1065 Effects of modification of proestrus length and duration of progesterone exposure on automated measurements of estrous expression in lactating Holstein cows
Bibliographic record
Abstract
Objectives were to investigate if longer proestrus, via longer exposure to pre-ovulatory estradiol concentrations, would induce behavioral estrus of greater intensity, and to investigate if longer exposure to progesterone would offset possible effects of shorter proestrus on estrous behavior. Three treatments consisting of different intervals between GnRH-PGF (5 or 7 d) and PGF-ECP (1 or 3 d) on a Heatsynch program were applied to lactating Holstein cows (n = 48). All cows were fitted with three activity monitors (Heatime, SmartDairy, and AfiActII) and enrolled into pre-synchronization at 40 ± 3 DIM, followed by random allocation to treatments at 57 ± 3 DIM. Treatments were 5d3d (GnRH-5d-PGF-3d-ECP), 5d1d (GnRH-5d-PGF-1d-ECP), and 7d1d (GnRH-7d-PGF-1d-ECP). The AI was performed at a fixed time 48 h after ECP, except for those detected in high activity before timed-AI. Ovarian ultrasonography and blood samples were performed at injection days, day of AI, and 2, 5, and 7 d after timed-AI. Rates of estrous detection, ovulation (until 84 h after ECP) and presence of CL 7 d after timed-AI were not different among treatments (P > 0.05). Although the goal of 5d3d was to increase proestrus length, 6 of the 10 cows that showed high activity in this treatment did so before or at the day of ECP. Consequently, proestrus length was not different among treatments (3.0 ± 0.2, 3.2 ± 0.2, and 2.7 ± 0.2 d, for 5d1d, 5d3d, and 7d1d, respectively; P > 0.05). Pre-ovulatory follicle diameter was not significantly different among treatments and was 20.9 ± 0.7 mm (multiparous) and 19.2 ± 0.9 mm (primiparous). Odds of estrous expression were not influenced by parity, BCS, or progesterone concentration and follicle diameter at the PGF injection. Parity and BCS were the factors most frequently associated with measurements of estrus. Cows in 5d1d had estrus of greater duration (Heatime) than 7d1d (13.9 ± 0.9 vs. 11.1 ± 0.9 h; P = 0.04), whereas intensity of estrus (AfiActII) was greater for 5d3d cows (377.3 ± 43.0; P = 0.04) and tended to be greater for 7d1d (350.8 ± 41.3; P = 0.09), both in comparison with 5d1d (243.3 ± 45.8). Although estrous detection rate and proestrus length were not different among treatments, the use of a Heatsynch program with different GnRH-PGF or PGF-ECP intervals was capable of altering duration and intensity of estrus, likely due to changes in the endocrine profile during the estrous cycle.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 |
| 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) | 0.001 | 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".