More than one million acres of Colorado rangeland is infected with oak brush. The application of proper brush control and management practices could have a tremendous economic impact on the areas involved.
Numerous chemicals and combinations of chemicals have been used with limited success to control Gambel Oak. Those which show the most promise have been placed on the restricted use list because residues could have a detrimental effect on the environment.
Mechanical treatment such as roller chopping will give temporary improved forage yields for cattle. Sprouting will occur following mechanical application for eliminating mature oak brush. Within a few years the sprouts can present a more serious problem than the original stand of mature oak.
Goats have been used effectively to control the new growth of oak brush by keeping the sprouts defoliated. A field, mechanically treated in 1964, was grazed by goats five consecutive years beginning in 1968. Only an occasional small sprout could be found on the treated area in 1987.
A 400 acre pasture chained in 1973 and 1976 was grazed by 1000 Angora goats during 1983 to 1985. Approximately 50% of the sprouts were killed on the grazed area. Cattle numbers were decreased about 10% during the three-year period goats were in the pasture. Diet studies have shown goats prefer leaves and new growth of the oak brush over grass. As long as oak sprouts were plentiful the goats diet will exceed 90% oak leaves and sprouts.