Main Article Content
The influence of nitrogen and defoliation on digestibility and fibre content of Lolium multiflorum cv. Midmar
Abstract
The influence of different N fertiliser application levels (0, 150, 300
and 450kg N ha–1) in combination with different defoliation
intervals (every 2, 4, 6 and 8 weeks and twice a season) on the digestibility
and fibre component of ryegrass (Lolium
multiflorum) cv. Midmar was investigated. Organic Matter Digestibility
(OMD), neutral and acid detergent
fibre (NDF and ADF) were
determined. OMD, NDF and ADF content were significantly (P < 0.01)
influenced by N level, defoliation interval and the interaction between these
two factors. Nitrogen level had a lesser influence on OMD, NDF and ADF than
defoliation interval, because defoliation interval exerts a greater influence
on plant growth stage and maturity than N level. Increased N levels and
lengthening the defoliation interval decreased (P < 0.05) OMD. With
defoliation intervals of four weeks and shorter, increased N levels resulted
in decreased NDF and ADF content, but six weeks and longer intervals resulted
in
the opposite. It is essential to assess OMD and fibre content as part of the
pasture nutritive characteristics when evaluating a planted pasture as it will
contribute to the understanding of pasture manipulation for sustainable animal
production.
Keywords: acid detergent fibre, ADF,
annual ryegrass, NDF, neutral detergent fibre, OMD, organic matter
digestibility
African Journal of Range & Forage Science 2004, 21(1):
21–27
and 450kg N ha–1) in combination with different defoliation
intervals (every 2, 4, 6 and 8 weeks and twice a season) on the digestibility
and fibre component of ryegrass (Lolium
multiflorum) cv. Midmar was investigated. Organic Matter Digestibility
(OMD), neutral and acid detergent
fibre (NDF and ADF) were
determined. OMD, NDF and ADF content were significantly (P < 0.01)
influenced by N level, defoliation interval and the interaction between these
two factors. Nitrogen level had a lesser influence on OMD, NDF and ADF than
defoliation interval, because defoliation interval exerts a greater influence
on plant growth stage and maturity than N level. Increased N levels and
lengthening the defoliation interval decreased (P < 0.05) OMD. With
defoliation intervals of four weeks and shorter, increased N levels resulted
in decreased NDF and ADF content, but six weeks and longer intervals resulted
in
the opposite. It is essential to assess OMD and fibre content as part of the
pasture nutritive characteristics when evaluating a planted pasture as it will
contribute to the understanding of pasture manipulation for sustainable animal
production.
Keywords: acid detergent fibre, ADF,
annual ryegrass, NDF, neutral detergent fibre, OMD, organic matter
digestibility
African Journal of Range & Forage Science 2004, 21(1):
21–27
