The ritual method of slaughter as practiced in Islam and Judaism has been described as inhumane by some animal welfare organizations in the U.K. and the U.S. who have stated that it "causes severe suffering to animals.".
In 1978, a study incorporating EEG (electroencephalograph) with electrodes surgically implanted on the skull of 17 sheep and 15 calves, and conducted by Wilhelm Schulze et al. at the University of Veterinary Medicine in Germany concluded that "the slaughter in the form of a ritual cut is, if carried out properly, painless in sheep and calves according to EEG recordings and the missing defensive actions" (of the animals) and that "For sheep, there were in part severe reactions both in bloodletting cut and the pain stimuli" when captive bolt stunning (CBS) was used. This study is cited by the German Constitutional Court in its permitting of dhabiha slaughtering. However, recent studies have countered the Schulze study which is dated and relied on older EEG measurement techniques. Dr. Schulze himself also warned in his report that the stunning technique may not have functioned properly.
In 2003, the Farm Animal Welfare Council (FAWC), an independent advisory group, concluded that the way halal and kosher meat is produced causes severe suffering to animals. FAWC argued that cattle required up to two minutes to bleed to death when such means are employed. The Chairperson of FAWC at the time, Judy MacArthur Clark, added, "this is a major incision into the animal and to say that it doesn't suffer is quite ridiculous."
Halal and kosher butchers deny that their method of killing animals is cruel and expressed anger over the FAWC recommendation. Majid Katme of the Muslim Council of Britain also disagreed, stating that "it's a sudden and quick haemorrhage. A quick loss of blood pressure and the brain is instantaneously starved of blood and there is no time to start feeling any pain." The Ph.D work of Dr. Pouillaude concluded: "religious slaughter would thus be a less stressing mode of slaughter. Conclusions of all the scientific experiments converge towards a firmly supported certainty: properly carried out, religious slaughter is the most humane way because it leads to less trauma to animals to be killed to be consumed for its meat". 
In April 2008, the Food and Farming minister in the UK, Lord Rooker, stated that halal and kosher meat should be labeled when it is put on sale, so that members of the public can decide whether or not they want to buy food from animals that have been bled to death. He was quoted as saying, "I object to the method of slaughter ... my choice as a customer is that I would want to buy meat that has been looked after, and slaughtered in the most humane way possible." The RSPCA supported Lord Rooker's views."
For the Food and Agriculture Organization of the United Nations and the Humane Society International, "the animals that are slaughtered according to kosher and halal should be securely restrained, particularly the head and neck, before cutting the throat" as "movements (during slaughter) results in a poor cut, bad bleeding, slow loss of consciousness, if at all, and pain."
In Europe, the DIALREL project addressed religious slaughter issues by gathering and disseminating information and by encouraging dialogue between the spiritual and scientific communities. Funding for DIALREL was provided by The European Commission, and it began functioning in November 2006. DIALREL produced many fact sheets and ultimately published a final report in 2010, "Report on good and adverse practices - Animal welfare concerns in relation to slaughter practices from the viewpoint of veterinary sciences."
Certain Muslim and Jewish communities expressed frustration with the process of dialogue skewed for non-religious audiences.