Bovine Model for the Study of Reproductive Aging in Women: Follicular, Luteal, and Endocrine Characteristics1
Bibliographic record
Abstract
At present, there is no well-characterized animal model to study the effects of aging on fertility in women. The objectives of the study were to characterize age-related changes in ovarian and endocrine functions in old cows and to investigate the validity of a bovine model for the study of human reproductive aging. We tested the hypotheses that aging in cattle is associated with 1) elevated concentrations of gonadotropins and reduced concentrations of steroid hormones in systemic circulation and 2) increased recruitment of ovarian follicles during wave emergence. Daily ultrasonography was performed in 13- to 14-yr-old cows (n = 10) and their 1- to 4-yr-old daughters (n = 9) for one interovulatory interval to study ovarian function. Plasma samples were obtained every 12 h for determination of FSH, LH, progesterone, and estradiol concentrations. Circulating FSH concentrations were higher (P = 0.009) during follicular waves in old cows than in their daughters, but the number of 4- to 5-mm follicles recruited into a wave was lower (P = 0.04) in old cows. Plasma LH concentrations did not differ between groups (P = 0.4), but the ovulatory follicle in two-wave cycles was smaller in old cows (P = 0.04). Plasma estradiol concentrations were higher (P = 0.01) in old cows, and luteal phase progesterone tended to be lower (P = 0.1). We conclude that these changes are consistent with those reported for women approaching menopause transition. Therefore, our results validate the use of the bovine model to study reproductive aging in women.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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".