Prediction of temperate forage intake and digestibility in vitro techniques

M. Basery and R.C. Campling

Abstract

The relationship between forage dry matter (DM) intake' digestibility and the forage characteristics determined in the laboratory were examined for 19 temperate for ages to assess DM intakes,digestibility coefficients and chemical compositions. Forage characteristics were determined using five methods.They were NDF-cellulaseenzyme digestibility (ED), solubility in water (S), packed volume (PV), DM loss from nylon bags in water bath at 40 °C (S40) and DM loss from nylonb ags incubated in the rumen for 6 h and 24 h (R6 and R24). Forage DM intake was significantly ( p<0.001) correlated with forage cellulose content ( r = - 0.73),(p < 0.001)f,o rage N content( r = 0.78),E D ( r = 0.82) ,S ( r = 0.83) ,S 40( r = - 0.93) ,P V ( r = 0.86) ,R 6 ( r = 0.88) and R24 (r = 0.86). Predictione quationsf or forage DM intake were developed using values from the last five methods. Forage organic matter digestibility wa salso directly related to its cellulose content( r= -0.72, p<0.001), N conten (r = 0.45) ,E D ( r = ( 0.67p, <0.01) .S ( r = 0.49,P V ( r = -0.50) , R6 and R24 (r : 0.44 and r = 0.50 respectively). It is concludedth at forage DM intake and digestibility can be predicted from forage characteristics easuredin the laboratory.F or DM intake, the method based on the forage solubility in water (S and S40) were most accurate and convenient while for the prediction of digestibility,the enzyme digestion method was most suitable and worth further study.

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