A 2014 review of the "Prevalence and impacts of genetically engineered feedstuffs on livestock populations" seems to have come up with an animal version of the trillions of GM meals which 'prove' safety .
The stated purpose of the study is three fold.
GM feed 'prevalence' is described in a "summary of the suppliers of GE and non-GE feed in global trade".
Although it doesn't feature in the title, another purpose is to "briefly summarize the scientific literature on performance and health of animals consuming feed containing GE ingredients and the composition of products derived from them".
COMMENT Such reviews of the scientific literature have been done several times before, and can lead to very different conclusions depending on what's considered valid science; see for example THREE REVIEWS OF GM SAFETY - May 2012
GM feed 'impacts' take the form of a discussion of "field experiences", meaning an "analysis of publicly available data on the health of commercial livestock populations since the introduction of GE crops in 1996". These 'health' data are slaughterhouse records, from for example the US Department of Agriculture (USDA) . Hence the 'trillions' of meals which prove safety.
The study duly produced the desired echoes in the media . One contributor to Forbes Magazine, who claims to write "sceptically" about science, declared "the Debate About GMO Safety Is Over", obediently ignoring the difference between human food safety and the needs of livestock production and farmers' profits.
In so much as it gives an overview of the agricultural success of GM feed within the US meat and dairy industry, the study is fine. It clearly lies within the expertise of the lead author, agricultural extension specialist in the University of California at Davis, Alison Von Eenemmaan.
However, its title and stated purposes give no hint of the essentially political discussion and conclusions which follow. For example, the data are used to stress the "urgent need for international harmonisation of both regulatory frameworks for GE crops and governance of advanced breeding techniques to prevent widespread disruptions in international trade of livestock feedstuffs in the future".
GM Watch have voiced a suspicion that the mis-match between the title, the data, and the conclusions are less to do with science and more to do with the political timing of the paper's publication: the review appeared right in the middle of the US-EU 'TTIP' trade agreement negotiations which include the opening up of Europe to GM .
Since Van Eenemmaan's review is a good example of an over-interpretation of data collected for different purpose, it's worth being clear what its limitations are.
1. A lack of appropriate data.
Livestock feed studies are carried out to ensure any feed put on the market supports the required weight gain in the animals in the required (minimum) time: farmers' profits depend on this.
Such commercial studies, as Eenemmaan herself points out, "have focused less on GE risk-assessment and more on evaluating the nutritional properties of the GE crop ...". Livestock don't have to be all that healthy, they just need to grow fast enough to reach slaughter-weight without overt signs of disease before they meet their untimely end.
Eenemmaan's 'field data' come from slaughterhouse records. All livestock reaching the slaughterhouse are inspected for gross signs of disease and the outcome recorded. The animals wouldn't be sent for slaughter if the farmer didn't think they would make the grade and give him his profit.
As a 'proof of safety', such data are patently useless.
USDA remit is to ensure that the pounds-weight of raw materials being generated for the food-chain are being successfully achieved. The livestock feeding studies and the 'field' data form part of routine checks made to monitor how well USDA policy is working.
Realistic measurements of 'health' have to look at parameters which haven't already been cleaned up by the system: for example, reproductive success, live normal births, extent of veterinary intervention, levels of medication and number of animals eliminated from the supply chain and why.
2. A lack of control populations
In an epidemiological study, a comparison is made with a population as similar as possible except for the factor being investigated. Such studies are useful in suggesting links which can then be explored using controlled laboratory tests to show cause and effects.
Since there is a complete absence of any comparable contemporary non-GM fed livestock population, Eenemmaan used pre-GM (pre-1996) data instead.
The problem with this is that, over these decades, livestock husbandry has changed hugely, and the animals themselves have been intensively bred for faster growth and heavier weight. Eenemmaan herself points out that "The conversion of feed (consumed) to (body weight) gain decreased from 5 in 1985 to 3.8 in 2011 attributable most likely to improved genetics".
Compare this review with the findings of Danish pig-farmer Ib Pedersen [4,5].
Pedersen runs a large-scale, commercial pig farm. He has (like US livestock farmers) continued to produce acceptable animals for the food chain and make a profit throughout the introduction of GM feed. However, when he started to record health parameters, such as his vet's bills, the frequency of gastric upsets, and incidence of reproductive problems, he began to suspect that insidious feed-related adverse effects had crept into his herd.
Since his production unit was large enough, well-established, and populated with pigs with a stable genetic background, he was able to carry out a valid GM/non-GM feed comparison over time: he removed GM feed from the pipeline, and watched his pigs get measurably healthier.
The review appears to be little more than pro-GM propaganda based on somewhat wild assumptions regarding the strength of the data. Put another way, no matter how much inadequate information is collected, it remains inadequate. Only a controlled study can give information from which conclusions can be drawn.
Interestingly, GM feed might well be causing considerable human health problems.
USDA statistics show that antibiotic residues continue to increase in animal products which now, of course, come from livestock fed GM.
These drugs are given routinely because they make the animals fatter. There's no reason to suppose the humans eating antibiotic residues in their food won't be similarly affected. However, since humans live much longer than cattle and chickens, getting unnaturally fattened becomes a serious health issue.
Also, confined animal feeding operations, now also using GM feed along with antibiotics, are being linked to antibiotic-resistant pathogens. At least 23,000 Americans die as a result of antibiotic resistant infections each year.
No one seems to be checking whether the increased use of antibiotics is linked to failing livestock health linked to their GM feed, but it could be causing an awful lot of ill-health and premature death in humans.
 GENETICALLY MODIFIED MEALS FROM HOT AIR - June 2013
 ECHOING GM-FRIENDLY PROPAGANDA - November 2014
 HERE'S A TTIP - November 2014
 DANISH PIG FARMER WHISTLE-BLOWER - May 2012
 REAL-WORLD DATA ON GLYPHOSATE - October 2014
- A. L. Van Eenennaam and A. E Young, 2014, Prevalence and impacts of genetically engineered feedstuffs on livestock populations, Journal of Animal Science, 2.09.14
- Dr. Mercola, American Meat Production Uses More Antibiotikcs ?Than Ever, Despite Growing Threat of Antibiiotic-pResistant Disease in Consumers, www.mercola.com, 29.10.14
- Martha Rosenberg, American Are Huge: 5 Surprising Reasons Why We May Be Geting Fatter, 27.10.14
- Jon Entine, TheDebate About GMO Safety Is Over, Thanks To A New Trillion-Meal Study, www.forbes-.com, 17.09.14
- Why Jon Entine's "trillion meal study" won't save us from GMO dangers, GM Watch 29.09.14
- Junk science and GMO toxicity, GM Watch 23.10.14