A model for assessing Medicago Sativa L. hay quality

Author: G.D.J. Scholtz, H.J. van der Merwe and T.P. Tylutki
Year: 2009
Issue: 5
Volume: 39
Page: 301 - 305

A study was conducted to identify chemical parameters and/or models for assessing Medicago sativa L. (L) hay quality, using near infrared reflectance spectroscopy (NIRS) analysis and Cornell Net Carbohydrate and Protein System (CNCPS) milk prediction as a criterion of accuracy.  Milk yield (MY) derived from the CNCPS model, by replacing the average L hay in a complete diet with 168 representative South African L hay samples, was used as a criterion to evaluate and/or develop models for L hay quality grading.  The best single predictor of MY was the acid detergent fibre (ADF) content of L hay, which explained 67% of the measured variation.  A multiple linear equation (Y = 64.18 – b1ADF – b2ash – b3lignin) explains 96% of the measured variation in MY.  The relatively poor performance of crude protein (CP) (r² = 0.04) and other protein related parameters (r²< 0.25; adjusted-crude protein, ADF-CP, neutral detergent fibre-CP and soluble protein) in predicting MY suggests that protein content of L hay is an unreliable indicator of L hay quality.  It is clear that MY derived from the CNCPS model by replacing L hay in a basal diet with others in the South African L hay population can be significantly predicted with high accuracy by the developed empirical model named lucerne milk value (LMV) consisting of only  ADF, ash and lignin.

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