I'm not aware of any research on hoof growth and certain feeds, but I would not change the way I'm feeding in an attempt to reduce speed of hoof growth because there are many things far more important, such as overall health and milk production.
Hoof growth and need to trim hooves are really two different topics. I address this briefly in another
thread, but thickness of hoof seems to be what dictates whether or not the goat's hooves need to be trimmed more often, and that is related to genetics. If a goat has really thick hooves, they won't wear down as easily as one that has thinner hooves. I've had goats that need to have their hooves trimmed monthly and some that are fine for six months. I know a vet who raises boers who said she had a buck whose hooves only needed to be trimmed once or twice in his entire life, and he passed on that trait to many of his kids, which was one reason they loved him. I also see that my problem hooves are with goats whose mothers and/or fathers had more challenging hooves. Actually, my most high need hooves all go back to one doe, which was the fourth doe I ever bought. She was awesome in many ways and had outstanding parasite resistance, which she also passed on to her offspring, but I'm not a fan of their hooves, which have to be trimmed more than others.
If your goats are on sand or gravel or rocky terrain, they will wear down hooves faster. I know some people who mount their mineral feeder higher than their goats can naturally reach, and they put a cement block underneath it so that the goats have to step up on the cement block, which is rough and supposedly helps to wear down the hooves a little.
