Effect of melengestrol acetate on cyclicity induction in Bos taurus heifers
Notice bibliographique
Résumé
The aim was to compare the effect of progesterone on the estrus pre-synchronization protocol using intravaginal progesterone device (CIDR®, Zoetis, Brazil) or oral melengestrol acetate (MGA®Premix, Zoetis) on induction of estrous cyclicity and vaginal reaction in Bos taurus heifers. Prepubertal heifers (n = 245), Red and Aberdeen Angus, 18 months old and a body condition score of 2.74 ± 0.04 (1-5) were distributed randomly in three presynchronization groups: MGA (n = 84), uCIDR (n = 83) and CONTROL (n = 78). The MGA group was given 2500 mg daily of MGA mixed with mineral salt per heifer for 12 days (from D-26 to D-14). On D-24 a CIDR (previously used for 8 days) was inserted in the uCIDR group, and kept for 12 days (from D-24 to D-12). On D-12 0.6 mg of estradiol cypionate (ECP®, Zoetis) was injected im in MGA and uCIDR groups. CONTROL group was not administered any form of progesterone. On D0 uterus and ovaries were examined by transrectal ultrasound to observe the cyclicity, i.e. presence of corpus luteum. After ultrasound evaluation all heifers were injected with 2 mg of estradiol benzoate im (Gonadiol®, Zoetis) and a CIDR (previously used for 8 days) was inserted. On D7, 12.5mg of dinoprost tromethamine im (Lutalyse®, Zoetis) was given. The CIDR was removed on D9, and 0.6 mg of ECP and 200 IU of equine chorionic gonadotropin (eCG, Novormon®, Zoetis) were injected. The TAI was performed on D11 (48hr CIDR removal), and pregnancy diagnosis was performed on D41 (30 days after TAI). Data was analyzed using Proc Means, Proc Freq and Proc GLIMMIX on the statistical program SAS 9.3. The ciclicity rate after presynchronization was higher for MGA (79.7%, 67/84) and uCIDR (74.7%, 62/83) than CONTROL (7.7%, 6/78) (P < 0.0001). Estrous behavioral after pre-synchronization was higher for MGA (89.2%, 75/84) than uCIDR (78.3%, 65/83) and CONTROL (3.8%, 3/78) (P < 0.0001). Post-synchronization (D9) the number of heifers in heat was higher in MGA (91.6%, 77/84) than uCIDR (74.7%, 62/83) and CONTROL (57.7%, 45/78) (P = 0.0007). At the end of synchronization treatment (D9) more heifers with vaginitis were observed in the uCIDR group (16.9%, 14/83) than the other two groups (MGA = 4.76%, 4/84; CONTROL = 5.1%, 4/78) (P = 0.003). The pregnancy/AI was higher in heifers treated with MGA (69.04%, 58/84; P = 0.002) than uCIDR (50.6%, 42/83) and CONTROL (34.6%, 27/78). Also, the pregnancy rate in the end of the breeding season was higher in heifers treated with MGA (81%, 68/84, P < 0.0001) than uCIDR (67.5%, 56/83) and CONTROL (55.0%, 43/78). In conclusion, the presynchronization treatment with MGA was able to improve the estrous cyclicity and increase pregnancy rate after TAI and in the end of the breeding season in heifers. In addition, treatment with MGA may result in lower vaginitis in heifers than used progesterone intravaginal device.
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 machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| 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) | 0,001 | 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 source (Gemma direct ou Codex distillé), 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 ».