by Katharine Mertens, DVM
Poisonous plants
I just love looking at the world through the eyes of my now-6 year old son. As with all kids, his fresh outlook reveals truths often overlooked by jaded adult eyes. In explaining the world to him, I am prodded to re-examine common events and often find myself re-learning a lesson I thought already known.
This lesson concerns perspective, particularly as created by fences. We recently moved our retired, Thoroughbred gelding home, and have been enjoying watching him graze our back field. He roamed the area at leisure until the day I strung up the cross fence, intent on maximizing grazing potential. We only have one little acre for our 1,200 pound horse, but darned if I won’t try my best to keep a healthy pasture growing in spite of this limited acreage.
I’ll be learning as I go, but I intend to preserve my land with a mix of rotational grazing, hay supplementation, and complete pasture rest and over-seeding while I lease additional pasture during the fall.
Anyway, the first practice to affect our horse is the rotational grazing. No sooner is our cross-fence strung than Roadie (the one in the by-line photo) presses against it determined to eat what’s on the other side. Electrifying the wire-tape fence eliminates the leaning, but the fact remains: stringing a fence transforms Roadie’s field from one space to be enjoyed, to two spaces of ambivalence.
“Why does Roadie always lean against the fence, Mom?” asks Blair, as we watch our horse test the tensile limits of the wire-tape. You know the cliché answer, but it’s as true for us as it is for horses,
“Because the grass is always greener on the other side.”
Now that pasture growth has subsided with the drier weather, there’s another way in which I relearn that the stuff across the fence may not be as good as it seems. Driving around our area, some of the verdant oases seen earlier this spring reveal themselves now as weed-choked trouble.
All the pastures looked green a few months ago, but grazing livestock can reveal just how much of that green was actually weed—potentially toxic weed. In my opinion, the most noticeable toxic weed in our area is tansy. But others also flourish through the selective grazing practices of livestock: field horsetail, buttercup, alsike clover and foxglove.
The fact demonstrated by these flourishing toxic plants is this: given a choice, livestock are unlikely to touch them. Most poisonous plants have a nasty taste, and horses won’t eat them if other forage is available. I get nervous at this time of summer, though, now that the pasture grasses have been consumed and large tufts of weed remain for hungry grazers.
So the best way to avoid plant toxicity is two-fold: First, ideally, remove the problem weed (no easy task). Second, and easier, provide adequate supplemental hay once the grass is down in your pasture.
Remember, if it’s green and tall while all the grass is down, it’s probably been left behind for a reason and should be considered toxic until proven otherwise. Now if you’ll excuse me, I have some tansy to pull . . . .
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Katharine Mertens, DVM is the owner of Mertens Mammals, LLC, a mobile, equine veterinary practice based in Boring. You can reach the practice at 503-663-6400.
Katharine Mertens, DVM, is the owner of Mertens Mammals, LLC, a mobile, equine veterinary practice based in Boring. You can reach the practice at (971) 235-0005.