Page 3 - LN-CH 9

common ancestors for 4-6 generations (out-crossing) or of different breeds (cross-breeding)
or even different species (interspecific hybridisation).
It can be of the following types:
• Out-crossing is the practice of mating of animals, within the same breed, but having no
common ancestors on either side of their pedigree up to 4-6 generations.
– The offspring of such mating is called an out-cross.
– It is done to increase milk production, growth rate in cattle’s beef, etc.
-A single out cross helps to overcome inbreeding depression.
• Cross-breeding refers to the mating of superior males of one breed with superior females
of another breed.
– It helps in accumulate desirable qualities of two breeds into progeny.
– The progeny may be used for commercial production themselves.
– A new sheep breed, Hisardale is developed in Punjab by crossing Bikaneri Ewes and
Marino Rams.
• Interspecific hybridisation refers to crossing between male and female animals of two
different related species.
– Progeny may combine desirable features of both the parents.
– Progeny may be of considerable economic value.
– Example of interspecific hybridisation, is a Mule obtained by crossing a male donkey with
a female horse.
(c) Artificial insemination is a method of controlled breeding. The semen from selected male
parent is injected into the reproductive tract of selective female parent.
Its advantages are as follow:
– Helps to overcome problems related to normal mating.
– Semen can be stored and frozen for the later use.
– The disadvantage is its fairly low success rate.
V. Multiple Ovulation Embryo Transfer (MOET) Technology is a programme for herd
improvement.
(i) The method includes following steps:
(a) A cow is administered with hormones FSH-like activity, to induce follicular maturation
and superovulation.
(b) The cow produces 6-8 eggs instead of one egg, normally released per cycle.
(c) A cow is now mated with an elite bull or artificially inseminated.
(d) The fertilised eggs at 8-32 celled stages are recovered non-surgically and transferred to
surrogate mothers.
(e) The genetic mother can again be used for superovulation.
(ii) This technology is used for cattle, sheep, rabbits, buffaloes, mares, etc.
(iii) High milk-yielding breeds of females and high quality (lean meat with less lipid) meat-
yielding bulls have been bred successfully to increase the herd size in a short time.