Ben Franklin's tree-perching "Bird of Courage" has been transformed into a flightless butterball so top-heavy they are physically incapable of mating (necessitating artificial insemination). Turkeys are bred to grow so fast, a group of veterinary researchers concluded, "they are on the verge of structural collapse."

Wild turkeys grow to be 8 pounds; turkeys raised for meat are more like 28 pounds. Their skeletons cannot adequately support such weight, leading to degenerative hip disease, spontaneous fractures, and up to 20% mortality due to lameness in problem flocks. An editor at the leading U.S. agribusiness weekly wrote:

Turkeys have been bred to grow faster and heavier but their skeletons haven't kept pace, which causes 'cowboy legs.' Commonly, the turkeys have problems standing...and fall and are trampled on or seek refuge under feeders, leading to bruises and downgradings as well as culled or killed birds.

Commercial breeds may outgrow their cardiovascular systems as well as their skeletons. Modern-day turkeys have been bred to grow so fast that up to 6% simply drop dead from acute heart failure at just a few months of age. It still may make good economic sense in the end, though. In fact, the sudden deaths of turkeys have been regarded by some in industry as a sign of "good flock health and fast growth rate as in the case of sudden death syndrome (flip-over) in broiler chickens." As one producer wrote, "Aside from the stupendous rate of growth...the sign of a good meat flock is the number of birds dying from heart attacks."

Two prominent poultry researchers offer the following economic analysis:

The situation has forced growers to make a choice. Is it more profitable to grow the biggest bird possible and have increased mortality due to heart attacks, ascites, and leg problems, or should birds be grown slower so that birds are smaller, but have fewer heart, lung and skeletal problems?...A large portion of growers' pay is based on the pound of saleable meat produced, so simple calculations suggest that it is better to get the weight and ignore the mortality.

This raises both animal welfare and food safety concerns. The public health implications arise from a physiological trade-off between maximal muscle mass and optimal immune function. As detailed in a review I just had published in an international agriculture journal, there appears to be an inverse relationship between disease resistance and growth rates of farm animals accelerated by selective breeding or genetic engineering. This may explain why turkey products have been found to be among the most contaminated of meats.

Every year the Centers for Disease Control and Prevention tests the U.S. retail meat supply for the presence of fecal bacteria. When consumers think of manure in ground meat, hamburger comes to mind, but the latest survey found only 7 out of 10 samples of beef positive for E. coli, compared to more like 9 out of 10 samples of turkey, including the type blamed for human urinary tract infections. Turkey also had the highest contamination rates for Enterococcus faecalis and multidrug resistant Enteroccocus faecium. For a video on last year's CDC report, see Fecal Bacteria Survey.

In today's NutritionFacts.org video-of-the-day, U.S. Meat Supply Flying At Half Staph, I profile the landmark new report this year Multidrug-Resistant Staphylococcus aureus in U.S. Meat and Poultry that found that supermarket turkey was the meat most contaminated by staph bacteria (77% of turkey samples) and multidrug-resistant staph (79% of turkey staph), including the dreaded MRSA, the "superbug" now responsible for killing more Americans than AIDS. Turkey products also beat out other meats for contamination with Clostridium difficile, as reviewed in Toxic Megacolon Superbug.

The Pew Commission on Industrial Farm Animal Production, which included a former U.S. Secretary of Agriculture, concluded that "The present system of producing food animals in the United States...presents an unacceptable level of risk to public health...." Tomorrow's video-of-the-day will explore the public health implications of industrial pork production, and on Thanksgiving Eve I'll review the latest on MRSA in U.S. Retail Meat.

-Michael Greger, M.D.

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