The effect of wilting chicory on its voluntary feed intake and digestion by red deer

Abstract

Two experiments were conducted at Palmerston North, New Zealand during 1997, to investigate the effects of wilting chicory to reduce its bulkiness upon voluntary intake of fresh feed and dry matter (DM), apparent digestibility and voluntary water intake. In Expt 1 fresh chicory was cut and wilted for 48 h to determine the drying rate; wilting for 24 h increased DM content from 87 to 173 g/kg, reduced in vitro organic matter digestibility (OMD) by 0·016 (P<0·05) and was selected for use in Expt 2. In Expt 2, chicory was fed either fresh (113 g/kg DM) or wilted (250 g/kg DM) to castrated male red deer kept indoors over two time periods, late autumn and early spring. Chemical analyses showed that wilting slightly lowered the concentration of water-soluble carbohydrate from 185 to 158 g/kg DM, but did not change any other aspect of composition. There were no significant differences between fresh and wilted chicory in apparent digestibility of DM, organic matter (OM), hemicellulose and cellulose. Wilting significantly lowered voluntary intake of fresh feed (P<0·01), but significantly increased voluntary DM intake from 49 to 57 g DM/kg W^0·75/day (P<0·05). Wilting chicory lowered feed water intake (P<0·01) but increased drinking water consumed (P<0·001), with total water intake still being slightly lower (P<0·05) for deer fed wilted chicory.

It was concluded that wilting chicory increased DM intake by reducing its bulkiness, without seriously affecting digestibility, and it is suggested that the feasibility of breeding forage chicory for higher leaf DM content should be investigated. A comparison with literature values showed that DM contents of fresh forages < c. 150 g/kg are likely to restrict the voluntary DM intake of ruminants.