Emissions of ammonia, nitrous oxide and methane from the manure of feedlot-finished cattle receiving diets with rumen undegradable protein

Author(s)

Larissa de Melo Coelho

• Document type: Master's Dissertation
• Press: Jaboticabal. 2021-07-03.
• Institution: Universidade Estadual Paulista (Unesp). Faculdade de Ciências Agrárias e Veterinárias. Jaboticabal
• Defense date: 2021-05-19
• Advisor: Telma Teresinha Berchielli; Abmael da Silva Cardoso; Juliana Duarte Messana; Liziane de Figueiredo Brito

Abstract

The inclusion of higher levels of rumen undegradable protein (RUP) in bovine diet is adopted as a strategy to improve the efficiency use of amino acids, and reduce nitrogen (N) excretion to the environment. Thus, it is necessary to evaluate the effect of sources of RUP in diets on methane (CH4), nitrous oxide (N2O) and ammonia (NH3) emissions in the manure of feedlot-finished cattle. The evaluated hypothesis was that the use of different RUP sources in diet would reduce N loss via urine and contribute to a reduced N2O, CH4 and NH3 emission to the environment. The experimental design was completely randomized, with nine replicates per pen (chambers for the evaluation of N2O, CH4 and NH3 emissions from manure, considering feces and urine), arranged in an area of 65 m2, near the feeders, where the manure was deposited the most frequently. Manure came from Nellore animals fed with three treatments as follows: soybean meal (SM, RDP source), by-pass soybean meal (BSM, RUP source) and corn gluten meal (CGM, RUP source). The confinement lasted 112 days, during which weekly samplings of N2O and CH4 were performed. After removing the animals from feedlots, NH3 emission was evaluated during 77 days. The protein sources used in the diet did not affect the N and C concentration in urine, C concentration in feces, and N balance (P > 0.05). There was a higher C/N of feces (P < 0.001) and urine (P < 0.001) in the BSM source than the CGM source and a higher concentration of N in the feces in the CGM source than the BSM source (P = 0.012). The manure from animals fed with sources of RUP (BSM and CGM) presented higher concentration of N (P = 0.036) and ammonium (P = 0.001) compared to SM source. However, RUP sources presented lower C/N in relation to SM source (P = 0.001). The RUP sources resulted in a higher N2O emission than the RDP source (P = 0.030), while BSM resulted in a higher N2O emission than CGM (P = 0.038) (SM = 633, BSM = 2521, and CGM = 1153 g ha-2 N-N2O); however, there were no differences in CH4 and NH3 emissions (P > 0.05) In conclusion, the use of RUP in diets did not affect N excretion of animals or CH4 and NH3 emission from manure, but increased N2O emission from the manure. (AU)

• FAPESP's process: 19/11864-2 - Emission of greenhouse gases in bovine excreta supplemented with rumen undegradable protein in confinement
• Grantee: Larissa de Melo Coelho
• Support Opportunities: Scholarships in Brazil - Master