Purina is a pet food company that has been around since the late 1800s. Its main competitor is ALPO, which was founded in 1936 and produces a variety of dry and wet dog and cat food. Another major competitor of Purina is IAMS, which was founded in 1946 and produces a variety of pet food products for cats and dogs. Both ALPO and IAMS are well-known brands in the pet food industry and have been competing with Purina for many years.