Biological Manipulation of Blackbrush (Coleogyne ramosissima Torr.) by Browsing with Goats

Abstract

The purpose of this study was to provide data on responses of Angora goats and blackbrush (Coleogyne ramosissima) to a biological manipulation program. Blackbrush utilization levels averaged 30, 16, and 6 percent (545, 367, and 147 kg p er hectare) for the heavily, moderately, and lightly browsed pastures, respectively; removal rates of 77, 38, and 19 percent (1164, 582, and 291 kg per hectare) were projected. Statistically significant differences in body weight loss (P=0.052) were noted for goats browsing in different replications. Goats lost an average of 14 and 19 percent of body weight in replications one and two, respectively. Differential weight loss app eared to be related to variable crude protein levels in blackbrush twigs. Small, but statistically significant differences were noted between replications for crude protein (P:0.002) and phosphorus (P=0.019) content in blackbrush twigs. Crude protein content averaged 4.9 and 4.4 percent for replications one and two, respectively; phosphorus content averaged 0.18 and 0.15 percent for replications one and two, respectively. No statistically significant differences in plant production were noted among stocking rates; this was primarily a result of the low utilization levels. Site (replications) affected plant response (P:0.135), and terminal branches produced more current season\u27s growth than did basal branches (P:0.162)

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