Sexual hunting. Diagnosis of heat in cows. Signs of heat and its duration in a goat: video During the period of heat, the female

Sexual arousal

Sexual arousal (general reaction) is a change in the behavior of the female that occurs in connection with the maturation of the follicle. Sexual arousal is manifested by a more or less pronounced general reaction of the body in the form of anxiety, refusal to feed, sometimes anger, as well as a decrease in milk production, a change in the quality of milk and other signs.

It is characterized by estrus, general arousal, heat, maturation of follicles on the ovary and ovulation. These manifestations are interconnected, but do not occur simultaneously. General arousal begins with an increase in the complex of sexual reflexes caused by the development of follicles. The estrogen hormone secreted by the follicles causes hyperemia and swelling in the genital organs, thickening of the mucous membrane of the genital tract. As the follicles mature, pronounced signs of estrus appear, and then heat and ovulation.

Expressed in anxiety, refusal to feed, decreased milk production, changes in milk quality and other signs. At this time, the female can jump on the male or other females, allows other females to jump on her, but does not allow the male to jump on her.

Sexual hunting. Diagnosis of heat in cows

No factor can play a more positive or negative role in artificial insemination than heat detection. Since the functions of the bull are now performed by humans, their task is to recognize and interpret the signs of heat in the cow. For those involved in dairy breeding, a reliable heat detection program is of particular importance to enable the use of the best genetic material through AI. And for those raising beef cattle, a little extra effort in implementing an AI program will pay big dividends in the form of increased production.

With a minimum of one to four daily observations of your herd, plus the use of heat detection or timing tools, your AI program can generate significant economic benefits.

Heat is a short period of sexual receptivity in uncovered cows and heifers, usually occurring every 18-24 days.

As soon as an egg begins to develop in a cow's ovary, estrogen begins to be produced. This hormone causes changes in the reproductive, circulatory and nervous systems of the cow. These changes are signs of sexual heat.

Immediately after the egg is released, the corpus luteum, which develops at the site of the burst follicle, begins to secrete a second hormone - progesterone. This hormone suppresses the development of eggs and signs of heat for about three weeks or the duration of pregnancy.

A cow is only capable of fertilization when an egg ovulates or is released from the ovary. This will happen no earlier than 10-14 hours after the end of the 8-18 hour period of heat.

Since sperm must remain in the cow's reproductive tract for some time before it can fertilize an egg, insemination should occur several hours before ovulation. Sperm can remain viable in a cow's reproductive tract for 24 hours.

This means that to achieve the highest fertilization rates, cows must be inseminated in the last two-thirds of heat or within a few hours of heat. This will be approximately 24 hours after the cow first shows signs of standing heat. As a rule, it is difficult to determine the moment of the onset of sexual heat in cows.

The main sign is mounting a standing cow

The surest sign of sexual heat has always been that a cow or heifer allows other animals to mount her, while remaining motionless. This phenomenon is called standing hunting. This is the surest sign that the cow is ready for fertilization. Cows in heat try to stay together, taking turns mounting each other. But there are other signs that you should be able to recognize.

Additional signs

Mounting other cows. Cows that are in heat usually try to jump on other cows that are not in heat. But remember that only those cows that stand and allow themselves to be mounted by other animals of the herd are truly in heat. And a cow that is mounting may or may not be in heat.

Tousled hair on the root of the tail after cage

Detection and synchronization of sexual heat

Ruffled fur at the root of the tail. If the cow was mounted by other cows, then her hair at the root of the tail will be tousled or worn out. It is easier to notice this sign in winter, when the coat becomes longer. The dirty forelimbs of mating animals can also leave marks on the lower thighs, flanks and even the shoulder blades of a cow in heat.

Friendliness. In addition to attempting to pounce on other animals, cows in heat may follow them, stand nearby, or rest their heads on the backs or rumps of other cows. Sometimes cows sniff, poke, or lick other animals in the herd. Cows in or before heat usually stick together.

Sniffing and rubbing muzzles against other cows

Nervous and restless state. Cows usually start to get nervous and moo more often than usual. They become restless, wander around in search of the bull, walk along fences, or watch people working nearby with special attention. Livestock breeders who know their animals well can often determine the presence or approach of heat in cows by their alert behavior, shiny eyes and nervous state. A decrease in milk yield may also be observed.

Discharge of clear mucus from the vagina. Another good indicator is mucus hanging in strings from the vaginal opening or smeared along the tail or back of the thighs. During hunting, the reproductive tract secretes a viscous, clear mucus that resembles egg white. For example, you may see a clear mucus discharge in the gutter or behind a cow in heat. When a cow mounts other animals, the angle of her body causes mucus to flow out.

Swollen vulva. If you carefully examine the vaginal lips, you will notice that they are moist and slightly swollen. Because of this, their surface becomes smoother in comparison with the dry, wrinkled vaginal lips of a cow that is not in heat, and the individual hairs on the vulva are now wet and matted.

The inner surface of the vulva also undergoes changes. Increased blood flow in the small network of blood vessels under the skin of the vulva gives it a pink color. Conversely, the tissue inside the vulva of a cow that is not in heat is pale in color.

As a general rule, additional signs should be used only as aids to confirm the main signs of heat. And when working with beef cattle, there may be less opportunity to get close and notice numerous additional signs. Mucus hanging in threads from the vaginal opening and smeared on the tail or thighs.

Bloody mucus is a sign of earlier sexual heat. Although this is not a constant sign, it is often observed between the second and fourth days, regardless of whether the cow is calving or not. Bloody discharge is not a sign of sexual heat. They simply mean that the animal was in heat a few days ago. After 15-20 days, it is necessary to observe the manifestations of signs of the next sexual cycle.

Nothing replaces observation

Whether your cattle are in barns, in the pasture, in feedlots or on the range, you need to spend at least 30 minutes twice a day watching them for signs of standing heat. In limited indoor conditions, more frequent observations (3-6 times) will significantly improve the effectiveness of heat detection. The diligent livestock breeder will make heat detection part of his daily routine and establish observation periods. physiological estrus hunting cow

Be sure to provide good floor covering so that cows can stand firmly while mounting. A surface that is slippery, frozen, or irritating to the hooves will reduce cage activity. In addition, the hooves themselves must be in good condition to ensure normal activity. In small herds, dry cows may be placed next to cows that you suspect are in heat, as dry cows are active in mating.

You must train beef cows or dairy heifers to come to feed, salt, water or shade so that you can observe them in a limited area at least twice a day.

The reason for observing twice a day is simple: if you observe once a day, you are likely to miss cows that showed signs of standing heat earlier or will show them later.

Table 1

Signs to look out for during the 18 hour heat period

	Behavior	External genitalia		Bloody discharge	Tail fur ruffled
Early stage Mounts other cows	Moos, wanders like a “ghost” along the fences, butts, follows others, cows, is very nervous	The lips of the vulva become red and slightly swollen	Very noticeable when mounting other animals		No, but maybe in cows that were bred by a cow going into heat
Middle stage Stands and accepts the bait but continues to bait others	Smug, friendly, still follows other cows, doesn't eat, restless	The lips of the vulva are red and swollen, the walls of the vulva are moist and shiny	Abundant and transparent		Slightly noticeable sometimes
Late stage Not worth picking up, but still stalking others	All signs of nervousness, chasing other cows and butting are gone	The swelling subsides	Shrinks and becomes very sticky and rubbery	1-3 days after all signs of hunting disappear	Most clearly at any time

A study conducted by Virginia Tech and State University confirmed the importance of two-time testing. The researchers found that only 28.6% of all inseminations involved cows that were in standing heat both times. This means that in 71.4% of cows standing heat was observed only once a day. And if the time you choose to check the cows once a day does not coincide with the time when these cows show signs of standing heat, then they will be missed.

