Dairy producers continue to be challenged to make more with less. When it comes to reproductive efficiency, in vitro embryo production (IVF) is a technology that is here to stay as it significantly reduces the genetic interval and complements the beef on dairy programs that have added a valuable revenue stream. According to the American Embryo Transfer Association, the number of IVF embryo transfers in dairy cattle has grown by five-fold in recent years, growing from 40,000 in 2015 to just shy of 200,000 in 2020. While the adoption curve for IVF has accelerated, the challenge of improving the number of viable embryos per ovum pick up (OPU) session remains. While about 80% of in vitro bovine oocytes undergo fertilization, only 30-40% develop to day 7 blastocyst stage, and only 50% of the transferred embryos establish a pregnancy (Wrenzycki, 2016). This leaves a lot of room for improvement! This article explores the current data on how EPA/DHA omega-3 improves embryo development and how this essential nutrient can be utilized to improve IVF results for both donor and recipient cattle.
RESEARCH SUPPORTING DONOR BENEFITS
EPA/DHA omega-3 is an essential nutrient that is highly involved in many basic biological functions, including embryo development, cell signaling, immune regulation and energy utilization. While the research on its impact as a possible remedy to early embryo loss in dairy cattle was started back in the early 80’s, more recent work has focused on understanding the mechanisms in which EPA/DHA is involved in the embryo development process. This new data has strong implications specifically for improving IVF results, and of course it applies equally as well to developing embryos of conventional pregnancies. Let’s look at a couple recent studies that support the benefits for donor cattle – improving embryo quality, embryo development rate and number of viable embryos per OPU. This first study is an in vitro study performed at the National Institute for Ag Research (INRA) in France where just one micromolar of DHA omega-3 was compared to a control with no omega-3 (Figure 1, Oseikria 2016). This very low level of DHA yielded significant improvements in the day 7 blastocyst growth rate, while a trend was also shown regarding the number of cells per blastocyst. This is one of the first studies to hone in on the impact and essential role that DHA has in those early days of an oocyte’s development.
The second study was a follow-up study from the same lab where researchers performed a feeding study, with EPA/DHA compared to an iso-energetic/iso-lipidic control diet (Figure 2 & 3, Freret 2019). Similar to the in vitro study, the blastocyst growth rate showed a positive trend with EPA/DHA. This study also showed significant improvements (+29%) in the percent of good quality or freezable embryos. One other important finding in the Freret 2019 study was a measurement of the timing of EPA/DHA from the diet being taken up into the plasma and follicular tissue. While levels in the tissue were already elevated compared to control cows at the two week measurement, they continued to climb to a significantly higher level by week five and leveled out by week seven (Figure 4). This quantification of the amount of EPA/DHA transfer to tissues helps answer the question of our ability to deliver these fatty acids to the small intestine even with the challenge of rumen biohydrogenation. This timing of uptake also helps guide our recommendations on how long EPA/DHA needs fed before having significant impacts on embryo development and embryo quality…it is not instant gratification!
RESEARCH SUPPORTING DONOR BENEFITS
While these two recent studies are focused on how EPA/DHA improves results with donor cattle, the base of the research on EPA/DHA over the past 20 years has centered on benefits that are more aptly applied to the recipient cows – improved uterine environment receptivity, improved conception rates and embryo survival, resulting in more pregnancies and more calves. Reductions in pregnancy loss from feeding EPA/DHA have been well established (Santos 2005, Silvestre 2008). These studies compared feeding EPA/DHA to an iso-lipid control diet, resulting in a 50% or more reduction in pregnancy loss between day 32 and 60. Why does EPA/DHA have such a significant impact on reducing pregnancy losses? The answer lies in its innate role in embryo development, coupled by the anti-inflammatory nature of this essential nutrient. As EPA/DHA has direct effects on embryo development…larger embryos release more interferon-tau (IFN-t) which reduces PGF2a spikes, thus helping maintain the corpus luteum/pregnancy. There is also the impact on improving uterine environment receptivity by reducing inflammation, also resulting in lower spikes of PFG2a, thus better pregnancy maintenance.
Whether talking donors or recipients, the feeding rates are the same and vary based off of the body weight of the heifer or cow (Figure 5). For donor animals, Strata with EPA/DHA is ideally fed for 60 days prior to ovum pick-up for maximum benefit (based on Freret 2019). Since these essential fatty acids are stored in the tissue where they can be drawn upon as needed, primarily by the immune and reproductive systems, the rate can be varied based on the length of time available to feed the product. If time on Strata is only 30 days prior to beginning OPU, the feeding rate should be doubled to achieve higher levels of EPA/DHA stored in the reproductive tract more quickly. Expect the number of good quality embryos to improve over the first 12 weeks of implementing the program before plateauing at the higher levels of viable embryos per OPU. For recipients, Strata should be fed ideally for 60 days prior to implantation and extended to 60 days post implantation. If the amount of time on Strata is shortened significantly, then the feeding rate should be doubled to attain the higher levels absorbed in the tissues in that timeframe.
|Heifer/Cow BW, lb.||60-Day Rate
Figure 5. Feeding rates for Strata with EPA/DHA
ECONOMICS OF EPA/DHA
While the science of feeding EPA/DHA for improved IVF is compelling, the math still needs to make sense. Here’s a quick economic example to simply work through the numbers: If the cost of an IVF session is $1100 and the average number of viable embryos per OPU is 4.7 (2021 AETA Annual Report), then the cost per viable embryo is $234. Given the 29% improvement from feeding EPA/DHA (Freret 2019), the number of viable embryos per OPU increases to 6.1, thus lowering the cost per viable embryo to $180. That’s $54 less cost per embryo, or $329 savings on 6.1 embryos) simply from providing the essential nutrients she needs for proper embryo development. The cost to feed 30 grams of Strata to a 1400 lb. donor would be roughly 10 cents per day, totaling $6.34 for the 60 days prior to OPU…a small cost vs. the value of improving the number of viable embryos.
The math for feeding EPA/DHA to recipients is a little to harder quantify given the value that is lost when an IVF pregnancy fails…not only the value of the pregnancy as we measure it in conventional terms, but also the value of the genetics and future impact on the herd. The average loss of a conventional pregnancy is $323 (Cabrera 2014). However, the revenue lost when IVF pregnancies fail is often double or more given the additional cost of the embryo plus greater loss of genetic gain. When feeding Strata to recipients for 60 days prior to implantation, plus 60 days post-implantation, the cost is roughly $12.60 for the 120-day period…a small investment to provide essential nutrients that reduce the loss of valuable embryos. Whether IVF is your focus, or you’re simply striving to improve the health and reproduction on your clients’ dairy herds, EPA/DHA is an essential nutrient that they should not be without. To learn more about how to improve embryo outcomes with EPA/DHA, visit ProtectHerEmbryos.com or reach out to us.