Fecha/hora: 15/06/2024 17:55:25

Biblioteca(s): 	INIA Las Brujas.	
Fecha corriente: 	07/02/2023	
Fecha de la última actualización: 	24/04/2023	
Autoria: 	DA CUNHA, L. L.; BREMM, C.; SAVIAN, J.V.; ZUBIETA, Á. S.; ROSSETTO, J.; CARVALHO, P. C. DE F.	
Afiliación: 	LAIS LEAL DA CUNHA, LAIS LEAL, Grazing Ecology Research Group, Federal University of Rio Grande Do Sul, RS, Porto Alegre, Brazil; CAROLINA BREMM, State Foundation of Agricultural Research, Rua Gonçalves Dias, 570, Bairro Menino Deus, RS, Porto Alegre, Brazil; JEAN VICTOR SAVIAN, INIA (Instituto Nacional de Investigación Agropecuaria), Uruguay; ÁNGEL SANCHEZ ZUBIETA, Grazing Ecology Research Group, Federal University of Rio Grande Do Sul, RS, Porto Alegre, Brazil; JUSIANE ROSSETTO, Grazing Ecology Research Group, Federal University of Rio Grande Do Sul, RS, Porto Alegre, Brazil; PAULO CÉSAR DE FACCIO CARVALHO, Grazing Ecology Research Group, Federal University of Rio Grande Do Sul, RS, Porto Alegre, Brazil.	
Título: 	Relevance of sward structure and forage nutrient contents in explaining methane emissions from grazing beef cattle and sheep.	
Año de publicación: 	2023	
Fuente/Imprenta: 	Science of the Total Environment, 2023. Volume 869, Article number 161695. doi: https://doi.org/10.1016/j.scitotenv.2023.161695	
ISSN: 	0048-9697	
DOI: 	10.1016/j.scitotenv.2023.161695	
Idioma: 	Inglés	
Notas: 	Article history: Received 18 March 2022; Received in revised form 30 December 2022; Accepted 15 January 2023; Available online 21 January 2023; To be published 15 April 2023. -- Corresponding author:  da Cunha, L.L.; Grazing Ecology Research Group, Department of Forage Plants and Agrometeorology, Faculty of Agronomy, Federal University of Rio Grande Do Sul, Bento Gonçalves Ave., 7712, RS, Porto Alegre, Brazil; email:laiscvet@gmail.com -- Editor: Kuishuang Feng --	
Contenido: 	ABSTRACT.- Forage nutrient contents are an important factor explaining the dry matter intake (DMI), average daily gain (ADG), and methane emissions (CH4) of ruminants fed indoors. However, for grazing animals, the forage nutrient contents might be limited in explaining such response variables. We aimed to verify the explanatory power of forage nutrient contents and sward structure on daily intake, performance, and CH4 emissions by sheep and beef cattle grazing different grassland types in southern Brazil. We analyzed data from five grazing trials using sheep and beef cattle grazing on Italian ryegrass (Lolium multiflorum), mixed Italian ryegrass and black oat (Lolium multiflorum + Avena strigosa), pearl millet (Pennisetum americanum), and multispecies native grassland. We used mixed models, including the forage nutrient contents [crude protein (CP), neutral detergent fiber (NDF), and acid detergent fiber (ADF)], sward structure (sward height and herbage mass) and their interactions, as fixed effects and trial, season, methodologies, animal species, grassland type, and paddock, as random effects. The model for DMI (kg DM/LW0.75) had an adjusted coefficient of determination (R2adj) of 71.6 %, where 11.3, 23.1, and 37.2 % of the R2adj were explained by the forage nutrient contents, sward structure, and their interaction, respectively. The ADG (kg/LW0.75) model presented an R2adj of 74.2 %, with 12.5 % explained by forage nutrient contents, 29.3 % by sward structure, and 32.4 % by their interaction. The daily CH4 emission (g/LW0.75) model had a lower adjusted coefficient of determination (R2adj = 47.6 %), with 16.8 % explained by forage nutrient contents and 30.8 % explained by sward structure, but no effect of the interaction. Our results show that in grazing ecosystems, the forage nutrient contents explain a small fraction, and the greater explanatory power for DMI, ADG, and CH4 emissions models is related to sward structure descriptors, such as sward height and herbage mass. Moreover, the interaction between these variables explains most of the variation. In conclusion, forage nutrient contents and sward structure have different influences on DMI, ADG, and CH4 emissions by grazing ruminants. Because of its relevance to daily CH4 emissions, offering an optimal sward structure to grazing animals is a major climate-smart strategy to improve animal production and mitigate CH4 emissions in pastoral ecosystems. © 2023 Elsevier B.V.	
Palabras-Clave: 	Forage chemical composition; Grasslands; Livestock; Pastoral ecosystems; Sward height.	
Categoría del tema: 	A50 Investigación agraria	
Registro original: 	INIA Las Brujas (LB)	
Ejemplares: 	LB - (103301-1) - PXI - AP - DD - Science of the Total Environment/2023 -  -  - DIS