Timely hunting in cows is the key to proper, and most importantly, timely fertilization. Grandfather's definition methods are good for domestic cows, when the animal is visible and the slightest deviations are noticeable. But in order to determine the beginning of a hunt in a large herd, one needs to know under what conditions it begins, how long the process lasts and what are its signs. I understand that it is difficult to fully disclose the topic in one article, so we will try to highlight the main thing.
Why is it important to determine readiness for reproduction
Timely detection of the beginning 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 about 8-10 months, and physiologically female individuals are ready for fertilization only by one and a half years. Let the bull to the immature heifer is impossible. It will be harmful both to her and to the future calf.
She can become pregnant, but the development of the fetus will occur simultaneously with the development of the mother's body. And it will inevitably harm the young cow and her cub. After such an early pregnancy, the Burenka will never be a record holder for milk, plus you should not expect a healthy offspring from her.
It is also bad if the cow goes for a walk. There are two reasons for this. The first - the owner intentionally did not reduce it, wanting to optimize the time of delivery. The second is that the Burenka had a chat with inexperience or negligence of the owner. In both cases, walking cows significantly increases the likelihood of ovarian problems. And this is a direct road to infertility.
If a healthy cow calved without pathologies, then it is advisable to inseminate her for 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 the hunting of cows, it is desirable to clearly know the cycle of each cow. Cows are a polycyclic species of mammals. The hormonal cycle of cows continues for 21 days. It is divided into three stages - the first is excitement, then - inhibition and, finally, - a stable period.
When a cow is excited in the body, an active egg maturation phase occurs. This process is accompanied by a "take-off" of estrogen. This is called estrus, during which the cow is in a state of hunting or, more simply, walking. But in itself estrus is divided into several time periods. These periods, as well as hunting synchronization, will be discussed in the following chapters.
Sedation usually occurs about 3-4 days after estrus, although it happens a day earlier or later. The yellow body begins to form during this period. The synthesis of LH (luteinizing hormone) in the pituitary gland provokes the release of progesterone, which "crushes" the hunt. The cow calms down until the next cycle. Being in a stable condition, she will not let the bull. At this time, estrogen is practically not produced, but progesterone predominates.
Correctly identify the beginning of the hunt in cows in a large herd is quite difficult. Therefore, specialists massively apply various synchronization schemes of this process.
Synchronization is called a slowdown, or, conversely, the acceleration of hunting time in cows.
At the moment there are three such schemes:
- exposure to prostaglandins (PG protocol);
- exposure to prostaglandin, as well as release hormones (the program is known as "Ovsynch" or the GPG protocol);
- Exposure to progesterone and prostaglandin plus FGSS.
According to the PG protocol, when a period of stability comes (zero point of reference), 2 ml of the drug “Prosolvin” is injected into the animal. On day 11, repeat the injection. After 72 hours from the last injection, the first initiation of the hunt begins. After another 24 hours - the second. This scheme gives up to 60% of real pregnancies.
According to the "Ovsynch" scheme, Fertagil is first injected, after 7 days Prosolvin and Fertagil is repeated after three days (all 2 ml intramuscularly). The hunt 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, the Krestar is injected - 2 ml, on the 8th day they make “Prosolvin” - 2 ml and on the 10th day “Phillon” - 500 units. 56 hours after the last injection - a cow in a hunt. In all three schemes, up to 3-4% of false pregnancies are observed.
Standard signs of hunting in a cow are arousal and unusual behavior. But, how do we understand that the hunt came, if the character and temperament of all the cows are different, and in a large herd you will not follow all of them?
To do this, there are clear reference signals, the same for all cows, which can be used to learn about the beginning of the process. At the first stage of hunting, most cows are worried, mooing strongly and rushing around the pen or pasture. The lips of the vagina slightly swell and a transparent substrate is released.
In the second stage, the cow is also worried, but the behavior becomes friendly, she can lick her sisters around the herd. At the same time the vagina swells up strongly and becomes bright red. Allocations are also enhanced.
In the third, final stage, the discharge becomes pink and thick. The cow is no longer so actively interested in others, but with the approach of the bull freezes in anticipation.
How long each period lasts is impossible to say for sure. But the third period is considered the best time for conception, and it can last 7–20 hours.
There are many methods for determining the hunting of cows, they will be devoted to a separate publication. But there is one unmistakable way that people have been using for thousands of years. When taking out for a walk in the herd, they launch the so-called bull-sniffer.
Seed channels he had clamped or clipped, but he determines the hunt accurately. True, such a bull needs to be launched for no more than a couple of hours, otherwise the scent may disappear.
Many owners at the first signs of hunting immediately rush to drive a cow. And then they wonder why a cow will not become pregnant with a calf. So, you need to reduce only the second, and better at the third stage, but not the first. In addition, before and after mating, a cow cannot be milked and fed for two hours.
Correct determination of the stage of hunting is one of the most important moments in breeding cattle.
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