Submitted to: Journal of Animal Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 4/14/2013
Publication Date: 8/1/2013
Publication URL: http://handle.nal.usda.gov/10113/57176
Citation: Hales, K.E., Bondurant, R.G., Luebbe, M.K., Cole, N.A., MacDonald, J.C. 2013. Effects of crude glycerin in steam-flaked corn-based diets fed to growing feedlot cattle. Journal of Animal Science. 91(8):3875-3880. Interpretive Summary: Increasing corn prices has made it desirable to identify alternative feed resources for beef cattle. Crude glycerin is a byproduct of biodiesel production from soybeans and its availability as a feed has increased as a result of the growth of the biofuel industry. Corn and a source of fiber are typically found in beef cattle finishing diets. We have found that when up to 7.5% of the steam-flaked corn diets are substituted with glycerin, cattle body weight gain increased; however, over 7.5% results in a decrease in body weight gain. Feed efficiency decreased with increased substitution of glycerin for corn. Adding glycerin to cattle diets is more effective when it replaces alfalfa hay rather than corn. In vitro digestibility studies showed that inclusion of glycerin in place of corn decreased the digestibility of the feed. These studies suggest the moderate inclusion of glycerin in beef cattle diets can be used as a strategy to reduce diet cost.
Technical Abstract: Crude glycerin is a byproduct of biodiesel production and has recently become more available as a livestock feed with the growth of the biofuel industry. Two experiments were conducted to evaluate the use of crude glycerin (GLY) as a feed ingredient in steam-flaked corn (SFC)- based growing diets fed to beef cattle. In Exp. 1, crossbred steers (n = 50, initial BW = 282 ± 2 kg) were used to determine the effects of GLY when included at 0, 2.5, 5, 7.5, and 10% of DM in a growing diet on cattle performance. In Exp. 2, crossbred steers (n = 54, initial BW = 283 ± 1 kg) were used to determine the effects of replacing SFC (REPSFC) or alfalfa hay (REPAH) with 7.5% GLY or a control diet without GLY (CON) on growing steer performance. In Exp. 1, final BW tended to respond in a quadratic manner (P = 0.09) in which it increased from 0 to 7.5% GLY and decreased from 7.5 to 10% GLY. Dry matter intake did not differ (P > 0.23); yet, ADG responded quadratically (P = 0.04); where it increased from 0 to 7.5 GLY and decreased from 7.5 to 10% GLY. Feed efficiency (G:F) decreased linearly (P = 0.05) with increasing GLY concentration. In Exp. 2, final BW was greater for steers fed REPAH than CON or REPSFC (P = 0.04). Steers fed REPAH had a greater ADG than CON or REPSFC (P = 0.04). When GLY replaced SEC, ADG increased from 0 to 7.5% GLY where it was maximized before decreasing from 7.5 to 10% GLY inclusion. Replacing 7.5% alfalfa hay (AH) in a growing diet with GLY can be beneficial to animal performance, which is likely the result of GLY being greater in energy than AH.