Assisted reproduction techniques in horses – clinical application by different programs around the world
Bibliographic record
Abstract
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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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.005 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.002 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
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 teacher head, 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".