Duration and time of sexual heat

Researchers from Cornell University have shown that in a typical beef or dairy herd, 22% of cows show signs of heat between 6 a.m. and noon. Then, between noon and 6 pm, the percentage of signs of heat decreases to 10%, and between 6 pm and midnight it increases to 25%. It was also proven that the animals remained in heat for approximately 18 hours.

Housing facilities may vary.

Recent research from Virginia Tech (Dr. Ray Nebel) suggests that the onset of estrus (both gestation and duration of onset) may be becoming shorter (see Charts 1 and 2). Additionally, Dr. Nebel's work shows that on commercial dairy farms, where livestock are kept in confined spaces, the expression of heat signs is fairly consistent over a 24-hour period (see Chart 3). This is likely due to management elements such as 3 milkings a day, continually improving diets and improved housing conditions. It is clear that in such conditions, more intensive heat detection methods are required to maintain good reproductive efficiency.

Methods for detecting the heat of cows

The most accurate sign of a female’s readiness for mating and the optimal time for insemination is the period of sexual heat in the presence of estrus and sexual arousal.

Currently, there are several ways to determine heat and other signs of sexual arousal in cows and heifers.

1. Visual - visual observation of animal behavior.

2. Reflexological - using a probe bull.

3. Vaginal - examination of the vagina and cervix using a vaginal speculum.

4. Rectal - palpation of the ovaries through the rectum (rectum).

5. Hormonal - determination of the content of the hormone progesterone in the blood, urine or milk of animals.

6. Electrometric - measurement of the electrical resistance of the mucous membrane of the vaginal vestibule.

7. Ultrasound - ultrasound examination of the degree of development of the preovulatory follicle.

Each method has its pros and cons. Some of the disadvantages include the following. The undetectability of sexual heat in animals with “quiet” heat and in animals with diseased limbs. Often pregnant cows accept a bull without noticeable resistance and, conversely, young heifers will fight off the bull when they are in heat. During the winter months, redness of the vaginal walls is not always obvious. The possibility of rupture of the follicle and release of the egg with its further loss due to careless manipulation of the ovaries.

When to inseminate beef cows

The frequency of sexual cycles of beef cattle breeds is determined by several factors. For mature cows, post-calving rest and condition status are essential to restarting cycles. Typically, first-calf heifers take longer to recover from the sexual cycle than adult cows. This is because the feed they consume must support their own growth plus milk production for the calf.

The onset of sexual cycles in an unbred heifer is determined by her age, weight and breed. For example, a 13-month-old Angus heifer begins sexual cycles when she reaches a weight of 270 kg, in contrast to a crossbred Charolais heifer.

Heat detection is most convenient in fenced areas such as feedlots or pastures to detect heat.

It is easier to detect heat in fenced areas

The best times to observe beef cattle are early morning and late evening, when signs of heat are strongest.

One of the most convenient ways to detect heat in beef cattle is to keep the herd in feedlots or other similar conditions. However, if beef cows are kept in open pastures, then in this case artificial insemination can be successfully carried out. But you should find an opportunity to place them in a more limited area, where it will be easier for you to observe signs of heat.

On large beef farms where artificial insemination is planned to be carried out in a short time, it is necessary to provide for the organization of pastures to monitor signs of heat. Cows should be moved to such pastures at least two weeks before breeding begins. Due to their small size, such pastures are convenient for conducting observations and at the same time allow for organizing grazing, watering and fattening of animals.

On any given day, approximately 5% of normally cycling cows should show signs of heat. After insemination, the bloods are removed from that herd. With this system, after about 10 days, half of the herd will remain and the load on the pasture will be reduced by half.

The use of feed with high palatability and high energy content helps ensure that the entire herd gathers in one place every day. At this time, it is very convenient to monitor signs of heat in cows.

In dry areas, organizing a watering hole in one place creates a cluster of animals around it and makes it easier to identify cows ready for insemination. Compulsory feeding of silage, concentrates or liquid feeds with high energy content twice a day in winter also provides an ideal opportunity to detect heat.

When to inseminate dairy cows

Well-nourished heifers show the first signs of heat at the age of 9-11 months, although they may ovulate earlier. On the other hand, poorly nourished heifers may not come into heat until they are 20 months of age or older.

However, the time of insemination of any heifer depends on its size and ability to calve. Research shows that small heifers can have significant calving difficulties, which can cause decreased milk production in the next lactation, infertility, or even death of the calf or the heifer.

Ease of calving depends more on size than age. Generally, most dairy heifers can be bred at 13-14 months of age, provided they have received enough feed to achieve minimum weight and height

Cows' first heat period can last anywhere from two to six weeks after calving, but this does not mean they are ready to be bred. It usually takes about 40 days for a cow's uterus to fully recover from a previous pregnancy.

Until the uterus has fully recovered, fertilization rates will be low.

ABS research data provides extensive information on the timing of artificial insemination. Between May 22 and August 1, 1975, a large beef cattle herd of over 3,000 cows was monitored for heat signs beginning at dawn and continuing until midday. Observation then resumed between 3 and 4 p.m. and continued until dark. The time elapsed from the moment the first signs were observed in each cow until the moment she was inseminated was carefully taken into account. Insemination was carried out in the morning according to the “once a day” scheme.

Due to the size of the herd, the number of cows to be bred and the distances that had to be covered meant that a significant proportion of inseminations were carried out later than usual after the first signs of heat had been detected. The graph shows that 49% of the 2091 first inseminations were carried out 24-30 hours after the first signs of heat were detected.

It is clear that estrus in cattle is a random phenomenon, so cows come into heat at any time of the day. Data show that 95% of cows ovulate 17 to 38 hours after the onset of the stillness reflex; this means that they will ovulate throughout the day. Therefore, establishing the best time for each cow on commercial farms is almost impossible. Electronic heat detectors give us a better idea of ​​when cows started mating, but they don't tell us when a cow will start ovulating. The data also suggests that when signs of heat are detected in livestock on a commercial farm, there is also a happy case, since when a cow is in heat, it is not mounted many times, not to mention attempts to establish whether this is the first mounting or the last.

The results will not be surprising once we understand the variation in the reproductive cycle of livestock. Let's repeat:

* There is a fairly even distribution regarding when the onset of estrus was first noted. This means that cows come into heat every hour during the day.

* On average, a cow takes 7.1 +/- 5.4 hours to mount.

* The average number of times a cow is mounted is 8.5 +/- 6.6.

* Ovulation occurs 27.6 +/- 5.4 hours after the first mounting.

* It is believed that sperm is capable of fertilization within 24 hours after insemination; however, ABS staff are conducting research in this area to determine possible differences between bulls.

Researchers will continue to try to determine the ideal time for insemination. However, we believe that before implementing any changes during insemination, managers should ask themselves how changes to the insemination protocol may affect cows.

For dairy cattle the following must be considered:

* Amount of time cows must remain isolated.

* Total residence time on the cement surface.

* Body temperature of a cow during the summer heat.

* Fatigue of the inseminator.

For beef cattle the following must be considered:

* Number of livestock

* Fatigue of the inseminator (especially for inseminators who have not inseminated cows for the last 10-11 months).

* Whether cattle were sorted after observing heat signs using synchronization.

Some management changes to implement a different breeding protocol may have an adverse effect on the cow instead of benefiting the cow.

One last note: the question “is a cow really in heat?” has much more significance for reproduction than the question “at what time should a cow that is in heat be inseminated?”

Normal sexual cycle

Estrus and ovulation can be controlled by treating cows with prostaglandin, progesterone or gonadotropin during the mating cycle. The specific use of each of these drugs will be reviewed.

Cycling cows include those cows that regularly came into heat before treatment. The corpus luteum develops at the site of ovulation. This tumor produces the hormone progesterone, which prepares the uterus for pregnancy. If pregnancy does not occur, the corpus luteum begins to regress approximately 18 days after the start of the sexual cycle and a new follicle with an egg begins to develop.

