Iv never heard of that before..20 hours is way to long for a pup,especially a toy breed! Even when my oldest yorkie was spayed I was allowed to give her her breakfast at 9am, and she was spayed at 5pm..she only had to go without food for 8 hours but by no means without water,and she was under 2lbīs!
I would also get a second opinion,20 hours is a long time even if they do plan on giving him glucose.
Toy breeds need to eat regulary becuse the sugar in their blood can drop REAL fast,and they need to drink regularly because they can dehidrate just as quickly.I know a woman on another board that took her male in to be neutered..she had already had him without food all ready for surgery,but the vet later delayed surgery and he went even longer without eating...he died that day due to low blood sugar which weakened him,making the anestesia fatal
He just didnt wake up..
20 hours in a very long time for these little ones..I would deffinately get a second opinion
