The single suckler system of rearing calves is similar to that occurring naturally in wild cattle, where each calf is suckled by its own mother until it is weaned at about nine months old.
Cows kept on poor forage (as is typical in subsistence farming) produce a limited amount of milk.
A calf left with such a mother all the time can easily drink all the milk, leaving none for human consumption.
The small amount of milk available for the calf under such systems may mean that it takes a longer time to rear, and in subsistence farming it is therefore common for cows to calve only in alternate years.
In more intensive dairy farming, cows can easily be bred and fed to produce far more milk than one calf can drink.
The latter system is preferred by some as it accustoms the weaners to the presence of people and they are trained to take feed other than grass.
Many calves are also weaned when they are taken to the large weaner auction sales that are conducted in the south eastern states of Australia.
[6] Calves suffer from few congenital abnormalities but the Akabane virus is widely distributed in temperate to tropical regions of the world.
The virus is a teratogenic pathogen which causes spontaneous abortions, stillbirths, premature births and congenital abnormalities, but occurs only during some years.
These conditions also display seasonal patterns, with omphalitis being more common in the summer months, and respiratory diseases and diarrhea occurring more frequently in the fall.
[8][9] Calf meat for human consumption is called veal, and is usually produced from the male calves of dairy cattle.
In addition to other bovid species (such as bison, yak and water buffalo), these include the young of camels, dolphins, elephants, giraffes, hippopotamuses, deer (such as moose, elk (wapiti) and red deer), rhinoceroses, porpoises, whales, walruses and larger seals.
However, common domestic species tend to have their own specific names, such as lamb, foal used for all Equidae, or piglet used for all suidae.