That looks like some kind of ”wire-y” Corriente bull (with a mild Brahma hump). A mix?? Tend to be kinda small, and lean. Makes them a good bull to breed to a heifer (so her firstborn isn’t big, running the risk of getting hung up), but neighbors hate to see those Corriente bulls. They’re notorious for jumping fences (and doing what bulls do, with the neighbors’ cows).