estrus

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estrus

 [es´trus]
the recurrent, restricted period of sexual receptivity in female mammals other than human females, marked by intense sexual urge. See also estrous cycle. Called also estruation, estrum, and heat. adj., adj es´trual, es´trous.

es·trus

(es'trŭs),
That portion or phase of the sexual cycle of female animals characterized by willingness to permit coitus; readily detectable behavioral and other signs are exhibited by animals during this period.
Synonym(s): heat (3)
[G. oistros, mad desire]

estrus

also

oestrus

(ĕs′trəs)
n.
The periodic state of sexual excitement in the female of most mammals, excluding humans, that immediately precedes ovulation and during which the female is most receptive to mating; heat.

estrus

[es′trəs]
the cyclic period of sexual receptivity in mammals other than primates, marked by intense sexual urge and coinciding with the time that fertilization can take place.

es·trus

(es'trŭs)
That portion or phase of the sexual cycle of female animals characterized by willingness to permit coitus; readily detectable behavioral and other signs are exhibited by animals during this period.
Synonym(s): estruation, heat (2) , oestrus.
[G. oistros, mad desire]

estrus

the time during the reproductive cycle in animals when the female displays interest in mating and in most species will stand to be mounted by both sexes and mated by males. In most cases the animal is about to or has just ovulated, and is therefore pregnable, but some, including pregnant ones, may not be in true estrus.
At the time of estrus there are behavioral signs and changes in the external genitalia. In cows these include the passage of very clear mucus, swelling of the lips of the vulva and hoof brush marks on the side of the rump. Mares show frequent urination with squatting, elevation of the tail, swelling and winking of the vulva and rhythmic extrusion of the clitoris. Ewes are not demonstrative other than positioning themselves close to the rams or teasers. Goat does bleat a lot, rub themselves against fixed objects and hold their tail high, urinate frequently and evert the clitoris. Bitches wander away, stand with their tails held to one side and are attractive and receptive to males. Queens may be very demonstrative, especially Siamese. They rub against anything, crawl with their belly close to the floor, roll and vocalize with a deep, throaty growl.

estrus detection
in natural mating the male is, in most situations, the best possible detector. In artificial breeding or in hand mating the need to pick cows which are on heat is of paramount importance. Techniques available include the use of infertile teasers combined with heat mount detectors, tail paint, chin ball or siresine harnesses. In dairy herds it is usual to dispense with the teasers and depend on other cows to pick out and mount the cows that are in heat.
In sheep crayon or paint marking harnesses are used. In mares individual teasing with a pony or similar manageable male is used. In the other species detection is by simple visualization.
estrus expectancy chart
a wall chart for use at the dairy which points out those cows which are due to come into estrus during the next day or two and need to be observed closely.
false estrus
behavioral and external genital signs of estrus without ovulation occurring.
estrus induction
see estrus synchronization (below).
no visible estrus
abbreviated NVO (to accommodate the British spelling of oestrus) or NVE. Diagnosis indicating reproductive inefficiency; applied to cows which are not observed as being in estrus for a variable period, usually 50 days, after calving. Includes cows with anestrus due to various causes and failure of staff to observe or record estrus. A percentage of more than 10% of cows in a herd which have no visible estrus is an indication of a herd problem.
silent estrus
ovulation occurs, as detected by palpation or estrogen levels in the blood in the absence of behavioral signs.
estrus suppression
prevention of estral activity in companion animals without spaying them is practiced frequently. A variety of progestins are available and, at times, intravaginal and intrauterine devices have been used for this purpose. See also contraception.
estrus synchronization
aimed at having all of the animals in estrus, and later calving or lambing, at the same time. Prostaglandin injection is a common technique used to induce estrus in cows.
unexpressed estrus
see silent estrus (above).
References in periodicals archive ?
Differences between the study results could be due to estrus detection method, artificial insemination protocols, sire, semen, season, and herd management.
Timing of insemination for dairy cows identified in estrus by a radiotelemetric estrus detection system.
Comparison of three estrus detection systems during summer heat stress in a large commercial dairy herd.
Vixen fertility may be increased by improving several causes such as careful selection of male foxes for AI accurate estrus detection the exact time and location of insemination as well as optimizing semen processing handling and insemination technique (Bodmer et al.
Before the start of this study, the farmers were educated about the importance of estrus detection in village level camps and inseminators were taught and urged to adopt the accurate semen handling and AI procedures.
Also, this finding may explain the differences in pregnancy rates observed after the timed AI at 54h after the device removal in ewes without estrus detection in the CIDR group (3 of 4) in comparison with the OB group (1 of 4).
In order to calculate the wean-to-estrus interval, the beginning of the estrus period was characterized as the midpoint between the time of the first observed positive response to back pressure (immobilization reflex) and the previous period of estrus detection.
Artificial insemination systems within two days of estrus detection or at fixed time for suckled beef cows
In order the estrus detection, the cows were accompanied by teaser bulls in a 25:1 ratio and watched four times a day at cement pens and pasture area.
As the signs of estrus in buffaloes are less obvious than in cattle, the estrus detection accuracy is one of the major problems limiting the use of A.
Several factors have been suggested to be responsible for reduced conception rate including management practices, genetics, diseases, physiological disturbances, anatomical defects, feeding practices, estrus detection errors, embryonic mortality (Dekruif, 1978; Roussel et al.