I have a friend that has a 6 yr old gelding pony..She has noticed a milky white residue on the ground after he has urinated..Is this something to worry about?
The Pony eats sweet feed and hay and has access to a mineral salt block.
My research came up with ideas ranging from Calcium / Phosphorus imbalances, excess Protein in the diet, to perhaps mucus in the urine from a bladder infection, or some other medical condition.
There could be a concern as to feeding a pony sweet feed, as pony's tend to be very easy to overfeed. There could be some imbalances going on, especially if the hay happened to be alphafa hay. If your friend is not familiar with the needs of ponies it would be good to have a consultation with a veterinarian or equine nutritionist.
The best advice is to be suspect of any unusual coloration or change in urine and first and formost consult a veterinarian.
"Horses Third Addition" is a great resource for new owners and has a bunch of medical issues described. it is available used on Amazon often for under ten dollars.
Hope this is helpful to your friend Kristine. Let us know what comes of it.