There is an interesting story here. It's just that the movie doesn't tell it very well.
KING CORN: A REVIEWThe film King Corn is a propaganda piece and full of misleading statements. First, the hair test that Dr Macko uses to estimate the percentage of corn in the diet, while useful for what it was intended, gives somewhat misleading results in this application. First, a little background on this test. This test depends on the fact that in nature, some elements, such as carbon, have different forms with different weights, due to having differing numbers of neutrons in their nucleus, and thus slightly variable weights. These differing weights of the same elements are called isotopes (from the Greek isos =equal topos=place). Thus in the case of carbon, we have the normal isotope C12 with 6 protons and six neutrons for an atomic weight of 12, and we have isotope C13 with 6 protons and 7 neutrons for an atomic weight of 13. In nature there is a mixture of these two isotopes, and plants take up and use both isotopes from the CO2 in the air to use in building plant tissue, and we have both isotopes in our body used interchangeably in our tissues and chemical reactions.The test Dr. Macko is using to differentiate corn from other plant materials in the diets of humans and livestock utilizes the fact that a class of plants, called C4 plants, which includes corn, preferentially take up a different proportion of these two isotopes of carbon to make their tissues than do the class of C3 plants, which comprise the vast majority of other plants including forages.. These ratios of isotopes of carbon continue on in the food chain, and their proportions can be measured in the hair to determine which proportions of plants have been consumed, either C3 or C4 (assumed in the film to be corn). What this film does not disclose however, is that livestock consume a number of other C4 plants in their rations other than corn. Sorghum is also a C4 plant. It is grown extensively throughout the West in dryer states such as Texas, Oklahoma, Kansas, Nebraska, and parts of Colorado. In areas where it is grown it is used almost exclusively for livestock feeding. Thus, the above test would be incapable of differentiating an atom of carbon as coming from livestock fed corn or sorghum. This same rationale would also apply to millet, which is also a C4 plant used for livestock feeding, grown in the northern central states, chiefly the Dakotas and Nebraska.When we turn to plant foods directly consumed by humans, we also find a problem with the test used. Sugar cane is also a C4 plant, and thus the sugar derived from it would be indistinguishable from corn in whatever form consumed as far as the hair test described. These factors thus makes this test somewhat unreliable as a measure of exactly how much corn is in our diet, either directly or in the diets of the livestock we consume.Next, I want to turn to their description of cattle feeding, and their reporting of its effects. It is somewhat disappointing that the makers of this film did not avail themselves of the opportunity to educate themselves as to the facts regarding the cattle feeding industry when they had a good opportunity to do so. First, as to their claim that feeding corn causes death within 120 days. Curiously, their reference for this appears to be a random passer-by they met during filming. The reality is quite different. Traditionally feeders take in either grass fed calves at 450 to 600 pounds, or grass fed yearlings (1 year old animals) at 550 to 800 pounds, and finish them out with a mixture of grains, protein supplements, roughage, and vitamin/mineral supplements to a slaughter weight of 1100 to 1400 pounds. Cattle are usually fed an average of 177 days if started on feed as yearlings, and 237 days if started as calves, according to John D. Lawrence, extension livestock economist, with the article available at http://www.extension.iastate.edu/agdm/livestock/html/b1-35.htmlThe grain or energy component of the ration is balanced with whatever grain happens to be available and most cost effective locally. In the Mid-west that would be corn. In other parts of the western US, sorghum, millet or barley would be the energy component of choice, and in the eastern US soft wheat would often be the feed of choice.Dairy cows are also fed a high concentrate ration required for high milk production. They are feed high rates of grain over many milking cycles with obviously no early death, as a high value dairy cow obviously would not be fed such high grain diets if it would lead to early death.The acidosis referred to in the movie certainly can become a problem. It is caused by an overgrowth of lactic acid producing microorganisms in the rumen when high-carbohydrate foods are introduced too rapidly and abruptly. It is easily controlled or prevented by introducing high-concentrate feeds gradually over a period of time, a common practice used in all feeding and dairy production situations. The idea that grain feeding i
May 3 - 09:04 AM
Richo, this is one of the most informative posts I have ever read! I suggest you post this information on other forums, including IMDb but maybe edit some of the science speak down a bit. Thank you for the post!
Jul 1 - 03:03 AM
Jul 9 - 05:33 AM