Models to predict nitrogen excretion from beef cattle fed a wide range of diets compiled from South America.

Autor:	Souza VC; Department of Animal Science, University of California, Davis, CA 95616, USA., Congio GFS; Noble Research Institute LLC, Ardmore, OK 73401, USA., Rodrigues JPP; Department of Animal Production, Animal Science Institute, Universidade Federal Rural do Rio de Janeiro, Seropédica, RJ 23897-000, Brazil., Valadares Filho SC; Department of Animal Sciences, Universidade Federal de Viçosa, Viçosa, MG 36570-900, Brazil., Silva FAS; Department of Animal Sciences, Universidade Federal de Viçosa, Viçosa, MG 36570-900, Brazil., Rennó LN; Department of Animal Sciences, Universidade Federal de Viçosa, Viçosa, MG 36570-900, Brazil., Reis RA; Department of Animal Science, Universidade Estadual Paulista, Jaboticabal, SP 14884-900, Brazil., Cardoso AS; Range Cattle Research and Education Center, University of Florida, Ona, FL 33865, USA., Rodrigues PHM; Department of Animal Nutrition and Production, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, Pirassununga, SP 13635-900, Brazil., Berchielli TT; Department of Animal Science, Universidade Estadual Paulista, Jaboticabal, SP 14884-900, Brazil., Messana JD; Department of Animal Science, Universidade Estadual Paulista, Jaboticabal, SP 14884-900, Brazil., Cajarville C; Department of Animal Production and Health of Production Systems, Animal Production Institute, Facultad de Veterinaria, Universidad de la República, San José 80100, Uruguay., Granja-Salcedo YT; El Nus Research Center, Corporación Colombiana de Investigación Agropecuaria, San Roque, Antioquia 250047, Colombia., Borges ALCC; Department of Animal Science, Universidade Federal de Minas Gerais, Belo Horizonte, MG 31270-901, Brazil., Kozloski GV; Department of Animal Science, Universidade Federal de Santa Maria, Santa Maria, RS 97105-900, Brazil., Rosero-Noguera JR; Faculty of Agricultural Sciences, Universidad de Antioquia, Medellín, Antioquia 050034, Colombia., Gonda H; Department of Animal Nutrition and Management, Faculty of Veterinary Medicine and Animal Science, Swedish University of Agricultural Sciences, Uppsala 75007, Sweden., Hristov AN; Department of Animal Science, The Pennsylvania State University, University Park, PA 16802, USA., Kebreab E; Department of Animal Science, University of California, Davis, CA 95616, USA.
Jazyk:	angličtina
Zdroj:	Translational animal science [Transl Anim Sci] 2024 May 09; Vol. 8, pp. txae072. Date of Electronic Publication: 2024 May 09 (Print Publication: 2024).
DOI:	10.1093/tas/txae072
Abstrakt:	The objective of this meta-analysis was to develop and evaluate models for predicting nitrogen (N) excretion in feces, urine, and manure in beef cattle in South America. The study incorporated a total of 1,116 individual observations of N excretion in feces and 939 individual observations of N excretion in feces and in urine (g/d), representing a diverse range of diets, animal genotypes, and management conditions in South America. The dataset also included data on dry matter intake ( DMI ; kg/d) and nitrogen intake ( NI ; g/d), concentrations of dietary components, as well as average daily gain ( ADG ; g/d) and average body weight ( BW ; kg). Models were derived using linear mixed-effects regression with a random intercept for the study. Fecal N excretion was positively associated with DMI, NI, nonfibrous carbohydrates, average BW, and ADG and negatively associated with EE and CP concentration in the diet. The univariate model predicting fecal N excretion based on DMI (model 1) performed slightly better than the univariate model, which used NI as a predictor variable (model 2) with a root mean square error ( RMSE ) of 38.0 vs. 39.2%, the RMSE-observations SD ratio (RSR) of 0.81 vs. 0.84, and concordance correlation coefficient ( CCC ) of 0.53 vs. 0.50, respectively. Models predicting urinary N excretion were less accurate than those derived to predict fecal N excretion, with an average RMSE of 43.7% vs. 37.0%, respectively. Urinary and manure N excretion were positively associated with DMI, NI, CP, average BW, and ADG and negatively associated with neutral detergent fiber concentration in the diet. As opposed to fecal N excretion, the univariate model predicting urinary N excretion using NI (model 10) performed slightly better than the univariate model using DMI (model 9) as predictor variable with an RMSE of 36.0% vs. 39.7%, RSR 0.85 vs. 0.93, and CCC of 0.43 vs. 0.29, respectively. The models developed in this study are applicable for predicting N excretion in beef cattle across a broad spectrum of dietary compositions and animal genotypes in South America. The univariate model using DMI as a predictor is recommended for fecal N prediction, while the univariate model using NI is recommended for predicting urinary and manure N excretion because the use of more complex models resulted in little to no benefits. However, it may be more useful to consider more complex models that incorporate nutrient intakes and diet composition for decision-making when N excretion is a factor to be considered. Three extant equations evaluated in this study have the potential to be used in tropical conditions typical of South America to predict fecal N excretion with good precision and accuracy. However, none of the extant equations are recommended for predicting urine or manure N excretion because of their high RMSE, and low precision and accuracy. Competing Interests: The authors report no conflicts of interest. (© The Author(s) 2024. Published by Oxford University Press on behalf of the American Society of Animal Science.)
Databáze:	MEDLINE
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