ABSTRACT
The production of milk naturally depends on a constant supply of calves, which, since for most people it’s not a good idea to keep a bull, depends on artificial insemination. Three months after the birth of a calf is the time to begin thinking about getting the cow pregnant again. Cows have a threeweek (17-to 24-day) cycle and are only on heat (known as estrus) for 12 hours. Detecting this is not easy and is dependent on close observation of the animal’s behaviour. Signs include a swollen vulva, with secretions, restlessness and calling. The cycle can be reset by a vet with ingestion of progesterone. An AI shot costs £30 and sperm can be ordered; with a little practice and training it’s possible to administer it yourself. A cow might come into calf in March and have a milking season until November. Two heifers could be alternated if desired to maintain a year-round supply of milk, provided sufficient grazing is available.
