In 1892, Cary taught the first veterinary science course at the Alabama Agricultural and Mechanical College, now Auburn University.
He became Alabama's first State Veterinarian in 1905, during which time he led in establishing meat and dairy inspection laws.
His campaigns to eradicate bovine tuberculosis and Texas tick fever were among the many accomplishments that led to his recognition as the Father of Veterinary Medicine in the South.
When farmers sought hog cholera serum at low prices, Cary used his influence to establish a plant at Auburn to make it.
His Saturday clinics and summer institutes taught farmers about the prevention and treatment of diseases of animals.