Assisted reproduction techniques in horses – clinical application by different programs around the world
Notice bibliographique
Résumé
Assisted Reproductive Techniques (ARTs) in horses has seen a fast growth in the last few yers. Some of the ARTs which are currently being used in the equine around the world are: embryo transfer, intracytoplasmic sperm injection (ICSI), nuclear transfer, oocyte transfer, preimplantation genetic diagnosis (PGD), embryo cryopreservation and sexed semen. The collection of embryos by uterine flushing followed by embryo transfer is a successful technique which has been widely accepted in many horse breeds and is used in various countries around the world. One of the fastest growing techniques is Intracytoplasmic Sperm Injection (ICSI) in combination with Ovum Pick Up (OPU). In 2016, ten equine reproduction programs around the world included OPU-ICSI in their services. In 2017, five more groups were added to this list. Cloning by Somatic Cell Nuclear Transfer (SCNT) has been successfully used by different groups in Argentina, Brazil, Canada, Colombia, Korea, Italy and United States. Nowadays the cloning industry is mainly centered in South America, in Argentina, Brazil and Colombia, where slaughterhouse ovaries are widely available and the maintenance costs for a large recipient herd are much low, compared to countries from North America or Europe. Oocyte transfer (OT) has been applied by three different clinical programs around the world. After the recent increase of the efficiency of the OPU-ICSI technique, OT is less frequently used. Preimplantation Genetic Diagnosis (PGD) has been mainly used in equine embryos to determine the sex of the embryo. In some breeds, one sex is preferred over the other and by means of PGD, the need to produce pregnancies from the undesired sex can be avoided. Additionally, PGD has also been used to detect specific mutations associated with genetic disorders or genes associated to specific phenotypes as, for example, coat color. Until recently, only small (< 300 m) equine in vivo derived embryos could be cryopreserved. In 2011, the successful vitrification of large embryos (> 300 m) was described for the first time after collapsing the blastocoele cavity before vitrification. Anyway, this technique is not being used in large-scale commercial programs. Although sexed semen by flow cytometry is widely included in cattle production systems, its use in equine programs presents some disadvantages. In September 2017, the preliminary results produced after selection of equine female sperm cells by means of magnetic nanoparticles were reported. These results are extremely encouraging, since the technique is simple, efficient and does not affect sperm viability, even after freezing and thawing. The aim of the present work is to present an update of the use of ARTs in equine reproduction programs around the world.
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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 | 0,005 | 0,002 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,001 | 0,000 |
| Bibliométrie | 0,000 | 0,001 |
| Études des sciences et des technologies | 0,000 | 0,002 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,001 | 0,001 |
| Intégrité de la recherche | 0,000 | 0,001 |
| 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 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 ».