Bruno Sanches, DVM, Ph.D., VP of Operations – Vytelle
In vitro fertilization (IVF) leads the way regarding efficiency of quick genetic improvement, especially as farmers aim to accelerate the genetic selection in cattle, moreover, their herds. This technology allows producers to capitalize on the best genetics in their herd, thereby shortening generation intervals, without disrupting the herd’s reproduction program.
Instead of continually milking the same cow, IVF allows for differentiation in a herd, but eliminates the need to liquidate and start over. Put more simply, one positive IVF mating can monumentally progress genetics for an average milking shed.
Shortening Generation Intervals
Artificial insemination (A.I.) was adopted decades ago by the dairy industry to increase the number of sire decedents with elite genetic merit. More recently, the generation interval—that is, the measure of how quickly superior genetics are propagated into the next generation—can be condensed due to the association of genomics and sexed semen. Using genetic selection in cattle allows the genetics of young females to be valued and evaluated prior to joining the milking herd.
Nowadays, the generation interval has been tightened further by in vitro fertilization technology. For heifers who are six months and up, or for cows up to 100 days pregnant, IVF brings new genetics from these types of dairy cattle into a herd in just one generation. Because of this, a cow may have several offspring from multiple sires in the same amount of time it would take to produce one calf through A.I. or natural breeding processes.
Embryo transfer and IVF technology allow for producers to make the same genetic progress in one generation that would traditionally take five generations when using A.I. or natural breeding. Superior individuals from both sides (sire and dam) can be used to contribute to the next generation’s genetic improvement.
A More Natural Approach
Using hormone-free IVF technology means that no shots are ever needed to prepare donors for aspiration. Oocyte collection is always performed with no follicle stimulating hormones (FSH). This makes the collection process less labor intensive and easier on animals, while also eliminating any costs associated with using FSH.
Follicular development begins when cattle are two weeks old, and cattle continually grow and regress these follicles on the ovary throughout their entire lives. This is different from conventional embryo production (MOET), which only occurs once females reach puberty. Hormone-free in vitro fertilization is a more natural process that allows ovum pick-up (OPU) to occur as soon as a veterinarian can palpate the ovaries of a heifer. This is usually done as young as six months old.
Part of the OPU process is viewing a young heifer’s ovaries and follicles with an ultrasound device. Trained veterinary reproductive specialists use the ultrasound device and a needle to aspirate the follicles. Afterward, oocytes are collected, cleaned, and fertilized to the sire(s) of choice using pre-sorted or conventional semen. This creates embryos that are then transferred into recipient females.
A new follicular wave is naturally available for OPU every six to ten days. Because of this, oocytes from heifers can be collected weekly through the second trimester of gestation. Collection for cows can begin 15 days post-calving and last through the second trimester.
Even though hormone-free IVF makes it easier on donors and producers, no technology is bulletproof when attempting to overcome reproductive management issues during genetic selection in cattle. For IVF to be the most effective, producers must do the following:
- Ensure both nutrition programs and herd health are promoting low embryonic loss and good conception rates
- Pay attention to proper vaccination requirements and processes
- Perform proper training of all personnel involved in reproduction programs
- Use essential calving management protocols
By addressing these basics, producers will be able to enhance the maximum potential of IVF.
Capitalizing on the Best Genetics
During genetic selection in cattle, breeders can capitalize on and quickly reproduce genetics that suit the needs of their operations. Producers can quickly identify and select animals based on desired performance traits by using decision-support tools that are driven by genomic evaluations and advanced analytic engines.
A producer’s ability to use genomic data, paired with the use of in vitro fertilization technology on heifers as young as six months old, can lead to a rapid increase in genetic gain. Elite-performing females can be selected far earlier, allowing producers to avoid any delays associated with evaluating offspring performance and gathering phenotypical measures.
Using the youngest females in the herd as donors will greatly optimize the herd’s potential. This creates a much more sustainable population with higher genetic performance cattle.
Expected Results
IVF technology has dramatically evolved in the past 15 years due to recipient management, advanced embryo media formulations, and synchronization protocols.
A recent study was completed by Teagasc, the Agriculture and Food Development Authority. This organization is known for providing integrated research, advisory, and training services to the agriculture and food industries, as well as rural communities in Ireland. During this study, hormone-free OPU technology was used to produce embryos from 40 elite dairy dams (Crew, et al 2021). A parallel beef embryo study was conducted using the same design.
During the study, pregnancy rates of 1,200 lactating dairy cows in nine herds were evaluated, and a standard ten-day Progesterone-Ovsynch protocol was used to synchronize the cows. Once they reached estrus, 20% of the cows were bred using A.I., while the remaining 80% received an embryo seven days later. Fifty percent of the cows receiving embryos received a fresh IVF embryo while the other 50% received a frozen one.
Pregnancy rates were collected on day 32 after synchronized estrus, and they quickly demonstrated that fresh IVF embryos beat the rate of A.I. conception. This is demonstrated by the following study results:
- A.I. Breeding: 43.8% of the cows were pregnant
- Fresh IVF Embryo Breeding: 61.1% of the cows were pregnant
- Frozen Embryo Breeding: 40.1% of the cows were pregnant
The results of this study demonstrate how using fresh IVF embryos allows for higher conception rates in herds when comparing to conventional A.I. However, IVF embryo pregnancy rate results as a whole—both fresh and frozen combined—were actually comparable to that of A.I. pregnancy rates.
The availability of cutting-edge, hormone-free IVF technology today allows producers to successfully and confidently use early-identified, elite-performing genetics sooner. This allows young dairy females to contribute to the genetic pool of the herd a lot earlier, while still maintaining their fertility for breeding opportunities in the future.