Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 11/15/2008
Publication Date: 1/31/2009
Citation: Lewis, J.B., Jenkins, K., Patterson, J., Cole, N.A., Osterstock, J., Tedeschi, L., MacDonald, J. 2009. Effects of corn processing method and wet distiller's grains plus solubles (WDGS) inclusion and source on in situ digestibility and ruminal Ph of crossbred steers [abstract]. In: Abstracts of 2009 Southern Section of American Society of Animal Science Conference, January 31-February 3, 2009, Atlanta, Georgia. Paper No. 120, p. 40.
Technical Abstract: Six ruminally and duodenally cannulated crossbred steers (472kg) were used in a 6 x 6 Latin square design to determine effects of corn processing method and wet distiller's grains plus soluble (WDGS) inclusion and source on in situ digestibly and ruminal pH. The 6 finishing diets were dry-rolled corn (DRC) or steam-flaked corn (SFC) based, with and without 20% WDGS from corn (CWDGS) or sorghum (SWDGS). All diets contained 10% alfalfa hay, 5% glycerin, and 0.70% supplement that provided vitamins, minerals, monensin, and tylosin. Diets were formulated to contain 6% dietary fat, 0.70% calcium and 13.5% crude protein. Periods were 21 days in length with 16 days for adaptation and 5 days for collections. Ruminal fluid pH was tested 4 times a day for 3 days with sampling adjusted 2-h each d so that ruminal pH was tested every 2-h over a 24-h period. Samples of DRC, SFC, CWDGS, and SWDGS were incubated in situ for 0, 2, 4, 8, 12, 16, 24, and 48-h. Samples were incubated only in steers consuming diets containing that sample. Average ruminal pH was greater in steers consuming DRC-based diets than SFC-based diets (P < 0.01), and was greater in steers consuming SWDGS than CWDGS and no WDGS (P < 0.01). Average ruminal pH for steers consuming CWDGS did not differ from steers that did not consume WDGS (P = 0.65). There was no effect of WDGS on in situ digestibility of corn (P > 0.13); however, SFC had a greater soluble fraction (P < 0.01) and a smaller potentially digestible fraction (P < 0.01) than DRC. The indigestible fractions of DRC and SFC did not differ (P = 0.12). Steam flaked corn had a greater effective ruminal digestibility than DRC (P < 0.01). Corn processing method had no effect on the soluble fraction (P > 0.21) or the indigestible fraction (P > 0.19) of WDGS. The potentially digestible fraction of CWDGS and SWDGS did not differ in SFC-based diets (P = 0.71), but was greater for SWDGS than CWDGS in DRC-based diets (P = 0.02). The effective ruminal digestibility was greater for CWDGS than SWDGS regardless of corn processing method (P < 0.01). An interaction of corn processing method and WDGS for feed efficiency is not explained by an interaction of in situ digestibility.