88 Effect of Follicular Ablation and GnRH on Recipient Synchrony in Holstein Heifers
Bibliographic record
Abstract
In Holstein heifer recipients that are synchronized with a single dose of prostaglandin F2a (PGF2a), only 65% (on average) are eligible to receive an IVF embryo 7 ± 1 days after oestrus. The high variability in time to onset of oestrus after PGF2a treatment and the small size of the corpus luteum (CL) on the day of embryo transfer (ET) may explain these results. Synchronizing ovulation might decrease the variability of the interval from treatment to ovulation and maximize the size of the CL. For this purpose, Holstein heifers were randomly allocated (using the lottery method of sampling) to 3 groups: (1) Control (n = 88), a single dose of PGF2a (500 µg of cloprostenol, Merck, Darmstadt, Germany; Day 0) and transrectal ultrasonography of the ovaries on Day 0 to determine the diameter of the largest follicle, on Days 2, 3, 4, and 5 to determine occurrence of ovulation, and on Day 10 to determine presence and diameter of the CL; (2) follicular aspiration (n = 15), ultrasound-guided follicular aspiration (FA) 4 days before PGF2a administration and ovarian evaluation as described above; and (3) FA + GnRH (n = 19), FA at Day –4, gonadotropin-releasing hormone (GnRH, 100 µg of gonadorelin acetate, Vetoquinol USA, Fort Worth, TX, USA) on Day 2, and ovarian examination as described in the control group. Data were analysed by one-way ANOVA and proportions by Chi-squared. The interval (days) from PGF2a treatment to ovulation was not different among groups (3.2 ± 0.4, 3.1 ± 0.2, 3.0 ± 0.1, respectively). However, the variability (residuals) in the FA + GnRH group was the smallest (P < 0.05; high degree of synchrony) in the study (0.1 ± 0.1). Likewise, the FA group (0.5 ± 0.1) had a smaller interval (P < 0.05) compared with the Control group (0.8 ± 0.1). Interestingly, 86% of heifers from FA + GnRH group ovulated in a single day (Day 3; P < 0.05) compared with the FA and Control groups (55% and 53%, respectively). Considering the day of ovulation (only recipients that ovulated 2 to 4 days after PGF2a treatment) and CL diameter (>20 mm; Nogueira et al. 2012 R. Bras. Zootec. 1, 2129-2133; Yoshida et al. 2012 Anim. Sci. J. 83, 207-212), heifers in the FA and FA + GnRH groups had higher proportion (P < 0.05) of animals selected to be transferred at Day 10 compared with the Control group (93%, 95%, and 67%, respectively). In conclusion, FA induced a more synchronous ovulation and increased the number of recipients ready to be transferred at Day 10 (7 ± 1 days after ovulation). These effects were further improved with the administration of GnRH.
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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) | 0.000 | 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".