Hi Jan,
That's a pretty sizable drop in 2 hours but I know that Vetsulin is a faster acting one. I've never used it so I don't know if that's typical. Normally, on an AlphaTrak meter, you want to be on the lookout for signs of hypoglycemia for any reading below 68. Can you test him again? If his numbers are still dropping, give him a small amount of food with honey or Karo syrup in it to help get his blood sugar back above 68. You'll want to keep testing every 30 minutes or so until you're sure he's staying in safe numbers. I'll find the link to the Hypo instructions and post here too incase you need it. Looks like Radar has earned a dose reduction! Hopefully, someone with more experience with Vetsulin will chime in soon.
Keep us posted!
Joan