Looking at the picture below, you will see that the sexual cycle begins with estrus a day. Then, from days 2 to 4 or 5, the cow is in the corpus luteum stage of development. From days 6 to 17 we have a fully formed corpus luteum. After this, in the last four or five days of the cycle, the corpus luteum regresses (dissolves), and the cow with a normal reproductive cycle naturally comes into heat again.

Wave-like development of follicles

Recently, ultrasound technology has allowed scientists to more fully study the development of follicles in beef and dairy cows. In each sexual cycle, follicle growth occurs in waves and throughout the entire cycle. Individual waves of follicular development are characterized by the rapid growth of numerous small follicles. Cows are born with all the eggs they will ever have. They do not continuously produce eggs during their reproductive life.

The average cow has about 70,000 eggs at birth. These eggs are contained in follicles located deep in the ovarian tissue. When a heifer reaches sexual maturity, eggs begin to grow in mature follicles, which will eventually ovulate and release the egg for fertilization. Most cows have two or three waves of follicular growth that occur during each mating cycle. At the beginning of each wave, eggs begin to grow in numbers from 200 to 600. One of the follicles gets the opportunity to grow much larger than the others (>12 mm). This large follicle becomes “dominant” and is able to regulate or limit the growth of other, smaller, subordinate follicles. If the follicular wave occurs at the beginning or in the middle of the sexual cycle, then the dominant follicle, like the other subordinate follicles, will die. Only when the waves occur towards the end of the sexual cycle will the dominant follicle continue to develop fully and ovulate.

In cows that typically have two follicular waves during heat, the first wave will begin on day 0 (the day the heat begins) of the cycle and will last until day 10. At this point, the dominant follicle (along with the small subordinate follicles) dies (degenerates). Immediately after the death of the previous follicle, the second wave begins. This second wave produces a new dominant follicle, which remains until the end of the cycle (day 21) and eventually ovulates, thus freeing the egg for fertilization. The three follicular waves in cows usually last an average of 8 days each, with the dominant follicle developing and ovulating in the third wave

The growth of follicular waves, or the dynamics of follicular waves, is important for determining the timing of hormone administration during the synchronization of sexual heat. The purpose of synchronization is to stimulate the development of a new follicle and the correct time of ovulation. Understanding the dynamics of follicular waves can greatly assist in designing synchronization protocols that optimize oestrous response and increase fertility rates.

10 Key Rules for Successful Heat Detection:

1. STO: Establish standardized operating procedures (STO) for heat detection, including the following: when, where, observed signs of heat and to whom to report.

2. Accounting: All identified hunting arrivals must be entered on a form.

3. Interaction of animals in the group: Observe the sexual activity of animals in the group.

4. Keep hoof disease to a minimum: A cow with diseased hooves usually does not jump or allow other animals to jump on her.

5. 3 times a day: Hunting observation three times a day is the minimum amount. It is preferable to watch the hunt 4 times a day, since on average the hunting period lasts only 8 hours.

6. Timing is important: Do not observe heat while feeding or milking.

7. Location, location, location: Visual observation should be made where the animals have a stable surface under their feet with few obstacles to interfere with interaction.

8. Use heat detection aids wisely: Heat detection aids should be used as a supplement to, but not a substitute for, visual heat detection.

9. Forced ovulation programs: Hormonal treatment increases the possibility of detecting estrus and allows artificial insemination to be carried out without monitoring the estrus.

10. Don't skip any of the points!

The sexual cycle is a complex neurohumoral reflex process, accompanied by a complex of physiological and morphological changes in the genital organs and throughout the female’s entire body from one stage of sexual arousal to another (or from one ovulation to another).

Sexual cycles appear with the onset of puberty and are repeated with a certain frequency. By old age, sexual functions in animals fade away; The climacteric period in sheep and goats occurs at 8-10 years, in pigs - at 7-8 years, in dogs and cats - at 10-12 years, in rabbits - at 4-5 years.

A number of changes occur in the sexual cycle, easily noticeable, and sometimes imperceptible even with modern, subtle microscopic, chemical and biological research methods. In the sexual cycle, it is customary to distinguish three stages: 1) arousal; 2) braking and 3) balancing.

The alternation of these stages is a biological property of female farm animals that have reached sexual maturity. After the occurrence of the first sexual cycle in an animal, they are periodically repeated (in cows, pigs, mares after 21-24 days, in sheep - 17 days) throughout the entire sexual life, until the onset of menopause in the animal.

The alternation of sexual cycles constitutes their rhythm. In some animal species (cattle, single-hoofed animals, pigs), sexual cycles are repeated regularly, on average every three weeks (polycyclic animals); others (dogs, wild animals) exhibit only one or several sexual cycles during the year (monocyclic animals). There are also polycyclic animals with a limited sexual season (sheep, goats, etc.). In such animals, sexual cycles clearly and regularly appear only at a certain time of the year (sexual season), and then the animal experiences prolonged anaphrodisia. Animal owners, by creating certain living conditions for their animals (changes in ambient temperature, reducing the length of daylight hours, etc.) can avoid sexual seasonality in sheep and get year-round lambing from them.

Depending on the stages of the reproductive cycle, specific phenomena that arise and occur in the genital organs, as well as in the entire body of the female, manifest themselves in different ways.

Excitation stage of the sexual cycle- the period of vivid manifestation of all sexual processes - is characterized by the manifestation of four phenomena: estrus, sexual arousal (general reaction), hunting, maturation of follicles and ovulation. Each of these phenomena is specific and reflects one aspect of the sexual cycle. The phenomena listed above occur in mutual connection, but do not arise and manifest themselves in animals simultaneously, but develop and fade according to their own laws and conditions of existence of the organism. With each phenomenon, the animal exhibits a rhythmic increase in morphological and physiological signs, followed by their inhibition and balancing.

In the stage of excitation, all reflexes in an animal are subordinated to sexual reflexes, up to the weakening or even complete inhibition of such a powerful reflex in an animal as food. In females, blood pressure increases, the composition of the blood changes, and the quality of milk changes. Experts note the most dramatic changes in the genital organs, in which cells not only of the muscle and mucous layers grow, but also of nerve formations. In the endometrium and especially in the myometrium, blood flow increases, oxidative processes increase significantly, manifested in increased oxygen absorption by the uterine mucosa, catalase and peroxidase activity (G.V. Zvereva). The stage of arousal begins with a gradual increase in the complex of these processes in the reproductive apparatus, caused by the development of follicles.

Estrus– the process of secretion of mucus from the genital organs as a consequence of morphological changes in the female reproductive system. Estrus is diagnosed by examining the external genitalia, vagina, cervix and examining the mucus released from the genitals using clinical and laboratory methods. Estrus in an animal is accompanied by pronounced proliferative processes. We note severe hyperemia of all parts of the reproductive apparatus, neoplasm and proliferation of the glands of the mucous membrane of the oviducts, horns, body and cervix. Instead of 3-4 layers of epithelium, the mucous membrane of the vagina and genitourinary vestibule is covered with 18 - 20 layers; At the same time, epithelial cells are rejected. Therefore, microscopy of a vaginal smear predominantly reveals squamous epithelial cells and leukocytes. During estrus, we register severe hyperemia of the genital organs, swelling of the mucous membrane and increased functioning of the glands of the vestibule, cervix and fallopian tubes. In some animals (dogs, less often cows), during hyperemia of the genital organs, we record the rupture of small blood vessels with bleeding, as a result of which the mucus takes on a bloody tint. During the period of estrus, the cervix of animals opens and through it mucus is released into the vagina, which subsequently flows from the external genitalia of animals. The layers of multilayered epithelial cells that have grown in the vagina undergo keratinization and are rejected. Therefore, microscopy of a vaginal smear reveals a continuous mass of anucleate cells - scales (in some animals there is a large number of leukocytes). All parts of the animal’s reproductive system are enlarged, juicy, and their excitability is increased. A veterinarian, with a careful vaginal examination of the cervix, can distinguish between first, second and third degree estrus based on the degree of cervical dilatation and the amount of mucus released.

