| Fillies began ovulating and advertising estrus by adopting a distinctive posture between one and two years of age. |
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| However, existing evidence suggests that family breakups, onset of estrus, and breeding opportunities are linked. |
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| The number of males and the number of females in estrus within a 10-mile radius of the male was recorded at each location. |
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| Researchers in Africa have observed that bulls are always looking for mates, using smell and hearing to seek out females in estrus. |
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| We observed individual females throughout behavioral estrus and quantified mating order and territorial status for each of a female's consorts. |
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| Around 18 hours after giving birth, females experience postpartum estrus, and mate again. |
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| Estrogen induces estrus unaccompanied by a preovulatory surge in luteinizing hormone in suckled sows. |
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| Women's sexuality is not limited to a specific period of estrus, as it is in almost all other mammals. |
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| This study involved the 29 females that showed estrus cycles with swellings during the 2002 mating season. |
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| Female chipmunks are in estrus for 1 day a year in late April or early May. |
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| A female may come into her brief period of estrus at any time during the mating season, which runs from late November through mid-January. |
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| Males will mate with females that inhabit their territory or seek out estrus females if no territory is established. |
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| To assess whether shadowing was linked to estrus, we required an estimate of the likely estrous period for females. |
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| After producing a foal, her periods of estrus are more difficult to detect, and she remains with the father of her offspring. |
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| Chenoweth described biostimulation as the positive stimulatory effects of a bull on estrus, ovulation, or pregnancy. |
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| A beef cow has a 21-day estrous cycle, the period from one estrus, or heat, to the next. |
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| Judging from mating rate, I found that female topi antelopes in estrus preferred lek males to resource defenders. |
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| We collected female urine by bladder palpation and pooled the samples over 7-20 days per female to control for variation due to estrus. |
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| All three trials were terminated immediately following a timed insemination to a synchronized estrus. |
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| However, if a female's cubs are killed, then the female comes into estrus early and has more cubs. |
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| The number of males and the number of females in estrus within a 10 m radius of the male was recorded at each location. |
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| On the afternoon of estrus, the resident male appeared to actively defend the receptive female on his territory. |
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| Therefore, if high population density results in increased contact between individuals, this may stimulate ovarian activity and synchronize estrus between females. |
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| The first point is that growth rates that are either too high or too low will increase the age at first estrus in gilts. |
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| The period between estrus ranges from 18 to 28 days with an average of 22 days. |
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| Ovarian cysts are non-ovulated follicles with incomplete luteinization which result in nymphomania or irregular estrus. |
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| When a female is in estrus, or when a male is in musth, an elephant apparently can detect airborne hormones. |
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| Producers must use natural methods of reproduction without the use of reproductive hormones to trigger and synchronize estrus. |
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| However, it is also possible that in years of late snow-melt, pikas may lose litters or reabsorb litters and then breed again in post-partum estrus. |
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| Temporary heat stress near the time of estrus and ovulation can reduce oocyte quality by altering meiotic processes, directly affecting conceptus quality and survival. |
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| Researchers made comparisons according to lactation number, days since calving, and the amount of milk given 10 days before the day of estrus. |
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| Measurements of progesterone would be most useful between days 20 to 25 following estrus. |
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| Gilts managed to perform at higher growth rates result in heavier gilts at first estrus and breeding. |
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| Moreover, it's been demonstrated that concrete flooring can impair cow locomotion, expression of estrus and grooming. |
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| Two trials in Texas demonstrated a dramatic drop in pregnancy rates for females displaying estrus during June through September compared with earlier months. |
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| That let them make sure the production level was linked closely to when the estrus occurred, not overall lactation milk. |
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| Similarly, animals managed at the lower limits of growth rate and weight gain delay the onset of estrus for significant times. |
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| Wisconsin researchers report that high-producing cows are in estrus for a shorter period of time than lower producing herdmates. |
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| Also, there was no difference in duration of estrus, the average number of mounts per estrus, or the total mounting time during estrus. |
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| Leaving the female with the male for about 20 days allows these females to restart estrus cycles and become pregnant. |
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| Eurasian beavers have one litter per year, coming into estrus for only 12 to 24 hours, between late December and May, but peaking in January. |
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| Ovulation occurs at the very end of estrus. |
