FSH/LH protocol may improve calf LOPU response in Holsteins
Bottom line
A new comparative study suggests that adding luteinizing hormone to follicle-stimulating hormone may improve ovarian response before laparoscopic ovum pick-up, or LOPU, in prepubertal Holstein-Friesian calves. In the study, the FSH/LH regimen produced significantly more ovarian follicles than FSH alone, building on earlier work showing that hormonally stimulated Holstein calves as young as 2 months can undergo minimally invasive LOPU for oocyte collection. That matters because LOPU paired with in vitro embryo production is being explored as a way to shorten the generation interval and accelerate genetic gain in dairy cattle. (researchgate.net)
Why it matters: For veterinary professionals working in bovine reproduction, the study points to a potentially more effective superstimulation protocol in very young donors, where follicle recruitment is a major bottleneck. Prior reviews and calf LOPU studies have shown that outcomes depend heavily on stimulation timing, donor age, and hormone regimen, and that prepubertal calves can respond to gonadotropins despite their immature hypothalamic-pituitary-ovarian axis. If the FSH/LH advantage holds up in larger datasets and translates into better embryo yield, it could influence protocol design for elite donor programs, while also raising practical questions around cost, handling intensity, and welfare oversight in repeated procedures. (researchgate.net)
What to watch: Watch for follow-up data on whether the higher follicle counts with FSH/LH also improve usable oocyte recovery, blastocyst output, pregnancy rates, and repeat-procedure safety in commercial settings. (researchgate.net)
Key facts
- Study type
- Comparative study
- Species
- Prepubertal Holstein-Friesian calves
- Procedure
- Laparoscopic ovum pick-up, or LOPU
- Comparison
- FSH alone versus FSH/LH regimen
- Main finding
- FSH/LH produced significantly more ovarian follicles than FSH alone
- Earlier work
- Hormonally stimulated Holstein calves as young as 2 months can undergo minimally invasive LOPU for oocyte collection
- Potential use
- LOPU with in vitro embryo production is being explored to shorten the generation interval and accelerate genetic gain in dairy cattle
- Limitation
- The article does not report embryo yield, pregnancy rates, or repeat-procedure safety
A new study comparing hormonal superstimulation strategies for laparoscopic ovum pick-up in prepubertal Holstein-Friesian calves found that an FSH/LH regimen generated significantly more ovarian follicles than FSH alone. The finding adds a new layer to a fast-moving area of bovine assisted reproduction, where veterinarians and breeding programs are trying to collect oocytes from genetically valuable calves months before puberty. (researchgate.net)
The broader context is that LOPU in young calves is not new, but protocol optimization remains a major challenge. Earlier published work has shown that Holstein calves between about 2 and 6 months of age can be hormonally stimulated and repeatedly subjected to LOPU, with the goal of producing embryos in vitro and transferring them to adult recipients. Reviews of the field describe this approach as a tool for accelerated genetic gain because it can shorten the generation interval and disseminate elite maternal genetics earlier than conventional breeding allows. (pmc.ncbi.nlm.nih.gov)
What appears to distinguish the new comparison is its focus on adding LH activity to a calf LOPU superstimulation protocol. The available summary indicates this is the first experimental evaluation of a combined FSH/LH product in prepubertal Holstein calves for this purpose, extending ideas that had previously been used more often in adult superovulation programs. According to the indexed text, the FSH/LH protocol produced the strongest ovarian response, while a pure FSH approach delivered more average results, and a single low-dose FSH/LH approach produced the weakest response. (researchgate.net)
That result is biologically plausible in light of what is already known about calf reproductive physiology. Reviews of prepubertal embryo production note that very young calves, especially in the first few months after birth, experience a transient activation of the hypothalamic-pituitary-gonadal axis and have a large pool of recruitable follicles. Other literature has suggested that LH-like activity, including from eCG-containing protocols, may work synergistically with FSH to support follicular development. At the same time, earlier Holstein calf studies found that not every change in gonadotropin schedule improves outcomes, underscoring that more follicles do not automatically mean more competent oocytes or more embryos. (pmc.ncbi.nlm.nih.gov)
Outside commentary specifically on this new paper was limited in accessible sources, but the wider literature is fairly consistent on the strategic value of calf LOPU-IVEP. Reviews describe it as powerful for genetic acceleration, while also emphasizing technical and biological constraints, including variable oocyte competence, the importance of stimulation length, and the possibility of adhesions or bleeding with repeated procedures. One recent review also noted that FSH priming may increase ovarian vascularization, which could have implications for procedural risk even as it improves recruitment. That means protocol refinement is not just about maximizing follicle counts, but about balancing yield, embryo competence, and calf welfare. (pmc.ncbi.nlm.nih.gov)
Why it matters: For veterinary reproduction teams, this study is most relevant as a protocol signal rather than a practice-changing endpoint. More follicles at LOPU may improve the odds of recovering more cumulus-oocyte complexes, but commercial usefulness depends on downstream performance, including maturation, cleavage, blastocyst production, transfer success, and the ability to repeat collections safely. In elite dairy breeding programs, even modest gains in embryo output from very young donors could be meaningful. But field adoption will still hinge on labor demands, hormone availability, procedural expertise, economics, and how programs communicate risks and expectations to pet parents and livestock clients alike. (researchgate.net)
There is also a regulatory and practical backdrop. FDA educational materials note that FSH and LH are central to follicular control in cattle, but real-world synchronization and superstimulation protocols often involve combinations of products and extra-label decision-making that require careful veterinary oversight. Because prepubertal calves are not standard embryo donor candidates, any expansion of these techniques will likely keep veterinarians at the center of protocol selection, animal monitoring, analgesia and surgical planning, and welfare review. (fda.gov)
What to watch: The next key question is whether the FSH/LH advantage in follicle numbers translates into better embryo production efficiency, not just better ovarian response. Watch for full peer-reviewed publication details, larger comparative datasets, and any reporting on repeatability, adhesions, pregnancy outcomes, and cost-benefit performance under commercial dairy breeding conditions. (researchgate.net)