Digestive Question

[Anastasia Hurley <ahurley@cncx.com>]

Hi, 

I am having a problem with 2 of my horses. One ¼ horse and one smallish
grade that looks part TB

They are both having bouts of diarrhea. They are not in the same field -
grade horse is in with a buddy mare that is fine, ¼ horse is by himself.
They are getting ½ alfalfa and half oat hay. No fever  - both look ok.
Worming is up to date with ivermectin. The frustrating thing is they
sometimes pass regular manure but the backs of their legs and the rain
sheets are pretty gross with liquid manure.  I have been treating with
fastrack (probios), and rinsing off dirty legs and sheets!

History
The little grade gelding was bought 1st of december and was on all alfalfa.
Did not have problem until recently.  
¼ horse was bought last spring  - no problems like this until Jan 1.  

Possible causes:

Water - The water piped in from a large lake that cattle graze by. Could it
be giardia? All of my other horses are ok and they all get water from this
same source, but have different tubs. 

Virus??

Bacteria??

Worms - I just wormed with ivermectin 2 weeks ago - no improvement. 

Nervousness?   - I don't think so as the manure seems fine when I am
walking, riding, handling them.

New Grass - ¼ horse has some new grass in paddock but not a lot. Little
grade horse is in dirt paddock. 

All are eating well and seem ok but for this one problem. Does anyone have
any suggestions for how to deal with this problem? 

Grade gelding is losing weight and was not in great shape when purchased. 

¼ horse was never an easy keeper, but I was having some luck with putting
weight on him until this.

Thanks 


Stasia