Dwarf and tall elephant grass silages: intake, nutrient digestibility, nitrogen balance, ruminal fermentation, and ingestive behavior in sheep.

The objective of this study was to evaluate the exclusive supply of dwarf or tall elephant grass silages, harvested at 60 days of growth, without wilting or the use of additives, on intake, apparent digestibility, nitrogen balance, rumen parameters, and ingestive behavior of sheep. Eight castrated male crossbred sheep (57.6 ± 5.25 kg body weight), fistulated in the rumen, were distributed in two 4 × 4 Latin squares with four treatments and eight animals per treatment and four periods. The treatments consisted of four elephant grass genotype silages (Mott, Taiwan A-146 2.37, IRI-381, or Elephant B). There was no effect of silages (P > 0.05) on dry matter, neutral detergent fiber, and total digestible nutrient intake. The dwarf-sized elephant grass silages provided higher crude protein intake (P = 0.047) and N intake (P = 0.047), while the IRI-381 genotype silage provided higher non-fibrous carbohydrate intake compared to Mott (P = 0.042), without differing from Taiwan A-146 2.37 and Elephant B silages. There were no differences (P > 0.05) among the digestibility coefficients of the evaluated silages. It was observed that silages produced with Mott and IRI-381 genotypes caused a slight decrease in ruminal pH (P = 0.013), and the propionic acid concentration was higher in the rumen fluid of the animals fed with Mott silage (P = 0.021). Therefore, dwarf or tall elephant grass silages, produced with cut genotypes at 60 days of growth and without the use of additives or wilting process, can be used in sheep feeding.

Tall and short-sized elephant grass genotypes: morphophysiological aspects cut-and-carry, and grazing management / Capins-elefante de porte alto e baixo: aspectos morfofisiológicos, manejo do pastejo e de capineiras

ABSTRACT: Elephant grass (pennisetum purpureum schum.) has been grown only in cut-and-carry systems for a long time. However, interest in its grazing management has been increasing because of the selection of short-sized genotypes, which have gained new relevance since 1988 with the registration of 'mott' grass. in this sense, tall and short-sized genotypes present important differences in morphology, quality and productivity; although, environmental factors also exert influence on these aspects. This review aimed to approach how the elephant grass size can influence the morphophysiological characteristics, management decisions, and exploitation of this species. the morphophysiological aspects and the elephant grass sizes are important to direct their utilization in the different production systems. The research results from previous decades suggest that the particularities of the tall-sized genotypes, such as great forage accumulation, high organic reserves content, and stem elongation, favor their management in cut-and-carry systems and industrial sectors. Conversely, the short-sized elephant grass genotypes present aspects as higher leaf proportion in the harvested forage, leaf/stem ratio, and tillering. these factors facilitate their exploitation in grazing systems.

RESUMO: O capim-elefante (pennisetum purpureum schum.) foi durante muito tempo cultivado apenas em capineiras. porém, o interesse pelo seu manejo sob pastejo vem aumentando por conta da seleção de genótipos de porte baixo, que ganhou nova relevância a partir de 1988, com o registro do capim mott. Neste sentido, genótipos de porte alto e baixo apresentam diferenças morfológicas, produtivas e qualitativas importantes, mesmo que fatores ambientais também exerçam influência sob estes aspectos. o objetivo desta revisão foi abordar como o porte do capim-elefante pode influenciar características morfofisiológicas, decisões de manejo e formas de utilização da espécie. Os aspectos morfofisiológicos e o porte do capim-elefante são importantes para direcionar sua utilização nos diferentes sistemas de produção. os resultados de pesquisa das últimas décadas sugerem que as particularidades dos genótipos de porte alto, como elevado acúmulo de forragem, reservas orgânicas e alongamento dos colmos favorecem seu manejo sob corte e sua utilização em setores industriais. já o capim-elefante de porte baixo apresenta aspectos como elevada proporção de folhas na forragem colhida, alta relação folha: colmo e elevado perfilhamento. Estes fatores facilitam sua utilização em sistemas de produção a pasto.