Potential of Caatinga forage plants in ruminant feeding

Abstract

-Caatinga is the most important biome for the livestock in the Brazilian semi-arid region. This review paper aimed to present information on different forage aspects of caatinga vegetation for ruminant feeding. Caatinga vegetation is formed mainly by shrubs and small trees, usually presenting thorns, deciduous leaves, and leaf abscission occurring frequently at the onset of the dry season. Additional components of the botanical composition in this biome includes the families cactaceae, bromeliaceae, and a herbaceous component formed by grasses, legumes, and forbs, often presenting annual cycle. Quantitative information of caatinga vegetation is scarce in the literature, mainly for the herbaceous stratum. Methodological aspects such as lack of standardization across evaluations make comparison regarding forage potential of caatinga plant species difficult. Index species must be identified within each caatinga type. Quantitative aspects of biological N 2 fixation by caatinga species have not been extensively studied. Regarding forage nutritive value, it is necessary to study N availability for ruminants in caatinga plants, since large proportion of this element may bind to fiber components (ADIN). Manipulation of caatinga vegetation is an alternative to change forage quantity and quality for grazing animals, affecting their performance as a result. Studies measuring qualitative and quantitative variability of native forage resources from caatinga are mandatory in order to improve animal feeding management, with the ultimate goal of creating sustainable animal production based on caatinga vegetation.Key Words: chemical composition, native plant, quantitative aspect, semi-arid Potencial de plantas forrageiras da Caatinga na alimentação de ruminantesRESUMO -Considerando a importância do bioma Caatinga na pecuária da região semiárida brasileira, o presente trabalho objetivou apresentar informações sobre diferentes aspectos forrageiros de plantas da caatinga, com vistas à alimentação de ruminantes. A vegetação de caatinga é constituída por arbustos e árvores de pequeno porte, geralmente dotados de espinhos, sendo caducifólias, em sua maioria, perdendo suas folhas no início da estação seca. Complementam ainda a composição botânica desse bioma, cactáceas, bromeliáceas e um componente herbáceo, formado por gramíneas e dicotiledôneas, predominantemente anuais. Informações, principalmente sobre o aspecto quantitativo de plantas da caatinga, notadamente para o estrato herbáceo ainda são escassas. Dificuldades e desuniformidade de metodologias de avaliação, além de falta de detalhamento das metodologias utilizadas, dificultam a comparação de resultados quanto ao potencial forrageiro de algumas plantas. A fixação biológica de N atmosférico por espécies da caatinga até o momento foi pouco estudada, notadamente quanto aos aspectos quantitativos.Faz-se necessária uma avaliação mais profunda sobre a disponibilidade do nitrogênio, uma vez que parte deste pode estar ligado a parede celular (NIDA). A manipulação da caatinga ...

Influence of the period of year on the chemical composition and digestibility of pasture and fodder selected by goats in caatinga

“…Leaf and steam average NDF levels were 521.3 and 765.7 g/kg DM, respectively. These values were higher for stems and lower for leaves than values found by Santos et al (2009), who observed average NDF content of 593.9 g/kg DM while studying the diet of fistulated sheep in a Caatinga area, in the same location and assessment period. Stems have high NDF content, as they have higher structural carbohydrate amount in relation to leaves, increasing pasture NDF and ADF amount.…”

“…Average crude protein content was 153.10 g/kg DM, lower than the result found by Pfister (1983), 192.00 g/kg DM, for goats in Caatinga during the rainy season. Santos et al (2009), while studying fistulated sheep in the same experimental area, found results below those of this study, possibly due to goat selectivity during grazing, having a diet with higher protein content in relation to sheep According to Goetsch et al (2010), several factors may influence forage selection, with concentrate supplementation among them, allowing for higher or lower diet selection, according to genotype. Results found in this study indicate that animals were able to select forage as to keep extrusa CP above the minimum required for rumen microorganism growth.…”

“…However, animal grazing performance indicates higher values due to selection during grazing, which is conducted by sheep and especially goats. Shrub and tree forages generally have lower digestibility coefficients than those found for herbaceous plants (SANTOS et al 2009). Probably due to high lignin concentrations and secondary compounds found in these layers.…”

“…Caatinga includes forages that can reach CP contents higher than 200 g/kg DM. However, Caatinga forage digestibility is usually low (ARAÚJO FILHO et al, 2002;SANTOS et al, 2010), as native Caatinga forages often have high tannin contents. Moreover, fiber and lignin content increase during the dry period.…”

Dry matter yield and bromatological composition of gliricidia in different crop densities

“…However, according to SANTOS et al (2010), as an alternative to reduce these costs, producers may use forage with good nutritional value and good yield, which are adapted to the soil and weather conditions of the region.…”