Is Embryo transplant is most feasible with cattle?

Answer 1

I am assuming that this question should read, "Is embryo transplanting feasible with cattle?" The answer to this topic will vary greatly among cattle farmers, with many of them answering that it is not. But as the practice becomes more widespread and the techniques to perform the procedure become more common, a greater percentage of farmers may look to embryo transplanting (ET) as a long-term economic improvement to their operation.

In the simplest of terms, one of the best cows in the herd for production (and any other characteristics the farmer wishes to propagate) is chosen to be the DONOR MOTHER. This cow is given a complex series of hormone injections that will cause her to ovulate with a great number of eggs, such as 10 or more. The donor cow is bred, usually artificially, to the best bull that money can buy, which fertilizes a great number of these eggs.

Ten days later, the donor cow is FLUSHED, which is a process of extracting the eggs through a tube while injecting a flushing fluid simultaneously. This process is normally handled by a veterinarian.

Embryos are usually analyzed under a microscope for any abnormalities. The healthy ones are saved, and can be stored indefinitely in liquid nitrogen at -160 degrees F.

SURROGATE MOTHERS in the herd are then determined, either by forcing ovulation through injection, or by patiently waiting for their cycle, and instead of breeding the cow, a fertilized embryo is placed in the uterus instead, using a pipette-and-plunger type of tool.

The costs involved: shots to the donor cow are about $200 total, and the flushing cost and embryo selection is about $300. Because of today's availability of "sexed semen", the farmer can even exert influence on the number of female calves that will be produced. Let's say the female rate is 80% and there are 10 viable embryos. For most farmers, propagation of female genetics is the goal. There are those who produce bulls for the national market, but they are the minority. This group has used ET for decades already.

So, we have 8 potential heifers from a $500 expense, and lets say 25% of these embryos fail, leaving us with 6 viable heifers. We have implanted 8 surrogate mothers (remember 2 failed). So we saved the breeding and semen costs for the six successful mothers, to the tune of about $120. So now the true cash outlay for the farmer is $380 for 6 viable heifers that are GENETICALLY SUPERIOR to probably any of the other calves in his herd.

Here's the benefit: for a dairy farm, 3 years later these heifers are milking cows, and produce just 1,000 lbs. of more milk each year than their peers. This is a value of $130 per animal per year, or $780 per year for the half dozen animals that were ET produced. If these animals have a 5-year production life (and that is realistic) they have returned a gross ADDITIONAL milk production value of $3900. This was with the original $380 invested. Ten times the money in 8 years.

There are other long-term benefits to the propagation of superior genetics such as: better feet and legs, better feed to milk conversion (or feed to meat conversion for beef farmers) more longevity, more size, straighter legs, larger udders, etc. It really depends on the focus of the ET selection process.

ET requires a great deal of management with regard to sanitation, to TIMING, and to care in selection. One must remember that all of the bad traits are propagated as well. But for farmers who already conduct their own artificial inseminations (and many do) the process of embryo transplanting is very similar. As economic margins on the farm continue to tighten, farmers will look for ways to develop greater production per unit in order to be able to meet ever rising costs such as taxes, insurance, and land payments.

Answer 2

There are many disadvantages to this procedure, the most common are:

• Abnormalities of the reproductive tract of the donor cow or heifer due to disease or injury could prevent her from being flushed.
• Response of donor cow upon being flushed with gonadotrophin hormones is unpredictable. A cow can give 0 to as many as 30 eggs
• Only 60% of transfers to recipient cows will be accepted by those cows. Sometimes it can be as high as 80% or as low as 20%.
• Not all cows are ideal for use as recipient cows. A potential recipient cow must be palpated to see if her reproductive tract is normal, no twisted cervix or a history of calving problems.
• Cows must be in good condition and cycling normally to be used as donor or recipient cows.
• Recipient cows may need to have surgery done on them to transfer the embryo from the donor cow to their uterine horn.
• Donor cow may not catch when artificially inseminated, as normal AI rates are between 60% to 80%.
• It's not cheap to do ET. You'll be looking at anywhere from a $2,000 to around or over $10,000 for just one donor cow and a couple recipients, not including the extra money spent on the times you will be unsuccessful with either the donor or the recipients.