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Publication Date

1993

Location

New Zealand

Description

Pasture samples from temperate and tropical species were collected before and after grazing, at regular intervals, on 3 dairy farms in New South Wales over a period of 3 years. All samples (n=693) were analysed on a near-infrared (NIR) spectrophotometer with a scanning monochromator. Subsets of samples selected for calibration and validation, were analysed by wet chemistry methods for estimated metabolisable energy (MID), crude protein (CP), organic matter (OM), acid-detergent fibre (ADF), Ca, P, Mg, K, Na, S, Cu, Mn and Zn. These data were used lo develop NIR equations using partial least squares analyses. Standard errors of laboratory analysis (SEL; % of mean), were 2.08, 2.13, 0.05 and 0.31 for MID, CP, OM and ADF respectively; standard errors of validation corrected for bias (SBVc; % of mean) were 5.0, 6.1, 2.0 and 5.4 for the respective nutrients. SEL were higher for minerals, ranging from 3,7 for Mn to 13.5 for Ca, which was a major contributor to higher SBV c values for mineral equations.

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Near-Infrared Spectroscopy Analysis of the Nutrient Content of Dairy Pastures

New Zealand

Pasture samples from temperate and tropical species were collected before and after grazing, at regular intervals, on 3 dairy farms in New South Wales over a period of 3 years. All samples (n=693) were analysed on a near-infrared (NIR) spectrophotometer with a scanning monochromator. Subsets of samples selected for calibration and validation, were analysed by wet chemistry methods for estimated metabolisable energy (MID), crude protein (CP), organic matter (OM), acid-detergent fibre (ADF), Ca, P, Mg, K, Na, S, Cu, Mn and Zn. These data were used lo develop NIR equations using partial least squares analyses. Standard errors of laboratory analysis (SEL; % of mean), were 2.08, 2.13, 0.05 and 0.31 for MID, CP, OM and ADF respectively; standard errors of validation corrected for bias (SBVc; % of mean) were 5.0, 6.1, 2.0 and 5.4 for the respective nutrients. SEL were higher for minerals, ranging from 3,7 for Mn to 13.5 for Ca, which was a major contributor to higher SBV c values for mineral equations.