What does his current diet consist of?? I have concern that a young horse needing to gain that kind of weight gain
. Either his diet is not optimal or he has some underlying reason for his poor weight.You have addressed his teeth & worming but ulcers are another consideration.
you may be wanting to consult a vet re: His heath & feeding program
As far as beet pulp it is a inexpensive & good supplement feed for helping with weight.Once your horses get a taste for it most just love it.Good feed to mix with your grain & complete feed or supplements without really upsetting the balance of things,Alone it doesn't really meet alot of nutitional needs.