Vetri-Science UT Strength Canine - 60 ct

I have a Female Rottweiler (spayed) that is 4 1/2 years old, 115 lbs, and very prone to getting UTI’s. How many of these chews should I give her per day?

Pic of the back has been added.

The directions say:

Up to 15 lbs – ½ Chew Daily
16-30 lbs – 1 Chew Daily
31-60 lbs – 2 Chews Daily
61-90 lbs – 3 Chews Daily
Over 90 lbs – 4 Chews Daily