I was told by my trainer that she read somewhere that Endure Fly Spray was not to be used on bay/black horses (because of a reaction they could have). I have always loved it and used it on all my horses (including my bays!) and never had a problem. I actually love the fly spray and feel like its one of the best ones on the market today.
Has anyone else read this? I tried to do a quick Google search on it and nothing came up.
Never heard that, and Endure is one of a handful of fly sprays that I can use on my horses, all bays, and no one has a reaction. One of mine (the darkest one, in fact) has had some hives in the past from different fly sprays, so I have a short list of the those I've tried that don't cause him problems, and Endure is one (also Mosquito Halt and Flysect Super C).
Never had that problem. That's actually my favorite flyspray (would like to use it on my sensitive horse, but I'm terrified of causing hives!), and used it on a barn full of black and dark bays for a long time. No fading, nothing. They all looked great.