Sexual arousal(general reaction) - a change in the behavior of the female during the arousal stage that occurs in connection with the phases of follicle maturation. Sexual arousal occurs later than estrus and is manifested by a more or less pronounced general reaction of the animal’s body in the form of anxiety, refusal of food, sometimes malice, as well as a decrease in milk production, a change in the quality of milk and other signs.

When sexually aroused, the female shows “interest” in the male, can jump on him or other females, allows other females to jump on her, but does not always allow the male to mount her. As the signs of estrus and sexual arousal increase in the animal, the concentration of follicular hormone in the blood increases, which, acting on the nervous system of the animal, causes sexual desire.

Hunting(estrus) - a positive sexual reaction of a female to a male, i.e. the manifestation of a sexual reflex in a female, expressed in her peculiar behavior in the presence of a male. During the hunt, the female strives to approach the male, taking a position for sexual intercourse, often performs the act of urination, ending with the rhythmic contraction of the labia, and allows mounting and coitus. In agricultural enterprises, the hunting of females is determined by a male - a sampler. The opinion that sexual heat in females can be determined without a sampler is incorrect. You can notice the general arousal of the female, estrus, but not hunting, since hunting is a strictly specific phenomenon (reflex) - the reaction of a female to a male. The reflexogenic method is the only way to diagnose heat. When testing in some animals, the reaction of the female to the male is decisive; in others (sheep), the reaction of the male to the female in heat is also taken into account, which he detects primarily with the help of olfactory perceptions.

Ovulation– release of an egg cell from an ovarian follicle. A section of the ovary shows two zones: the cortical - follicular and medullary (vascular), abundantly penetrated by large blood and lymphatics, nerves and smooth muscle fibers. The cortical zone consists of delicate connective tissue rich in fibrocytes, spindle-shaped. There are very few collagen and elastic fibers in the cortical zone. This layer contains follicles and corpus luteum. In the follicles, germ cells - oocytes - undergo the growth stage. During development, the structure, size, shape, number and location of follicles in the ovary change.

It is customary to distinguish several stages of follicle development. At first, the follicles are small and are called primordial (primary) follicles (folliculi primarif). They are located in the superficial layer of the cortex (under the tunica albuginea). In the center of the primordial follicle there is, as a rule, one small egg (first-order oocyte), surrounded by one layer of flattened follicular cells. However, there are follicles with several eggs. The transformation of primordial follicles into secondary (growing) and then mature Graafian (cavitary) vesicles occurs as follows. Initially, the primordial follicles and the eggs contained in them increase in size, the flattened follicular cells turn into cubic and then into cylindrical. Next, the follicular cells multiply intensively and surround the egg in several layers, forming a transparent membrane (Zona pellucida). Such follicles with several layers of follicular cells around the eggs are called secondary. These secondary follicles do not yet have a cavity; they are located deeper in the ovary than small follicles. As they develop, secondary follicles turn into Graafian vesicles (named after the Dutch scientist R. De Graaf). As a result of their transformation, follicular cells secrete liquid in drops, which, merging, compresses the follicular epithelial cells, and a small cavity is formed between them. After this, the follicles begin to grow faster, their cavity becomes more and more stretched with follicular fluid. The resulting follicle consists of a connective tissue membrane, which experts call theca folliculi, and multilayered epithelium - the granular layer. In the connective tissue membrane of the follicle, two layers are distinguishable: the outer (fibrous), denser, and the inner, or vascular, layer, consisting of loose tissue and blood vessels. Inside the Graafian vesicle there is a large cavity filled with follicular fluid and an oviductal tubercle (thickening of the granular layer) located on the inner side wall of the follicle. The egg cell is located in this oviductal tubercle. The egg itself is surrounded by a layer of follicular cells, of which the innermost, immediately surrounding the egg, is called the corona radiate.

Graafian follicles in the ovaries are large formations, reaching a diameter of 4-6 cm in mares, 1-2 cm in cows, 1-1.2 cm in pigs, and 0.5-0.7 cm in sheep and goats. In this case, Graafian follicles occupy the entire thickness of the ovarian cortex, protruding on the surface of the ovary. Experienced veterinarians can palpate such follicles in cows and mares during a rectal examination, determining their approximate size, shape and degree of maturation.

Females have a lot of follicles, and therefore eggs, in the ovary. An adult cow has 140,000 eggs in one ovary, a pig has 120,000, a goat has 28,600, and a young dog has 200,000 (B.P. Khvatov). With age, their number decreases sharply, and cows over 10 years old have 2,500 eggs in their ovaries. Consequently, many of them die along with the follicles. The process of follicle death is called atresia, and dying follicles are called atretic.

The process of opening a mature follicle and releasing an egg cell from it is called ovulation (ovulation reflex). The mechanism of ovulation itself has not yet been fully elucidated. One thing is certain: this is a complex reflex act regulated by the central nervous system. This is evidenced by the fact that ovulation in cows and horses most often occurs at night, early in the morning (in a quiet, calm environment). In all animals, ovulation is accelerated by the act of mating and other neurosexual stimuli (the sight, smell of a male, etc.).

Shortly before ovulation, the blood vessels of the ovary (especially the follicle) dilate, blood flow increases, and follicular fluid increases. The wall of a mature follicle becomes thinner, and a conical elevation appears on its surface, devoid of blood vessels and follicular cells (a light spot). In this place, under the influence of an increase in intrafollicular pressure and the action of the collagenase enzyme, which loosens the follicle membrane, the membrane ruptures and an oval hole is formed, through which the follicular fluid slowly flows out with the egg. Ovulation occurs under the influence of luteinizing hormone with the participation of follicle-stimulating hormone.

After ovulation, a depression with flabby edges forms at the site of the burst follicle, which is easily identified in large animals during rectal palpation of the ovary. The ovary becomes reduced in volume and soft. The bursting follicular cavity of the follicle is filled with spilled blood, and then with rapidly growing cells of the follicular epithelium (granular layer). The follicular cells then transform into luteal cells, which produce a yellow pigment called lutein. The emerging luteal cells gradually replace the blood clot (it is resorbed) and fills the entire cavity of the follicle. From the connective tissue elements of the follicle, radial septa are formed, which, together with vessels and nerves, go from the periphery to the center. This is how the corpus luteum (it is called by its color) is formed, divided into segments by connective tissue cords. On palpation, the resulting corpus luteum (corpus luteum) is denser than the follicle; in cows, the corpus luteum often protrudes mushroom-shaped on the surface of the ovary, and during a rectal examination, a veterinarian can distinguish it well by palpation from the follicle, which is often larger in size than the follicle.

The corpus luteum in an animal is a temporary endocrine gland that secretes the corpus luteum hormone - progesterone. Progesterone in females causes the uterine mucosa to prepare for nidation of the embryo and the development of placentas, and promotes the preservation of pregnancy in a pregnant animal and the proliferation of glandular tissue of the mammary gland. Progesterone prevents the growth of new mature follicles in the ovaries and their ovulation; for this reason, pregnant females do not have sexual cycles.

