Effects of parity, age at calving and stage of lactation on fatty acid composition of milk in Canadian Holsteins
Bibliographic record
Abstract
Bilal, G., Cue, R. I., Mustafa, A. F. and Hayes, J. F. 2014. Effects of parity, age at calving and stage of lactation on fatty acid composition of milk in Canadian Holsteins. Can. J. Anim. Sci. 94: 401–410. The objectives of the present study were to study the effects of parity, age at calving and stage of lactation on individual fatty acids and fatty acid unsaturation indices in milk of Canadian Holsteins. One morning milk sample was collected from each of 3185 dairy cows between February and June 2010 from 52 commercial herds enrolled in the Quebec Dairy Production Centre of Expertise, Valacta. Individual fatty acid proportions (g 100 g−1 of total fatty acids) were determined for each sample by gas chromatography. Editing for registration status, cow, sire and dam identification, breed, country, age at calving and stage of lactation reduced the data set to 2573 cows representing 46 herds. The statistical model included the fixed effects of parity, age at calving and stage of lactation each nested within parity and random effects of herd-year-season of calving and residual. First-parity cows had relatively higher proportions of beneficial unsaturated fatty acids, from a human health standpoint, and lower proportions of potentially undesirable saturated fatty acids in milk fat as compared with later parity cows. Milk fatty acid profile varied with stage of lactation. The proportions of short- and medium-chain fatty acids (C6:0 to C14:0) were low in the beginning of lactation and increased during the early part of lactation. Long-chain fatty acids (especially C18:0 and oleic acid) and unsaturation indices (C16, C18 and total) showed an opposite trend to that of short- and medium-chain fatty acids. The study showed that parity and lactation stage contribute to variation in bovine milk fat composition.
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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 | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".