[Shawna]

Oops, forgot this..

IF refrigerating the product does cause issues, that could be another reason it failed.

And

Heatguard kills L3 and L4 stage larvae. I’m not sure why one would need to continue giving it up to three months after heartworm season ended. If giving every 30 to 45 days it should kill any L3 and L4 still maturing under the skin??