FSH/LH protocol may improve follicle yield before calf LOPU: full analysis

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A new cattle reproduction study suggests that adding LH activity to hormonal superstimulation protocols may improve preparation for laparoscopic ovum pick-up in prepubertal Holstein-Friesian calves. According to the study summary, calves treated with an FSH/LH regimen developed significantly more ovarian follicles than those given FSH alone, a result that could strengthen efforts to collect more oocytes from genetically valuable donors before puberty.

That question matters because juvenile embryo technologies have been pursued for years as a way to compress the dairy generation interval. LOPU followed by in vitro embryo production and embryo transfer has been described as a route to faster genetic gain by allowing embryo production from calves as young as 2 to 6 months, well before conventional breeding age. Earlier work from McGill University and Boviteq reported that repeated LOPU in young Holstein calves can yield viable embryos and even healthy live offspring after transfer, but also underscored a persistent challenge: oocytes from prepubertal donors are generally less developmentally competent than those from adult cattle. (pubmed.ncbi.nlm.nih.gov)

Against that backdrop, superstimulation protocol design has become a key area of optimization. Prior studies have tested the timing and composition of gonadotropin regimens before LOPU, including different FSH dosing intervals and the addition of eCG, which has LH-like activity. In one 2018 Theriogenology study in Holstein calves, researchers found no significant difference among protocols in the mean number of follicles aspirated or oocytes recovered, but the FSH-plus-eCG arm produced a higher rate of transferable embryos than one FSH-only schedule. Review authors have suggested that LH activity may work synergistically with FSH to support follicle development in prepubertal donors, where the hypothalamic-pituitary-ovarian axis is still immature. (pubmed.ncbi.nlm.nih.gov)

The new report appears to push that line of inquiry further by directly comparing FSH alone with an FSH/LH combination in prepubertal Holstein-Friesian calves. Based on the available summary, the main signal was a significantly larger follicle population in the combined-treatment group. Without the full manuscript, it’s not yet possible to assess study size, dosing details, oocyte recovery efficiency, embryo development rates, or statistical effects on blastocyst production. Still, the result is biologically plausible in light of prior literature showing that follicle size and endocrine support are closely tied to oocyte competence in juvenile cattle. (mdpi.com)

Expert commentary specific to this new paper was not readily available, but the broader field has been consistent on the opportunity and the limitation. Reviews of prepubertal embryo production in cattle describe the technology as promising for elite genetics and breeding acceleration, while also noting that gains in follicle numbers do not automatically translate into better embryos or pregnancies. In other words, more follicles are useful only if they produce oocytes that can survive in vitro maturation, fertilization, culture, transfer, and gestation at acceptable rates. (mdpi.com)

Why it matters: For bovine veterinarians, theriogenologists, and embryo transfer teams, this study is most relevant as a protocol signal rather than a practice-changing conclusion. If adding LH improves follicular recruitment reliably, it could increase procedure efficiency in calf LOPU programs and help make juvenile donor work more predictable. That could be especially important in high-value dairy breeding programs using genomic selection, where every additional month trimmed from the generation interval has economic value. But veterinary teams will still need data on total oocytes recovered, usable embryo output per session, recipient pregnancy rates, donor safety, repeat-procedure tolerance, drug availability, and cost before changing standard operating procedures. (pubmed.ncbi.nlm.nih.gov)

There’s also a clinical and ethical layer. LOPU in calves is a specialized surgical reproductive technique, and any push toward more intensive juvenile donor programs has to be weighed against anesthesia, handling, repeat intervention, and welfare considerations. Past work has shown the approach can be repeated and can produce transferable embryos, but commercial uptake depends on more than technical success alone. Veterinary professionals will want to see whether the FSH/LH approach improves the whole chain of outcomes, not just ovarian response on the day of aspiration. (pubmed.ncbi.nlm.nih.gov)

What to watch: The next step is the full publication or conference paper with methods and outcome tables, especially data on recovered cumulus-oocyte complexes, blastocyst yield, pregnancy establishment after transfer, and whether any benefit from FSH/LH holds up across repeat LOPU sessions and real-world embryo program economics. (pubmed.ncbi.nlm.nih.gov)