Impaction

[Sarah Ralston <ralston@AESOP.RUTGERS.EDU>]

My reaction to Tract Guard, based on the literature with it, is
that I would definitely NOT give it to my endurance horse at competitions.
the "reduction in acidity following meals of grain" implies a fair
amount of bicarbonate, and the action of drawing water INTO the
gut is not what you want if the horse is even marginally
dehydrated. Probably ok given as recommended, and maybe the
day or two before a ride to encourage drinking, but you
can get the same effect on drinking behavior with 
plain old electrolytes formulated for endurance horses.

Sarah and Fling