The degree of development of the corpus luteum and its endocrine function depends on the fate of the follicle and egg cell. There are three possible outcomes for a developing follicle: 1) ovulation, 2) follicular atresia and 3) luteinization of the follicle. In the case when, after ovulation, the animal does not become pregnant, the corpus luteum of the ovary undergoes reverse development (involution) - and veterinary specialists call this corpus luteum the corpus luteum of the reproductive cycle. When an animal becomes pregnant, the corpus luteum in the ovary greatly increases, occupying most of the ovarian parenchyma. Veterinarians call this corpus luteum of the ovary the corpus luteum of pregnancy. The corpus luteum of pregnancy is present in a pregnant animal throughout the entire period of fruiting and only towards the end of pregnancy or after birth undergoes reverse development. Sometimes in some animals the corpus luteum of the reproductive cycle or former pregnancy lingers in the ovary for more than 30 days (retained corpus luteum).

The delayed corpus luteum leads in animals to the development of anaphrodisia (cessation of sexual cycles) of varying duration. This phenomenon is widely diagnosed by veterinary specialists during a gynecological examination of animals that do not come into a state of sexual heat for a long time after birth.

A corpus luteum may not form at the site of the follicle if atresia of the follicle occurs. Sometimes the corpus luteum of the ovary is formed without ovulation of the egg, when hemorrhage occurs in the cavity of the unbursted follicle and the follicle cells are replaced by cells of the corpus luteum (luteinization of the follicle).

During a rectal examination, a veterinarian has the opportunity to monitor the growth of the follicle and determine the four phases of its development: 1) pre-ovulatory phase - maturation of the follicle; 2) ovulation phase; 3) post-ovulation phase, characterized by the development of the corpus luteum at the site of the ovulated follicle; 4) the equilibration phase, when the corpus luteum resolves and new follicles begin to develop.

In small animals, methods for diagnosing the phases of follicle maturation have not been developed.

Braking stage– the stage of weakening signs of sexual arousal and estrus. This stage begins immediately after the arousal stage. Hunting in the female is replaced by a pronounced retreat, gradually giving way to an indifferent attitude towards the male; In place of the ovulated follicle, the corpus luteum develops. With the weakening of hyperemia, the volume of all areas of the reproductive apparatus decreases. The cervix closes, mucus is not secreted, the glands of the genital apparatus undergo reverse development, and the epithelial layers that have grown in the vagina are rejected. When viewing a vaginal smear, mainly nuclear cells and scales with a large number of leukocytes are visible. The animal calms down, gradually recovers, the quality of milk, blood composition, the structure of the mucous membrane of the genital tract and other changes that arose during the stage of excitement are leveled out. The female becomes aggressive towards the male; try to bite him, hit him or run away from him. This negative sexual reaction of a female to a male is called withdrawal.

Thus, a feature of the inhibition stage is the predominance of involution phenomena, i.e. reverse development of morphological and physiological processes that occur during the stage of excitation.

Equilibration stage in animals it occurs after the stage of inhibition of sexual processes and continues in the animal until the onset of a new, next stage of excitation. In the balancing stage, the general condition of the female is balanced, she has an indifferent or negative attitude towards the male (absence of sexual heat), the animal’s ovaries contain both follicles and corpus luteum. In the genitals, both proliferative and degenerative processes are equally expressed. The female's cervix is ​​closed. Microscopy of a vaginal smear reveals predominantly mucus, as well as leukocytes, squamous stratified epithelial cells with a well-defined nucleus, and anucleate cells (scales). At the same time, this stage should not be called rest, since during this period in the female’s body, in her reproductive apparatus, extremely diverse active processes take place, manifested by certain physiological and morphological changes. This is how follicles and corpus luteum form and atresia in the ovary; the uterus reacts with contraction upon rectal palpation; Histological examination of the uterus and vagina reveals signs of the formation and death of cellular elements. In the vaginal smear they find mucus, leukocytes, whole epithelial cells, and already rejected anucleate scales, i.e. signs of both proliferation and degeneration.

For owners of private household plots, peasant farms and agricultural enterprises, of all stages of the reproductive cycle, a thorough knowledge of the stage of initiation of the sexual cycle in animals is of greatest importance due to the fact that only during this period is fertile fertilization of the female possible. It must be borne in mind that the formation and duration of manifestation of the phenomenon of the stage of excitation of the sexual cycle in females of each animal species is different.

Sexual cycle in cows

In cows, the manifestation of phenomena in the arousal stage of the sexual cycle occurs in the following sequence: estrus, sexual arousal, heat and ovulation. Estrus in cows in most cases lasts 2.5-3 or more days. In practice, animal owners and farm specialists diagnose (determine) estrus by examining the external genitalia and by vaginal examination. 1.5-2 days (and sometimes later) after the first signs of estrus, the behavior of the female begins to change. Sexual arousal is diagnosed by changes in the behavior of the cow: the cow becomes more mobile, restless, roars, often steps on her limbs, we note a deterioration in food consumption, and milk yield decreases. But such cows do not always allow the bull to be mounted. In some cows, sexual arousal may be completely absent. Therefore, it is very important for owners of private household plots, peasant farms, and artificial insemination technicians to identify heat, which in cows lasts on average 12-18 hours, in winter it is shorter – up to 13 hours. Hunting in cows usually occurs in the morning and evening hours. Ovulation can be determined rectally by a veterinarian and artificial insemination technician. In cows, ovulation occurs 10-15 hours after the end of heat (24-30 hours from the start of heat), in most cases in the evening and morning. Coitus in cows shortens sexual heat and accelerates the onset of ovulation. In the winter - stall period, the stage of arousal of the sexual cycle in cows is manifested by weakly expressed signs of estrus, sexual arousal (sometimes it may not appear), short heat and, in some cases, the absence of ovulation. For this reason, the stage of excitement in winter often goes unnoticed by animal owners. The use of a test bull in agricultural enterprises eliminates the possibility of missing heat and allows the artificial insemination technician to correctly select the time for fruitful insemination.

Timely detection of heat in cows is the key to correct, and most importantly, timely fertilization. Old-fashioned detection methods are good for domestic cows, when the animal is in plain sight and the slightest deviations are noticeable. But in order to determine the beginning of hunting in a large herd, you need to know under what conditions it begins, how long the process lasts and what its signs are. I understand that it is difficult to fully cover the topic in one article, so we will try to cover the main thing.

Why is it important to determine readiness for reproduction?

Timely detection of the onset of the process is important not only for young heifers, but also for cows that have already given birth. Sexual maturity in cattle appears at approximately 8-10 months, and physiologically females are ready for fertilization only at one and a half years. A bull should not be allowed near an immature heifer. This will be harmful to both herself and the future calf.

She will be able to get pregnant, but the development of the fetus will occur simultaneously with the formation of the mother’s body. And this will inevitably harm the young cow and her baby. After such an early pregnancy, the cow will never be a record holder for milk, plus you shouldn’t expect a healthy offspring from her.

It’s also bad if the cow over-walks. There may be two reasons for this. The first is that the owner deliberately did not reduce her, wanting to optimize the time of birth. The second is that the cow has gone too far due to the inexperience or negligence of the owner. In both cases, the likelihood of problems with the ovaries increases significantly in cows that wander. And this is a direct road to infertility.

If a healthy cow has calved without pathologies, then it is advisable to inseminate her within 30 days, the maximum time until the next fertilization is 90 days. Then there may be problems either with conception or with the cow itself.

Hormonal cycle in cows

To determine heat in cows, it is advisable to clearly know the cycle of each cow. Cows are a polycyclic mammal species. The hormonal cycle of cows lasts 21 days. It is divided into three stages - the first is excitation, then inhibition and, finally, a stable period.

When aroused, an active phase of egg maturation occurs in the body of cows. This process is accompanied by a “rise” of estrogen. This is called estrus, during which the cow is in heat or, more simply put, walking. But estrus itself is divided into several more time periods. We will talk about these periods, as well as the synchronization of hunting, in the following chapters.

