lördag 22 oktober 2011

Kycklingar då och nu

Matt Ridley:

Ten years ago, Dr. Gerry Havenstein at North Carolina State University did a careful study of weight gain in chickens, comparing (under identical conditions) a modern 21st-century breed with a 1957 breed that had been kept going. He found that, at six weeks of age, the modern chicken was six times as heavy and had 9% more breast meat. Of that improvement, he found, 85% came from genetics and only 15% from better feed.

By 2001, when the study was done, a chicken reached the weight at which it would be killed in one-third of the time and after eating one-third of the food compared with the 1957 breed. That represents a considerable reduction in waste and in the amount of land devoted to growing feed per chicken.

In the decade since, there has been a consistent and linear increase in both weight gain and food-conversion efficiency in the broiler industry. Outside the lab, on the farm, chickens have accelerated their daily rate of growth by about 0.89 grams per year.

Några tidigare inlägg på temat:
- Världens bomullsproduktion 1980-2011
- Världens spannmålsproduktion upp sju procent 2008
- Mjölkproduktion 2007 kontra 1944

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