While working with the numerous skulls I've been testing I downloaded and "somewhat" studied the dental charts for identifying age of cattle by their teeth. This is the method that butchers use to determine whether certain cuts of the carcass are processed or not according to the federal rules. I tried checking a few living cattle but beyond very young. . . I am a flop at it.
I had an owner email to ask if I knew whether Dexter teeth matured earlier than other breeds? Due to a severe leg injury this owner had to process a cow that was only 3 1/2 years old, but the butcher determined her age to be 5 based on her teeth. The owner said the teeth were far more mature than an angus of the same age.
I butchered a bull this fall that was pushing the age limit only had about 2 weeks before he was over age. I kept the skull and looked a the teeth. He only had 2 permanent. At that age is next set should have been starting to come in but still had baby teeth there. So I would say they mature slower than commercial cattle.