Collection and Recovery of Embryos

COLLECTION AND RECOVERY OF EMBRYOS

Aim: To demonstrate collection and recovery of embryos from cattle

Materials required: Catheters (Foley PVC catheter) , flushing medium (enriched Phosphate Buffered Saline – EPS), petri dishes, stereozoom microscope

Method:

  • The embryos are collected on day 6 or day 7 when they are late morulas or early blastocysts.
    • The superovulated and inseminated donor cow is suitably restrained first.
    • Caudal epidural anaesthesia is induced.
    • The rectum is evacuated of faeces.
    • The vulva and perineum are thoroughly cleansed and the whole procedure performed as aseptically as possible.
    • The three way Foley PVC catheter (Fig) is inserted into the uterine horns using a speculum and cervical dilator with introducer (Fig).
    • The cuff is inflated to occlude the lumen of the horn of the uterus.
    • 300 ml of flushing medium (enriched Phosphate Buffered Saline – EPS) warmed to body temperature is infused using a syringe on 50 ml aliquots. The flushings are collected in 50-100 ml aliquots. The horn is gently squeezed per rectum to displace embryos.
    • When most of the flushing medium has been collected, the cuff is deflated and the catheter removed. A second, sterile Foley catheter is now inserted into the opposite horn and the procedure repeated.

Recovery of the Embryos

  • The collecting vessels (graduated cylinders) are allowed to stand for 30 min. The majority of the fluid is decanted so that 20-30 ml remains. This is then searched using a round-bottom collection dish and a microscope at a low magnification.
  • Each embryo is carefully aspirated into a Pasteur pipette and transferred into fresh EPS for evaluation.
  • The embryos will be at slightly different stages of development. Evaluation is done on morphological appearance.
  • Embryos remain viable for about 7 h in EPS medium

Questions:
Last modified: Tuesday, 15 May 2012, 8:06 AM