In a world first, a sheep named Dolly was born in 1996. She was a clone of her mother, created using the genetic material from a cell in the ewe’s udder. Dolly sparked an intense public debate on cloning.
In response, a year later, a high-level report on the Implications of Cloning for the Welfare of Farmed Livestock (http://www.fawc.org.uk/reports/clone/clonetoc.htm) made many recommendations. The recommendations stated that, to protect animal welfare, only people who have the necessary skills in the complex techniques, surgeries and aftercare, should be allowed to clone animals. Importantly, the report stated that cloning, without strict controls, might result in significant animal welfare issues, as well as changes to the nature of the animals involved. Some of these issues are discussed below.
Only a tiny percentage of cloning attempts have successful births and very few offspring are healthy. They can suffer and die from respiratory distress, low-blood sugar, weak immune systems, deformities and many other problems. This means, to produce a handful of successfully cloned animals, hundreds of other animals have their eggs harvested or are surgically implanted with embryos. Both procedures are often done repeatedly to the same animals.
A common problem is that cloned animals are significantly bigger at birth than normal offspring. This means painful delivery for the mother, often requiring surgery. Large offspring may also die or suffer from abnormal organ growth, poor breathing and suckling. The causes for oversized offspring need to be better understood so that further painful births can be avoided.
Some cloned animals may be produced so that they grow faster and can therefore be slaughtered sooner. However, there are already serious problems with fast growth in intensive animal production. For example, meat chickens may grow large so quickly that they suffer from skeletal abnormalities, lameness, metabolic diseases and high rates of mortality. To promote other large, rapidly growing cloned animals would add to existing animal welfare concerns.
Since Dolly’s birth, technology has moved on, but it is still far from producing commercially cloned farm animals. Although studies have found that food from cloned animals is safe to eat, at present animal welfare costs and animal wastage outweigh any benefits of cloning.