Further Links Contact Us Search Help

Syllabus | Exams | Assessment | Other resources | Site reviews | Careers

Agriculture

Home > Agriculture > Electives > Animal Management > Embryo transfer

Animal Management - Elective 2

---

Embryo transfer

This material addresses aspects of the following syllabus outcome:

A student:

Syllabus content areas addressed in this material include:

Students learn about:

• processes in agricultural systems by:
  • relating knowledge of animal hormonal systems and reproductive anatomy to breeding techniques and reproductive management
  • evaluating management techniques available to farmers to manipulate the rates of growth, development and reproduction in farm animals, including the use of chemicals and hormones
• innovation, ethics and current issues by:
  • outlining some of the issues (for example economic, management, social, legal and ethical) that may have an impact on the successful implementation of new technologies in animal production systems.

Source: Extract from Stage 6 Agriculture Syllabus Board of Studies NSW (1999)

Embryo transfer is the process of removing embryos from one female (known as the donor) and placing them in another female, the surrogate mother, where they develop. The surrogate mother gives birth to an offspring that is genetically unrelated.

Embryo transfer is carried out on a variety of agricultural animals, to a greater or lesser extent depending on the species. It is used extensively in the beef cattle industry.

The basic steps in embryo transfer are outlined below. To best understand how embryo transfer works you need to be familiar with the action of several hormones. These include:

• prostoglandin
• progesterone
• follicle stimulating hormone (FSH)
• oestrogen.

Perhaps you should check your notes to make sure you understand how these hormones work.

Steps in embryo transfer

1. Identify donor and recipient cows.
   
   

   Donor cows are superior quality cows. Their purpose is to donate their superior genetic material.

   Recipient cows are surrogate mothers that will give birth to calves that are genetically unrelated.

   
   
2. Synchronise oestrus of donor and recipient cows by using injections of prostoglandins and CIDR (Controlled Internal Drug Release device). It is very important that both donor and recipient cows are at the same stage of oestrus for a successful transfer to take place.
   
   
3. Superovulation of the donor cows is done by administering FSH injections to stimulate more follicles are to grow and release their ova. The FSH is injected twice a day decreasing the dose for three to five days. Prostoglandins are also injected on the third day and the CIDR removed.
   
   
4. Oestrus should occur on the fifth day of the process. All cows should be heat detected.
   
   
5. Donor cows should be artificially inseminated 4 to 22 hours after the onset of oestrus.
   
   
6. One week after inseminating, the donor cows are flushed. The embryos are collected and may be frozen to be used later, or kept fresh to be used as soon as possible.
   
   
7. The embryos are implanted into the recipient cows. If all goes well, the embryo will attach to the lining of the uterus, and a normal pregnancy will continue.
   
   
8. The recipient cows will give birth to calves that are genetically unrelated.

What are the advantages of embryo transfer?

Embryo transfer allows one superior cow to produce a greater number of calves in her lifetime, than normal. This can increase the rate of genetic improvement in a herd.

Are there any disadvantages of this technology?

The disadvantages of embryo transfer are as follows:

• It decreases the size of the gene pool
• It is very costly
• It is very labour intensive.

Further information

If you would like to find out more about embryo transfer you should investigate these web sites.

Genetics Australia

Question

The donor cows used in embryo transfer are artifically inseminated rather than mated naturally. Discuss the reasons for this practice.

Answer