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| Males of monestrous species also exhibit a cycle, being sexually active only during the females' estrus. |
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| Mating lasts for fifteen to sixty minutes, though the pair may briefly copulate for a minute or two when the sow is not in estrus. |
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| Thus, unbred does come back into estrus 28 days later, or even 28 days after that if not bred the second time. |
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| Embryonic development in superovulated dairy cattle exposed to elevated ambient temperatures between the onset of estrus and insemination. |
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| Turkalo explained that males periodically enter into a condition called musth, during which they search for females in estrus and become hyperaggressive toward other males. |
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| Three rut detection methods were compared, being the most effective that of vasectomized buffalos, and there were established the most important features of estrus and estral cycle. |
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| During the anovulatory or transition season, ewes will not come into estrus unless an additional drug is used at the same time as removal of the progesterone. |
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| That's because a female panda's estrus, the time during which she can become pregnant, occurs only once a year for one to four days. |
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| In another study, estrus was suppressed and many pseudopregnancies developed when four or more female mice were grouped together in the absence of a male. |
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| In a fertility and early embryonic development study in rats, atazanavir altered estrus cycling with no effects on mating, fertility or early embryonic development. |
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| The result of this growth pattern is that animals managed to reach these levels of growth performance are often beyond 180 days of age before they exhibit estrus. |
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| It could explain the reduced estrus activity. |
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| Since several animals are often treated at once, the use of these products has the added benefit of synchronizing estrus and thus tightening the lambing season. |
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| This group, averaging 46.4 kilograms of milk per day, were in estrus 6.2 hours on average, compared with the lower production group at 10.9 hours. |
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| Multiparous ewes were cervically inseminated at a synchronized estrus. |
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| Another important physiological change related to sexuality in humans was the evolution of hidden estrus. |
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| This short phase lasting only about a day is also known as estrus or colloquially, heat. |
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| Most importantly, during estrus she will stand still when mounted by another cow or bull. |
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| Detection of estrus, becomes reliant on observation in the absence of bulls. |
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| Calves can recognize their mothers using vocal and vocal behaviour may play a role by indicating estrus and competitive display by bulls. |
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| Ewes have estrus cycles about every 17 days, during which they emit a scent and indicate readiness through physical displays towards rams. |
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| Daily injections of a pineal extract prevented permanent estrus and kept estral cyclicity going despite constant exposure to light. |
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| One problem is that female dogs go into estrus, which is the only time embryos can be implanted, only every 6 to 12 months. |
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| Females exhibiting no signs of estrus and male rabbits were also evaluated and compared. |
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| Also, the bull's ability to locate cows in estrus and breed them is clearly vital to the success of the operation. |
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| Women evolved from having constant estrus to having monthly menses and hidden ovulation in response to a surge in the death rate of women and infants during childbirth. |
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| Removing the CIDR insert, following a five mL injection of Pharmacia's Lutalyse Sterile Solution on day six, causes a drop in progesterone, triggering estrus and ovulation. |
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| A cow in standing estrus with an 11-mm follicle has the same chance of becoming pregnant and maintaining the pregnancy as a cow with a 16-mm follicle. |
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| Alsheimer-Laroche believe the rapid decrease in available light following the hunter's moon triggers hormonal changes in the doe, which eventually incite estrus. |
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| Actually, Interest in scrapes picks up during the post rut because unbred does and female fawns come into estrus and advertise that fact at the scrapes. |
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| At the spot, I had made a mock scrape with my boot, baring the ground, and placing doe estrus in it along with a tarsal gland I had taken from another buck. |
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| The biopsied embryos were transferred into 25 estrus synchronized does, two embryos per recipient, except one recipient was transferred three embryos. |
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| Reproductive management involved natural estrus and induced estrus in the anestrous period, using the hormonal treatment recommended by Westhuysen and Ritar et al. |
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| Eastern gray females can rarely enter estrus as early as five and a half months old, but females are not normally fertile before at least one year of age. |
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| Two months after beginning the experiment, artificial insemination of heifers was implemented by a specialized inseminator after confirmation of estrus. |
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| Observations on estrus and inseminations were registered four times a day. |
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| The researchers monitored the female rats' estrus cycles and found they showed this sensitivity to moderate stress only when they were in a high-estrogen phase. |
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| Dog 4 was in proestrus and estrus during the challenge period. |
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| The cycles were regarded as normal when they showed typical stages of proestrus, estrus, met-estrus and di-estrus stages, which normally lasts for 4-6 days. |
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