Methoxyl as an Indicator of the Nutritive Value of Forage

Abstract

Summary A study was made of the relationships between the digestibility and methoxyl content of forages and between forage digestibility and the fecal methoxyl content. The three forages studied were of different botanical composition, were both grazed and hand-fed, and each was harvested at several stages of growth. The coefficients of digestibility of the clipped forage were determined in the conventional digestion trial, whereas those of the grazed forage were estimated by the chromogen technique. The digestibility of the dry matter and the methoxyl content of the hand-fed forage were highly significantly correlated (r = −0.83). The methoxyl content of forage appears to be useful as a relative index of forage digestibility for selecting among similar forages of widely different digestibility. The regression of dry matter digestibility on the concentration of methoxyl in feces was not statistically different for the three forage mixtures or for grazed and hand-fed forage. The pooled regression of percentage dry matter digestibility (Y) on percentage fecal methoxyl (X) , representing all forages ( i.e. , grazed and hand-fed), is: Y = 94.18−9.586X, and the correlation coefficient obtained for 107 observations is −.742.