I began keeping computerized records of all my clients since 2002. I always review the flush history of each donor prior to scheduling. This certainly allows me to better manage the appropriate dosing of each donor. I also can duplicate any of your transfer information.

You now have the opportunity to access your records through the web site. I will store each event on the web and you can set up your account to find any information you need. We all know how easy it is to misplace your paper copies left on transfer day! You can now get them on the web.

The average number of transferable embryos per flush is about seven. There are many cows however that produce zero and many cows that will produce more.

This is a common question and like most answers, the number of flushes is variable depending on the individual donor. In most situations, if maximum embryo production is the goal, I recommend a one year flushing cycle for the donors. In other words, if the donor calves in October, she can start flushing in December and can be flushed every 30-45 days through the breeding season. Typically in the Southeast, the heat of Summer then slows down production so that cow can then be flushed again the following Fall season. I then prefer to breed donor back to put her calving in the same season she was removed from. 

Most cows work great in this scenario. Some cows that don’t flush well are recommended to breed back sooner. 

I prefer to keep cows in production. The only time I decide to continue flushing past the year cycle is the old donor or a cow of extreme immediate popularity. I usually tell people if you continue to flush that donor until she will not produce viable embryos, she becomes a poor candidate to ever become pregnant again.

The management of your recip population is the most critical in the success and economics of your program. The days of having a group of cows that you continually use over and over for embryo transfer are hopefully gone! It was normal protocol to have a field of cows for recips that we reused 4-5 times that had many stale, dry cows in the population. The extended dry periods and repeated hormonal protocols for synchronization left us with a field of subfertile cows.

I typically recommend using recips no more than two times. That includes the cows that receive embryos two times as well as the cow that never receives an embryo. If she fails to synchronize twice, she is not an acceptable recip. I believe it is better to get that cow bred and either try her the next season or sell her as a pregnant cow and replace her.

Since the advent of CIDR protocols on donors, the interval between flushes has been drastically reduced. Much work has been done to prove that donors can be successfully flushed on 30 day intervals.

Typically for mature cows in good body condition, they can start the superovulation protocol 45-60 days after calving. This interval needs to be longer (60-75+) for first calf heifers or heavier milking females.

The guidelines for your recip cows will be the same as your donors. Body condition and age still play an important role in the decision.

There is definitely a difference in donor and mating pregnancy rates. There are cows that will consistently produce 70% pregnancy rates and some cows that will struggle to maintain a 50% rate. This variable exemplifies the fact that this business is based on averages but you must have many numbers to have an “average”. Don’t get caught up in the success or lack of success on small numbers.

I am going to describe a situation that has worked very well for some of my clients. The key to the usefulness of this program is accurate heat detection in the recipients. This will not work if you are not able to accurately identify return heats on your recips.

 I schedule flush days every 35-40 days. This allows you time to check for heats in your recips that are used. Most of those heats will be 12-16 days after transfers (19-23 days from heat). The 35 day interval will allow you time to resynchronize those open recips for the next flush in addition to the recips that are not used or are new to the program. This protocol will greatly reduce the time your recips will stay open and give them more opportunities to get pregnant in an acceptable window of time. 

The greatest expense in any ET program is the recips. It is very important to maximize pregnancy rates in your pool of recip cows. This program allows you to produce a higher percentage of ET pregnancies in your herd. 

If heat detection in the recips that have embryos transferred into them is not an option, we can pregnancy check those cows and resynch the open cows on the next cycle. That will still allow you to reuse those recips in a shorter window of time but is obviously not as good as the first plan.

We currently use two primary protocols. When we utilize heat detection programs, we recommend the Select Synch + CIDR (GnRH + CIDR followed in 7 days by CIDR removal + Prostaglandin injection). Recips are then heat detected and time of standing heats are recorded. Only the recips with recorded heats are then checked on transfer day.

We commonly use Fixed Time ET (FTET) Programs now eliminating the need for heat detection. The protocol we use is Co-Synch + CIDR. The protocol is the same as for heat detection except the recips are also given a dose of GnRH (Cystorelin, Factrel, Fertagyl) 48 hours after CIDR removal and Prostaglandin injection. All recips are then brought through the chute on transfer day. Typically, we will use approximately 80% of the recips synchronized.

Again, realize you need to generate many numbers for an actual average to be accurate. Typically, you can expect 60-65% pregnant on fresh embryos and 50-55% on frozen embryos. There will be days you will do better and days you will do worse. Remember, you need to have many transfers before your average is accurate for your situation.

The statistics say that most collections will produce some nonfertile and degenerate embryos. If your donor has an unusually large percentage of these nonviable embryos, we make sure we address the issues that can cause this effect. First variable to evaluate is semen quality. Obviously, high quality semen is essential to the success of ET. However, I do believe semen always gets the blame! Be sure your semen is evaluated preferably prior to using in a flush. Just like donor variability in fertility, there is much variation in the ability of bulls to produce viable embryos. If you have any doubts, especially on semen collected from young, highly conditioned show bulls, have your semen evaluated. Also be sure your semen handling techniques are sound. Consistently check your thermometer to assure accuracy. 

Many other factors affect embryo quality. Stress (hot weather, injury, temperament). Always try to minimize stress in your donors and recips. 

Finally, there is certainly an inherent genetic predisposition in some donors that make them poor candidates for ET programs. All cows do not produce viable embryos.

Donor cows again are treated as individuals. There is much variation in each donor’s response to FSH. There are some donors that will receive 20cc of FSH and some that we only use 6-8cc. This is a trial and error process. Most donors are started on a standard dose and changes are made due to their response.

Commonly, we find donors that will “overstimulate” on a standard schedule. This overstimulation typically means that donor has produced large numbers of ova (25-60+). When this situation occurs, it is very difficult to produce viable embryos due to the levels of hormones created. That donor is then placed on a reduced dose and manipulated to try to optimize her stimulation.