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"Get fired up" (Taste, May 25) contained a number of inaccuracies about differences in beef from various production practices. I'm assuming that while beef isn't specifically mentioned in the story that the author is referring to beef since swine and poultry can't digest the fiber in grass.

First of all, while the fat from grass-fed beef is somewhat higher in omega 3 fatty acids, there may actually be less omega 3s than in grain-fed beef if the meat has less marbling, which is usually the case. There is no significant difference in protein content.

Most cattle are raised and fed in facilities allowing them to spend time outdoors if they so choose. Anyone raising cattle knows that keeping cattle healthy is paramount and no one using facilities that compromise health will stay in business very long.

One of the persistent myths is that meat offered for sale contains antibiotics. That would be illegal. Antibiotics are used in a couple different ways by cattlemen. The first is treating acute infections and grass-fed cattle aren't immune from this problem. Some cattle are fed a low level of antibiotic to prevent liver infections caused by acidosis which is caused by a sudden increase of starch in the diet. The third use is to add an ionophore to the diet to improve feed efficiency by altering the colony of microbes in the rumen to improve feed efficiency and, by doing so, to improve sustainability.

This practice also reduces methane emissions. Ionophores also reduce the potential for acidosis. One of the great opportunities for cattlemen to improve sustainability is to figure out practical ways to include ionophores in the diets of grazing cattle. The Food and Drug Administration classifies ionophores as antibiotics but most cattle nutritionists disagree, arguing that while they have an effect on bacteria they work by altering the gut environment to favor more beneficial bacteria. The ionophores pass through the digestive tract and do not relocate into muscle tissue. (I was co-author of a scientific paper on the use of an ionophore in cattle rations that was published in 1976.)

All meat contains hormones. Using them in beef production does boost weight gain along with an improvement in conversion of feed into beef which makes them another effective tool for improving sustainability without dramatically raising hormone levels in the meat. What does increase hormone levels dramatically is pregnancy, and carnivores of all species have been safely eating meat from pregnant females for millions of years.

Grazing is a most useful soil management practice but the nutritional quality of grazing forages is highly variable and doesn't always provide an optimum diet for the animal. In many scenarios there isn't enough starch or sugar to meet the animal's needs and sustainability would be improved by adding some grain to the diet. About a decade ago a Life Cycle Assessment of the entire American beef industry was performed and found that while beef is produced in a wide variety of ways and in a wide variety of environments, the predominant American system of utilizing fibrous feedstuffs through most of the production cycle and a high energy, predominantly grain ration for the last few months is the most sustainable.

As for the quality of the beef from different types of production, there are some differences. Generally, grain finished beef is better for tenderness and marbling, and grass-fed beef is usually leaner. Flavor is a matter of personal preference, and while I prefer grain fed, I have had some very good grass-fed beef as well.

I thank you for choosing beef and encourage you to choose whatever type you prefer, knowing it was raised responsibly.

John Schafer, of Buffalo Lake, is a farmer and research committee chairman, Minnesota Beef Council.