Wow, what country are you in? Here in New Zealand, it is so common for horses to react to the toxins in the grass. Even when you do a pre-purchase exam for the vet, there is a specific question " Does your horse suffer from being grass affected". We have several different products made to help but to be honest, if the horse is grazing grass, he is eating toxins. You can limit the effects but some horses are more sensitive than others. You need to feed a good quality toxin binder twice a day ( often the main ingredient is yeast so you need one that has a top quality , batch tested yeast) I use Duwell Toxin binder. But if your horse is already showing signs of spookiness and you think his vision is impaired, ( all signs of being grass affected. ), then the best option is keep the horse off the short grass as the rocket fuel is in the tip and keep him on longer, old grass or have a dry yard where he can eat hay for 6-12 hours before you go jumping, hacking. If I have a spooky horse I always start with a week completely off the grass and eating hay on a toxin binder, see how he feels on a different diet and then slowly introduce fresh grass again. I did loads of tests on my farm and the potassium was very high which makes horses behave very extreme, tight muscles, staring at nothing in the distance, spooky at grass moving, super sensitive to noises and all my competition horses would stay off the grass 12 hours before jumping . Then you have to ensure you keep them on lots of hay so they don't end up with ulcers ... another issue.

@@KirstinKellyEquestrian Kirstin I am from the country you people hate...where the Springboks come from. Thanks for your update. Any further papers I can read will be nice. My problem is that I am getting old so I don't compete anymore. My horses run on the farm and on Sat/Sun I catch them and go for outrides. I have ended up on the ground a few times now as the one gelding seems to spook at a bird flying past on the next farm. I will try your suggestions and I believe they will work. Most of my problems occur when he grazes in the marsh areas or where the dam is which is full of water grass.

@@user-mkru lol I'm not into rugby so your all good. Andrew has a really good article too www.andrewscottequestrian.co.nz/grass-staggers.html

It could be pain, have the fitting of your saddle checked or a vet exam to check

Thanks for your lovely feedback. Try listening to it often, so you get into a great mindset before you get on to jump.

Then that rules out that the rider is weak one side , then it’s either unsure, lacking in confidence or could be naughty too