title: Sites of digestion in beef steers fed bermudagrass hay and supplemented with high-nitrogen feeds alone or mixed with tallow.
abstract: Five crossbred beef steers (329 kg) were used in a 5 x 5 Latin square experiment with 14-d periods to determine the effects of supplementation with high-nitrogen (N) feeds alone or mixed with tallow on sites of digestion with a basal diet of bermudagrass hay. Hay was 1.93% nitrogen, 75% neutral detergent fibre and fed at 1.83% of body weight (dry matter; DM). Supplements were basal (B; 105 g DM): 81.8% dried molasses product (DMP) and 18.2% calcium carbonate (CC); soybean meal (S; 942 g DM): 88.0% soybean meal, 9.8% DMP and 2.2% CC; S mixed with 9.8% tallow (SF; 1041 g DM); corn gluten and blood meals (CB; 662 g DM): 62.5% corn gluten meal, 20.8% blood meal, 13.6% DMP and 3.0% CC; CB mixed with 13.2% tallow (CBF; 757 g DM). Total N intake was 117, 185, 187, 174 and 172 g/d, and duodenal N flow was 121, 148, 143, 162 and 169 g/d for B, S, SF, CB and CBF, respectively, being lower for B than for other treatments and higher for supplements with the corn gluten and blood meal mix than for soybean meal (P less than 0.05). Duodenal microbial N flow was 39, 51, 49, 38 and 45 g/d for B, S, SF, CB and CBF, respectively, being greater (P less than 0.05) for supplements with soybean meal than with corn gluten and blood meals. Duodenal flow of feed N was greater (P less than 0.05) with than without high-N feeds and for supplemental corn gluten and blood meals than for soybean meal (78, 90, 86, 117 and 116 g/d for B, S, SF, CB and CBF, respectively). In conclusion, mixing of tallow and high-N feeds did not affect the extent of ruminal N disappearance, and soybean meal supplementation increased duodenal N flow less than did supplementation with corn gluten and blood meals. Increased duodenal N flow with soybean meal was associated with about equal elevations of ruminal outflow of microbial and feed N, whereas the corn gluten-blood meal mix affected the intestinal protein supply by increasing ruminal escape of feed protein.
authors.affiliation: University of Arkansas, Fayetteville 72701.
authors.forename: K M
authors.initials: KM
authors.lastname: Landis
authors.forename: A L
authors.initials: AL
authors.lastname: Goetschi
authors.forename: L A
authors.initials: LA
authors.lastname: Forster
authors.forename: A C
authors.initials: AC
authors.lastname: Brake
mesh_terms: D000821:Animal Feed; D000818:Animals; D001419:Bacteria / Q000254:growth & development; D002417:Cattle / Q000378:metabolism*; D004041:Dietary Fats / Q000378:metabolism*; D004043:Dietary Fiber / Q000378:metabolism; D004044:Dietary Proteins / Q000378:metabolism*; D004063:Digestion; D056890:Eukaryota / Q000254:growth & development; D005527:Food, Fortified; D006863:Hydrogen-Ion Concentration; D008297:Male; D006109:Poaceae; D012417:Rumen / Q000378:metabolism / Q000382:microbiology / Q000469:parasitology
chemical_list: D004041:Dietary Fats; D004043:Dietary Fiber; D004044:Dietary Proteins