Frequently Asked Questions
You may have a cow that has a pedigree that is desirable or maybe she has excellent EPD's (Expected Progeny Differences) or maybe she has proven herself by producing a calf or two that has excelled phenotypically. This is the type of cow that should be considered as a donor for embryo transfer.
Most would say the average lifespan of a cow is somewhere between 9 to 12 years. Basically her lifespan depends on how many years her teeth say long enough for her to intake adequate nutrition to sustain herself and raise a calf. Having said that and considering most heifers will calve somewhere between 2 and 2 ½ years and maybe a little older for some American breeds, you could expect to get 7 – 10 natural calves from this cow. If you use embryo transfer as a means to get more calves from a superior cow, you could increase the offspring from this cow tremendously. The average donor flushes 7 embryos. From those 7 embryos you can expect to get 4 or 5 pregnancies.
The Donor Cow:
There are several considerations necessary before choosing your donor cow. As discussed previously, she should be able to produce calves that you intend to use as replacements for yourself or are easily sellable. Secondly, she needs to be a fertile cow and respond to the super ovulation drugs in order to produce numerous eggs for fertilization. Then, she must have acceptable structural correctness in order to insure longevity in her offspring. Another major consideration is docility. A calm cow that doesn’t get too excited about being moved around and in and out of a chute will most likely produce more embryos.
The Recipient Cow:
Recipient cows can be of any breed. Most recipient cows are crossbred cows. The biggest consideration when choosing your recips is again…docility. The recip that enters and exits the chute calmly has a much better change of sustaining the embryo and becoming pregnant. A great candidate for a recipient cow is one that you know raises a good calf every year. Heifers are not good candidates for recips because of the possibility of calving issues. Your recipient cow should produce adequate milk and have a nicely formed bag and acceptable teat size, after all she will be raising some of your finest genetics.
Protocol for setting a donor for flush. It is a 16 day process from the start of set up for flush until the actual flush:
- Preheat set up – We like for all donor cows to have a known heat or estrus date prior to the beginning or the actual set up for the flush.
- Day 0 – Insert a cidr into the donor's vagina.
- Day 2 – Donor is given a shot of GNRH (Gonadotropin-releasing hormone). The trade name is Cystorelin.
- Day 4 – The donor begins super ovulation shots. She will be in the chute twice a day for the next 3 days. The most common super ovulation drug is Folltropin
- Day 7 – The cidr is pulled and the donor receives 2 doses of prostaglandin. The trade name used by Genuine Genetics is Estrumate.
- Day 9 – The donor will be in heat and will be bred to the bull or bulls of the owner’s choice 3 times. After the last breeding she will receive another shot of Cystorelin.
- Day 16 – The donor is flushed 7 days after breeding. She will have a spinal block and the embryologist will flush both uterine horns into a petri dish. After the flush is completed, the embryologist will place the petri dish under the microscope and begin searching for embryos. The embryos are quality graded by the embryologist. Grade 1 being the best, grade 2 are good and grade 3 embryos need to be transferred to recipient cows fresh or discarded as they are not suitable for freezing. The embryos will be transferred to recipient cows starting with the grade 3 embryos unless the owner request that all quality 3 grade embryos are discarded. Then the grade 2 embryos will be transferred followed by the grade 1’s. If there are not enough recipient cows for all the embryos, the embryologist will freeze the remaining embryos. They are stored in liquid nitrogen and will last forever.
- Day 0 - If you are planning to do fresh embryo transfer, your recipient cow has to have a cidr inserted on the same day as the donor and given a shot of GNRH (Cystorelin) on Day 0.
- Day 7 – Pull the cidr and give prostaglandin (Estrumate) and add an estrus patch on top of her tail head and watch for heat approximately 2 days later.
- Day 16 – Embryo transfer takes place on the same day that the donor is flushed.
Setting up a recipient cow for frozen transfer is the same as setting up for a fresh embryo transfer, but has to coincide with a transfer day at Genuine Genetics. There is a calendar on our website that will list the embryo flush/embryo transfer dates with information on what day to begin the set up process for your recipient cows. You can access the Calendar page here.
A recipient cow actually has a 3 day window in which to have a heat cycle. She can be in heat on day 8, 9, or 10 with day 16 being the embryo transfer date. As a general rule, cows nursing calves will take a little longer to have a heat cycle than those not nursing calves after the cidr is pulled and Estrumate is given.
The embryo is transferred into the uterine horn on the side from which the recipient cow ovulated.
Your recipient cow has a 3 day window for estrus. She can be in heat 8, 7, or 6 days before embryo transfer. In any case, our embryologist will check your recipient cow for a corpus luteum which is the follicle that remains on the ovary after ovulation. He will give a grade to the CL to decide if the recipient cow had a estrus cycle that prepared her for pregnancy. If so an embryo will be put into the uterine horn on the side from which the recipient cow ovulated. If not, he will pass the recipient cow. Our goal is to get as many recipient cows pregnant with embryos as possible and save you the transfer fee or use a valuable embryo.
A donor will that is going to be flushed only 1 time can be expected to stay at the center approximately 1 month. She should arrive 10 days before flush set up day so she can have a pre-flush heat to insure that she is cycling and ready for breeding.
There are several choices of drugs to use for super ovulation. Your cow may respond to one and not the other. Most donors are started on Folltropin. Depending on the stimulation of the donor, the dosage can be adjusted or an alternative drug may be used for a subsequent attempt to produce embryos. Our embryologist will check for stimulation before he begins a flush. If there is no ovary stimulation, then there will not be a flush. The charges for set up and super ovulation will still apply, but a fee of $140.00 will be charged instead of the $280.00 fee for a flush.
The average cow produces 7 embryos per flush. From these 7 embryos you could expect to get 4 or 5 pregnancies. She could produce many more than that or none at all. There are many factors that play into viable embryos. The semen quality place a huge roll in the number of fertilized eggs (embryos). Your donor may have some unfertilized eggs. Also some egg cells released from the ovaries may be of inferior quality and even though fertilized they qualify as degenerate and unsuitable for transferring or freezing.
IVF means In Vitro Fertilization. Simply put, the eggs are fertilized in a Petri dish. In Vitro Fertilization starts with oocytes. Oocytes are immature eggs that are taken from the ovaries by going through the uterine wall. The oocytes are incubated for 24 hours, then a technician using a microscope will identify the eggs that are suitable for fertilization, move them to a new petri dish and fertilize them using a few drops of semen from a straw. The eggs are put into an incubator for 7 days then the technician will check the petri dish for fertilized eggs. These fertilized eggs will be graded and those suitable for transferring or freezing will be put into a straw to be transferred or frozen.
A cow for artificial insemination will be at the center no less than 10 days.