The productivity of Angora goats grazing improved and native pastures in south-eastern Queensland

Abstract

Two groups of Angora wether goats were grazed over 1 year on replicated areas (0.4 ha each) of either pure N-fertilized Pangola grass (Digitaria decumbens Stent.) pasture or native pastures containing Acacia, Eucalyptus and groundsel (Baccharis halimfolia L.) regrowth. Half of the goats in each group were given a cobalt bullet and their health, liveweight change and fleece growth were monitored. When adequate levels of native pasture were available (>800 kg green matter/ha) performance of goats on the different pastures was similar over the spring and summer grazing periods. In the winter period, fleece growth rate and yield were significantly (P<0.05) lower and liveweight loss (11 g/day) occurred in goats grazing native pastures. In the same period, goats on Pangola grass pastures supplemented with cobalt continued to grow (39 g/day) and maintained high fleece yields while unsupplemented goats on the same area lost weight rapidly (84 g/day), indicating the onset of cobalt deficiency. Over a 9-month period, the population of regrowth acacias and eucalypts less than 1.5 m high were markedly reduced, and groundsel was completely eliminated from the area. In this period, the palatable native grasses were selected in preference to blady grass (Imperata cylindrica (L.) Beauv.), which increased as a proportion of declining total grass yield.