1063 The characterization of estradiol concentration before insemination and its effect on fertility in dairy cattle
Bibliographic record
Abstract
The objectives of this study were to: (1) characterize variations in plasma concentrations of estradiol (E2) within a population of dairy cows, and (2) determine associations between E2 categories, LH, ovulatory response, first service conception rate, number of services and days open. Lactating Holstein cows (35 primiparous, 65 multiparous) received one injection of PGF2α (cloprostenol, 500 µg, d 0) followed by GnRH (gonadorelin, 100 µg, d 3; Presynch) and were subjected to an Ovsynch protocol starting on d 10, with timed-AI (TAI) occurring at ∼75 d postpartum. Blood samples were collected immediately before (0h) and 2h after the second GnRH of Ovsynch to determine plasma E2 and LH concentrations, respectively. Cows were ranked based on plasma E2 concentrations, from highest to lowest, and those in the top (n = 33) and bottom (n = 33) thirds were classified into HIGH- and LOW-E2 categories. The continuous variables were analyzed using MIXED procedure of SAS and the binomial data were modeled against E2 categories and parity and analyzed using the GLIMMIX procedure of SAS. Plasma E2 concentrations (pg/mL) ranged from 0.1 to 9.2 (CV 78.7%) with an overall mean ( ± SEM) of 2.0 ± 0.1. The plasma E2 was greater for cows in HIGH-E2 category than those in LOW-E2 category (3.7 ± 0.2 vs. 0.5 ± 0.2 pg/mL; P < 0.01). Similarly, cows in the HIGH-E2 category had greater concentrations of plasma LH than cows in the LOW-E2 category (13.5 ± 1.0 vs. 5.9 ± .1.0 ng/mL; P < 0.01). The categories of E2 did not influence ovulatory response to the second GnRH of the Ovsynch (P < 0.05). The first service conception rate tended to be greater for cows in HIGH-E2 category than those in LOW-E2 category (44.1 vs. 24.2; P = 0.10). Further, cows in the HIGH-E2 category had a tendency for fewer number of services (2.2 ± 0.2 vs. 2.7 ± 0.2; P = 0.10) and lesser days open (138.6 ± 11.6 vs. 171.5 ± 11.7 d; P = 0.06) than cows in LOW-E2 category. Parity did not influence plasma concentrations of E2 and LH, ovulatory response to the second GnRH of Ovsynch, number of services or days open (P > 0.05). However, primiparous cows tended to have greater first service conception rate than multiparous cows (50.0 vs. 25.6%; P = 0.06). In summary, plasma E2 concentrations were highly variable in a tested population of dairy cows and cows in the HIGH-E2 category had a tendency for greater first service conception rate and fewer number of services and lesser days open.
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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 | 0.001 |
| 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".