The debate continues to swirl about the safety of livestock feed from genetically-modified crops, but a review of scientific literature on the performance and health of animals consuming genetically-modified feed shows no difference between feed containing GE ingredients and that which does not.

The review, which appears in the October issue of the Journal of Animal Science, looks at scientific data going back to 1983 before GE varieties were introduced in 1996 through 2011 when feed containing GE ingredients were prominent. In all, the study represents more than 100 billion animals.

“An extensive search of peer-reviewed literature and field observations of animals fed diets containing GE crop products have revealed no unexpected perturbations or disturbing trends in animal performance or health indicators,” the study concludes. “Likewise, it is not possible to distinguish any differences in the nutritional profile of animal products following the consumption of GE feed.”

According to the review, research is ongoing in the field of GE crops enhanced for animal nutrition, which “reflects both the importance of feed markets for GE crops and the potential nutritional improvements that can be brought to the quality of feedstuffs using this technology.” The review notes to ways in which plant breeding can help increase the efficiency of livestock production, including raising the crop yield per hectare, or by improving the rate of conversion of vegetable calories into animal calories.

The authors note a small number of experimental animal feeding studies have generated controversial results “suggesting deleterious health effects of GE crops.” These studies have been criticized by international scientific organizations for flawed methodology. Despite the flaws and a large amount of data and literature proving otherwise, these studies have been the basis for new regulations in some countries and have also fueled the fire for mainstream media.

“The media attention developed to these sensational studies is exacerbating the continued controversy associated with the safety of GE food and feed and is bolstering arguments calling for the mandatory labeling of milk, meat, and eggs from GE-fed animals,” the review states.