Braking usually occurs approximately 3-4 days after estrus begins, although it can happen a day earlier or later. The corpus luteum begins to form during this period. The synthesis of LH (luteinizing hormone) in the pituitary gland provokes the release of progesterone, which “suppresses” the desire. The cow calms down until the next cycle. Being in a stable state, she will no longer let the bull near her. At this time, estrogen is practically not produced, but progesterone predominates.

Process synchronization

It is quite difficult to correctly identify the start of heat in cows in a large herd. Therefore, specialists widely use various synchronization schemes for this process.

Synchronization is the slowing down or, conversely, acceleration of the hunting time in cows.

At the moment there are three such schemes:

• exposure to prostaglandins (PG protocol);
• exposure to prostaglandin, as well as releasing hormones (the program is known as “Ovsynch” or the GPG protocol);
• exposure to progesterone and prostaglandin, plus HSFA.

According to the PG protocol, when a period of stability begins (zero reference point), the animal is injected with 2 ml of the drug "Prosolvin". On day 11 the injection is repeated. After 72 hours from the last injection, the first initiation of the hunt begins. Another 24 hours later - the second one. This scheme gives up to 60% of real pregnancies.

According to the “Ovsynch” scheme, “Fertagil” is first injected, after 7 days “Prosolvin” and after another three days “Fertagil” is repeated (all 2 ml intramuscularly). Hunting is initiated after 16 hours and after 24 hours. This scheme is common in the West and gives 65-80% success.

The third scheme is the most expensive, but it gives up to 90% success. First, they inject "Crestar" - 2 ml, on the 8th day they inject "Prosolvin" - 2 ml and on the 10th day "Philligon" - 500 units. 56 hours after the last injection, the cow is in heat. According to all three schemes, up to 3-4% of false pregnancies are observed.

https://youtu.be/bP1meeEJJpM

Definition of hunting

The standard signs of heat in a cow are agitation and unusual behavior. But how will we understand that the hunt has begun if the character and temperament of all cows is different, and in a large herd you can’t keep track of everyone?

For this, there are clear reference signals, the same for all cows, by which you can find out about the beginning of the process. At the first stage of the hunt, most cows become restless, moo loudly and rush around the paddock or pasture. The vaginal lips swell slightly and a transparent substrate is released.

At the second stage, the cow is also worried, but her behavior becomes friendly, she can lick her herd sisters. In this case, the vagina swells greatly and becomes bright red. The discharge also intensifies.

In the third and final stage, the discharge becomes pink and thick. The cow no longer actively shows interest in others, but as the bull approaches, she freezes in anticipation.

It is impossible to say exactly how long each period lasts. But the third period is considered the best time for conception, and it can last 7-20 hours.

Important little things

There are many methods for determining heat in cows; a separate publication will be devoted to them. But there is one unmistakable method that people have been using for thousands of years. When taken out for a walk, a so-called sniffing bull is introduced into the herd.

Its seminal canals are pinched or cut, but it detects heat unmistakably. True, such a bull should be left out for no more than a couple of hours, otherwise the sense of smell may be lost.

Many owners, at the first sign of heat, immediately rush to remove the cow. And then they wonder why the cow doesn’t become pregnant with a calf. So, you need to reduce only at the second, or better yet, at the third stage, but not at the first. In addition, before and after mating, the cow should not be milked or fed for two hours.

Correct determination of heat stage is one of the most important points in cattle breeding.

If you want to talk about your own experience, write comments.

Missed heat in cows lengthens the service period and leads to increased costs for maintaining the herd; the farm loses up to 15% of calves and reduces milk production. Pedometers, detectors, and electronic heat indicators help determine heat with almost one hundred percent accuracy.

WITHOUT CALVES AND MILK

Without being able to detect heat in cows in time, farms lose up to 15% of calves and reduce milk production, says Tatyana Moroz, VNIIPLEM specialist. And if the time of insemination is chosen incorrectly, then fertilization does not occur and the service period of the animal increases, which means that the costs for maintaining replacement young stock and non-lactating cows, for treatment and re-insemination of animals, and even for their culling due to infertility increase.

According to Oleg Bespalov, manager of the milk production management system at DeLaval, one missed hunt increases the service period by 20-22 days. The average cost of one day of service period is estimated at 70 rubles. per cow (mainly feed costs).

The problem of detecting hunting on tethered farms is especially pressing.

For successful reproduction, it is important to properly maintain cows; first of all, animals need daily exercise. When a cow stands all day, her muscle tone decreases, which can later cause infertility, notes Marina Goryainova, chief livestock specialist at the Kuban Agricultural Information and Consulting Center. Often, the absence, insufficient amount or excess of one of the components of the feed ration (vitamins, proteins, carbohydrates, calcium, phosphorus, manganese, iron, cobalt, etc.), even with good overall nutrition, can lead to infertility.

Iodine and vitamin E are especially important - with its deficiency, puberty is delayed, defective sexual cycles occur (without ovulation of the egg), the placenta is delayed, which leads to the occurrence of gynecological diseases and abortions.

It turns out that even if heat is detected, pregnancy does not occur. This is due to low levels of hormones to support pregnancy, poorly developed ovaries, and the fact that the walls of the uterus are not adapted to support the fertilized egg, continues Goryainova.

DETERMINING THE HEAT CONDITION OF COWS BY EYE

The best way to identify a cow in heat is visual observation, says Deputy General Director of Venera-Vet Lidiya Kornienko-Zhilyaeva. - The insemination technician determines the onset of sexual arousal by external signs: increased motor activity, leakage of mucus from the genital tract, poor appetite of the cow, mooing. In addition, hunting is indicated by the fact that other animals jump on the cow, ready for insemination. The specialist notes for himself the time of appearance of these signs and then observes the animal during the day and determines the time of the beginning of active sexual heat, when the cow stands motionless, when other animals jump on her. It is at this moment that the cow should be inseminated.

Marina Goryainova is convinced that visual observation is effective only when kept in a tether. When animals are fixed in stalls, it is easier for milkmaids and cattlemen to notice the approach of sexual heat: cows are poorly milked, restless, and have mucus discharge.

Tatyana Moroz notes that the optimal time for insemination can be determined by the maturity of the dominant follicle by examining the ovaries through the rectum. However, not all farms can attract a qualified specialist in the field of rectal examinations.

According to Goryainova, the most effective and closest to natural conditions method for detecting cows in heat when kept loose is to use a sampler bull in the herd, which accurately detects cows in heat, capturing specific odors - sex pheromones. The probes detect heat even in those cows that do not show external signs of sexual arousal, that is, they are in a state of “quiet” heat. This allows you to select 15% more cows for insemination than with visual observation.

The test bull is released into the pen of the females twice a day, for 1.5-2 hours in the morning and evening, and observed. But keeping a test bull among females for a longer period of time is not recommended, as this can cause inhibition of sexual reflexes.

NON-HUMAN FACTOR

Often, the harbingers of heat begin at night, and by the morning all signs are no longer noticeable and it is difficult to determine the time of insemination. In addition, in the cold season, signs of hunting are less pronounced than in the warm season.

In winter and autumn, more animals are in a state of “quiet” hunting, when there are no characteristic signs (jumping, motor activity), and it is difficult to visually identify such a hunt, and even more so to determine the time of insemination.

It is much more accurate to identify heat if you do not rely on visual signs, but use tests, indicators and other auxiliary means, says Boguslav Jodorowsky, manager of the Draminski company.

For example, the Draminski electronic heat and early pregnancy indicator is based on measurements of the electrical resistance of the mucus in the cow's vagina. Indeed, during estrus, hormonal changes occur in the cow’s body, which is reflected, in particular, in the properties of the secreted mucus.

From the beginning of estrus, there is less electrical resistance of the mucus. And after estrus there is a high level of resistance.

