Intake, digestibility and rumen dynamics of neutral detergent fibre in cattle fed low-quality tropical forage and supplemented with nitrogen and/or starch

Abstract

The objective of this work was to evaluate the effects of nitrogenous compounds and/or starch supplementation on the intake, digestibility and rumen dynamics of neutral detergent fibre (NDF) in cattle fed low-quality tropical forage. Four crossbred heifers (Holstein x Zebu) with a body weight 231.9 +/- 15.5 kg and fitted with ruminal cannulae were used. The forage fed to the animals consisted of low-quality signal grass (Brachiaria decumbens Stapf.) hay, with an average crude protein (CP) level of 51.6 g/kg, on a dry matter (DM) basis. Four treatments were evaluated: control, without supplementation; supplementation with nitrogenous compounds (CP of the roughage was raised to 100 g/kg), on a DM basis; supplementation with starch at a ratio of 200 g/kg DM of roughage; and supplementation with nitrogenous compounds and starch as described above. A mixture of urea, ammonium sulphate and albumin was used as a source of nitrogenous compounds at a ratio of 4.5:0.5:1.0. The experiment was carried out according to a 4 x 4 Latin square design in a 2 x 2 factorial arrangement. There was a positive effect of the nitrogenous compound supplementation on the DM and NDF intake (P < 0.01). In contrast, starch supplementation decreased forage intake (P < 0.10). Nitrogen supplementation increased the digestibility coefficient of DM and NDF (P < 0.05). Supplementation with nitrogen and starch together increased the microbial assimilation of nitrogenous compounds in the rumen (P < 0.05). We observed that nitrogen supplementation increased the estimated weighted degradation rate of NDF by 14.8%, whilst starch supplementation decreased this rate by 32.5%.

The effect of Mediterranean thyme (<i>Thymbra spicata</i> L. var. spicata) essential oil on fattening performance and ruminal parameters in lamb

“…Briefly, after centrifugation at 1000 g for 15 min the samples were subjected to the distillation with potassium hydroxide (2 N) without prior acid digestion. The liberated NH 3 was collected in flasks with boric acid and titrated with diluted hydrochloric acid (0.1 N) (Souza et al, 2010).…”

Energy sources and supplementation levels for beef heifers raised during the dry season

“…Energy food with lower quantities of non-fibrous carbohydrates, containing higher concentrations of fiber of rapid ruminal degradation could contribute for higher digestibility of dietary fiber, on the contrary, food high in non-fibrous carbohydrates reduce digestibility of the dietary fibrous portion especially in diets with low protein contends (Souza et al, 2010).…”

Suplemento de baixo consumo para vacas de corte não-gestantes

“…Empregou-se o óxido crômico como indicador para estimativa da excreção fecal e o dióxido de titânio como indicador do consumo de suplemento (TITGEMEYER et al, 2001). A FDNi foi utilizada como indicador interno para estimativa do consumo de pasto.…”

“…O óxido crômico foi acondicionado em cartucho de papel (15 g) e aplicado via sonda A avaliação das características nutricionais foi realizada na metade do período experimental por intermédio da técnica dos indicadores. Empregou-se o óxido crômico como indicador para estimativa da excreção fecal e o dióxido de titânio como indicador do consumo de suplemento (TITGEMEYER et al, 2001). A FDNi foi utilizada como indicador interno para estimativa do consumo de pasto.…”