TECHNICAL INFO

 
Blastocyst In vitro production of embryos from oocytes collected from calves, cows and lambs involves three steps.  These are the in vitro maturation (IVM), fertilisation (IVF) and culture (IVC) of bovine oocytes through to transferable embryos.
  • In vitro Maturation

When oocytes are collected they are not ready to be fertilised.  They have to undergo both nuclear and cytoplasmic changes before they are ready to fertilise.  This process requires the release of the oocyte from inhibitory substances which surround it in the follicle and exposure to stimulatory substances contained in the maturation media (simulate ovulation hormones).

The quality of the oocytes collected will significantly affect the number of good quality embryos produced.

  • In vitro Fertilisation

The fertilisation process which occurs over a 24 hour period is one of the most important steps in the production of IVF embryos.  Sperm batches must be tested prior to use for freedom of contamination and embryo production performance.  Some batches are unsuitable.  Semen must therefore be supplied several weeks before the date of intended use so that quality control procedures are met.

  • In vitro Culture

Cell division takes place in special media constructed to be similar to that experienced by an in vivo embryo to produce a transferable embryo in 7 days.

  • Oocyte Collection

Oocyte collections can be carried out surgically in juvenile calves aged from 8 weeks to 4 months (JIVET - see below). 

In older calves (aged from 5 - 7 months and older) and in cows, oocyte collection can be done non-surgically using an ultrasound to guide a needle to follicles on the surface of the ovary. 

Ultrasound pick-up from a young heifer >

 

 Oocyte collection can be done by the Animal Reproduction Company or by trained collaborators.  It can be done at a collection centre or in many cases it can be done on your property.

 

Equipment used for ultrasound collection >
  • Infertile Donors

Donors which have been made infertile by embryo transfer procedures or have become infertile due to disease or any other reason can have oocytes collected by ultrasound pick-up and produce offspring using IVF technology.

  • Juvenile IVF Technology (JIVET)

In vitro technology allows the production of offspring from calves as young as 8 weeks of age.  Calves which have a high yield of oocytes at 8 weeks of age can be surgically collected at least three times before going into an ultrasound pick-up program if more offspring are required. 

Surgical collection is performed using the same procedures as embryo transfer in sheep.  A mid ventral incision is made under full anesthesia and the ovaries exposed.  The oocytes are aspirated from the surface of the ovary using a needle and syringe.  

<  Surgical collection of oocytes from the stimulated ovaries of a juvenile donor

Once collected and placed in maturation media, the oocytes can be transported long distances by plane or car to the embryo production laboratory.