Deer and Elk grow antlers which are shed and regrown each year. Depending upon age and nutrition, antlers can have many branches and grow to spectacular size.
Pronghorn, sheep, goats, and bison grow true horns. These are bony outgrowths of the frontal bone. Horns are not branched, do not shed, and continue to grow throughout the animal's lifetime. Pronghorn do shed the sheath (made of keratin like your fingernails) on their horns each year.