The major sign of Zinc deficiency is metabolic abnormalities. The symptoms can include joint stiffness, excessive salivation, swelling of the feet and deformations of the hooves, and other conditions. These include Dandruff like scales over the body. It can be difficult to diagnose but there are recommended levels in blood serum.  It is often associated with excess calcium in the diet and high sulfur in the diet. A minimum of 10 ng/kg of ration is recommended to prevent issues. The recommendation is to have between 45 and 50 ppm in the diet. Another recommendation for treatment is to give a dose of 1g of zinc sulfate orally per day, if not signs of recovery after 2 weeks, then look for other causes of the condition. The information is from the book “Goat Medicine” by Mary Smith and David Sherman.

 The best solution is to prevent the deficiency by having a good mineral program that provides the zinc that is needed in the diet and do not give excessive amounts of calcium or sulfur in the diet.

I have not had any experience with Zinpro, if it was recommended by your veterinarian, I would expected that it is effective when used as directed by the vet. I would start by looking at some of the better on-line supplier companies for the product if your vet does not know where you can get a supply.  In the long term, make sure you are using a good quality mineral mix for your animals to prevent deficiency.