Welcome to FDMB.
Squeem3 is correct. Since 2018, the American Animal Hospital Assn (AAHA) no longer recommends Vetsulin for the treatment of feline diabetes. Vetsulin, or as it's known outside of the US -- Caninsulin, was developed for the treatment of diabetes in dogs. As a result, it is not suitable for cats since cats have a much faster metabolism than dogs. What this means is that Vetsulin doesn't last for the 12-hour cycle. (And FYI, a cycle is 12-hours/2 cycles in a day. A cycle is NOT a day in length.) I'm linking the
guidelines from the AAHA for your convenience and it may be a means of starting a discussion with your vet. The two insulins that are recommended, as noted above, are Lantus (or its generic/biosimilar, glargine) or Prozinc.
There have been any number of vets who have published in well respected journals that home testing is essential for managing diabetes. Also, there is a section starting on page 10 of the AAHA guidelines that supports home testing. As a comparison, could you imagine any human doctor telling you to not test your (or a family member's) blood glucose levels? In a few words, not testing is unsafe. A cat cannot easily communicate that their blood glucose level is dangerously low or if it's unsafe to give an insulin injection. The only way you know is to home test. While many people opt to use a pet specific glucometer (e.g., AlphaTrack), the strips are expensive. Even more people here use a Relion (Walmart) meter as the strips are the least expensive around. We have lots of resources to help you learn how to home test. If you were to poll our members, there are likely a handful of cats who won't tolerate getting their ear poked with a sharp object. The majority, though, learn that what you're doing helps them to feel better and if you give a treat when you test, it will speed up the process of your cat putting up with the pokes.
As far as prescription food, I'd encourage you to read the label. There is nothing in the food that is "prescription." In fact, the pet food manufacturers lost a class action lawsuit for calling their foods prescription. The Hill's M/D dry food is high in carbs -- approximately 18% carbs. We consider low carb as under 10% and many members here feed their cat a diet that is roughly 5% carb. The ingredients are also not ideal. My favorite ingredient is powdered cellulose. This is the polite term for sawdust.
We also encourage that you feed your cat canned food rather than dry. There are a couple of reasons. Most dry food is very high in carbs. There are only 2 or 3 brands that are low in carbs. Cats have a limited thirst drive. In the wild, they get most of their liquid from eating live prey. Dry food is, well, dry. The limited moisture in dry food is not great for the kidneys. It's especially the case for a diabetic cat since diabetes is hard on the kidneys. The AAHA guidelines also support the use of canned food over dry. There is an excellent website, written by a vet, that discusses
feline nutrition.
If you like/respect your vet, I'd have a frank discussion with her. Vets in a general practice have to treat any animal that comes through the door (as well as any they have to visit if they also treat farm/large animals). In other words, they can't be experts at everything. A lot will depend on whether your vet will encourage you to keep learning and asking questions or is more of the "my way or the highway" type of thinking. I got push back from my vet over prescription food when I was returning a ton of it. I then asked her what the percentage of carbs was in what she asked me to buy. She didn't know. When I told her, she was embarrassed.
Please let us know how we can help.
