阅读说明：本技术 一种母牛性控双胎的方法 (Cow sex-controlled double-fetus method ) 是由 甘蔗 甘甜 于 2019-11-07 设计创作，主要内容包括：本发明公开了一种母牛性控双胎的方法,包括：在受体母牛自然发情受精满6天后通过胚胎移植植入同性别的胚胎一枚。本发明在不增加饲养成本的条件下额外获得安全可持续繁衍的优良母牛,将极大推进我国母牛良种的改良速度和存栏量。(The invention discloses a cow sex control twins method, which comprises the following steps: one embryo of the same sex is implanted by embryo transfer 6 days after the recipient cow has naturally estrated and fertilized. The method additionally obtains excellent cows capable of safely and sustainably breeding under the condition of not increasing the breeding cost, and greatly promotes the improvement speed and the stock quantity of the improved cows in China.)

1. A method for sexing a cow to control twins, comprising: one embryo of the same sex is implanted by embryo transfer 6 days after the recipient cow has naturally estrated and fertilized.

2. The method for sex controlled twinning of cows according to claim 1, wherein the sex controlled embryos are obtained by inseminating a recipient cow in heat and an embryo donor cow with sex controlled semen, respectively.

3. The method of claim 2, wherein the estrus synchronization between the recipient cow and the donor cow is within 24 hours.

4. The method of claim 1 wherein the recipient cow is not inseminated during the first estrus and is inseminated during the next estrus.

5. The method for sexually controlling twins in a cow according to claim 1, wherein when the recipient cow is a primiparous cow, a female embryo is implanted and the primiparous recipient cow is over 20 months old; male embryos are transferred to a multiparous recipient cow.

6. The method for sexual bijection control of cows according to claim 1, wherein sexual bijection control of cows is obtained by: and (3) carrying out insemination 27-32 hours after the heat of the embryo donor cow is started, or carrying out insemination when the follicle develops like the mature grape-shaped elasticity and breaks with touch, and after 7 days, flushing the obtained embryo and then transplanting the embryo to a recipient cow which carries out insemination 27-32 hours after the heat is started.

7. The method of claim 1, wherein the source of ova from which the embryos are implanted comprises ova from initial estrus in a virgin cow up to 20 months of adult pregnancy.

8. The method for sexing cow to control twins according to claim 1, wherein the embryo for embryo transfer is collected by the following method:

1) putting an embryo donor cow into a fixing frame, fixing a platform, and performing primary tail root anesthesia;

2) taking out excrement in the rectum and cleaning the periphery of the anus;

3) washing pudendum, disinfecting with ethanol, and opening cervix;

4) inserting the three-way catheter ovum-flushing device into the uterine horn through the cervix until the balloon part of the catheter can be filled with 7-20 ml of air;

5) connecting one pipeline of the catheter with a glass bottle filled with 500-1000 ml flushing fluid through a first latex tube, hanging the glass bottle at a position higher than the level of the cow uterus by more than 1 m, and connecting a second pipeline of the catheter with an egg collecting container positioned on the ground through a second latex tube;

6) clamping a second latex tube, opening a first latex tube to enable the egg flushing liquid to automatically flow into a uterus by pressure, then clamping the first latex tube, and simultaneously opening the second latex tube to enable the egg flushing liquid to flow into an egg collecting container;

7) repeat steps 4) -6)6-7 times at each lateral uterine horn.

9. The method of claim 8, further comprising aspirating the rinse solution from the bottom of the egg collection container after collection and examining the eggs under a stereomicroscope.

10. The method of claim 1, wherein the recipient cow is a cow and the embryo is a beef cow embryo.

Technical Field

The invention relates to the technical field of mammal breeding, in particular to a cow sex-controlled twins method.

Background

Cattle are herbivorous single-fetus animals, have a very low twinning rate of only 0.15% -2.99% in a natural state, and 91% -94% of individuals cannot breed in the born heterosexual twinned female calves. The cow brood can improve the breeding efficiency and the economic benefit of raising cows, and the artificial induction of cows to produce twin can improve the reproductive capacity of cows by times and increase the number of commercial cows. Since the 30 s of this century, people have made some progress in attempting to improve the twins rate of cows by genetic selection, drug induction, hormone immunization, and the like.

Genetic selection of twins, an economic trait, has low heritability, and it is very difficult to improve the twins rate through genetic selection, and people in the industry want to increase twins through genetic selection, and the attempt is not successful at present; at present, it is known that exogenous gonadotropins such as PMSG (pregnant mare serum gonadotropin), FSH (follicle stimulating hormone) can be utilized to stimulate multiple follicles in cow ovaries to develop and mature for ovulation, fertilization pregnancy; it is also possible to immunize cows with inhibin antiserum. However, twins achieved with hormones cannot be used on a large scale in production until no method for controlling one egg per row of ovaries has been found, as it is common to have more than two embryos in one uterine horn, while one uterine horn of a cow has significant resistance to maintaining more than one embryo and a cow embryo rarely migrates from one uterine horn to the other, in which case abortion, dystocia and embryo death tend to occur.

Disclosure of Invention

Aiming at the technical problems, the invention provides a method for controlling twins of cows by sex, excellent cows which can safely and continuously propagate are additionally obtained under the condition of not increasing the feeding cost, and the improvement speed and the stock quantity of the improved cow seeds in China are greatly promoted.

