MUTANT "double muscle" pigs and cows are being bred to potentially help ward off beef and pork shortages.

       Shocking images of the super-sized farm animals have emerged as scientists reveal selective breeding and genetic mutation behind the monstrous muscles.

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       Some to have seen online images of the burly cattle are convinced they must be on steroids Credit: Getty - Contributor 5

       The pigs turned their food into muscle at a faster rate than normal 5

       However Belgian Blue cattle can often endure a slew of serious health problems Credit: Alamy

       A Belgian breed of cattle, the Belgian Blues have a naturally occurring mutation called "double-muscling" - which turns them into beefcakes.

       And the breed's bodybuilder profile certainly comes at a high price as they often suffer a slew of serious health problems.

       Pregnancies are very difficult, and the animals almost always require C-sections to deliver their babies.

       Once the calves are born, they may have a number of birth defects, including enlarged tongues, which can make it difficult for them to nurse.

       However, some of those to have seen online photos and clips of the burly cattle are convinced they must be on steroids.

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       "It should be illegal to inject steroids into any animal... it takes it out of its natural healthy looking character," wrote one.

       "Insane...pathetic what they did to these poor creatures," wrote one of the millions of YouTube viewers to have seen the 'muscles from Brussels' breed.

       However, others hit back to point out their bizarre appearance is actually down to a natural occurring genetic mutation.

       One replied: ‘This is a Belgian breed of cattle that looks like this because of a genetic mutation that results in increased muscle mass.

       "So stop this steroid and animal cruelty nonsense."Double muscling occurs in animals which lack a certain protein that regulates its muscle growth.

       Although it is natural, the way the mutation has been perpetuated is not, says PETA (People for the Ethical Treatment of Animals).

       The meat industry selectively breeds animals who exhibit this mutation to produce bigger animals and, therefore, more meat

       Likewise, footage has emerged showing pigs that look like they’ve been on gorging on steroids and pumping iron in the gym.

       But these unlike the cows, these pigs have not grown like this naturally or through drugs.

       They are the result of research being carried out in South Korea that will either have you licking your lips or recoiling in revulsion.

       Jin-Soo Kim, a molecular biologist at Seoul National University who is leading the work, told science journal Nature, that by altering the genes you can quickly create the perfect pig for slaughter.

       He said: “We could do this through breeding.

       “But then it would take decades.”

       Years of cross-breeding has created the enormous Belgian Blue cattle.

       But Kim’s team have by-passed this method and created the bulked-up pigs by tinkering with a “myostatin gene”.

       This gene usually keeps the growth of muscle cells in check.

       But when that gene is altered this does not happen and therefore the pig begins growing more than twice its normal size.

       The editing produces a higher muscle mass and this means more meat to yield and less fatty pork.

       So far, Kim and his colleagues have yielded more than 30 piglets.

       They say it is safe because rather than transplanting genetic information from one species to another they have simply edited genes.

       It is hoped that the sperm from the pumped-up pigs will be sold around the world to boost meat production.

       But presently no country allows its people to eat the genetically modified products.

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       Bacon butties, the impressive muscle tone of a new breed of super-sized pig Credit: Seoul National University 5

       Belgian Blues have a naturally occurring mutation called 'double-muscling'

       The musclebound beefcake cow which has sparked a roid rage row on the internet