NUTRITIONAL-VALUE OF PLANTS SELECTED BY CAMELS (CAMELUS-DROMEDARIUS) IN THE BUTANA AREA OF THE SUDAN

Nutritional values and seasonal differences in diets selected by camel s (Camelus dromedarius) from the Butana grassland of the Sudan were st udied. Four fistulated female camels and one male camel grazing and br owsing on their natural pasture were observed at 2-week intervals for 2 years. Selected fodder plants were collected, botanically classified , and chemically analysed. Digestibility and energetic values of the p lant samples were examined using the nylon-bag technique and the in vi tro gas-production test (HFT), respectively. A total of 17 different p lant species mere eaten by camels. Only five species were found during the dry season. Cymbopogon nervatus was the only plant species remain ing towards the end of dry season in 1990 (severely dry). This plant s pecies was avoided when alternative plants were available. Camels were able to select the most nutritive diet during the green season; they spent 80.7 % of the total feeding time on dicotyledonous plants and 19 .3 % on monocotyledonous plants. The animals significantly (p < 0.001) gained weight during the green season and thereby compensated for los ses that occurred during prolongation of the dry season. The mean dige stibility and energetic value of the diet selected by camels were calc ulated on a feeding-time basis. The total potential digestibility of t he diet during green, dry and severe dry seasons was 48.6 +/- 6.1, 34. 5 +/- 0.9, and 33.2 +/- 0.2 % of DM, respectively. The average metabol izable energy of the diet during these seasons was 7.07 +/- 1.02, 4.96 +/- 0.2, and 4.7 +/- 0.4 MJ/kg respectively. There was a significant influence of season on the digestibility and energetic value of the pl ant species selected. The digestibility of Sorghum vulgaris straw was tested throughout the observation period in nylon bags as an indicator of microbial activity in the forestomach; no significant seasonal dif ference in digestibility was observed. Thus, the camels were able to m aintain microbial fermentation throughout the seasons. Cymbopogon nerv atus pastures are insufficient to support the nutritional requirements of dromedaries.