222 THE USE OF IN VITRO FERTILIZATION TO STUDY BOVINE IDIOPATHIC INFERTILITY
Notice bibliographique
Résumé
A 4-year-old beef bull underwent a breeding soundness evaluation at the Western College of Veterinary Medicine (Veterinary Hospital, University of Saskatchewan); no apparent abnormalities were observed after conventional semen evaluations. However, the clinical history of this bull indicated that no pregnancies resulted from natural service of 52 cycling cows over a period of 2 years. Completed services were observed. The objective of this study was to use in vitro fertilization (IVF) technology to evaluate whether the sperm from this infertile bull could successfully fertilize oocytes in vitro. Fresh semen was collected with an electroejaculator and frozen in a computer-controlled rate freezer. Concentration and motility parameters were assessed by using computer-assisted semen analyses. Sperm morphology was evaluated on eosin-nigrosin-stained slides, and Coomassie blue staining was used to evaluate the presence of intact acrosomes. Within each evaluation technique, frozen–thawed semen from bulls (n = 2) with proven fertility was used as a positive control and samples of dead sperm (produced by repeated frozen–thawed cycles until reaching no sperm motility) were used as a negative control. Frozen semen from the infertile bull was used for IVF assay. Data were analyzed by ANOVA (sperm motility and the presence of acrosomes) or the chi-square test (cleavage and blastocyst rates), with a P-value of 0.05. Our infertile bull showed an average motile sperm percentage of 91.7 ± 2.2%, with 78.6 ± 3.5% progressive motility. After cryopreservation procedures, frozen–thawed semen had an acceptable general and progressive percentage of motility of 57.8 ± 6.7% and 43.9 ± 9.2%, respectively. Sperm stained with Coomassie blue showed a greater proportion of intact acrosomes in the fresh semen (63.6 ± 4.3% v. 40.4 ± 3.7%; P < 0.05); however, frozen–thawed semen from both the fertile bull and the control were similar (40.4 ± 3.7b% v. 45.5 ± 2.2b%, P < 0.05). In vitro fertilization results revealed a low cleavage rate at 48 h postfertilization (19.8 ± 6.3%) and blastocyst rate (2.4 ± 2.8%) when using frozen–thawed semen from the infertile bull, compared with the control (56.7 ± 8.2% and 26.3 ± 4.5%, respectively; P < 0.001). Moreover, cleavage and blastocyst rates obtained by using the negative control (21.1 ± 3.2% and 1.1 ± 1.9%, respectively) were similar to those of the infertile bull (P > 0.10). It was noted that ova fertilized with either frozen–thawed semen from the infertile bull or the negative control did not produce blastocysts before Days 8 and 9 of embryo culture, which is a characteristic of parthenogenesis. The results from this IVF study suggest that in this bull, there was a missing or defective factor blocking one of the steps in the fertilization process. Further investigations to identify this factor will increase our knowledge of male fertility, and could lead to new methods of evaluating and regulating fertilizing ability.
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 | 0,002 | 0,002 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,001 |
| 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 ».