How much browse is available for goats that graze Mediterranean woodlands?

Abstract

The difficulty of determining the intake of browse grazed by goats is widely recognized. We suggest that a reasonable estimate of the amount of edible browse available to goats grazing shrubby Mediterranean vegetation can be derived from actual grazing data of goat herds that have obtained most of their annual maintenance requirements from pasture dominated by shrubs or shrubby trees. We have conducted such estimates on three forests in the Hills of Judea, two of which were grazed by milking herds and one by a herd producing mainly kids. The estimated long-term annual carrying capacity of the shrubby vegetation ranged between 457 and 725 grazing days per ha of shrub cover for the milking herds and 735 grazing days per ha for the non-milking herd. Assuming an average daily DM intake of 1.5 kg/goat/day, the amount of browse DM consumed from the woody vegetation was estimated to be between 686 and 1103 kg/ha of shrubby vegetation. In the literature, estimates of annual DM production of new growth of shrubby vegetation range widely between 200 and 2000 kg/ha, but as most estimates do not indicate the cover of the woody vegetation, the actual amounts produced by a unit area of shrubby vegetation could well be higher. The browse ingested by the goats in the Judean Hills is evidently somewhere between half to one-third of the annual above ground DM production. The estimates derived in the present study define a range of useable browse production on Mediterranean woodland that is derived from actual, long-term use of shrubby pasture by commercial goat herds. They indicate that the nutritional value of the pasture for goats is, as a rule, more than double that for sheep or cattle.