Because it has been so widely quoted, we have become numb to what was once a sobering statistic: we will need to feed 9 billion people by 2050. For many, this is not a reality we can easily wrap our heads around. But maybe our attention shouldn't be focused on this momentous undertaking. Instead, we must better utilize what we already produce.

Almost 40 percent of the food grown on our nation's soil never makes it to a human mouth. It is lost somewhere along the supply chain from seed to landfill.

Annually, 160 billion pounds, or enough food to fill the Rose Bowl, is thrown away. A quarter of these wasted calories trace to household food disposal. At landfills, food waste accounts for a larger volume of discarded material than plastics and metal. This organic material does not undergo a traditional composting process; it generates methane, the second most prevalent greenhouse gas (GHG) in the U.S.

Enter the ruminant. Focus has long centered on ruminants as a source of GHG, but little mention has been made of how dairy cattle actually reduce the GHG output of the human food industry. Feeding by-products to our herds reduces the likelihood that waste will be disposed of in less environmentally friendly manners.

Data from Cornell University compared the GHG emissions from feeding waste products to cattle versus disposal via combustion. On average, rations were 31 percent by-products. With this diet, the predicted total GHG release was 9 kilograms of carbon dioxide equivalents per cow daily. Had the by-products been burned as waste material, 46.2 kilograms of carbon dioxide would have been released.

The use of by-products in dairy diets reduces the environmental impact of human waste and enhances our efficiency. It does so by making use of feed components that do not compete with the human food chain but complement it.

With the expected population gains, by-product production from the human food system will grow. We would all benefit if these additional materials would be fed to cattle and not landfilled, if we are to feed a growing planet. While we will never completely eliminate waste, we must take advantage of all possible avenues to limit it.

This editorial appears on page 750 of the November 2013 issue of Hoard's Dairyman.