Authors: Sticker LS; Bunting LD; Wyatt WE; Wolfrom GW
Abstract: Forty-eight Angus and Brangus steers (249 kg initial BW) were used in a randomized complete block design. Steers grazed annual ryegrass (Lolium multiflorum [L.] Lam.) for 107 d and were sampled at 35 and 70 d. Treatments consisted of a corn supplement (C) or corn supplement plus either 80 mg.steer-1.d-1 of lysocellin (L) or 60 mg.steer-1.d-1 of tetronasin (T). When compared with C, ADG of L- and T-fed steers was higher (P less than .05) for the complete 107-d study (1.15 vs 1.25 kg/d). At 35 d, ruminal acetate:propionate ratio tended (P = .07) to be higher for C than for L- and T-fed steers (4.6 vs 3.8). When compared with T, steers fed L tended (P = .11) to have higher acetate:propionate ratios. Ruminal concentrations of ammonia and free amino acids were not affected (P greater than .05) by treatment, but ruminal proteolytic activity tended (P = .13) to be lower for L- and T-fed than for C steers at 70 d. Ionophores did not alter (P greater than .05) ruminal mineral concentrations, but ruminal Mg concentration tended (P = .14) to be higher for T- than for L-fed steers at 70 d. When compared with L- and T-fed steers, C steers had lower (P less than .05) plasma concentrations of Mg (23.7 vs 21.9 mg/liter) and Ca (113.0 vs 104.2 mg/liter) at 35 d. Plasma mineral concentrations were similar (P greater than .05) for L- and T-fed steers. Data are interpreted to indicate that L and T may improve ADG, decrease ruminal acetate:propionate ratio, and alter mineral metabolism.
Keywords: Amino Acids/analysis; Ammonia/analysis; Animal Feed; Animals; Calcium/analysis/blood; Cattle/blood/*growth & development/metabolism; Ethers/pharmacology; Fatty Acids, Volatile/analysis; Furans/pharmacology; Ionophores/*pharmacology; Lolium; Magnesium/analysis/blood; Male; Random Allocation; Rumen/chemistry/*drug effects/metabolism; Weight Gain/drug effects|
Journal: Journal of animal science Volume: 69 Issue: 11 Pages: 4273-8 Date: Nov. 1, 1991 PMID: 1752803 |
Sticker LS, Bunting LD, Wyatt WE, Wolfrom GW (1991) Effect of supplemental lysocellin and tetronasin on growth, ruminal and blood metabolites, and ruminal proteolytic activity in steers grazing ryegrass. Journal of animal science 69: 4273-8.
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