Ovum Pick Up (OPU)
OPU, also known as oocyte collection, is the process where oocytes (eggs) are aspirated from the mares ovary. Our reproductive specialists perform OPU from donor mares via ultrasound guided trans-vaginal aspiration under either standing sedation or epidural anaesthesia. Any oocytes obtained following the procedure are shipped overnight via special delivery to Avantea for oocyte maturation, ICSI and embryo development.
ICSI – Intra-Cytoplasmic Sperm Injection
This is a procedure whereby a single sperm is injected through the outer surface of a mature oocyte. If the oocyte is successfully fertilised by the sperm, an early embryo (blastocyst) will develop. Following ICSI, early embryos are cultured in special laboratory conditions for 7-9 days, by which time they are equivalent to a ‘normal’ 4-5 day embryo. These embryos are still very small at this stage and therefore can be successfully frozen, stored and subsequently transported at the desired time for embryo transfer into a suitable recipient mare.
What are the success rates?
Success rates are variable with this procedure and are limited by the number of follicles available for aspiration at the time of the procedure. If a mare has 16 or more follicles suitable for aspiration, we would hope for a 50% oocyte recovery rate, if at least 6 of those oocytes go on to mature, we would anticipate producing an embryo 67% of the time, but this is by no means guaranteed.
To avoid disappointment, we recommend a minimum of 10 suitable follicles (between both ovaries) and will scan your mare the week prior to the procedure to ensure that she is a suitable candidate. If your mare has inadequate numbers of follicles, we may suggest postponing the procedure until she has further follicular growth but we will discuss this with you at the time.
What are the risks?
Whilst we will take every precaution to ensure the safety of your mare, there is an associated risk with both rectal examination and trans-vaginal aspiration. A percentage of mares develop a mild fever and slight discomfort following OPU. Your mare will receive a prophylactic dose of anti-inflammatories and antibiotics prior to the procedure and may be required to stay in hospital overnight for monitoring.
Should you have any further questions about the above procedures, please do not hesitate to contact Camilla Scott, RCVS Recognised Specialist in Veterinary Reproduction (Equine) at Rossdales, by email to camilla.scott@rossdales.com
Laboratory Support
Our BEVA-approved laboratory provides PCR testing for Contagious Equine Metritis (CEM) screening and for a range of other infections, including Klebsiella pneumoniae, Pseudomonas aeruginosa, Streptococcus equi (strangles), Rhodococcus equi (summer pneumonia), Lawsonia intracellularis (proliferative enteritis) and Equine Herpesviruses 1 and 4.
We additionally examine aborted equine foetuses and their placentas for EHV-1 screening and the wider diagnosis of cause of abortion. Blood samples can be examined for accurate foal IgG analysis and for all other reasons, involving haematological, biochemical, endocrinological and serological tests, including specific R. equi and S. equi antibody assays.
See our comprehensive range of laboratory tests here