Effect of day length on cause of mortality, leg health, and ocular health in broilers
Bibliographic record
Abstract
An experiment was conducted to study the effect of day length, sex, and genotype (Ross × Ross 308 and 708) on mortality causes, bird mobility, footpad health, and ocular size, with 4 trials within the experiment. Four graded day lengths were chosen to allow the study of relationship between day length and health parameters, including 14L:10D, 17L:7D, 20L:4D, and 23L:1D. The primary statistical tools used to assess the day length relationships were regression analysis (Proc Reg and RSReg of SAS). Data were also analyzed as a 4 (lighting program) × 2 (sex) × 2 (genotype) factorial arrangement. Total mortality, as well as mortality due to metabolic and skeletal disease, decreased linearly with increasing inclusion of darkness (7- to 32-, 7- to 38-, and 7- to 48-d periods). Infectious disorders were quadratically related to day length (7- to 48-d period only), with birds under 20L having the highest level. Day length was linearly or quadratically related to average gait score in a positive fashion, and the incidence of birds falling in painful gait score categories increased linearly with increasing day length. Average footpad lesion scores increased with increasing day length (28 and 35 d). The 23L photoperiod resulted in heavier eye weights than other lighting programs. Males had a higher mortality and morbidity rate and a higher average gait score than females. Average footpad score was lower for males than females (28 and 35 d). Overall mortality was higher for 308 than 708 broilers; hence, levels of specific mortality causes were higher. Average gait scores were lower for 308 than 708 birds in 2 of the 3 time periods measured and footpad lesions were higher. To conclude, many aspects of broiler health improve with decreasing day length.
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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 | 0.000 |
| 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) | 0.000 | 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".