Danish pig farmer whistleblower

May 2012
Photo by Klaus Höpfner at de.wikipedia [GFDL (
or CC-BY-SA-3.0 (], from Wikimedia Commons
The Danish pig industry is well-known for combining intensive production with outstanding productivity (almost 30 weaned piglets per sow per year), and exceptionally low antibiotic use (as much as a quarter of what some countries find they have to apply). In fact, antibiotic use in Denmark is strictly controlled by veterinarians and is recorded.

Danish pig farmers might be about to become well-known for something else: they may prove the world's whistle-blowers for problems arising in livestock given GM feed.

Before any new feed crop is put on the market, its feeding value is tested.

Feed assessment consists of compositional analysis (how much protein, fat, carbohydrates, trace nutrients etc. it contains), and a feed conversion study (how much meat the animals produce when given the new feed). GM crops may also have some additional testing carried out on an analogue of the novel protein they contain.

Once such assessments have been made and found commercially acceptable, the feed is considered substantially equivalent to other feeds and becomes GRAS (generally recognised as safe). After that, the feed will be available in the market and no further monitoring takes place.

Very little in the way of official records are kept (either in the USA, Europe or anywhere else in the world) of what happens on the farm once the feed goes into large-scale use. Effectively, the livestock which become your food are guinea-pigs in an uncontrolled experiment. This real-life 'experiment' is uncontrolled because no one is required to keep a note of the health of the animals before and after introducing GM feed. If a farmer's experiences are bad, all he is able to pass on is anecdotal evidence, and such information is easily dismissed. Worse still, if there's an ongoing slow decline in animal health, farmers and veterinarians may not be aware of anything going wrong, because any problems quickly become “a new norm”.

However, Denmark is one country which keeps its finger on the farmyard pulse much better than most. Danish pig-farmer, Ib Borup Pedersen, who has a flair for observing and recording, has been so disturbed by what what he's finding in his styes, that he's caused a storm by telling the farming press.

For example, after changing his pigs' feed from GM to non-GM, he recorded:
  • A huge reduction in diarrhoea within two days (at one point two years previously, when the diarrhoea was at its worst, there were nearly 30% deaths a month and not enough surviving sows to nurse the piglets)
  • No deaths from bloat and ulcers (previously one per month), nor from loss of appetite (previously two per year)
  • Two to four extra weaning piglets per sow and 0.3 more live births per sow
  • Weaned piglets are stronger and more evenly sized
  • Labour requirements have reduced by 20-30 man-hours per month
The farmers also considers that the piglets are more active and that his medicine usage has been halved.

The economic realities of farmer Pedersen's findings are that the extra cost of GM-free feed is tiny compared with the losses due to productivity-failure, deaths and medical bills. In fact, as he has pointed out, his savings from reduced medicines alone have paid for the extra cost of buying GM-free soya.

His concern over GM feed has focused on its probable contamination with 'Roundup', glyphosate-containing, herbicides. So much so that he told the press
“I believe that the effects of DDT and Thalidomide can be described as trivial compared to the effects we are now seeing from the use of GMO crops that are sprayed with Roundup”.
The Danish pig research centre (the VSP) has already press-released plans for a trial of the effects of GM feed on the pig gastrointestinal tract later in 2012. The centre stresses that this is in response to negative experiences with glyphosate-treated GM soya feed in America, and that the study is being undertaken for the sake of the animals. Its trial will involve 100 growing pigs* fed GM and non-GM soya and cereals.
*Note. Growing pigs are about 10 weeks old or 30 kg body weight (i.e. fully weaned) until slaughter at about 110 kg, and are given a diet which optimises growth rate. Commercially, this is a very important stage at which the feed must be right as the diet affects meat and fat quality and quantity.


Modern pig-feed is based on soya (the cheapest form of protein available) diluted with a larger proportion of maize. This is not a natural diet for the animals and has to be very heavily processed to optimise its nutritional composition and remove anti-nutrients. Both soya and maize in European pig feed are now routinely genetically transformed varieties.

All soya contains natural anti-nutrients including: antigenic proteins which will induce allergic reactions in the gut; enzyme disrupters which compromise protein digestion; and indigestible sugars on which unwelcome gut microbes can thrive. These must be removed from the feed or they will cause a failure to thrive. Feed manufacturers are well able to process soya so as to reduce the known anti-nutrients to perfectly safe levels for pigs at all stages of their lives. But what quantity of unknown allergens, enzyme-disruptors or novel sugars might remain in GM soya?

Then, there's the 'Bt' insecticidal protein present in GM maize: this is damaging to plants (see Bt IS TOXIC TO PLANTS - July 2011) and alters the composition of the maize (see PIG FEEDING STUDY NOT REASSURING - February 2012), both of which could upset the pigs' digestive system.

And then, there's the Roundup. The Danish farmer has done his homework. He knows there's a stack of evidence pointing to a health risk from the Roundup herbicide accumulated by both GM soya and some GM maize. Unexpected substances such as those outlined above could also arise in the feed due to the GM plants' need to deal with the toxic herbicide they've absorbed.

If you put GM soya plus all its unknowns in a feed with GM maize plus all its unknowns plus Roundup with all its 'confidential' (secret) ingredients, let's face it, you can't predict a safe outcome.

The VSP was quick to distance itself from farmer Pedersen. It insists its study is being undertaken in response to US reports, and that its interest is in the animals' health. However, it has designed an experiment in which the control is the GM-contaminated feed and the test is non-GM feed. The study will then observe whether growing pigs (at the least vulnerable stage of their short lives) show improvement in health when the standard, GM, feed is withdrawn from the diet. This protocol will serve to test, not so much GM-soya safety, but possible commercial implications and the veracity of the farmer's claims.

Since agri-research facilities in Denmark are controlled by the farmers or government, they are less influenced by the biotech industry, and there's less chance of a cover-up of inconvenient truths. Let's hope that the trial about to start in Denmark will be followed by more detailed tests on farrowing sows and their weaning piglets, and on GM maize as well as GM soya.

GM-Free Cymru has interviewed farmer Pedersen to produce 'A Danish Dossier'.

You might also like to suggest to DEFRA that, given the importance to the UK pig industry of getting to the bottom of this problem, it would be good to help the Danish scientists out.

(If you want to remind yourself about the host of problems emerging in relation to Roundup herbicide, check out WHY LOOK OUT FOR GM SOYA? - February 2011. A lot more evidence has come to light since this summary was compiled.)

  • Maria C. Walsh, 2011, Effects of short-term feeding of Bt MON810 maize on growth performance, organ morphology and function in pigs, British Journal of Nutrition 107
  • Hamlet Protein and HP 200, and, 2012
  • Feed formulation - square method, Pinoy Agribusiness, 23.06.10
  • Infopaks on Nutrition, Department of Agriculture, Forestry and Fisheries, South Africa,,, accessed May 2012

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