In Denmark, an increasingly high number of pigs are arriving at slaughterhouses with visible injuries caused from being beaten with planks and chains, according to IceNews.

It cites a Copenhagen Post report that the reason for the growing rate of abuse may be the new system, introduced in 2006, which rewards the fast loading of animals onto transport vehicles. In the past two years alone, the number of pig abuse cases in Denmark has increased five-fold.

The University of Copenhagen's Department of Veterinary Disease Biology and Denmark's leading slaughterhouse, Horsens' Danish Crown, have both recognised the trend which has seen some instances of over 30 pigs arriving at abattoirs with serious injuries from a single truck.

Professor Henrik Elvang Jensen of the University of Copenhagen claimed that studies into the injuries indicated that most had occurred while the animals were still on farms. Professor Elvang Jensen said that pipes, chains and other blunt instruments were the likely cause.

The new system which came into place in 2006 where farmers are rewarded for fast transportation of the animals was also called into question.

"When a system is like that it can provoke a violent reaction if the farmer suddenly sees 30 pigs running in the wrong direction," the professor said.

Danish Crown's pork production committee head, Erik Bredholt, said that the practice of beating animals was entirely unacceptable.

He added: "Every farmer knows you don't get your pigs loaded on to the truck faster by beating them."

Mr Bredholt argued instead that the rise in porcine trauma had little to do with the new system but was rather a reflection of the increased economic pressure most farmers are currently facing, reports IceNews.