Effects of pasture improvement on the nutrition of eastern grey kangaroos and wallaroos.
The nutrition of the eastern grey kangaroo (Macropus giganteus) and the wallaroo (Macropus robustus) was studied in 2 areas in the New England Tablelands of E. Australia during 1978-9. The pastures on one of the areas had been extensively improved with P fertilizers and the introduction of exotic grasses; the other site was largely unimproved with the pastures dominated by Poa spp. The quality of food eaten by the two spp. was higher on the improved area than the unimproved. However, stomach fill indices indicated that animals on the unimproved area were eating a greater quantity of food than were those on the improved area (3.0 and 2.6, resp., for kangaroos and 4.6 and 3.9, resp., for wallaroos). Grey kangaroos on the unimproved area recycled a greater proportion of urea to the gut than those on the improved area. For wallaroos the pattern of seasonal change in the level of urea recycling differed on the two areas, but overall more urea was recycled on the unimproved area. Energy appeared to be a limiting resource on both areas.