Encroacher woody plant browse as feed for cattle. Cattle diet composition for three seasons at Olifants Drift, south-east Botswana

The significance of encroacher woody plant browse (among other factors) in the composition of the diet of cattle was quantified for July 1996, March 1 997 and September 1997. This is important because browse in general is typi cally ignored in carrying capacity estimates for cattle, while woody encroa chers are considered a result of high cattle densities in communal rangelan ds and therefore undesirable for cattle as feed. There were significant dif ferences in the activities of cattle and woody species utilized between the 3 months. Encroacher moody species (mainly D. cinerea and G. flava) contri buted 84.2% in March, 48.3% in July and 21.4% in September towards cattle's diet out of all the woody species browsed. The woody species recorded high crude protein levels as compared to the grasses. Both the grasses and brow se, however, were found to be deficient in phosphorus and the major mineral s, except calcium. A temporary protein deficiency for cattle was anticipate d in September as the proportion of browse in the cattle's diet was very lo w due to the scarcity of browse during this period. There were, however, la rge quantities of low quality grass cover and cattle tended to graze more, hence no problems were expected with the overall energy supply. The importa nce of browse (especially woody encroachers) towards cattle's diet in a com munal grazing system, even in a good rainfall year, is emphasized. There is , however, a need for more research to focus upon the dynamics and importan ce of this much neglected food supply. (C) 1998 Academic Press.