Understanding In-Vitro Fertilisation (IVF)

In-Vitro embyro production, colloquially known as IVF, is an embryo recovery technique.

IVF differs from conventional MOET embryo recovery. Both techniques have their advantages and disadvantages, but both are potent tools in advanced bovine reproduction.

IVF involves the recovery of immature oocytes directly from the ovaries of cows using ultrasound guided needle aspiration. The small needle is placed into follicles where the oocyte is located, while suction is applied to recover the oocyte from the follicle.
A cow has approximately 350,000 follicles at birth, which continually become recruited during their life.

Oocytes recovery rates range from 0-100+, depending on many factors including age, breed and genetics. Quality of oocytes recovered depends on age, breed, genetics, nutrition, body condition, vitamin and mineral status, disease and stress among other factors.

Additionally, the use of follicle stimulating hormone (Folltropin) has been found to significantly improve oocyte quantity, resulting in more competent embryos leading to higher conception rates and more live calves.

Once the immature oocytes are recovered they are placed in maturation media and incubated for 24 hours. This incubation period mimics the environment of the dominant follicle of the cow up until ovulation (oocytes release).

After 24 hours maturing in the incubator, the matured oocytes are placed with semen. This step is known as In-Vitro Fertilisation, and where the Term IVF comes from. We expect 50-75% of oocytes collected to become fertilised. Once fertilised, an oocyte is referred to as an embryo. Like oocyte quality, semen quality also has a big influence on fertilisation rates, development embryo quality and survivability.

Over the next 7 days, the embryos are grown in special media in incubators in the laboratory. On day 7 (8 days post oocyte collection) embyros are graded, with suitable living embryos frozen or transfered fresh into recipient cows. We expect approximately 25-35% of oocytes collected to get to the freezing stage, with the use of FSH, we expect this rate to improve markedly to 50-70%.

Once grown, the transfer of fresh or frozen embryos is the same for either IVF or MOET.