Effects of encapsulated nitrate on growth performance, carcass characteristics, nitrate residues in tissues, and enteric methane emissions in beef steers: Finishing phase

Citation

Lee, Chanhee & Araujo, R. & Koenig, K. & Beauchemin, Karen. (2017). Effects of encapsulated nitrate on growth performance, carcass characteristics, nitrate residues in tissues, and enteric methane emissions in beef steers: Finishing phase. Journal of Animal Science. 95. 3712. 10.2527/jas2017.1461.

Plain language summary

A finishing feedlot study was conducted with beef steers to determine effects of encapsulated
nitrate (EN) on growth performance, carcass characteristics,methane production, and nitrate residues in tissues. A total of 132 crossbred steers were backgrounded in a feedlot for 91 d and transitioned for 28 days to the high-concentrate diets evaluated in the present study. We concluded that inclusion of 2.5% EN in a finishing diet (equal to about 2% nitrate) did not cause nitrate toxicity or any health problems in the long term. In comparison with supplemental urea, feeding EN improved feed efficiency, but there was no reduction in methane production.

Abstract

© 2017 American Society of Animal Science. All rights reserved. A finishing feedlot study was conducted with beef steers to determine effects of encapsulated nitrate (EN) on growth performance, carcass characteristics, methane production, and nitrate (NO3 −) residues in tissues. The 132 crossbred steers were backgrounded in a feedlot for 91 d and transitioned for 28 days to the high-concentrate diets evaluated in the present study, maintaining the treatment and pen assignments designated at the start of the backgrounding period. The steers were initially assigned to 22 pens (6 animals per pen) in a randomized complete block design with BW (18 pens) and animals designated for methane measurement (4 pens) as blocking factors. Five animals in each pen designated for methane measurement (total of 20 animals) were monitored for methane emissions in respiratory chambers twice during the experiment. Pens received 3 dietary treatments (7 pens each): Control, a finishing diet supplemented with urea; 1.25% EN, control diet supplemented with 1.25% encapsulated NO3 − in dietary DM that partially replaced urea; and 2.5% EN, control diet supplemented with 2.5% EN (DM basis) fully replacing urea. The final pen designated only for methane measurement received a fourth dietary treatment, 2.3% UEN, the control diet supplemented with unencapsulated NO3 − (UEN) fully replacing urea. The cattle weighed 449 ± SD 32 kg at the start of the 150-d finishing period. The 2.5% EN diet decreased (P < 0.01) DMI compared with Control and 1.25% EN diets. Feeding EN tended to increase (P = 0.092) ADG compared with Control, and G:F was improved (P < 0.01) for EN compared with Control. No differences in methane production (g/d) and yield (g/kg DMI) were observed among treatments. Inclusion of EN in the diets increased (P ≤ 0.03) sorting in favor of large and medium particles and against small and fine particles. Plasma NO3 − and NO2 − concentrations were elevated (P < 0.01) with EN in a dose-response manner, but total blood methemoglobin levels for all treatments were low, below the detection limit. Feeding EN increased (P < 0.01) NO3 − concentrations of samples from muscle, fat, liver, and kidney; NO3 − concentrations of these tissues were similar between 1.25% EN and 2.3% UEN. In conclusion, inclusion of 2.5% EN in a finishing diet (DM basis; about 2% NO3 −) did not cause NO3 − toxicity or any health problems in the long term. In comparison with supplemental urea, feeding EN improved feed efficiency despite increases in sorting against dietary EN.

Publication date

2017-08-02

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