Often associated with dropping grain. Check the teeth. Your vet or an equine dentist should check your horse's teeth once or twice a year routinely and remove any sharp edges by "floating" (filing). A painful tooth will also cause this behavior.
Rock-hard haunch muscles coupled with an unwillingness to move points to tying up. This is a painful condition that occurs most often in a hardworking horse, fed high percentages of grain to hay, after a day of rest. Keep the horse's back and hindquarters warm, don't move him; and call the vet.
This can mean anything from horses taking advantage of a warm sunny day in the winter to founder or an abscess in the hoof which makes standing painful. Collect other information to find out more.
Watch for changes in how he reacts to grooming. If he usually enjoys grooming but today he objects when you brush his back, look and feel closely for a sore spot that may have come from a longer-than-usual ride with a saddle that does not fit well or a dirty saddle pad.
Poor nutrition, a heavy parasite load, and the pituitary tumor associated with Cushings' disease can cause horses to keep their winter coat; the first two can disrupt the normal spring shedding cycle. Older horses normally grow their winter coats earlier and keep them longer than other horses. Keep your horse on a regular deworming program, and consult with your vet about other possible causes.
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