192 THE USE OF FIXED-TIME TECHNIQUES AND eCG TO SYNCHRONIZE RECIPIENTS for FROZEN–THAWED BOVINE IVF EMBRYOS
Bibliographic record
Abstract
Two experiments were designed to investigate the use of eCG in a fixed-time embryo transfer (FTET) protocol for Chinese Yellow crossbred recipients receiving in vitro -produced (IVP) bovine embryos. In Experiment 1, cows were observed for spontaneous estrus (Group 1) or following 500 µg cloprostenol (PGF; Schering-Plough Animal Health, Montreal, Quebec, Canada; Group 2) with nonsurgical embryo transfer 7.5 or 8.0 days later. Cows in Groups 3, 4, and 5 were treated with a CIDR insert (Bioniche Animal Health, Beijing, China), 2 mg estradiol benzoate (EB), and 50 mg progesterone (Sigma-Aldrich, Canada) i.m. on Day 0, PGF on Day 5, CIDR removal on Day 7, and 1 mg EB i.m. 24 h later with nonsurgical transfer of Holstein IVP embryos 8.5 days later, without estrus detection. In addition, cows in Group 3 received no further treatment, whereas cows in Group 4 received 400 IU eCG i.m. (Pregnecol; Bioniche) on Day 5, and cows in Group 5 received eCG on Day 7. Holstein embryos were produced utilizing slaughterhouse ovaries and standard IVF procedures. Expanded blastocysts of quality grade 1 (IETS) were cryopreserved in 10% ethylene glycol and 20% fetal bovine serum using standard procedures. Straws were thawed in a 30°C water bath, and embryos were expelled directly into holding medium and evaluated prior to nonsurgical transfer (NT) ipsilateral to the corpus luteum (CL). Pregnancy was diagnosed ultrasonically 30 d later. Although pregnancy rates, based on numbers of recipients synchronized, numerically favored the administration of eCG on Day 5, there were no significant differences ( P = 0.40) among groups (Group 1: 15.4%, n = 52; Group 2: 20.0%, n = 50; Group 3: 19.2%, n = 99; Group 4: 28.1%, n = 96; Group 5: 21.3%, n = 75). In Experiment 2, Chinese Yellow crossbred cattle were synchronized with a CIDR insert plus estradiol and progesterone on Day 0, PGF on Day 5, CIDR removal on Day 7 and estradiol on Day 8, and were randomly assigned to received no further treatment (Group 1; n = 400) or an injection of 400 IU eCG on Day 5 (Group 2; n = 391). Recipients with a detectable CL received a frozen-thawed IVP Holstein embryo by NT 8.5 days after the second injection of estradiol without estrus detection, as in the first experiment. Pregnancy diagnosis was done ultrasonically 30 days later. Although CL size, cow age, and embryo quality, prior to transfer, were recorded, no effects on pregnancy rates were demonstrated ( P = 0.30). Pregnancy rates, based on recipients receiving embryos, did not differ ( P = 0.5) between groups (Group 1: 21.4%, n = 154; Group 2: 24.5%, n = 290). Overall pregnancy rates (based on the total number of recipients synchronized) were significantly higher ( P < 0.001) in Group 2 (eCG; 18.2%) than in Group 1 (no eCG; 8.3%), because of the significantly higher ( P < 0.03) percentage of recipients used following treatment with eCG (74.2% vs. 38.5%). Results indicate that the administration of eCG on Day 5 of an 8-d synchronization protocol for FTET of frozen-thawed bovine IVP embryos will improve pregnancy rates in beef recipients, especially those of marginal quality.
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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 | 0.000 |
| 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) | 0.002 | 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".