When making measurements, it is very important to catch the moment of resistance growth - it means that the best moment for insemination - ovulation should occur within the next two to three hours. During estrus, measurements should be taken twice a day, notes Boguslav Jodorowsky. - An electronic indicator allows you to detect the next heat or early pregnancy 3-4 weeks after fertilization, when the resistance results remain at a high level.

Jodorowsky believes that if a cow does not have hormonal problems, then using heat meters can determine heat in 100% of cases.

The “Hunter” estromer is also based on measuring the electrical resistance of mucus, but it is already accompanied by a table with digital values ​​​​obtained as a result of measurements, according to which the insemination technician determines the most favorable time for insemination. According to Olga Kovalkova, deputy head of department at Petrolaser, this device can be used both on the farm and in the pasture.

Often, due to serious drug treatment of endometritis, retained placenta and other complications after calving, the cow does not come into heat for a long time or is in a state of “quiet” heat, but other animals in the herd still react to this cow by jumping, notes Sergey Pashin, manager of “ BelAgroSystem.

Usually, when an adult cow is in a well-defined heat, other animals jump on her about 20 times during the hunt, each jump lasts no more than 2-3 seconds, so during the entire sexual cycle of the cow, a specialist has only 60 seconds to notice the heat. You need to watch the cow all day long; no specialist can do this,” says Pashin. - Instead, it is easier and more convenient to use the Kamar heat detector.

This device is an ampoule that is attached using special glue to the back of the animal at the base of the tail. When an animal jumps on a cow and presses on the detector, the gel ampoule in it bursts and the color of the detector changes from white to red.

According to Pashin, using Kamar detectors it is possible to identify cows in heat with a probability of 95%. Such devices cost only about 40 rubles. and operate error-free, the only drawback is that they are inconvenient to use on farms where mechanical or electric brushes are installed for self-cleaning cows - in this case, the detectors may come off or give a false signal.

COUNTING STEPS

When a cow approaches sexual heat, in addition to the visually observed changes in the vagina and mucous membrane, an increase in her motor activity can be noted as a distinct sign, says Vasily Atamanenko, a specialist at Westfalia-Surge. - This is the basis for the operation of the Rescounter device, which has a built-in pedometer or activity meter. The device is placed on the cow's leg or built into the collar. The cow's activity causes electrical impulses in the pedometer, which are counted and entered into the memory of the DairyPlan computer system.

Using such a system, it is possible to calculate the average activity level for each animal over 10 days. This indicator is used for comparison with current values; noticeable deviations from the average indicate hunting.

The average activity of cows over 10 days must be calculated based on the same two-hour period, explains Atamanenko. - For example, if from the first to the tenth day in the period from 10 to 12 o’clock the average activity value of a cow was 10, and on the 11th day in the same period of time the activity value was 15 and after this two more increased values ​​were noted , the system generates an alarm for the operator. The advantage of using such a device is that you can monitor the animal regardless of its location - both in the pasture and in the milking parlor.

According to Atamanenko, if Rescounter is located on the leg of an animal, then it detects up to 92% of cows in heat, and if on the neck - then 77%. The fact is that the collar usually records a lot of unnecessary movements (tilts of the neck, blows from other animals). And the accuracy of identifying a “silent” hunt with Rescounter reaches 70%. If the “quiet” heat is determined by the inseminator, then the accuracy ranges from 10-30%.

A similar device is also included in the Affarm farm management system.

The pedometer does not cause the animal any stress or discomfort. All information about the cow’s physical activity per day is sent to the central computer to the dispatcher, and he sees which cow needs to be sent to the veterinarian and which to the artificial insemination technician,” says Evgeniy Korshunov, director of the Kaliningrad branch of Bauer Techniks.

The activity sensor is also offered by DeLaval. Located on the collar, it records the cow's behavior 24 hours a day and also analyzes the behavior pattern of each animal over several days. Information from the activity sensor is transmitted through the antenna to the central processor of the system, which processes all the information and, if high activity is detected, issues a warning to the user that the animal has shown high activity. In this case, the inseminator must check whether this animal is in heat and, if the result is positive, inseminate it.

According to Oleg Bespalov, the location of the sensor on the collar is better than on the leg, because it causes less discomfort to the animal. He estimates that the DeLaval activity sensor detects heat with an accuracy of 95%, but in any case a visual inspection of the animal is also required. - Usually 3-5% of cows in the herd are in a state of “quiet” heat. And if, with an average sexual cycle of 23-24 days, bursts of activity are recorded every 5 days, then this most likely indicates an illness in the cow. Therefore, the use of pedometers allows not only to detect heat, but also to promptly identify and treat sick animals,” says Victor Gridin, consultant at Profimilk.

SOFTWARE METHOD FOR DETERMINING HEAT IN COWS

To manage a dairy herd, you can use computer programs on the farm, which can consist of separate modules: reproduction calendar, milk production, registration of physical activity with heat detection, feeding management.

The DairyPlan, Afifarm, Alpro, CMW programs work on this principle. Using modules, they monitor animals during milking: they take into account milk yield, control the process of cooling milk and washing milking equipment, and contain information on feeding rations and portion distribution for individual cows.

To control the reproduction of the herd, each program has an electronic schedule for all cows. The program provides information in advance on those animals that should come into hunting in the near future. An artificial insemination specialist will be able to select the appropriate semen from a specific bull for each cow. The arrival of cows in heat is determined by recording and analyzing the animal’s physical activity using activity sensors or pedometers (sensors that are attached to the leg). Information from the sensors is sent through an antenna to a central computer, the results are processed and presented in the form of graphs or numerical values. The computer, using special selection gates regulated by the selection module, separates a cow in heat from the general herd so that a veterinarian and an artificial insemination technician can begin working with her.

If a highly qualified artificial insemination technician works on a farm, he will be able to identify animals in heat with an accuracy of 90-95%, so computer programs that include pedometers in this case will simply make the specialist’s work much easier,” says Marina Goryainova.

SYNCHRONOUS HUNTING

In conditions of intensive dairy farming, many farms are switching to synchronizing sexual heat in cows - that is, they carry out hormonal treatment of several animals at once. If they do not have health problems, then 85-90% of cows usually come into heat, says Ismail Shapiev, head of the reproduction department of the All-Russian Research Institute of Genetics and Breeding of Farm Animals. - This is very convenient for carrying out artificial insemination and maintaining the reproduction schedule.

Tatyana Moroz notes that the most optimal time for inseminating a cow is 6-10 hours after the end of visible signs of heat.

Typically, the lifespan of an animal is about three to four lactations, during which time hormonal injections do not have time to cause any harm to the health of the animal, Marina Goryainova is convinced.

But according to Lydia Kornienko-Zhilyaeva, hormonal stimulation has a bad effect on the health of the animal. If at the time of injection the cow is sick, but there are no visible symptoms yet, she may remain infertile altogether.

Such methods contradict the natural processes in the animal’s body and are therefore extremely undesirable, she says.

Farm "Orlovskoye" (Oryol region)Ekaterina Eliseeva, chief specialist:- In order to comply with the calving and insemination schedule, we strictly monitor the condition of the animals and conduct obstetric and gynecological medical examinations. From the third day after calving, we begin to monitor the cows in order to identify incipient gynecological diseases in them. Endometritis is especially dangerous; it is what leads to cow barrenness. Then we carry out a special course of treatment with antibiotics and immunostimulating drugs. We pay special attention to animal feeding. After all, even if we provide the required amount of feed, but upset the balance of minerals, this will immediately affect reproduction, either the hunt will be “quiet”, or insemination will not give positive results and repeated insemination will be required, and maybe more than one. It is especially important that animals receive enough iodine from their feed, which is directly related to reproductive functions. To compensate for the deficiency of this element, we use premixes. To determine heat, we use the Okhotnik estromer produced by the Petrolaser company. The error in the operation of this device is 30%. Moreover, sometimes it shows that the cow is in heat when she is already pregnant. Often, results for the same animal differ when measured in the pasture versus indoors. If a cow suffers from any gynecological diseases, they also interfere with obtaining an accurate result. However, we have very experienced artificial insemination technicians on our farm who can identify an animal in heat with 95% accuracy. Thanks to this, we maintain a high calf yield - about 90%.

