Review: Inhibition of prolactin as a management tool in dairy husbandry
Bibliographic record
Abstract
Accumulating evidence supports that the hormone prolactin (PRL) is galactopoietic in dairy ruminants. Accordingly, the inhibition of PRL secretion by the dopamine agonists quinagolide and cabergoline causes a sharp decline in milk production and could be useful in several critical periods. First, PRL inhibition may reduce the incidence during the periparturient period of metabolic disorders caused by the abrupt increase in energy demand for milk production. Metabolic disturbances can be lessened by reducing milk output by milking once a day or incompletely in the first few days of lactation. The injection of cows with quinagolide for the first 4 days of lactation reduced milk production during the first week of lactation without any residual effects. Blood glucose and calcium concentrations were higher and β-hydroxybutyric acid concentration was lower in the quinagolide-treated cows. Second, PRL inhibition may help sick or injured lactating cows, considering that they can fall into severe negative energy balance when they are unable to consume enough feed to support their milk production. This leads to a weakened immune system and increased susceptibility to diseases. When cows were subjected to feed restriction and were treated with quinagolide, the decrease in milk production was accelerated without any residual effects. The quinagolide-treated cows had higher glucose and lower β-hydroxybutyric acid and non-esterified fatty acid concentrations than the control cows did. Third, PRL inhibition may facilitate drying-off in high-yielding cows, because they are often dried off while still producing significant quantities of milk, which delays mammary involution and increases risk of mastitis. Therefore, strategies that reduce milk production before drying-off and accelerate mammary gland involution could be an important management tool. In this context, inhibition of PRL was utilised to accelerate mammary gland dry-off. Quinagolide decreased milk production within the first day of treatment, and both quinagolide and cabergoline induced more rapid changes in several markers of mammary gland involution after drying-off. In addition, quinagolide improved the animals' resistance to intramammary infection. These results suggest that the inhibition of PRL could be a strategy for facilitating drying-off, reducing metabolic stress during the postpartum period, and alleviating acute nutritional stress during illness without compromising the overall productivity of dairy ruminants.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.002 | 0.001 |
| Bibliometrics | 0.003 | 0.003 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.002 | 0.002 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.002 | 0.002 |
| Insufficient payload (model declined to judge) | 0.008 | 0.003 |
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".