Preimplantation Development of Embryos in Labrador Retrievers.
Bibliographic record
Abstract
Canine reproductive physiology is considerably different from other mammalian species. The plasma progesterone concentration of the dog begins to increase a few days before ovulation. Preovulatory luteinization is typical in dogs. The oocytes of dogs are ovulated at the germinal vesicle stage (an immature diploid stage), and they complete meiotic maturation in the oviduct. Thus, canine oocytes and embryos spend a long time prior to implantation in the reproductive tract. Due to these singular reproductive features, the actual situation and mechanisms of early development, such as oocyte maturation, fertilization and subsequent embryogenesis, have not been fully elucidated for canine species compared with many other domestic mammalian species. To understand the timing of preattachment embryogenesis relative to the LH surge, early embryonic development was examined in Labrador Retrievers after artificial insemination. Both male and female Labrador Retrievers from a breeding colony for guide dogs for the blind were used in the present study. The embryo donors were 13 nulliparous animals that were 9-18 months of age and one multiparous animal that was 8 years of age. The day the plasma progesterone concentration exceeded 2 ng/ml was considered the day of the LH surge (day 0). A total of 14 bitches were inseminated by injecting freshly ejaculated semen into the vagina on day 4-6 after the estimated LH surge. On day 9-15 after the LH surge (day 4-10 after insemination), the reproductive tracts of the bitches were excised after ovariohysterectomy at private clinics. The embryos were flushed from the oviduct, isthmus and uterus. The number of ovulated oocytes was estimated by counting the number of corpora lutea present in both ovaries. The embryos migrated from the oviduct to the uterus beginning on day 11 after the LH surge. This transport must be completed within 24 h. By day 13 after the LH surge, all of the embryos had moved and were localized in the uterus. The embryos developed to the morula stage within 11-13 days and to the blastocyst stage within 14 days after the LH surge, respectively. These findings add to the current understanding concerning the physiology of preimplantation development and should help further develop assisted reproductive techniques in canine species, such as cryopreservation and subsequent embryo transfer.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".