Collective farm “Zavety Ilyich” (Sverdlovsk region)Galina Berdyugina, chief livestock specialist:- A year ago we started using the Afikim herd management system. We fitted an experimental group of 235 cows with pedometers to record motor activity. As a result, the proportion of repeat inseminations in this group was 33%, and where pedometers were not used, it exceeded 50%. The proportion of pregnant cows in the “computer” group was 58%, while in other animals it was less than 48%. The only drawback of pedometers is that the elastic bands that hold the device on the cow's leg often come off. We use pedometers in free-stall barns. Here the cows move a lot, this is a good prevention of diseases after calving. And when kept in stalls, there are problems in the post-calving period, mainly endometritis.

Breeding farm "Smena" (Moscow region)Galina Makarova,livestock breeder:- Every year on our farm we get more than 90 calves per 100 cows; last year, for example, the calf yield was 94%. Our high percentage of reproduction lasts about 30 years. I believe that this is the result of the coordinated work of a veterinarian and an artificial insemination technician. Our animals have virtually no complications after calving. We carry out systematic monitoring of new-born animals. If within 45 days after calving the cow does not come into heat, then the insemination technician takes note of her. Together with the veterinarian, he performs a rectal examination of the animal for hypofunction or ovarian cysts. The doctor then decides whether to use hormonal drugs to stimulate heat. According to the reproduction technology adopted on our farm, a cow should be pregnant 90 days after calving. Due to the intensity of production, we use special medications, since the average duration of use of a cow is four lactations, and highly productive ones (with a milk yield of 10 thousand liters or more) may have only two lactations, and hormonal drugs do not have a significant effect on animal health keep up. To determine cows in heat, a couple of years ago we used a device based on measuring the electrical resistance of mucus in the genital tract of a cow - an estromer. But now it has been abandoned due to serious measurement errors, which causes unproductive insemination. We currently employ a qualified artificial insemination technician who uses a visual method to identify cows in heat. In addition, we are planning to purchase a device to determine early pregnancy, which is based on the determination of the hormone progesterone in milk (ELISA). This device detects pregnancy on the 18-19th day. We will also buy an ultrasound machine. In feeding, we pay special attention to maintaining the sugar-protein ratio. If the diet contains a large amount of concentrates, then you need to maintain blood glucose levels (one option is to use molasses). We also monitor the content of zinc and selenium in the feed; for this we use premixes.

Collective farm "Malinishchi" (Ryazan region)Vladislav Dzhelalov, livestock breeder:- We use a visual method to identify cows in heat, and therefore errors can be associated primarily with the wrong choice of insemination time, but for this, the insemination technician carefully monitors the cow during the day, showing signs of sexual arousal. After calving, we inseminate the cow immediately, during the first heat. Our calf yield is now 95-96%. To prevent problems with reproduction, it is most important to feed the cow correctly. First of all, we pay attention to ensuring that the animal is not obese. Infertility in this case is more difficult to eliminate than with starvation or insufficient diet in micro- and macroelements. But when compiling diets, it is necessary to take into account the conditions of detention. During the cold period, we increase the nutritional value of diets by 25-30%, since a lot of energy is spent on maintaining vital functions, and this entails a drop in milk yield. We also use hormonal stimulation, but only with those animals that do not have gynecological diseases. Before administering the drug, we massage the uterus and ovaries rectally. Pregnancy is determined two to three months after insemination. Thanks to qualified specialists and timely treatment of complications after calving, we were able to increase the yield of calves by 10-12% in two years.

Olga Demidova

A gentle, fluffy creature - a cat - is a real symbol of home comfort. We choose a kitten according to our taste: large or miniature, smooth-haired or fluffy - there are dozens of cat breeds. They all look different. What unites them is that, having matured, cats invariably strive to be free in search of love. This is especially noticeable in the spring. During heat, cats become unlike themselves: they emit guttural screams, loudly call the cat, take poses characteristic of mating, and roll around on the floor.

It is necessary to understand that this behavior is natural for pets during the period of sexual heat and indicates the completion of the process of puberty in a young cat. Next, you will learn about what puberty in cats is, when a cat’s first heat occurs, and how to make this period the most comfortable for you and your pet.

Puberty: When do cats go into their first heat?

The end of puberty in your pet is indicated by its restless behavior, which indicates that the cat has entered its first heat.

Estrus is a stage of the cat's reproductive cycle, which is manifested by a positive reaction of the animal to cats.

Almost every owner is concerned about the question of when his cat will go into heat for the first time. The time of the onset of the first heat is different for each cat. It depends on how the animal is fed and where it is kept; Hereditary factors and breed play a role.

Typically, young cats show signs of their first heat between the ages of 6 and 10 months. However, large cat breeds, such as Persians or Maine Coons, mature later than their smaller counterparts.

The onset of sexual maturity of an animal does not mean that you can take your cat for mating. A cat’s body at 6-10 months is not physiologically ready for bearing and giving birth to kittens. The cat becomes fully ready for pregnancy and childbirth at the age of 16-20 months.

How long does a cat's heat period last and what are its signs?

The duration of the period when a cat seeks to continue its race is 5-7 days. If the cat does not become pregnant, the next heat occurs a week to a month after the previous one. During a cat's heat, you will notice the following changes in its behavior:

• Loud calling meow. A cat calling a cat can continue her “songs”, which are not very pleasant to the human ear, throughout the entire period of estrus. She will make purring guttural sounds day and night;
• Landing on the front paws. When a cat is ready to reproduce, she begins to take a mating position: lower the front part of her body to the floor and raise the back, while moving her tail to the side;

• Marking the territory. This behavior serves as another way to attract a male for mating. Cats are good at smelling the pheromones secreted by the cat in its urine;
• Overly affectionate behavior. Wanting to attract attention, the pet during estrus follows the owner's heels and rubs against his legs. Displays of aggression are also possible;
• The desire to run out into the street. Submitting to the instinct of reproduction, a cat during estrus will not miss the opportunity to jump out of an open door or window into the street. This behavior does not depend on whether the cat is walking outside or kept at home. Therefore, you need to carefully monitor your pet.

What to do to prevent the cat from asking the cat: what product to choose?

If you care about the health and peace of your cat and want your pet to show affection only when mating is necessary, the right solution would be to use drugs to regulate sexual heat.

Many breeders and cat owners use the modern drug Gestrenol to solve problems associated with sexual heat in pets and prevent unwanted pregnancy. You can use this drug starting from your pet’s second heat.

A cat in heat is a serious problem for the owner. Solve it with Gestrenol drops for cats

Cats can go into heat more than 10 times a year. But you can only breed a pet three to four times in 12 months. The rest of the time, the animal’s body must rest and recover after childbirth. Sometimes it is impossible to “endure” the heat, as is the case with ordinary outbred cats. Each heat that does not end in mating weakens the cat’s body and worsens the animal’s exterior qualities, for example, the quality of the coat. Such a pet is unlikely to be able to take a high place at the exhibition. Therefore, many cat breeders choose Gestrenol, a drug for regulating sexual heat, to calm their pets.

Efficiency

The drug is able to solve all of the above problems of cat behavior during heat; prevents unwanted pregnancy due to accidental mating;

Safety

Gestrenol is a bihormonal drug. Due to the use of two new generation hormones in its composition, the concentration of active substances in the drug is reduced tenfold. The product is designed specifically for cats; its composition takes into account the characteristics of this type of animal;