ARS | Publication request: Heat production and efficiency of energy utilization in finishing steers fed diets containing wet distillers grains with solubles (WDGS)

Submitted to: Joint Abstracts of the American Dairy Science and Society of Animal Science
Publication Type: Abstract Only
Publication Acceptance Date: March 3, 2008
Publication Date: July 23, 2008
Citation: Spiehs, M.J., Ferrell, C.L., Nienaber, J.A., Brown Brandl, T.M., Shackelford, S.D. 2008. Heat production and efficiency of energy utilization in finishing steers fed diets containing wet distillers grains with solubles (WDGS)[abstract]. Journal of Animal Science 86(E-Suppl. 2)/Journal of Dairy Science 91(E-Suppl. 1):583.

Technical Abstract: This study was conducted to evaluate heat production (HP) and efficiency of energy utilization in feedlot cattle fed diets containing WDGS. Steers (n=24, BW = 452.5 ± 36.8 kg) were assigned in a randomized complete block design to diets containing 0, 20, 40, or 60% WDGS on a DM basis providing calculated ME concentrations of 3.11, 3.06, 3.05, and 3.02 Mcal ME per kg and 0.70, 5.89, 7.63, and 9.36% fat, respectively. The trial consisted of three 96 h periods of total urine and feces collection followed by 6 h of indirect calorimetry with 8 steers per period (2/trt). Data were analyzed as a randomized complete block design. Regression analysis was conducted to determine linear and quadratic effects. There was a linear decrease in DMI (P < 0.01; R2 = 0.29) with increasing level of WDGS in the diet. As a result, ME intake decreased as levels of WDGS increased in the diet. Heat production was similar for cattle fed all four diets but retained energy (RE) decreased linearly (P < 0.01, R2 = 0.40) with increasing inclusion of WDGS in the diet. Due to the high fat content in WDGS, RQ decreased as WDGS increased in the diet. Based on this data, HP for cattle fed diets containing WDGS can be estimated using the following equation: HP = 174.9 + 16.4*DMI + 11.5*proportion of WDGS in diet. This study indicates that finishing cattle fed increasing levels of WDGS in the diet have decreased efficiency of energy utilization which could lead to decreased performance in the feedlot, primarily due to lower DMI. Keywords: distillers grains, energy, finishing cattle