Effect of dietary palmitic acid supplementation and milking frequency: 1. Milk production and composition in early-lactation dairy cows
Bibliographic record
Abstract
Dietary palmitic acid (PA) supplementation can be used to increase milk fat yield by dairy cows. Additionally, increasing milking frequency (MF) promotes milk production. Both practices are of interest to enhance milk performance, but their effects on milk properties are a concern from a milk processing perspective. Moreover, little is known regarding the possible interaction between those 2 practices on milk performance. This study aimed to evaluate whether milk responses of early-lactation dairy cows could benefit from the combined effects of PA supplementation and increased MF. Additionally, we determined the effects of the 2 practices on milk free fatty acids (FFA) content, milk protein fractions such as CN and whey proteins, and plasmin activity in milk. Eight early-lactation multiparous Holstein cows were randomly allocated to treatment sequences in a replicated 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments. Levels of treatments were dietary PA (0% or 2% on a DM basis) and 2 or 3 milkings per day at equal intervals of time. Periods lasted 21 d with 16 d for treatment adaptation before data and sample collection. Except for lactose concentration, no significant interaction between MF and PA supplementation was observed. Dry matter intake was not affected by treatment. Increased MF and PA supplementation both increased milk, fat, and protein yields, as well as milk efficiency. Palmitic acid supplementation increased the yield of 16 C fatty acids (FA) in milk at the expense of shorter de novo FA. Calculated desaturase indexes increased with PA, indicating an increased Δ 9 -desaturase activity or expression. In contrast, most desaturase indexes decreased with MF. Dry matter and NDF digestibilities were similar between treatments. However, PA decreased total and 16 C FA digestibilities. Transfer of 16 C FA into milk was increased with PA supplementation. Neither MF nor PA had an effect on FFA concentration in fresh milk. Milk concentrations of total N, true protein, CN, or whey proteins were similar between treatments. However, even if milk CP yield was increased by both PA and thrice-daily milking, CN yield was not affected by PA and only tended to be increased by thrice-daily milking. The effects of PA supplementation and MF on milk performance were additive. Under the conditions of this trial, increased MF and PA supplementation did not impair milk composition parameters of importance for milk processing.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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".