Can a cow be "stuck on cycle"?
Yes. Such cattle are called "cystic." There are two types of cysts: follicular and luteal. Follicular cysts generate a lot of estrogen so the animal appears to be in heat for an extended time (until the cyst ruptures naturally or hormone treatments are effective). Luteal cysts produce a lot of progesterone. These animals do not come into heat and act as though pregnant (no cycling). Again, a hormone injection can usually remedy the situation. These cysts can easily be diagnosed with an ultrasound machine, by blood testing, or more commonly by a competent veterinarian performing a reproductive exam on the animal.