Diet selection of cattle in the Pietersburg Plateau Bushveld of the Limpopo Province

Abstract

An experiment was conducted at the University of Limpopo to determine the diet selection of cattle in the Petersburg Plateau Bushveld, the aim being to identify important and palatable grass species during four seasons of the year and to determine their above-ground biomass production. For diet selection data, five permanently marked transects were randomly laid out per camp, each 100 m long. On each transect, grass tufts were identified and permanently marked at 1 m intervals (100 tufts per transect). Turfs were surveyed on a weekly basis to determine frequency, intensity of utilization and tuft height. A palatability index was determined for each species. Diet selection data were analysed, using descriptive statistics. For biomass production, five permanent 20 m x 20 m plots were randomly laid out per camp, in which biomass of grass were measured. Within each plot, five 1 x 1 m quadrates were randomly harvested. The biomass data was analysed using the General Linear Mixed Model. Means were compared, using a Tukey test at the 5% significance level. Digitaria eriantha, Eragrostis rigidior and Heteropogon contortus were the dominant grass species. On average, Brachiaria nigropedata, Panicum maximum and Digitaria eriantha were utilized at higher frequencies and intensities. Brachiaria nigropedata, P. maximum, Urochloa mosambicensis, Themeda triandra, D. eriantha, Schmidtia pappophoroides and H. contortus were regarded as the most palatable species. The circumference of the tuft of S. pappophoroides, E. rigidior and D. eriantha decreased highly significantly (P<0.01). The height of utilizable leaves of B. nigropedata, D. eriantha, P. maximum and S. pappophoroides decreased highly significantly, while the height of highest leaves of B. nigropedata, D. eriantha, P. maximum, S. pappophoroides, H. contortus and T. triandra also decreased highly significantly. Total biomass production was significantly higher (P<0.05) during autumn, while total biomass production during winter was low, compared to other seasons. Total biomass production did not differ significantly between spring and summer. Panicum maximum, x

B. nigropedata, D. eriantha, T. triandra, H. contortus, S. pappophoroides and U. mosambicensis were regarded as “key species” in the diet selected by cattle. Farmers in the Pietersburg Plateau Bushveld should graze their camps to assure the maintenance or improvement of perennial palatable grasses with high biomass production, which will result in overall improvement of veld condition.