In order to achieve the purpose, the invention adopts the technical scheme that:

a method for sexing a cow to control twins, comprising: one embryo of the same sex is implanted by embryo transfer 6 days after the recipient cow has naturally estrated and fertilized.

Preferably, embryo transfer is performed at day 7 after natural heat fertilization of the recipient cow, where implantation is easiest.

Preferably, the sexually controlled embryos are obtained by inseminating an estrus recipient cow and an embryo donor cow with sexually controlled semen, respectively.

More preferably, the recipient cows are synchronized to the heat of the embryo donor cows within 24 hours. The synchronous reproductive internal environment created by embryo transplantation after 7 days by the first artificial insemination is more matched with that created by artificial hormone treatment, the embryo implantation rate is improved to the maximum extent, and the sexual control twins probability is improved.

Preferably, the recipient cow is not inseminated when it is first in heat and is inseminated when it is next in heat. Thus, the physiological environment in the cow body can reach the optimal state by regulating hormone by itself, and the development of corpus luteum is the best.

Preferably, when the recipient cow is a primiparous cow, a female embryo is fed and the primiparous recipient cow is over 20 months old; male embryos are transferred to a multiparous recipient cow. Because large beef cattle are almost always difficult to produce, in order to reduce the difficult yield, the best method is to prolong the initial mating time, and the initial pregnancy is preferably 20 months later. The newly born cows can almost all have the possibility of dystocia, life threats can be formed for the recipient cows and the newborn cows, accidental losses are caused, the newly born cows can be artificially interfered by a sexual control technology to produce the cows, the sexually controlled cows can avoid the risk of dystocia of the newly born cows best, and the highest survival rate of the newborn cows is ensured.

Preferably, sexual control bull twins are obtained by the following method: the embryo donor cow performs insemination 27-32 hours after the estrus is started, or the follicle develops like the mature grape-shaped elasticity and performs insemination when the follicle breaks, and the embryo obtained after 7 days of flushing is transplanted to a recipient cow which performs the same operation (i.e. insemination 27-32 hours after the estrus is started). The operation greatly improves the conception and implantation rate, and provides a shortcut for fattening more bulls, improving the conception rate and reducing the cost.

Preferably, the source of eggs from which the embryo is implanted comprises eggs expelled during the initial estrus of a virgin cow up to 20 months of a ready-to-mate pregnancy. The collection and utilization of the ova of the virginator cows solve the source of the oocytes and realize the resource integration of the fine breeding cows.

Preferably, embryos useful for embryo transfer are collected by:

1) putting an embryo donor cow into a fixing frame, fixing a platform, and performing primary tail root anesthesia;

2) taking out excrement in the rectum and cleaning the periphery of the anus;

3) washing pudendum, disinfecting with ethanol, and opening cervix;

4) inserting the three-way catheter ovum-flushing device into the uterine horn through the cervix until the balloon part of the catheter can be filled with 7-20 ml of air;

5) connecting one pipeline of the catheter with a glass bottle filled with 500-1000 ml flushing fluid through a first latex tube, hanging the glass bottle at a position higher than the level of the cow uterus by more than 1 m, and connecting a second pipeline of the catheter with an egg collecting container positioned on the ground through a second latex tube;

6) clamping a second latex tube, opening a first latex tube to enable the egg flushing liquid to automatically flow into a uterus by pressure, then clamping the first latex tube, and simultaneously opening the second latex tube to enable the egg flushing liquid to flow into an egg collecting container;

7) repeat steps 4) -6)6-7 times at each lateral uterine horn.

Preferably, the method further comprises the steps of sucking the egg flushing liquid from the bottom of the egg taking container after the collection is finished, and inspecting the eggs under a stereoscopic microscope. Because of the large volume of irrigation fluid, which contains uterine mucus and cell debris, great care is needed to search for embryos.

More preferably, 30 ml of 20% compound iodine solution may be perfused in order to prevent infection of the embryo donor cows and pregnancy caused by the remaining embryos.

Preferably, the recipient cow is a cow and the implanted embryo is a beef cow embryo.

The invention has the following beneficial effects:

at present, the domestic dairy farms are mainly sex-controlled cows, female embryos of pure-breed beef cattle are transplanted on the 7 th day of normal artificial insemination of the dairy cows, a fine-breed beef cow of the pure-breed beef cattle is additionally obtained under the condition that the normal breeding of the dairy cows is not influenced, and the problem that the pure-breed beef cattle (such as pure-breed Belgian blue cattle and Charoland cattle) are difficult to produce is solved by using a sex-controlled double-fetus technology.

If the breeding potential of the male livestock is exerted to the maximum extent by the artificial insemination technology, the breeding potential of the female livestock can be fully exerted by the embryo transplantation technology, the breeding potential of the female livestock is exerted to the maximum extent by the artificial insemination technology, excellent cows capable of being safely and continuously bred are additionally obtained under the condition that the feeding cost is not increased, the improvement speed and the stock keeping quantity of fine breeds of cows in China are greatly promoted, the income of a cattle raiser is greatly increased, and the popularization of the technology is a technology 'revolution' of the cattle raising industry.

Detailed Description

In order to better understand the present invention, the following examples are further provided to illustrate the content of the present invention, but the present invention is not limited to the following examples.