“Watch the Fat”
by Chris Reinhardt, feedlot specialist
Since the advent of cattle feeding, we learned early on that cattle make very good use of by-product feeds that monogastrics—pigs, chickens, and people—can use very little of productively, especially if cellulose—fiber—makes up the majority of the feed. The corollary to that guideline is that if cattle have to compete with humans for a feedstock, humans win.
Three decades ago, wheat was a common ingredient in feedlot diets throughout the high plains. Today, the opportunity only occasionally presents itself due to temporary pricing inversions. We like our bread and Twinkies—humans win.
A similar, but more subtle phenomenon has taken place gradually over the past few years, since the ethanol industry boom began. Corn oil is worth more marketed to humans as that—corn oil—than to livestock in the form of distillers’ grains (DG), and the ethanol plants have developed novel technologies to extract an increasing amount of that oil, although not nearly all, from the by-product.
I am a capitalist and am in favor of ethanol companies finding a way to increase their income from their secondary product streams, but as a cattle nutritionist, I also must be aware of changes the removal of oil will make on the value of the by-product for cattle feed.
Early on, the fat content of corn DG was commonly between 11 and 13%; however, today, some corn DG with fat levels near 8%, and some as low as 4%. Fat in cattle feed contains about 2.25 times more energy than carbohydrates, so removing fat such that the void left is filled with predominantly cellulose, would be expected to result in a lower energy feed.
Recent research conducted at South Dakota State University concluded that for every 1% decrease in fat content of the finishing diet, we should expect a 1 Mcal NEg / cwt reduction in energy value. So if DG makes up 40% of the finishing diet, and fat content of those DG was formerly 12% and is now 8%, we’ve lost 1.6% fat in the final diet, or 1.6 Mcal NEg/cwt.
Wet DG with solubles has about 15% greater NEg vs. dry-rolled corn. If the value of DG over corn was previously 15% in a dry-rolled corn-based finishing diet, we can reasonably expect the new value to be about 12.5% over corn. So if we had been paying $5 / bushel for corn, we should expect a decrease in feed value of the DG of $5.24 / ton on a 100% dry matter basis.
More broadly, if the fat percentage in DG has decreased over time, the feed value of DG for a cattle finishing diet is also decreased, and the astute cattle feeder should adjust pricing expectations accordingly.
