Trends in growth and age at first calving for Holstein and Ayrshire heifers in Quebec
Bibliographic record
Abstract
The objective was to provide an overview of heifer growth in Quebec and analyze its relationship with age at first calving. Heifer body weights, wither heights, body condition scores, and breeding events collected from 1993 to 2003 were obtained and combined with first lactation data, mature body weights, type classification final score and frame/capacity, and estimated breeding values for milk, conformation, frame/capacity, and Lifetime Profit Index. Analyses were restricted to 39 animal-level variables. The resulting data set consisted of 44 989 Holsteins and 2294 Ayrshires with data available for at least one variable. The average age at first calving was 26.5 and 27.1 mo for Holsteins and Ayrshires, respectively. For Holsteins, average daily gains in body weights were 0.79, 0.89, 0.87, and 0.70 kg d -1 for 0 to 4 mo (birth to weaning), 4 to 10 mo (to target onset of puberty), 10 to 14 mo (to first breeding), and 14 mo to pre-calving periods of growth, respectively. Body weights at 14 mo, conception, and post calving were 398, 464, and 601 kg, respectively, and relative to mature body weight were 59, 68 and 89%, respectively. Correlations with age at first calving, corrected for herd and year of birth effects, were positive for body weight at conception (0.69), body weight at first calving (0.31), and number of breedings (0.37), and negative for the average daily gain from conception to post calving (-0.38) and body weight at 14 mo relative to mature body weight (-0.20). For Ayrshires, body weights and average daily gains were lower than for Holsteins, but body weights relative to mature body weight and correlations were generally similar. Holsteins and Ayrshires calved substantially earlier and at a heavier body weight compared with Quebec data from the 1980s. The results of this study suggest that heifer growth may not be a limiting factor in reducing the average age at first calving in Québec. Key words: Dairy cattle, field-recorded data, heifer, growth
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 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 | 0.000 |
| 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".