Normal cows have estrus within 40-50 days after giving birth (buffalo is a little later), and beyond this range are all cows with abnormal estrus. The normal estrus cycle of cows is 18-24 days, with each estrus lasting 12-21 hours. The luteal phase is 17 days, the follicular phase is 3-4 days, ovulation is ovulated 10-15 hours after the end of estrus, and the mature follicle is 13-19 mm in diameter.
Reasons why cows don't estrus:
01. Malnutrition
Infertility caused by malnutrition is called nutritional infertility, as long as it is not long, nutritional supplementation can restore reproductive function, or long-term nutritional imbalance, especially the lack of development stage, so that the development of reproductive organs is affected, and it is difficult to improve feeding to return to normal.
The nutrition of the cow is very special and very critical, the various trace elements, protein, energy requirements are more special, amino acid requirements and fattening beef cattle have a great difference, it is recommended to start from a young age, do not ignore, it is recommended to use the cow mother premix.
02. Improper management
1, the cow is too fat or too thin. Be sure to ensure that the cow is moderately fat, and the seven or eight points are the best.
2. If the cow lactates too much or weans too late, the role of lactogen is enhanced, the role of the lactogen inhibitory factor is weakened, the follicle cannot develop mature, and estrus cannot ovulate.
3. The envoys are too heavy, and now they basically do not exist
4, irregular deworming, the harm of parasites is everywhere, raise cows regularly deworm, once every six months
5. Feeding moldy and spoiled feed or feed mold toxins is too high, it is recommended that cows use double-effect mold for a long time to kill clear
6. Cows are fed lees in the reserve stage, resulting in stunting of cattle
7. Do not use cattle feed, but feed pigs and chickens
8. Poor environment in the barn, insufficient drinking water, lack of exercise, or insufficient light
03. Physiological
1. Heterosexual twins are sterile
2, white calf disease, also known as semi-male and female
3. Reproductive organs are underdeveloped or deformed
The first cow should be checked in time, and once found, it should be eliminated in time
04. Pathological
1. Long-lasting corpus luteum
Primary persistent cattle, cattle in a normal state of infertility in the uterus are more rarely cows secondary to certain uterine diseases (such as uterine pus, uterine effusion, fetal dry corpse).
Treatment: prostaglandins, chloroprostol, pregnant horse serum
2. Ovarian cyst
It is one of the important causes of estrus abnormalities in cattle.
Treatment: Gonadotropin-releasing hormone (GnRH), human chorionic gonadotropin (HCG)
3. Endometritis
It is one of the important causes of bovine infertility
Causes: Infection during mating, insemination, childbirth; sometimes through a continuation cycle, the infection is usually chronic
Treatment: uterine douching, uterine administration, antibiotics
4. Ovarian insufficiency
(1) Ovarian function is hypofunction, which is that the ovarian function is in a static state and does not appear cyclical activity; the cow has external symptoms of estrus, but does not ovulate or delays ovulation.
Long-term decline in ovarian function causes tissue atrophy and hardening, and the disease is easy for aging cattle.
(2) The performance is that the cow ovulates normally, but there are no symptoms of estrus, which is also called quiet estrus
Treatment methods: 1, increase nutrition, exercise 2, for the disease (systemic disease, infectious disease or parasitic disease), to treat the primary disease
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5. Oophoritis, salpingitis, tubal effusion, adhere to the treatment with antibiotics
6. Endometrial cystic hyperplasia
22-30% of sterile cattle
7. Uterine effusion and uterine empyema
Treatment: uterine cleaning, estrogen therapy
8. Hysteritis, secondary uterine wall cyst, cervicitis, vaginitis
9. Cervical cyst, cervical effusion
Reminder: Early embryonic death is also prone to repeated infertility or delayed estrus.
Finally, rational medication can be used to allow cows to ovulate rapidly
26 days after the birth of the cow, 3 to 5 bottles of chloroprostenool (size 2 ml: 0.2 mg) are injected.
40 days after the birth of the cow, followed by injection of 3 to 5 clprostol.
The role of chloroprostenol: it has a strong luteinizing effect, which can quickly cause the regression of the luteum, and inhibit its secretion, controlling the estrous cycle of animals.
If the cow does not have estrus within 2 to 5 days after 40 days after giving birth and 2 to 5 days after injection of chloroprostenool, then 50 days after the cow is given 2 gonamorelin (size 2 ml: 100 units).
At intervals of 7 days, that is, 57 days after the birth of the cow, 3 to 5 clonols are injected.
About 2 days after the beating, you can see whether the cow has estrus performance, if there is estrus performance, you can directly breed, if there is no estrus performance, you can inject 2 gonamorelin again 59 days after the cow is born.
At this time, regardless of whether the cow has estrus or not, it can be mated 60 days after the cow gives birth.
The above is a plan for large cattle farms to estrus at the same time, and it is also a very successful plan, and our small and medium-sized cattle farms can also refer to this plan to do so that cows can be bred in heat within 60 days after giving birth.