217 LUTEAL REGRESSION AND FOLLICLE DEVELOPMENT FOLLOWING PROSTAGLANDIN-F2a TREATMENT 3 DAYS AFTER OVULATION IN MARES
Notice bibliographique
Résumé
The corpus luteum (CL) is responsive to exogenous prostaglandin-F2a (PGF) 1 to 2 days after ovulation in the mare (Troedsson et al. 2001 Theriogenology 55, 1891–1899); however, complete and sustained demise of the CL beginning less than 5 days after ovulation in response to PGF treatment has not been documented. The present study was designed to compare the morphological and physiological response of the primary CL to PGF given at early diestrus with a more conventional treatment given at about mid-cycle. In addition, follicle status pre- and post-treatment were examined and compared between the treatment groups. On the day of pretreatment ovulation (Day 0), riding-type horse mares were randomly assigned to receive a single dose of PGF (Lutalyse, Upjohn, Kalamazoo, MI, USA;; 10 mg/mare, i.m.) on Day 3 (n = 17) or Day 10 (n = 17). Beginning on either Days 3 or 10, transrectal ultrasonography was used to determine follicle and CL diameters, determine luteal tissue gray-scale scores (echogenicity), and to detect ovulation. Follicular and luteal measurements and jugular blood samples were collected daily until the post-treatment ovulation. Structural and functional regression of the CL was indicated by: 1) a progressive decrease (day effect;; P < 0.0001) in mean diameter of the CL beginning 24 h after PGF treatment in the Day 3 and Day 10 groups;; 2) a precipitous decrease (P < 0.009) in mean plasma progesterone concentrations within 24 h in both groups followed by a more gradual decline to basal concentrations by the second day in the Day 10 group or after the fourth day in the Day 3 group;; and 3) an increase (P < 0.02) in mean luteal tissue echogenicity in both groups after the second day following PGF treatment. The mean intervals from PGF treatment to ovulation were not different (P > 0.2) between groups (combined, 9.9 days) but the mean (±SEM) interovulatory interval was shorter (P < 0.0001) in the Day 3 group (13.2 ± 0.9 days;; range, 7 to 20 days) than in the Day 10 group (19.2 ± 0.7 days;; range, 14 to 26 days). The greater the diameter of the largest follicle at the time of PGF treatment, the shorter the interval to post-treatment ovulation in the Day 3 (r = -0.57, P < 0.02) and Day 10 (r = -0.74, P < 0.001) groups. Growth rates of the preovulatory follicles were similar (P > 0.59) between groups (combined, 3.6 mm/day) but the maximum diameter was smaller (P < 0.05) in the Day 3 group (40.5 ± 1.2 mm) compared to the Day 10 group (43.4 ± 0.8 mm). Unexpectedly, more (P < 0.03) double ovulations occurred in the Day 3 group (6/17, 35%) than in the Day 10 group (1/17, 6%). In conclusion, an immature CL at early diestrus responded to PGF treatment in a manner comparable to a mature CL at mid-cycle. The Day 3 group ovulated an average of 6 days earlier than the Day 10 group as a result of the difference in timing of the PGF treatment between groups. Thus, these results warrant a reassessment of the prevailing concept that the equine CL is resistant to PGF-induced regression before 5 days after ovulation, especially when considering the potential benefits of a shortened interovulatory interval and an increased double ovulation rate.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».