Digital pressure is applied to the sac to extrude its contents. A small puncture is made in the membranes and the vas deferens grasped with fine forceps and dissected away from the accompanying vasculature. The vas deferens is ligated twice using sterile suture, cut between the ligations, and a 1-2 cm segment is excised. Alternatively, a loop is excised from the vas deferens and the cut ends cauterized with the hot tip of a pair of forceps. The procedure is repeated for the other testicle.
Digital palpation is used to replace the contents in the scrotal sac.
Abdominal musculature is closed with sutures. Skin incision is closed with sutures or clips. Male mice should be allowed to recover for one week before being used for mating. Forty-four hours later, the donor females should be injected with 5 IU hCG IP in 0.5 cc saline and mated. Following identification of the copulatory plugs 20-24 hr later, fertile embryos should be harvested at appropriate stages.