It goes beyond the practice of measuring common pounds of milk a year as a yardstick for a cow's performance. A report of the ranking data, updated twice a year, is available to producers nationwide. It's also part of commercially available computer databases. Net Merit rankings also help farmers pick animals to sell to artificial insemination and embryo transfer services. ARS researchers have adapted medical technology that gives accurate information on body composition while the hogs are still alive.
Scientists now chart changes in a pig's body composition as it grows.
These technologies could become especially useful in selecting breeding animals that produce the most lean meat. Corn-based feed costs about 18 to 23 percent less than commercial fishmeal. In ARS tests, tilapia gained about a pound of weight for every two pounds of feed when they ate either corn gluten meal, corn distillers' grain with solubles or corn gluten feed, plus soybean meal for extra protein. Tilapia sales are among the fastest-growing in U.S. aquaculture. Consumers in 1994 bought about 66.5 million pounds live weight of tilapia, of which 50 million pounds were imported.