Ethical treatment of farm animals has been a growing topic of concern ever since author Eric Schlosser wrote the shocking exposé Fast Food Nation in 2001.
Now, a provocative paper published this month in the journal Neuroethics argues for artificially reducing the suffering of livestock by engineering animals that lack the ability to sense pain.
In humans, there have been a few documented cases of people who have Hereditary Sensory Autonomic Neuropathy, a disorder in which the afflicted feels little to no pain.
But it's far more dangerous than it sounds, since a person with the disorder can't feel his or her own physical limits. That means they're often covered in bruises and cuts, may not be able to regulate body temperature and could easily accidentally kill themselves.
Now, scientists argue whether "pain-free" can join "free-range" and "hormone-free" when it comes to livestock.
The New Scientist details a bleak picture for livestock in factory farms:
Humans consume nearly 300 million tonnes of meat each year. Our appetite for flesh has risen by 50 per cent since the 1960s, and the trend looks set to continue. Most of this will likely come from factory farms, notorious for cramped quarters and ill treatment of animals. Battery farm chickens, for instance, routinely have part of their beaks removed without anaesthetic or pain relief to prevent them from pecking their neighbours.
The paper's solution is to reduce animal suffering in factory farming operations by genetically engineering livestock with a reduced or eliminated capacity to suffer.
Of course, that doesn't mean consumers will actually buy the product: despite FDA approval, few consumers are willing to buy meat they know is cloned or genetically-engineered.
The science behind the concept is a bit more nuanced.
Research indicates that the sensation of pain is distinct from the unpleasant feeling -- called "affective pain" -- connected to it, suggesting it might be possible to preserve "pain" while eliminating "suffering."
In the hopes of placating chronic itching, Zhou-Feng Chen, a neuroscientist at Washington University in St. Louis, has identified the genes that regulate affective pain. Chen and his colleagues engineered mice that lack enzymes that help neuron-to-neuron communication in the anterior cingulate cortex, a region of the brain thought to play a role in autonomous behavior.
When the team injected a toxic, irritating chemical into the paws of test mice, the animals licked them briefly. In contrast, normal mice continued to do so for hours -- suggesting that livestock can be spared suffering but feel the initial sensation of pain.