several have this same condition around their eyes and noses and a bit on the ears (see Odin’s eye, left). When I visit the lamb flock, I want to cry. But although they look horrible, they seem to eat, drink, and act normally in spite of what ails them. My vet came out last week and told me that it was not sore mouth — indeed a relief, but we still had no idea what it was. Each of us went to our own resources to try to figure this thing out.
Before my vet left last Tuesday, he suggested that I treat all symptomatic lambs with a long-acting broad-spectrum antibiotic, thinking that the mystery illness might eventually lead to infection — as could already be seen in several of the worst lambs. We sorted and treated the entire group that very afternoon, identifying more lambs with the same illness during that sorting.
The next day, my vet called back. He suggested I also treat them with a long-acting injectable anthelmintic normally used to deworm our sheep — it would kill any larvae that might be present anywhere in or on the sheep. I asked what he was thinking, and he mentioned “larval migration” — that somehow larvae had gotten into the skin or blood and were migrating until they reached the areas where we were seeing inflammation. Yuck! I honestly wished I hadn’t asked!
I also discussed this mystery illness with various shepherds over the past week. My friend Maggie in California mentioned that since the lambs had been eating thistles, the spines might have opened up the mucous membranes to other irritants. There are also nettles in that field, and since the lambs had been eating both, we began to suspect that this might be the cause for what I was seeing. It made a lot of sense as the skin seemed to be very irritated in places where there was no wool or hair cover. I also kept thinking that there might be a component of photosensitivity, since the blisters seemed worst in areas that are most exposed to the sun. I ran all of this past my vet, and he agreed that we had uncovered another possibility, but treatment would still include the antibiotic that we had already administered.
On Tuesday of this week, I had lunch with my mom, as is our usual routine. I mentioned that this problem had me stymied; I had sheep that needed to be delivered, but I didn’t want to risk it until I knew what the issue was. Everything was on hold until then – and that was bad! Mom asked whether I had seen the piece about wild parsnip on Friday evening’s local news. I admitted that I had seen the first part of it but had then returned to the kitchen and missed what they had to say. I also told her that my sheep LOVE to eat it until it goes to seed and is dried-up dead. And that’s when my mother solved what we had all been working on for years. She said, “Oh, well, they said it’s all over eastern Iowa, and that it causes rash and blisters that are brought on by touching the sap and then being exposed to the sun. Doctors and vets often don’t know what it is when they see it, but it’s appearing more and more as blisters that often get infected. Do you think that might be what your sheep have?”
I quickly Googled “wild parsnips” while sitting there at the table and my eyes were opened! Suddenly it all made sense! My sheep LOVE to eat this stuff, but the plant’s sap is toxic, growing more so throughout the year until the plant goes to seed. At that point, the toxicity begins to decline until the plant dries up and dies — and by that point, my sheep are no longer interested. The peak of intensity is in late June and July — exactly when we have seen these blisters appear on my sheep for the past three years! There is also a degree of photosensitivity, which coincides with what I’ve seen and suspected. Even better, this answer explains why only our lambs get symptoms, even though adult sheep move through the same field: the lambs go into the field first and eat all of the wild parsnip, so that when they move out and the adults come into the field, there is not any left to eat! The biggest lambs have the most symptoms because they get first dibs on the plants and can chase the smaller lambs away.
Not only did this cause fit all of the symptoms, but it also explained why the lambs always get it in the East Pasture, which is the one that contains the heaviest wild parsnip infestation. We have only one other pasture that has this plant in any quantity —the Pond Pasture — and all of the wild parsnip is in one section (far from water and shade) largely unvisited by the sheep until everything else is eaten down.
I printed out a copy of an online wild parsnips brochure and took it to my vet at the close of business on Wednesday. He looked it over and declared our mystery solved. The brochure described exactly what he had seen, and he was satisfied that it was not contagious. My sheep could be released from quarantine and begin travels to their new homes! I cannot tell you how happy I am to know what I am looking at when I walk among my lambs. Yet I will admit that my happiness is not complete. The only thing that will make me truly happy is when my lambs are once again clean-faced with no blisters, no bleeding, and no photosensitive rash. Then I will be truly happy! But still, mystery solved.