Johnson grass identification and information needed! - Ask Extension
I have two horses, a 19 yr old gelding and an 11 yr old mare. I've noticed 3-4 times over the last month that she has had episodes of short rapid ...
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Johnson grass identification and information needed! #152290
Asked September 11, 2013, 9:59 PM EDT
I have two horses, a 19 yr old gelding and an 11 yr old mare. I've noticed 3-4 times over the last month that she has had episodes of short rapid 'puffy' breaths, but no nasal drainage, no sweating. Then just over the past couple weeks I've noticed that my gelding, has had the same 'episodes' on about 3 or 4 occasions but the symptoms go away after 3-4 hours. I let them graze daily 2:00 - 8:00 pm on a pasture (5-way grass mixture) I've had horses for many years in this same pasture and never any problems. I've read alittle about Johnson grass being toxic to horses. Can you tell me about this grass and any tips on how to identify it. Should all johnson grass be sprayed w/a chemical to eradicate it from the pasture or can it be mowed down? We also square bale the pasture grass every year and have fed it to our horses without ever having any problems. Positive Identification would help decide my next step in treatment of my horses. thank you.
Harrison County Iowa
Expert Response
Johnson grass is a coarse grass that spreads rapidly. The leaves are up to 1.5' in length and form a sheath around the stem which may reach 3-8' in height. In horses, symptoms of poisoning can occur after a few weeks to months
of continuously grazing Johnsongrass or other sorghums, at any growth
stage of the plant. Hay containing sorghums also has been incriminated.
Affected horses gradually develop ataxia, incoordination, difficulty
backing, and dribbling urine, progressing to flaccid paralysis of the
tail and hind legs (www.thehorse.com) Texas A&m at http://essmextension.tamu.edu/plants/plant/johnsongrass/ has a good description of identifying Johnsongrass. From the symptoms you describe I would look more at another culprit. What else may be present in the pasture?
Thank you for your input on this. It is very perplexing because we have had horses for years in this very pasture. What would cause the symptoms in my horses that I mentioned? The 19 yr old gelding I've had since he was a weanling. The 11 yr old mare i bought recently at a local horse sale about an hour away.
The only other thing that was done/added differently this year was we put fertilizer/nitrogen and the setting on the spreader was incorrectly set so part of the pasture got a twice the amount of fertilizer that we requested. We fertilize when needed and do weed control. We had the company reps who we purchased the fertilizer come out and they suggested that we could have a grass sampling done by a company in Omaha to see what the level of nitrogen is in a few samplings of grass. What would be the correct and safe level of nitrogen for horses ? The rep told us that they don't think there is any johnson grass present in our pasture but there is plenty of rye grass. Would that maybe be the culprit? Again, I appreciate all the time you've given to my problem.
The only other thing that was done/added differently this year was we put fertilizer/nitrogen and the setting on the spreader was incorrectly set so part of the pasture got a twice the amount of fertilizer that we requested. We fertilize when needed and do weed control. We had the company reps who we purchased the fertilizer come out and they suggested that we could have a grass sampling done by a company in Omaha to see what the level of nitrogen is in a few samplings of grass. What would be the correct and safe level of nitrogen for horses ? The rep told us that they don't think there is any johnson grass present in our pasture but there is plenty of rye grass. Would that maybe be the culprit? Again, I appreciate all the time you've given to my problem.
Attached is a photo of the pasture in question. It has no trees, no creeks or running water through it. Thanks again for your input on this matter.
cindy myer
logan, ia
cindy myer
logan, ia
Attached is a photo of the pasture in question. It has no trees, no creeks or running water through it. Thanks again for your input on this matter.
cindy myer
logan, ia
cindy myer
logan, ia
I asked the specialist here if there were any plants that may cause your symptoms. Dr. Ensley replied for the horse respiratory case I
would be more concerned with a potential problem with ergot in the pasture
grass, we are seeing a very large increase in ergotized grasses on pasture this
year because of the cool wet spring.
Ergot is a fungal disease that affects wild and cultivated grasses, as
well as small grain crops such as wheat, oats, barley and especially
rye. It produces a toxin that reduces blood flow in humans, cattle,
sheep, swine and horses. The fungus only appears in seed heads and is present this year due to
late pasture and hayfield harvesting because of wet conditions. Infected
grass crops should be harvested to remove fungus infected seedheads and
destroyed, not fed to animals or grazed. All infected hay should be
destroyed and should not be used for animal bedding. If you mow the pasture this may decrease the ergot if it is present
