Effects of preweaning milk allowance on long-term metabolism in Holstein heifers
Bibliographic record
Abstract
Suboptimal preweaning nutrition of dairy calves has been causally associated with impaired adult metabolic health and lactation performance. However, the biological mechanisms linking early life nutrient supply and future performance remain insufficiently understood. Thus, the objective of this study was to characterize growth, reproductive performance, glucose metabolism, and the metabolic profile of growing heifers fed a restricted (RES) or an elevated (ELE) milk supply preweaning. Heifer calves (n = 86) born from a single herd of ∼120 dairy cows were blocked in pairs by the dam's parity and birth date. Within block, calves were fed an identical colostrum supply and randomly assigned to a milk replacer (MR) allowance level treatment of either 5.41 Mcal of ME in 8 L of MR/d (ELE) or 2.71 Mcal of ME in 4 L of MR/d (RES). The MR (150 g/L), containing 24% crude protein, 18% crude fat, and 45% lactose, was fed from d 2 after birth until calves were stepped down by 50% at d 49 and fully weaned at d 56. All calves were kept in individual hutches until wk 10 and had ad libitum access to fresh pelleted calf starter, chopped wheat straw, and water. Starting from wk 8, heifers from both treatments were fed and managed in the same way, and preweaning treatments were blind to caretakers. Blood samples for metabolomics analysis were collected at 330 d of age, and an insulin-modified intravenous glucose tolerance test was conducted at 370 ± 12 d of age. Heifers fed the ELE diet exhibited higher average daily gain in the preweaning period, leading to higher body weight at 70 d of age (+ 9 kg). At 330 d of age, growth advantages were no longer significant, and preweaning nutrition had no effect on age at first service, first service conception rates, age at conception, or number of services per conception. The metabolomic serum data sampled at 330 d of age revealed that carnitine, glycerolipid, and purine metabolism were predicted to be significantly affected by preweaning nutrient supply, reflecting long-term metabolic programming. At 370 d of age, during the first 20 min following the glucose infusion, blood insulin levels were greater (10.3 ng/mL vs. 7.7 ng/mL), the area under the curve for insulin tended to be greater, and insulin sensitivity was lower in RES heifers. Increasing the amount of MR fed to calves preweaning had a sustained impact on metabolic processes, but long-term differences could not be detected in growth or reproductive performance, potentially due to the low number of animals.
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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 | 0.000 | 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) | 0.001 | 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".