For a dog whose weight is between 49-51 lbs, what heartworm med strength would you give - 26-50 or 51-100?

Tessa always got 26-50, my vet says it covers dogs up to 53 or 54 lbs, not to worry. Another vet today (had credit there so had to use him) insisted on 51-100. She weight 51.2 today and is currently at her top range.

Argh, just my luck she's sitting right on the cut-off!

Since Tessa was 51.2, I would go for the 51-100 lb size. If you still have some of the smaller size, I'd give her those in the winter months when mosquitos are not likely. I don't think the larger size would cause problems but confirm with the vet. I'm guessing there is some leeway built into the weight ranges. Kind of like when you gas tank says empty but you usually have a few gallons left.

I have the same problem with flea stuff. I use Comfortis for Bearoff and Jenny. Their size is 40.1 to 60 lbs. Jenny weighed 59 at the beginning of the summer. I went for the 40-60# size, luckily for this purpose, Jenny lost weight. Bearoff is 52-54 lbs so he was more in the range.