Biotechnology is being harnessed in various aspects of the livestock industry to hasten breed development for improved animal health and welfare, enhanced reproduction, and improved nutritional quality and safety of animal-derived foods.
One of the earliest perfected technology is artificial insemination (AI) where new breeds of animals are produced through the introduction of the male sperm from one superior male to the female reproductive tract without mating. AI reduces transmission of venereal disease, lessens the need of farms to maintain breeding males, facilitates more accurate recording of pedigrees, and minimizes the cost of introducing improved genetics. Various technologies have evolved that led to the efficient use of AI in developing desired livestock, including the methods of freezing semen or cryopreservation and sperm sexing.
In case other artificial reproductive techniques fail due to difficulties such as blocked reproductive systems, non-responsive ovaries in the females, marginal semen quality and quantity in the male, and presence of disease, in vitro fertilization (IVF) is used. The fertilization of the sperm and the egg is conducted in vitro (outside the animal’s body) at specific environmental and biochemical conditions. To date, successful IVFs have been conducted in various animal species due to advances in embryo production and cryopreservation of reproductive cells. Since the birth of the first rabbit conceived through IVF in 1959, IVF offspring’s have been born in mice, rats, hamsters, cats, guinea pig, squirrels, pigs, cows, monkeys, and humans.
Embryo transfer from one mother to a surrogate mother makes it possible to produce several livestock progenies from a superior female. Selected females are induced to super ovulate hormonally and inseminated at an appropriate time relative to ovulation depending on the species and breed. Week-old embryos are flushed out of the donor’s uterus, isolated, examined microscopically for number and quality, and inserted into the lining of the uterus of surrogate mothers.