About the 'why it is done' part, the broad answer would be 'so that mankind gets to exploit the fruits of nature more than ever!'. In more specific terms, it is done to enhance the health, life expectancy and quality of livestock and related products for the improvement in the quality of consumption as well as to increase the economic yield.
Like everything else, the issue of genetic engineering in livestock also has two sides to it. Read on for a closer look at both the positive as well as negative attributes of this issue.
Genetic Engineering in Livestock - Pros and Cons
Usually, livestock are genetically manipulated for specific set of purposes - retention of desirable characteristics and elimination of the undesirable ones, increasing their life expectancy, genetically lowering their susceptibility to certain typical diseases, improving their breeding and reproductive abilities, improving their quality, etc.
Now, while genetic engineering has been able to successfully address all of these noble-enough issues by offering a solution to each problem sector, there do exist certain gray patches that have emerged as a side effect of humanity's stint at playing God.
The following paragraphs lay down both the pros and cons of genetic engineering in livestock as experienced and recorded till date.
◉ Better understanding of genetic structures of livestock animals and their diseases help scientists identify and isolate defective genes in order that successive generations are born healthy and do not risk inheriting the particular disorder.
◉ Also, the quality of livestock output can be radically altered. For instance, a genetic alteration in the DNA of pigs can yield low-fat pork and genetically altered hens can be used for high protein, low cholesterol eggs as well as a meatier anatomy.
For instance, milk of genetically modified sheep containing human clotting factor is highly recommended for people suffering from hemophilia. Also, genetically modified farm animals are often used for performing xenotransplantations when human donors are unavailable or transplantable organs are scarce.
◉ The biggest risk that genetic modification of livestock poses is transmission of artificial genetic anomalies to people who consume the products derived from these animals.
For instance, the growth and other hormones that are injected to make cattle produce more meat and milk ultimately gets transmitted to whoever eats beef and dairy that comes from such an animal.
In recent times, a lot of cases have come to the fore when people, especially infants and young children, have fallen seriously sick on consuming milk that came from cows who had received artificial hormone shots for increasing their milk producing capacities.
◉ Similar to the earlier point, a more direct health hazard from consuming genetically modified animal products is the risk of exposure to various harmful toxins that exist in the eat and hides of these animals as a result of increasing their resistance to disease-causing germs and parasites.
◉ The subject of xenotransplantation is still in its nascent stage and right now, the techniques are not advanced enough to coax the human body to accept a foreign organ from a different species of organism.
Let alone a different species, many a time the human body rejects organ transplants sourced from human donors! Therefore, the success rate, if any, is far from promising.
So, you see, there are both sides to this coin - one positive and practical while the other somewhat shady. Whether or not such genetic manipulations are ethical is a subject for the conscientious environmentalist and the vigilant PETA activist to ponder upon.
Speaking from a very simple and narrow consumerist point of view, when going ahead with carrying out genetic modifications in animals, the after effects of this on the consumer population must be taken into serious consideration.