Selección de especies leñosas por vacunos en silvopastoreo de un bosque semicaducifolio en Venezuela

Abstract

RESUMENPara determinar la selección de plantas leño-sas por vacunos en silvopastoreo de un bosque semicaducifolio tropical (BSCT), se evaluaron fragmentos epidérmicos en muestras de heces de 14 vacunos machos Brahman x Holstein (390,4 ± 18,0 kg peso vivo). Los animales pastaron durante 91 días sobre 81 ha localizadas en el estado Portuguesa, Venezuela, donde 50 ha correspondieron a un BSCT y el resto a pastizales con predomino de Cynodon nlemfuensis, Sporobolus indicus, Cyperus sp. y Axonopus sp. Empleando la técnica de puntos en cuadrante sobre transectas, en el bosque se identificaron 22 especies de plantas leñosas, agrupadas en 11 familias botánicas con 40,9% de las especies dentro de la familia Fabaceae. La especie Guazuma ulmifolia tuvo la mayor dominancia relativa (60,4%), acumulando conjuntamente con Pithecellobium lanceolatum y Samanea saman el 81,1% de este parámetro. Estas mismas especies mostraron los mayores índices de valor de importancia (162,6; 24,8 y 26,5 respectivamente). Las Poaceae presentaron la mayor frecuencia relativa de aparición de fragmentos epidémicos en heces con el 49,6%, mientras el conjunto de plantas leñosas presentó un 46,2%, del cual las Fabaceae alcanzaron el 80,7%. Las especies más seleccionadas fueron Inga laurina, Machaerium humboldtianum, S. saman y Sida acuta, con un Índice de Ivlev medio de 0,60 ± 0,09. La composición química del follaje de las plantas leñosas sugiere un patrón de selección ajustado a la oferta de nutrientes de cada especie, resaltando el valor estratégico del BSCT en sistemas de silvopastoreo en ambientes tropicales. SUMMARYThe woody plant palatability for cattle in a silvopastoral system on a semi-deciduous tropical forest (SDTF) was evaluated. Epidermal fragments in fecal samples from 14 male cattle Brahman x Holstein (390.4 ± 18.0 kg live weight) grazing during 91 days in 81 ha located in Portuguesa state, Venezuela were evaluated. SDTF was present in 50 ha; the rest of grassland, was mainly composed by Cynodon nlemfuensis, Sporobolus indicus, Cyperus sp. and Axonopus sp. Using the point quarter method on transects, 22 woody plant species were identified they were grouped into 11 botanical families, with 40.9% of species belonging to the Fabaceae family. Guazuma ulmifolia had the greater relative dominancy (60.4%), and together with Pithecellobium lanceolatum and Samanea saman reached the 81.1%. These same species showed the higher importance value index (162.6, 24.8 and 26.5 respectively). Poaceae had the higher relative frequency (49.6%) for epidermal fragments in feces; total woody plants reached 46.2% (Fabaceae: 80.7%). The most selected species were Inga laurina, Machaerium humboldtianum, S. saman and Sida acuta, (Ivlev

Removal of cattle accelerates tropical dry forest succession in Northwestern Mexico

“…It is likely that the affinity of livestock for species of the genus Acacia is linked to the fact that these species produce seed pods with high protein contents (close to 35%) (Bodmer & Ward, ). The findings from our study support the premise that cattle grazing affects species differently, favoring the establishment and development of some species through selective herbivory (competitive‐release; Dumont et al, ; Ojeda, Obispo, Canelones, & Muñoz, ) and/or facilitation of establishment (Miceli‐Méndez et al, ). Livestock also influence physical–chemical characteristics of the soil through compaction and the continuous deposition of nutrients (NO 3 ) in early stages of development, which may also compromise natural trajectories of forest succession by altering species performance and competitive interactions among species.…”

Valoración de dietas a base de Leucaena leucocephala (Lam.), Machaerium sp y Glycine max (Soya) para la alimentación de alevines de Colossoma macropomum (Cachama negra).

“…Korbut y cols. (2009) [36], reportaron la composición nutricional del Machaerium sp, que tiene un 17% de proteína bruta (PB) y M. humboldtianum 34,3% de materia seca y 18,3% de PB [37]. Son pocos los estudios reportados sobre el uso de Machaerium sp, en alimentación animal.…”

Nutritional Value and in Vitro Digestibility of Legume Pods From Seven Trees Species Present in the Tropical Deciduous Forest

“…Nutritional quality of forages and pods could be affected by their content of secondary compounds. For example, condensed tannins (CT) consumed in high concentrations can cause a reduction of the voluntary intake, digestibility and growth rates in grazing ruminants (Torres-Acosta et al 2008;Ojeda et al 2015). Therefore, it is important to determine the levels of these compounds in the different species and parts of plants as well as their biological activity.…”