Lethargy and unresponsiveness under saddle
Hi all, I'm a little concerned about my mare, Serrinna. Seri is a 15 year old half Arabian that I've been with for eleven years now. Recently she has been dull and unresponsive under saddle and almost lethargic with her movements. I know some may immediately jump to old age or arthritis but let me be clear that while she sometimes has a small amount of stiffness in the beginning of our work outs, she smooths out fine rather quickly. And also, I think I would have seen a gradual decrease instead of such a sudden one. I started noticing this at the end of Jan/beginning of Feb. Sometimes, by the end of winter, I notice a shorter, much less prominent version of this same situation but usually, with a couple of beautiful days, she gets right back to herself. We've taken advantage of lots a beautiful days but she's still in her winter blues.
What makes this extra concerning is that she has always been a horse that loves to please and loves her job. You never have to ask twice for a trot or canter, she's already there. She never have to push and push to keep her moving, you might have to slow her down a bit though. This horse would (and has tried to) ride through an injury, if you'd let her. But since Feb, I've been carrying a crop with me for that extra "hello? do you remember that your supposed to be listening to what I ask for?" and I feel like I'm trying to squeeze an old lesson nag to keep up the gaits I finally get.
She's eating and drinking well, she's been out to pasture since the weather has gotten better, she shows no signs of injury or pain (back, legs, hips, etc). She gets grain and hay and it's QUALITY grain. We had a problem with grain toxicity in other horses on the farm, Seri never showed major signs (hair and weight loss, etc) but she was treated with pro biotic minerals none the less, and we switched grains in mid Feb (after her lethargy had already started) to one that we trust to be clean.
Any ideas would be much appreciated, it's almost depressing to ride such a completely altered horse...