Body weight optimization of broiler breeder hens. 2. Reproductive performance
Bibliographic record
Abstract
ABSTRACT The objective of this study was to evaluate the effect of shifted gain from the pubertal to prepubertal phase (early growth; EG ) and timing of maximum pubertal growth (inflection point of a second growth phase; I2 ) on BW, feed efficiency, carcass composition, and reproductive performance of broiler breeder hens. Target BW trajectories were designed by changing coefficients of a 3-phase Gompertz model fit to the recommended Ross 308 BW target, B W = ∑ i = 1 i = 3 g i e x p ( − exp ( − b i ( t − I i ) ) ) . In each phase i , biologically relevant coefficients describe the amount of BW gain ( g i ), the rate of growth ( b i ), and the inflection point ( I i ), which is the age (wk) when the growth for that phase is at its peak. The study had a 6 × 2 factorial arrangement of treatments, with six I2 levels ( I from phase 2) and two EG levels. The I2 coefficients were 15, 17, 19, 21 (standard), 22, and 23. The EG treatments were: EG0, where g 1 and g 2 coefficients estimated from the standard breeder recommended BW were unchanged; and EG20, where 20% of the gain ( g 2 ) in phase 2 (pubertal phase) was shifted to phase 1 ( g 1 ; prepubertal phase). Two-hundred-eighty-eight Ross 308 pullets were randomly assigned to the twelve BW growth trajectories and fed using a precision feeding system from 0 to 60 wk of age. Weekly BW was analyzed using three-way ANOVA (EG, I2, and age as fixed sources of variation). Analysis of covariance was conducted on the remaining dependent variables with EG as fixed effect, I2 as a continuous fixed effect, and age as continuous effect. The observed BW followed the BW target trajectories for most of the experiment duration. Dorsal feather score decreased by 0.11/wk of earlier I2. Egg production, egg weight, and egg mass increased by 0.83%, 0.09 g, and 0.54 g/d for every week of earlier I2, respectively. Total eggs produced and estimated chick number per hen increased by 3.6 eggs and 4.4 chicks for every week of earlier I2, respectively. In conclusion, advancing BW gain around the pubertal phase of growth in modern broiler breeders increased egg and chick 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 | 0.000 | 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".