Does will begin oestrus again if they do not mate.

Females come into oestrus once a year, probably around December.

This breed is thought to go into oestrus throughout the year.

They have no identified breeding season, and probably come into oestrus several times a year.

Females come into oestrus only once during this period, lasting for three to five days.

Without understanding it he was calling to oestrus Cows, if any had been here to listen.

He tried to get closer to Breeze, whose oestrus smell was still powerful.

An oestrus female is often followed by courting males as with other species.

"None of us is in oestrus, Thunder," she said gently.

She found the source of the oestrus call.

"Quiet" females will remain with a single male in an isolated area throughout oestrus.

They were kept apart when Lola came into oestrus.

Sexually mature female hamsters come into season (oestrus) every four days.

Copulation can take place on land or in the water, and a pair will mate one to four times during an oestrus period.

Alternatively it is possible to check females and mate up only those animals that are in oestrus.

Most aggression and hierarchical behavior occurs between males when females are in oestrus.

The newcomer mates as soon as females are in oestrus.

When other rhinos come this way, they will be able to tell that the cow over there is in oestrus, ready to mate.

Immediately he rumbled, "Soon you will be in oestrus.

This period of advertised fertility is known as oestrus, "estrus" or heat.

She spotted Breeze, who had come into oestrus.

The dominant male smells the female's genitals, and follows her if she is in oestrus.

Oestrus lasts five days, and mating is unusually brief.

As in many mammals, oestrus lasts a short time; just 48 hours in the mountain goat.

They then experience estrus about every seven months until old age.

Females go into estrus up to nine times a year.

"I will guard you from the other Bulls until the end of your estrus."

Juveniles sometimes stay with their mother until she comes into estrus again.

This is when the three year and older cows come into estrus.

She began to come into estrus as the flight proceeded.

Females experience estrus again about a month after producing young.

All females come into estrus at virtually the same time.

Estrus occurs for only one day during the breeding season.

Females mark more often during the wet season when they are in estrus.

They never fight one another, unless two queens come into estrus at the same time.

Does of any breed or region come into estrus (heat) every 21 days for two to 48 hours.

If several females are held together under crowded conditions, they will often not have an estrus at all.

The male is allowed to sniff a female in estrus.

The female may eventually mate with more than one partner before her estrus is through.

Males chase the females to find out if they are in estrus.

Female goats go through a period called estrus, when they are ready to reproduce.

The female experiences estrus for only three to four days of the entire year, typically in June.

Females will enter estrus again after 20-24 days, even when pregnant.

Once females start coming into estrus, males from all around descend on the group.

Just being close to females in estrus may bring males to maturity.

Female animals, particularly those in estrus, are more often targeted than males.

When breeding, a male will follow and guard a female in estrus.

Bulls appear to associate with family groups if an oestrous cow is present.

During the mating season the oestrous female may mate with several males.

These bouts function only to determine access to oestrous females.

Despite their weaponry, males within a coalition rarely fight over oestrous females.

In the first phase, the male groups interact with the females who are all in oestrous.

Flanged males attract oestrous females with their characteristic long calls.

In response to fluctuating hormone levels during each oestrous cycle, some eggs are released to resume development.

This is because the oestrous periods of harem females tend to occur bunched together in time.

A loud postcopulatory call may be made by an oestrous cow after mating.

In species with oestrous cycles, females are generally only sexually active during the oestrus phase of their cycle.

Females are sexually active only during the oestrous stage, when they are 'on heat' for a few days each month.

The oestrous cycle of ringtail possum lasts 28 days.

In highly competitive situations such as males fighting for access to oestrous females or at limited drinking spots, the fights are brief.

Bulls engage in a behaviour known as mate-guarding, where they follow oestrous females and defend her from other males.

Unflanged males wander widely in search of oestrous females and upon finding one, will force copulation on her.

Packer and Pusey observed oestrous females attended by rival males, sometimes relatives and sometimes not.

Males compete mainly, say Packer and Pusey, by trying to anticipate oestrous in a female to be the first to consort with her.

Female Kangaroo Island dunnarts are oestrous.

The oestrous cycle (U.S: estrous cycle) is the reproductive system in most mammals.

If a female prematurely loses her litter, she can return to oestrous and produce a second litter in October as a replacement if conditions are right.

Game theory suggests that contests over oestrous females will be settled 'conventionally', by the recognition of asymmetries such as'owner versus rival'.

One difference is that animals that have oestrous cycles reabsorb the endometrium if conception does not occur during that cycle.

These animals do not reproduce well in captivity, due to the difficulty of handling musth bulls and limited understanding of female oestrous cycles.

The estrous cycle (also spelled oestrous) controls when a mare is sexually receptive toward a stallion, and helps to physically prepare the mare for conception.

The swamp wallaby exhibits an unusual form of embryonic diapause, differing from other marsupials in having its gestation period longer than its oestrous cycle.

However, hormones of the estrous cycle seem to be involved.

This is the time at which female dogs will have their first estrous cycle.

Bulls will fight one another to get access to estrous females.

Once an estrous female is detected, the male will attempt to court her.

When a male finds a female close to estrous, he stays with her.

The female estrous cycle is shorter, but happens in this time.

However before she enters estrous, he may be replaced by a more dominant male.

The estrous cycle lasts about 19-22 days, with the average being 21 days.

Domestication can affect estrous cycles due to changes in the environment.

Estrous females will mate with 4 to 16 males.

In an estrous cycle, the lining degenerates back to normal size.

However, a male that attempts to mate with an estrous female may face aggression from other males.

The estrous cycle in the female is 28 days with a three-day period of estrus.

In the presence of estrous females, the males bray loudly.

"The females are coming into estrous and are kind of randy.

Females in an estrous cycle attract males with a loud whistle.

In coastal areas, males may remain gregarious even during the estrous period of females.

The estrous cycle lasts about 46 days and the female usually is in heat for 6-7 days.

Estrus last 6 days on average, estrous cycle averages 30 days.

The testes of the males enlarge when females enter estrous.

Even within species significant variability can be observed, thus cats may undergo an estrous cycle of 3 to 7 weeks.

By contrast, participants using contraceptive pills showed no estrous earnings peak.

Estrous cycle duration was of about 33 days.

It was indicated as an oral treatment for estrous (heat) prevention in adult female dogs.