Precautions for dairy cow embryo transplantation, dairy farming

To select a suitable recipient cow, individuals with larger size and docile temperament should be selected as recipient cows.

In actual production, improved cattle are more suitable, preferably the improved offspring of Simmental cattle.

In terms of age, multiparous cows between 3 and 6 years old are better, and older cows over 10 years old cannot be used.

Primiparous cattle must reach sexual maturity, be over 16 months old, and weigh 75% of their annual weight before they can be used.

The recipient cattle are required to be healthy and disease-free individuals, especially those with no reproductive system diseases.

Cows that are too fat or too thin, have underdeveloped ovaries, have inflammation in their reproductive organs, or are infertile through artificial insemination are not suitable to be recipient cattle.

If the cow is transplanted at the right time during the estrus stage and is not in estrus, it will not be able to ovulate and form a corpus luteum, and embryo transfer will not be possible.

So it is necessary to transplant the cow at the right time during the estrus stage.

Recipient cows with abnormal estrous cycles are not suitable for embryo transplantation.

Short-term optimal feeding 6 to 8 weeks before transplantation, scientific supplementary feeding should be carried out on the recipient cattle to ensure that the body reaches the optimal reproductive state.

Supplementary feed 2.5 kilograms of concentrate per day. The supplementary feed must be nutritious and of high quality. At the same time, attention should also be paid to the supply of vitamin A, vitamin D, vitamin E, trace elements and mineral feed. .

Pay attention to environmental conditions and disinfection of items. The embryo operating room needs to be clean, dust-free, and odor-free. Therefore, it is best to carry out ultraviolet disinfection before transplantation. All instruments and supplies must be strictly disinfected and placed in an orderly manner. Organized and easy to use.

The arms of staff must be disinfected with alcohol cotton before operation.

Do a good job in observing the estrus of the recipient cow. Observing estrus is very important in embryo transplantation and is the basis for determining the transplantation time.

Non-surgical embryo transfer is performed on the seventh day after estrus.

Estrus observation requires a certain person and time, and the observer must have rich experience.

Observations are conducted 4 times a day, morning, afternoon and evening, for 1 hour each time, and the estrus performance and estrus time of each cow are accurately recorded.

Corpus luteum examination Before transplantation, a direct examination of the recipient cow is required to determine the development of the corpus luteum.

A good corpus luteum protrudes from the surface of the ovary, is soft and elastic, has a diameter of more than 1 cm, and has a solid bottom.

The ovaries of some cows are small, and the corpus luteum formed is also small, but the texture is very elastic and soft. Such cows can also be used for embryo transplantation.

Please note that the inspection movements should be gentle and do not squeeze hard to avoid injuring the recipient cow.

The operation of embryos should be carried out strictly according to the procedures for glycerin-frozen embryos: thawing and thawing liquid transplantation liquid are loaded into tubes and guns, while ethylene glycol-frozen embryos are directly loaded into guns after thawing, and no other operating procedures are required.

The purpose of appropriate anesthesia dose is to reduce the stimulation of transplantation to the recipient cow and make it stable. The second is to prevent rectal strain and facilitate operation. The anesthesia is done in the caudal vertebrae anesthesia method. If the anesthesia site is far behind or the dose is insufficient, the rectal strain will not be suppressed. If the dose is too high and the rectal sphincter muscles are excessively relaxed, a large tubular cavity will be formed in the body. Some people will be paralyzed in their hind limbs and unable to stand up, which will cause inconvenience to the transplant or even make it impossible to transplant.

Be proficient in embryo transplantation techniques. Embryo transplantation is the transplantation of early-stage embryos into recipient cows with the same physiological status so that they can continue to develop. The transplantation is usually performed on the seventh day of embryonic development. The transplantation site is the upper l/2 to lower l/3 of the lateral uterine horn where the corpus luteum is well developed. If possible, the deeper the better. The operator is required to transfer the embryos into place within a short period of time, in principle no more than 10 minutes. At the same time, attention should be paid to the coordination of both hands to avoid scratching the endometrium during the transplantation process.

Embryo quality must be guaranteed. Embryo quality is one of the important factors that determine the success of the transplant. Only good embryos can achieve a higher pregnancy rate. In practice, the quality of transplanted embryos must be above grade B, and frozen embryos must be grade A.

It is necessary to choose the appropriate transplantation season and time. The embryo transplantation should avoid the influence of hot summer and severe cold. The best transplantation time is March to May and lO to l1 months.

In order to improve the pregnancy rate of the group, repeatable transplantation is carried out. According to the information, the recipient cow can undergo two consecutive embryo transfers. If the two transplantations are not successful, the recipient cow cannot be used as a recipient cow again.