I lunged my horse yesterday and he was going fairly flat and wasn't striding as he usually does (have since been told by yard that we have run out of cortaflex so I'll put it down to this.) I looked over him and saw a funny line behind his ribs on his lower stomach, another livery said it was just a muscle line but it has literally just appeared overnight. He also seems tucked up around his stifle. I gave him the day off today as it was raining horribly, he still seemed tucked up. He has had lami once in the past but he is not footy at all, no digital pulse, no hot feet and completely sound when trotted. He has been eating/ drinking and in the field as usual (only goes out for 3 hours a day), doesnt seem colicy of over heated, digestive system functioning fine and seems well in himself.
Could having run out of cortaflex made him go tucked up? What are the other causes of this? I took some photos on my phone of the "muscle line" at the bottom of his ribs and around his stifle but it won't upload to the computer!