Cattle Services

To Flush or to IVF?

It’s a common question, both procedures have their advantages and limitations. Generally, conventional flushing is going to be cheaper than IVF and embryos produced from a flush tend to have higher conception rates. IVF is used more often in cases of pregnant donors or challenge breeders. Also, IVF is the ideal procedure to use expensive or rare semen as you can split one straw over several donors. IVF also offers the use of reverse-sorted semen and is a more effective use of frozen sexed semen. The latest developments in IVF have allowed us to grow embryos from pre-pubertal heifers, decreasing your genetic interval.

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Fresh versus frozen embryos?

Conventional or IVF embryos that are transferred fresh have the highest conception rates, an average of 10-15% higher conception rates than frozen embryos. Fresh transfer also allows for the use of non-freezable embryos. Frozen embryos allow for flexibility and convenience.

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Stimulated versus non-stimulated IVF?

There are companies that are completely structured around non-stimulated IVF but we believe there is a place for both programs. Stimulated programs are more expensive due to the use of FSH but often yield higher embryo development and higher conception rate per transfer. Non-stimulated programs are ideal for donors who naturally have a large pool of oocytes and when semen is not quite as expensive.

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What is IVF and how does it differ from conventional flushing?

For either program, you can give all shots at home and haul in on day of procedure or we can house them for the program. Both procedures must be done in a space that is temperature regulated and have a clean space. 

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For a flush, the donor goes through a superovulation program, is bred and embryos are flushed out a week later. The resulting embryos can be transferred fresh or frozen for later transfer. 

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For IVF, there are basically 4 parts to the process: set-up (on farm or at repro center), ovum Pick Up (OPU or aspiration), fertilization (done at TransOva), and freezing or transfer. For set-up, you would basically have to work the donor(s) through the chute 5 times (unless doing non stimulated) and then aspirate. The aspirated oocytes are shipped to TransOva (in Boonsboro, MD) the day of aspiration and are fertilized the next day and incubate for a week. Resulting embryos can be frozen or used for fresh transfer. 

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For IVF, you can use conventional semen, sexed semen or reverse sorted semen (a conventional straw is thawed and put it through a process that can sort Male or Female so you can gender select the embryos). The sexing process does affect fertility so you may see a decrease in fertilization rates, therefore embryo production. A distinct advantage of IVF is that one straw can be used to fertilize more than one donor with one straw of semen, whereas for a conventional you use as least 2 straws per donor. For a conventional flush, we recommend only using conventional semen.

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We often ask that you send at least 4 straws of semen. 2 of your primary mating choice and 2 of a back up. That way we are sure we have semen. Crazy stuff can happen, straws can blow up or be no good. We can return the unused straws with the frozen embryos. The average number of embryos produced but flushing or IVF is very similar, an average of 6 per run. This is affected by her group of oocytes that she has on the ovary, how she responds to stimulation, and how fertile those oocytes are. Typically hard breeders don't do as well.