Explain experiments of controlled breeding.

(A) Controlled breeding experiments are carried out using artificial insemination.
For hybridization,semen is collected from the male that is chosen as a parent and injected into the reproductive tract of the selected female by the breeder.
The semen may be used immediately or can be frozen and used at a later date.
It can also be transported in a frozen form to where the female is housed. In this way,desirable matings are carried out.
Artificial insemination helps us overcome several problems of normal matings.
Often,the success rate of crossing mature male and female animals is fairly low even though artificial insemination is carried out.
To improve chances of successful production of hybrids,other means are also used.
Multiple Ovulation Embryo Transfer Technology $(MOET)$ is one such programme for herd improvement.
In this method,a cow is administered with hormones with $FSH$-like activity to induce follicular maturation and super ovulation.
Instead of one egg,which they normally yield per cycle,they produce $6-8$ eggs.
The animal is either mated with an elite bull or artificially inseminated. The fertilised eggs at $8-32$ cell stages are recovered non-surgically and transferred to surrogate mothers. The genetic mother is available for another round of super ovulation.
- This technology has been demonstrated for cattle,sheep,rabbits,buffaloes,mares,etc.
- High milk-yielding breeds of females and high-quality (lean meat with less lipid) meat-yielding bulls have been bred successfully to increase herd size in a short time.