Effects of Age at Photostimulation on Reproductive Efficiency in Three Strains of Broiler Breeders Varying in Breast Yield
Bibliographic record
Abstract
As genetic selection for growth and BW in meat-type stock continues, the age at which photostimulation occurs needs to be increased. This trial studied the relationship between age at photostimulation and egg production and egg weight. Three strains of female broiler breeders varying in potential breast muscle yields were subjected to photostimulation at two ages, 20 versus 23 wk of age. Sexual maturity, egg weight, egg production, and carcass characteristics were assessed. Hens photostimulated at 23 wk of age weighed more and were older at sexual maturity than hens photostimulated at 20 wk of age. However, the reproductive response to the lighting cue was faster among hens photostimulated at 23 versus 20 wk of age. All three strains responded similarly to both photostimulation treatments. Hens photostimulated at 23 wk of age laid larger eggs throughout the entire production cycle, but the number of small eggs was not reduced. Overall, egg production was not affected by strain or treatment. Breast muscle weight was heavier for hens of an experimental line selected for breast muscle yield (EXP) than for hens selected for high egg production (Classic) or for a slow-feathering strain selected for egg production and moderate breast muscle yield (FSY) hens at 53 wk of age. Delay of photostimulation by 3 wk was effective, as hens on this treatment matured faster and had increased egg weights throughout lay, without experiencing a decrease in egg production.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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 | 0.001 |
| 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) | 0.000 | 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 teacher head, 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".