Question

Which of the following has been recently used for increasing productivity of super milch cows?
A. Artificial insemination by a pedigreed bull only
B. Superovulation of cow only
C. Embryo transplantation only
D. Superovulation, artificial insemination and embryo transplantation into a 'carrier cow'

Answer 1

The expected rate of cows responding in the desired manner to superovulation treatment is around 75% to 90%. The remaining 10% to 30% of flushed cows are unable to produce embryos which are of good and transferable quality. Therefore, a few other techniques are also required in assistance to superovulation to produce desired results.

Complete step by step answer:
i. Superovulation is the method by which the female cow produces more eggs in each estrus than the usual count by gonadotropin to increase the number of embryos produced. Usually, in this process, around ten more live eggs are collected in each estrus from suitable superovulated cows.
ii. Rectovaginal insemination is the safest and best method of insemination in cattle. An AI gun loaded with bull semen straw is delivered via the vulva of the cow to its vagina and the cervix.
iii. Embryo transfer is the method in which one or more embryos is removed from the reproductive tract of the donor female and it is transferred to recipient females. For increasing productivity of super milch cows, superovulation followed by embryo transplantation into a 'carrier cow' or a surrogate mother was done.
So, the correct answer is option D.

Additional information: Follicle-stimulating hormone (FSH) is widely used in the cattle industry. Super-stimulation is done in cows by the help of FSH treatment. It induces follicular growth and improves the efficiency of in-vivo embryo production.

Note: Flushing is a term used for the high quality feeds, generally grains given to the cow before the start of the breeding. It increases the reproductive performance of the cow. This differs between cows i.e. some donors are flushed 8-9 times or more and can provide a steady embryo production, while in some cows, flushing can only be done 3 or 4 times after this the embryo production in such cows starts declining.