Meat and milk from cloned bulls and cows should be safe to eat, a study suggests. The pilot study is the first to examine specific proteins and nutrients in the milk and meat from cloned animals and marks the start of efforts to plug an important gap in research that may one day lead to regulatory approval of clone-derived food.

In America and Japan, hundreds of elite animals, such as breeding bulls, already have been cloned, and there are more than 1,000 worldwide, said professor Xiangzhong (Jerry) Yang, director of the University of Connecticut's Center for Regenerative Biology. "We conducted extensive comparisons of the composition of milk and meat from somatic (adult cell) cloned animals to those from naturally reproduced comparator animals," he said. "We found no significant differences."

With Dr. Cindy Tian, Dr. Chikara Kubota and colleagues at the Kagoshima Prefectural Cattle Breeding Development Institute in Japan, he cloned an elite 17-year-old Japanese Black beef bull (called Kamitakafuku) and a particularly productive Holstein dairy cow (Aspen), using the same technique -- nuclear transfer -- used to clone the sheep Dolly. They then compared the meat and milk from the clones to that from animals of similar age, genetics, and breed created through natural reproduction.

Analysis of protein, fat and other variables routinely assessed by the dairy industry revealed no significant differences in the milk, they report in the Proceedings of the National Academy of Science.

One reason such studies have not been carried out is because the clone has to be butchered to assess meat quality and, given the effort to create clones, scientists have been reluctant to do this.

Yang said, "The two clones we killed from Japan were the first male clones in the world, born in 1998. It was a sad decision, but it is really important for society, public and regulatory agencies."

The researchers examined more than 100 meat quality criteria, of which 90% showed no noteworthy variations. However, about eight variables related to the fat and fatty acids in the meat were significantly higher in the meat from the clones, though within industry standards. "This is very desirable and highly expected," said Yang, explaining that animals with more fat or fatty acids in their meat were more valuable in Japan.

This study comes as the FDA is poised to rule on whether to allow food from cloned livestock to be sold for human consumption. "The data generated from our match-controlled experiments provide new science-based information to address public concerns about the safety of meat and milk from somatic animal clones," Yang said. "The experiments presented here are a pilot study to provide guidelines for more conclusive studies with larger numbers of clones from different genetic backgrounds in order to further increase the consumers' confidence."

In 2001, the FDA commissioned a committee from The National Academy of Sciences (NAS) to identify any safety concerns. The NAS reported that clones present "a low level of food safety concern" but said there was a lack of information. In a follow-up report in 2003, the agency concluded that cloned animals and their offspring posed no increased risk to food safety.