Producers are meticulous about how to accelerate their herd, and they heavily strategize mating decisions based on many elements, including EPDs, feed-efficiency databases, genomics, and years of production history. They also study donors and select sires with traits that can help to rapidly advance the rest of the herd. Donors can range in age from a first-calf heifer to a 13-year-old proven dam, but no matter the age, producers try to replicate their top donors across the entire herd for maximum results.
In natural breeding scenarios, cows typically only have one calf a year, and then return a few daughters to the herd throughout their lifetime. Fortunately, technology is readily available today to help guide and expedite the mating decisions made by producers across the board with bovine in vitro fertilization.
Since the 1980s, embryo technology has been available. The process used today has evolved immensely, however, and is much easier to implement now than it was before. In vitro fertilization technology, more commonly known as IVF, allows cows to make embryos while they remain in the breeding herd and calve on a regular interval.
Embryos produced by In vitro fertilization have taken off since 2010, surpassing in vivo derived (conventional) embryos since 2016. With such a growing popularity, producers may be wondering how their operation can get started making IVF embryos.
To determine which females in your operation have risen to the top, take plenty of time to pour over phenotype, genomic, and performance data. Because in vitro fertilization is so flexible, females that are open, 15 days postpartum, or less than 100 days into gestation all qualify to be donors. Additionally, female donors can range in age from yearling heifers to senior dams. Females can also qualify as donors if they are prepubertal, bred, or in anestrus, unlike conventional embryo transfer.
Ovum Pick Up
After donors have been selected, the in vitro fertilization process begins with ovum pick up (OPU). The OPU technician starts by palpating the ovary rectally, and then aligning the ovary with the ultrasound-guided needle assembly. This process collects immature oocytes from follicles that are on the donor’s ovaries. Every follicle should contain one immature oocyte, which will then be aspirated.
Even during pregnancy, anestrus, and before puberty, follicles always grow on the ovaries. These fluid-filled follicles eventually grow into follicular waves and are recruited out of the follicular pool.
Depending on the gonadotropin secretion, they will then grow from small to medium to large.
It takes less than 15 minutes for the OPU technician to complete this non-surgical procedure where small, medium, and large follicles are all collected off both ovaries. The best oocytes are identified after collection and then sent to the lab within 24 hours for fertilization. Embryo production is complete seven days after fertilization.
Bovine in vitro fertilization will not disturb a donor’s normal estrous cycle. The flexibility of in vitro fertilization allows producers to tailor their collections for each donor based on total embryo goals, as well as breeding plans for the whole herd and the individual donor.
“Minimizing stress post breeding is essential to maintaining any pregnancy. The OPU process is safe for pregnant donors up to 100 days of pregnancy,” says Nathan Schmidt, the Reproductive Director for Vytelle. “We work with the producer to maintain their donors’ natural reproductive cycles while replicating their elite genetics through hormone-free in vitro fertilization.”
OPU collections can be performed at:
- Up to 100 days pregnant on pregnant donors
- As early as 15 days post-calving for heifers and open cows
Producers who strategize with their OPU team can develop an efficient timeline of these types of collections around breeding. The OPU team will guide you to successfully accelerate your elite genetics.
Developing a Plan
When designing embryo programs, producers should ask themselves these questions, as well as review strategies with the OPU team to see how they can help you to reach your goals.
- What is your timeline for making embryos?
- How many embryos are you looking to produce?
- When do you want your donor(s) bred?
- Are you trying to maximize rare semen?
Maximize Total Annual Embryo Production
For producers looking to make as many embryos as possible in one year, OPU collections should begin as soon as 15 days postpartum, and then continue bi-monthly through 100 gestation days. Your donors can be prepared for breeding during this timeframe without needing to take a break from collecting oocytes. Particulars in this setup should be discussed in detail with the OPU veterinarian; that way, they will leave dominant follicular structures on the ovaries that suit synchronization protocols and the producer’s breeding timeline.
Getting Donors Bred
For producers with the top priority of getting the donor re-bred, she can be collected from 15 to 60 days postpartum and then take a break for breeding. Despite the fetus not being fully attached to the placenta until day 40, pregnancy checks can begin as soon as 28 days post-breeding. After the donor is checked safe in calf on day 40, ovum pick up can be resumed if more embryos are desired, through 100 days of pregnancy.
Maximize Embryos Per Collection and/or Rare Semen
For producers trying to maximize embryos per collection, or trying to maximize rare semen with a certain donor pool, it’s best to wait until the donor has a first heat post-calving. This ensures that the donor has resumed her regular cyclicity and has reached optimal hormone levels, which can occur anytime between 30 to 60 days postpartum.
A single semen unit can be used efficiently on multiple donors during IVF if they are collected on the same day. To ensure a successful collection and ideal fertilization timing, producers should discuss donor matings and order of priority with their OPU team.
Progesterone devices can be used to synchronize the donors to a producer’s whole herd breeding program. This should occur after the OPU to complete a synchronization protocol, but before the next collection.
Other IVF Applications
Even as frozen genetic sales are continually increasing annually, it’s best to remember that bovine in vitro fertilization can be used on a variety of donors unable to breed. For example, donors that cannot carry their own calf—possibly due to a previous injury or other reason—can still undergo in vitro fertilization. In addition, females who are prepubertal and carry the newest genetics can also be aspirated as soon as palpation is possible.
This hormone-free, advance reproductive technology is an exciting option for embryo transfer on young females—even before they have their first natural calf. This new technology allows genetic replication without ever hindering the natural reproductive and breeding processes.
Overall, producers with goals to advance genetics throughout the herd with embryo transfer will find that IVF works extremely well to keep donors in the breeding herd. The IVF process is simple, with no set up or shots required, and it can be done on open heifers or donors, up to 100 days pregnant. Producers should keep in vitro fertilization during donor pregnancy in mind as they are thinking of new ways to accelerate genetic progress on their operation.