Abstract:
The study assessed the difference between the performance of goats browsing on Acacia karroo communal browsing lands and open grasslands as well as determining nutritional composition of A. karroo leaves in the False Thornveld of Eastern Cape Province of South Africa at different times of the year. A total of 80 communal household goat herds and eight A. karroo browse trees were monitored for a period of 12 months in a parallel experiment. In the first experiment, most entries as births were recorded in large herds within the A. karroo encroached community, especially during the hot-wet season (November to February). Households with large herd sizes sold and slaughtered significantly (P<0.05) more goats than those with small herd sizes in both communities. Mortality was significantly (P< 0.05) higher during the hot-wet season in the open grassland. Households keeping small herds in open grassland had the lowest goat production potential (GPP) in the cool-dry season (May to August). The average daily gain (ADG) and body condition scores (BCS) of goats browsing in A. karroo encroached areas were generally higher than in open grassland, especially during the cool-dry season. However, the GPP and goat production efficiency (GPE) were not significantly (P> 0.05) different between the two communities across the seasons. In the second experiment, all selected A. karroo browse trees had crude protein (CP) above 110 g/kg of dry matter (DM) which is sufficient to maintain the requirements of goats at low to medium production. The A. karroo browse contained significantly (P<0.05) higher ADF (496.4±33.8 g/kg DM), CT (18.4±4.2 g/kg DM), Ca (26.8±0.8 g/kg DM) and Mg (2.9±0.03 g/kg DM) during the cool-dry season than other times of the year. There were no significant (P>0.05) differences on the amounts of NDF, TL, SP, P, S, Zn, Mn and Cu throughout the study period. The level of CP (182.4±6.7 g/kg DM) was significantly (P<0.05) higher during the hot-wet season than other times of the year. It was suggested that A. karroo leaves have the potential to be integrated into communal goat feeding systems in the Eastern Cape Province, South Africa. It was concluded that the goats which browsed A. karroo trees largely performed better in both growth and reproduction parameters than those which grazed in open grassland especially during the cool-dry season. Acacia karroo leaves relatively maintain considerable levels of CP and minerals throughout the year which are sufficient to support low to medium communal goat production.
