Range cattle live in groups of cows and calves; males are often separated until breeding season. Dominance in cattle is based on age, sex, weight, presence of horns, and territoriality. Breed also seems to play a role—heavier dairy cattle are dominant to lighter breeds, while lighter beef cattle are dominant to heavier breeds. When a heavier and older cow is introduced into a group, it is usually subordinate to existing members of the group. In large herds, triangular relationships between cows exist. In dairy cattle, hierarchies change constantly as cows are added or removed from the herd. Once a hierarchy is established, overt aggression is reduced.
Very little is known about vocal communication of cattle; most commonly noted are the moo, call, hoot, and roar. A distressed cow or calf will call or hoot, an aggressive bull may roar, and a hungry calf will give a high-intensity “menh.”
Under natural conditions, cows cycle throughout the year, with peak activity between May and July and low activity between December and February (northern hemisphere). The heat cycle is usually 18–24 hr and generally begins in the evening. Common estrous behaviors include reduced food intake, increased movement, flehmen, standing behind another cow and resting the chin on its back, and increased licking and sniffing. Aggression and mounting also increase during the cycle. Heat detection is an important practice, especially in dairy cattle, in which artificial insemination is common. There are many methods to augment the detection of heat, including placement of dyes on cows’ backs that will stain the estrous cow’s ventral torso and pedometers that record increased movement. On some farms, a teaser bull is still in use. Bulls on pasture will graze alongside proestrous cows; the bull will stand head to head with the cow or may rest his head on her back. As estrus progresses he will try to mount, licking her vulva and showing flehmen.
Parturition normally occurs at night on pasture, and the calf normally starts suckling in <3 hr. The newborn calf spends most of its time near the dam until it is ~4–6 mo old, when it forms unstable groups with other calves. Cows maintain bonds with their calves even when the next calf is born. On pasture, heifers are weaned when ~8 mo old and bull calves when ~11 mo old. Social status increases with age, and social relationships are not stable until at least 1 yr of age.