What is TVR-IVP?

Trans-Vaginal Recovery (TVR) is the name given to the non-surgical, ultrasound guided method of collecting eggs (oocytes) from the ovaries of donor cows. This technique is also referred to as Ovum Pick Up (OPU).

The donor is given an epidural. An ultrasound probe is carefully inserted into the vagina to enable the operator to visualise the ovaries on the screen. A fine suction needle, is passed through the vaginal wall and guided into each of the follicles (fluid containing egg). The oocytes are aspirated using a low vacuum pressure pump. The whole process is visualised on the screen, in order to achieve a very precise puncture without affecting the surrounding tissue on the ovary. The process takes approximately 15 minutes.

There is no special preparation of the donor required prior to the process.
In-Vitro Production (IVP) of embryos is an eight day process which occurs in an incubator in the laboratory. The process is broken down into the following steps:

  • The eggs are recovered from the TVR process, at the site of the collection, either at one of our centres or your farm. They are placed into a special media which helps them mature overnight to be ready for fertilisation. The tubes containing the media and eggs are placed into a portable incubator until they reach the Rukuhia IVP laboratory.
  • The following day, the eggs are fertilised with your nominated semen. One straw of semen, can be used on 5-8 donor cows. For the fertilisation process, the semen needs to be prepared to ensure optimal fertilisation.
  • The oocytes are then cultured in the incubator for a further 7 days to allow the development of embryos to the stage suitable for transfer into recipients, or vitrification.

The Advantages of TVR-IVP

  • Maximises the number of progeny from high merit cows within a given time frame. It is possible in a 6 week period to produce 24 embryos (or 12 calves) from a donor.
  • Allows repeat collections of oocytes from the same donor; cows can be collected twice weekly for many consecutive weeks (in contrast to MOET which can only be performed every 6 weeks). Donors can be TVR-ed more than 30 times without any issues.
  • Donors are not subjected to hormonal stimulation or cycle synchronisation. This reduces the risk of subsequent fertility issues sometimes associated with MOET.
  • TVR can be performed at any stage of the donor’s oestrous cycle.
  • The first TVR session can be performed as little as 30 days post-calving.
  • Fertile cows, after having had TVR performed, will usually get in calf without delay.
  • Allows greater flexibility in the use of different sires.
  • TVR can be performed on post puberty heifers, on lactating and non-lactating cattle and even on cattle up to 3 months pregnant.

In most situations we would prefer the donor cow to come on to one of our centres. The donor cow will first have to clear our entry health test requirements.

If TVR is to be carried out on your farm, basic yards are needed with a (preferably) covered head bail where cows can be securely held for collection. It is important that we have power near to the collection area. Alternatively, a rotary bail can be used. For embryology, a clean, warm room with power and a bench is required. We have a van equipped as a mobile embryology lab, which we can use where there is no suitable room or power.

TVR can be performed twice weekly and the recovered oocytes will be cultured in our modern, specially equipped laboratory at Rukuhia.

We aim to recover 7-8 oocytes per donor each time and on average 1-2 will develop to transferable embryos with an expected pregnancy rate of 50%.