In the present century when the secret of genetic sequences through generations of a population was unfolded, all biological sciences advanced rapidly and the application of which helped mankind to increase production from various species of animals and plants. The rate of improvement increased as the year’s passed-by consequent to advancement of technology. Among them artificial insemination can be ascribed as the greatest development in agriculture of the century as its contribution towards production enhancement is the highest in the world.
The technique of artificial insemination in cattle is based on a biological fact that the males generally produce large quantities of semen, which can be extended and preserved. With the introduction of artificial insemination technology there has been revolutionary changes in the animal production industry. The artificial insemination technology takes advantage of the capability of male animals to produce multiples of millions of male gametes, each of which represents half of the genetic constitution of its producer. Therefore a male highly selected for a desired genetic constitution through artificial insemination can satisfactorily change the genetic characters of the population. A reproductively sound cow may not usually produce more than eight calves in her lifetime, despite her ovarian potential to produce many thousands of gametes. With the application of Embryo Transfer Technology, higher rate of multiplication of highly selected female germplasm is possible, which can further revolutionize the cattle industry.
Even though the first successful ET was done in 1891(Heape, 1891) in rabbit, it took another sixty years for the first successful ET pregnancy (Umbaugh, 1949) and first successful ET calf (Willett etal1951) in cattle. Again it took around 20 years to apply this technique in commercial line in the western countries. The potential of this technique is yet to be exploited in many countries. We can multiply our own source of high quality germplasm by bio-technological tools like embryo transfer and micromanipulation of embryos including cloning.
- Increase the reproductive rate of females: A superior cow inseminated with superior bull semen will have best chance to produce a superior calf. The progress of genetic improvement of a population is limited through low rate female reproduction. Normally a cow can produce a maximum of one calf per year. But through multiple ovulation and embryo transfer (MOET) a superior female can produce 15-18 calves per year without affecting her reproductive efficiency.
- Bull production/Bull selection: Embryo transfer technology can be very well utilized to support the breeding bull production in cost effective way.
- Import/Export: The genetic material exotic to a country and desirable are now made available through semen or by import of animals. With the availability of frozen embryos, any combination of bull and cow living anywhere could be imported. In this advantage are various like, very low risk of disease transmission, less expensive, simple transportation procedures, passive immunity from native dam etc.
- Germ plasm preservation: gene preservation of species, which are under threat of extinction, is possible through ETT. The embryos of such species can be collected and preserved under frozen state in large numbers instead of rearing such animals for long time, which can be very expensive.
- Embryo transfer as part of other Biotechnology: Exploitation of other state-of art technologies such as IVF, bisection, cloning by nuclear transplantation, sexing. Production of transgenic animals etc. requires manipulating the oocytes or embryos in vitro depends on good embryo transfer result.
- Circumvent infertility: Embryo transfer technology can be used to circumvent infertility in certain extends as a diagnostic as well as treatment tool.
Heape, W. (1981).Preliminary note on the transplantation of mammalian ova within a uterine foster mother.Proc.of Royal.Soci.48:457-458.
Umbaugh, R.E. (1949). Super ovulation and ovum transfer in cattle.Am.J.vet.Res.10:295-305.Wright, J.M. (1981). Non-surgical embryo transfer in cattle. Theriogenology 15:43-56.
Willett EL, Black WG, Casida LE, Stone WH, Buckner PJ. 1951. Successful transplantation of a fertilized bovine ovum. Science, 113:247.