Hi Sue,
Then she told him to feed then shoot him right away. Others said wait for half and hour, others wait until 8am. He gets fed when i get up at 6am but I'd like him to have his food on the belly for a bit before he get his shot.
I always like to know "WHY" about what i'm told to do by anyone, including folks here and my vet, so I hope this helps you.
The typical "onset" of Prozinc begins at +2, in other words it takes 2 hours before a shot begins working noticeably in their body. The typical curve pattern is (or used to be) explained in the PZI stickies, so it might help you decipher what you are seeing with his numbers.
The pattern I used to see on Prozinc all the time was this:
preshot- -test, feed, shoot (right after each other)
+1 and +2 -rising numbers from the food and the previous shot wearing off
+3 -beginning of downward movement
+4 through +7 or 8 -a fairly even, low point of the curve, maximum effect of the insulin
+8 through +12 - rising numbers
It's obviously scary/dangerous to shoot and then find out your cat won't eat, so always test, then feed, then shoot.
Food hits the blood stream within minutes, but the insulin takes a couple hours, so IMO its desirable to shoot immediately after food. As soon as you know he has food in his stomach, get that insulin started. ;-)