Data/hora: 03/06/2024 09:20:37

Biblioteca(s): 	Epagri-Sede.	
Tipo da produção científica: 	Artigo em Anais de Congresso / Nota Técnica	
Data corrente: 	05/09/2023	
Data da última atualização: 	05/09/2023	
Autoria: 	BALDISSERA, T. C.; BARBOSA, A. M.; PINTO, C. E.; GARAGORRY, F. C.; LOPES, C. F.; RIBEIRO FILHO, H. M. N.	
Título: 	Can pasture pre-grazing heights targets be similar under full sun and shaded conditions? Animal response.	
Ano de publicação: 	2023	
Fonte/Imprenta: 	Animal - science proceedings, Roma, v. 14, n. 4, p. 557, 2023.	
Idioma: 	Inglês	
Conteúdo: 	The shading caused by trees introduced in pastures environments may alter pasture canopy structure which probably impacts grazing behavior. Understand grazing process due to the canopy structure plays a central role t define grazing management targets. The objective was to assess the influence of shading and canopy height management on short-term intake rate (STIR) of ewes to set pre-grazing management targets for a C4 (Axonopus catharinensis Valls, nom. nud.) and C3 (Lolium multiflorum Lam.) forage species. The experiments were carried out at Epagri/Lages-SC. For the C4 specie, the experiment was conducted during the summer of 2019 and for C3, during winter/spring 2020. The experiment for the C4 species consisted of 2  2 factorial, where it was evaluated two pre-grazing canopy heights (25 and 35 cm) and two light conditions (full sun and 50% of artificial shade). The experiment for C3 specie consisted in a factorial 4  2, with four pre-grazing canopy heights (12, 17, 22 and 27 cm) and two light conditions (full sun and 50% shaded system with the tree species Acca sellowiana). Both experiments were conducted in a randomized block design using the period of the day as blocking factor (evaluation in the morning or afternoon). For both experiments, STIR was assessed by the double weighing technique with grazing sessions of 45?50 min. Four Lacaune ewes (±80 kg and two years old) were used to determine STIR. In total, 16 and 32 grazing sections were performed throughout C4 and C3 experiments, respectively. Data analysis was performed using R environment. The variables were adjusted by linear mixed models using the lme4 package to define the best variance and covariance structures and model selection based on the Akaike Information Criterion (AIC). Tukey test was performed using emmeans package. In both experiments, STIR was not affected neither by the interaction light condition x canopy height nor by canopy height. In the same way, STIR was similar in different light condition for ewes grazing the C4 specie, averaging 10.1 g DM min1. However, for the C3 species, STIR was reduced (P = 0.01) in the shaded condition (4.5 g DM min1) compared to full sun light (7.1 g DM min1). Our results showed that similar pre-grazing management targes can be applied to pastures under full sun and shaded conditions, however depending on the species evaluated, reduction in the STIR can occurs due to shade. Also, as we evaluated two different species, with distinct shade responses, we could expect that similar response patterns are expected to happen for other forage species than the ones evaluated in this work.	
Thesagro: 	Grazing ecology; Herbage intake; Integrated crop-livestock systems; Pasture management.	
Categoria do assunto: 	L Ciência Animal e Produtos de Origem Animal	
URL: 	http://intranetdoc.epagri.sc.gov.br/producao_tecnico_cientifica/DOC_58562.pdf	
Registro original: 	Epagri-Sede (Epagri-Sede)	
Exemplares: 	Epagri-Sede - (108569-1) - UPC - AP - DD -  -  -  - DIS