The effect of wilting and soaking Eupatorium adenophorum on its digestibility in vitro and voluntary intake by goats

Abstract

An experiment was conducted to determine what effect simple treatments might have on the voluntary intake by goats in Nepal of Eupatorium adenophorum, an invasive weed that is usually only consumed by goats to a very limited extent. Samples of E. adenophorum were collected and either untreated, soaked for 2 h or wilted for 2 h before being oven dried (60 °C) and ground. Soaking and wilting had little effect on the chemical composition of E. adenophorum, but did increase ( P=0.036) its in vitro organic matter degradability, by approximately 8%. The short-term intake rate (STIR) of treated and untreated E. adenophorum was then estimated with eight goats. Soaking time (from 2 to 24 h) was not related to STIR ( r = −0.111, P=0.198), but the time E. adenophorum was left to wilt (from 2 to 48 h), was positively related to STIR ( r = 0.521, P<0.001), with values of STIR (g dry matter/min kg goat liveweight 0.75) being 0.405, 0.649, 1.058, S.E.M. 0.088 for E. adenophorum, that had been wilted for 0, 24 and 48 h respectively ( P<0.001). Liveweight change of goats and voluntary intake of E. adenophorum by goats was then estimated with 24 goats. E. adenophorum was fed either unwilted, or wilted for 24 or 48 h. It was fed as the sole forage or as a 3:1 mixture (dry matter basis) with Ficus cunia. There was a linear ( P<0.001) and quadratic ( P<0.01) increase in the intake of total forage and E. adenophorum with wilting time of E. adenophorum. Offering Ficus cunia increased total forage intake, but decreased E. adenophorum intake ( P<0.05). After four weeks, there was virtually no change in goat liveweight and no significant difference between treatments. The results suggest that wilting E. adenophorum for 24 h could increase its intake by goats, and thereby increase its usefulness, as a potential source of forage in the dry season of Nepal, when forage scarcity is a common constraint to livestock production.