OH boy, my favorite subject. This could be a long post.
I got Dexters after years of having other breeds, so being nervous about the larger breeds' size wasn't a factor, although I'm sure for some folks it is.
We have a small family, so don't need gallons of milk. I milked Jerseys for several years and it was just too much. I did graft beef calves onto the cows, but that was not always easy to accomplish. Dexters give me the amount of milk I want.
We don't need a lot of beef, and a Dexter steer lasts us a year. We put one in the freezer every fall and it works out fine for us. Also, usually have a waiting list of people wanting the smaller, leaner cuts of beef from our Dexters. We grass feed (hay in winter) only, and the Dexters do very well in this situation.
I had Jerseys and Dexters at the same time. My bigger Dexters were about the same size as my Jerseys. The Jerseys ate at least 1/3 more (more when fresh) and produced a lot more manure. Yes, they were producing more milk, but it was milk I didn't need. I now have smaller Dexters than what I started with and they eat even less.
The Dexters take our very cold, snowy winters very well. They stay in good condition every winter. They are easy on my fences and pastures. They like to browse more than other breeds, which works well on property that has a lot of brush and willows. My little bulls are easy to handle and gentle, any that aren't (cows or bulls go in the freezer). I'm an average sized woman and often have to doctor and handle the cattle by myself, so I do appreciate the Dexters' small size.
We are at 8000' elevation and brisket (high altitude disease) is a problem here. I have only heard of one Dexter that had it (and it was born here in Colorado). I don't know if that's due to the smaller size, and the heart not having to pump blood through more body mass, but that's the only reason I have come up with so far.
I also like that fact that the Dexter breed is small, but not miniature. They were not bred down from something else. It is a very old breed with a lot of history.
In 10 years of breeding Dexters I have never had mastitis, milk fever, pink-eye, or other serious disease in my herd. I have only had to have a vet help pull one calf. I vaccinate and worm regularly, and work closely with my vet on this. I have to treat a calf for scours occasionally, had one cow get ovarian cysts, one bull lost his fertility after several years, but that's about the extent of it. I was a vet tech for 12 years and saw lots of disease, calving and other problems in the local cattle that I just didn't have with my Dexters.
Dexters are not for everyone, just like Jerseys or Angus are not for everyone. I have seen people buy a Dexter, then are upset that they don't get 5 gallons of milk a day or 800# pounds of beef off one steer. The Dexter is a small dual purpose breed, designed to produce moderate amounts of milk and beef on less feed. She won't milk like a Jersey or finish like an Angus, so don't expect her to. But for those who have a small place, want a manageable amount of high quality milk and beef, and like something that's different, then Dexters are perfect.
Ok, I'll get off my soapbox now.
By the way, that's a very pretty heifer you have and looks like she'll make a fine family cow.