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The effective degradability of Agave americana L. (American aloe) in sheep


J H Hoon*, J N Swart1 and B R King

Grootfontein ADI, Middelburg Cape, 5900, South Africa

1Department of Animal Science, U.O.F.S., Bloemfontein, 9300, South Africa


Due to the frequent incidence of droughts in the arid parts of South Africa, drought feeding forms an integral part of farm management. For this reason, available fodder sources such as American aloe should be utilized optimally. Chemical analysis and digestion studies have indicated that the cell wall contents of American aloe are important components of the total digestible nutrients. Digestion and degradation of these components as an energy source take place mainly in the rumen. The aim of this study was therefore to determine the effective degradability of dry matter (DM), neutral-detergent fibre (NDF), acid-detergent fibre (ADF), cellulose and lignin of different inclusion rates of American aloe in the rumen, by using lucerne as a control. Six mature rumen fistulated Dorper ewes were used to determine the effective degradability of the different components of American aloe and lucerne on two American aloe: lucerne diets and a pure lucerne diet respectively. All animals were fed at a maintenance level according to the metabolic mass of each animal. The artificial fibre bag and chromium-mordanted methods were used to determine degradation rates and rates of passage respectively. Results obtained from these two methods were used to determine the following effective degradabilities:



The higher effective degradabilities obtained for the various components of American aloe on the 45% American aloe: 55% Lucerne diet, indicate that the inclusion of this proportion of American aloe in the diets of sheep, established the optimum rumen condition for the functioning of cellulolitic bacteria which is mainly responsible for the digestion and degradation of the cell wall contents.



Proceedings 33rd SASAS congress