title: Influence of processing method on comparative digestion of white corn versus conventional steam-flaked yellow dent corn in finishing diets for feedlot cattle.
abstract: Four Holstein steers (137 ± 2 kg) with cannulas in the rumen and proximal duodenum were used in a 4 × 4 Latin square design to evaluate the influence of processing method on comparative digestion of white corn. Treatments consisted of a basal finishing diet containing 80% corn grain (DM basis) as 1) dry-rolled white corn (DRWC), 2) steam-flaked white corn (SFWC) with 0.36 kg/L flake density (SFWC36), 3) SFWC, 0.31 kg/L flake density (SFWC31), and 4) steam-flaked yellow corn (SFYC) with 0.31 kg/L flake density (SFYC31). Characteristics of ruminal, postruminal, and apparent total tract digestion of OM, starch, and N were similar (P ≥ 0.08) for SFYC31 and SFWC31 treatments. Decreasing flake density of white corn (from 0.36 to 0.31 kg/L) did not affect (P = 0.22) ruminal OM digestion, but increased (1.9%, P = 0.07) apparent total tract OM digestion. Compared with dry rolling, steam flaking white corn increased ruminal (9.4%, P = 0.05), postruminal (14.4%, P < 0.01), and apparent total tract OM digestion (8.2%, P < 0.01), reflecting corresponding increases in ruminal (13.3%, P < 0.01), postruminal (43%, P < 0.01), and apparent total tract (12.3%, P < 0.01) starch digestion. Apparent postruminal and apparent total-tract N digestion also were greater (6.5 and 5.6%, respectively, P = 0.04) for SFWC than for DRWC. The DE value of SFWC and SFYC diets was similar, averaging 3.39 Mcal/kg. The DE value of SFWC was greater (8.1%, P < 0.01) than that of DRWC. Ruminal pH (4 h postprandial) averaged 5.74 and was not affected (P ≥ 0.48) by dietary treatments. Compared with dry rolling, steam flaking markedly enhances the feeding value of white corn, with optimal flake density being less than 0.36 kg/L. Although white corn has greater vitreous endosperm content, characteristics of ruminal starch digestion and undegradable intake protein are similar to conventional yellow dent corn when processed to a similar flake density (0.31 kg/L). However, postruminal and apparent total tract starch digestion tends to be slightly less for flaked white corn than for yellow corn.
authors.affiliation: Universidad Autónoma de Baja California, Mexicali, Baja California, México 21100. alejandro.plascencia@uabc.edu.mx
authors.forename: A
authors.initials: A
authors.lastname: Plascencia
authors.forename: R M
authors.initials: RM
authors.lastname: Bermúdez
authors.forename: M
authors.initials: M
authors.lastname: Cervantes
authors.forename: L
authors.initials: L
authors.lastname: Corona
authors.forename: H
authors.initials: H
authors.lastname: Dávila-Ramos
authors.forename: M A
authors.initials: MA
authors.lastname: López-Soto
authors.forename: D
authors.initials: D
authors.lastname: May
authors.forename: N G
authors.initials: NG
authors.lastname: Torrentera
authors.forename: R A
authors.initials: RA
authors.lastname: Zinn
mesh_terms: D000821:Animal Feed / Q000032:analysis*; D000822:Animal Husbandry; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D002417:Cattle; D004032:Diet / Q000662:veterinary*; D004063:Digestion / Q000502:physiology*; D005511:Food Handling / Q000379:methods*; D008297:Male; D009753:Nutritive Value; D013227:Steam; D003313:Zea mays / Q000145:classification*
chemical_list: D013227:Steam