Superovulation

EMBRYO TRANSFER IN CATTLE

Aim : To demonstrate the superovulation technique in cattle

Materials required : Super ovulatory hormones - PMSG/ hMG/ Porcine pituitary hormone/equine pituitary hormone/bFSH 

Method

Preparation and Superovulation of the donor

  • The donor is either observed for the signs of oestrus and the date recorded (schedule A) or given two injections of PGF2 a 11 days apart (PG1 and PG2) (schedule B). It is assumed that oestrus will occur 2-3 days after PG2 (Fig). It should be detected and recorded.
  • A superovulatory dose of porcine FSH is injected on three separate days, 9-13 days after observed oestrus (Schedule A) or 12-16 days after PG2 (Schedule B). If PMSG is used, a single injection only is given.
  • Forty-eight hours after the first FSH (or single PMSG) injection, PGI (Schedule A) or PG3 (Schedule B) should be given. The donor should be in oestrous 2 days later; it should be observed and recorded.
  • The donor should be inseminated during oestrus with a repeat 12 h later.
  • Embryos are flushed 7-8 days after the first AI.

Preparation of Recipients

  • For the best results, the oestrous cycles of recipients should be accurately synchronized with that of the donor. At least twelve recipients per donor should be available if provision for freezing embryo is not available.
    • If schedule A is used for the donor, then the recipients are injected with PG1 on day 0 with PG2 10 days later.
    • If schedule B is used for the donor then each recipient has PG1 on day 2, PG2 on day 13 and PG3 on day 24 (16-24 h before the donor receives PG3).
    • Oestrus should be observed on days 12, 13 and 14 (schedule A) or 26, 27 and 28 (schedule B) and recorded. Recipients receive embryos on day 20 (schedule A) or 34 (schedule B).

Questions:
Last modified: Wednesday, 20 June 2012, 6:22 AM