Nutritive value of oats and Sudan grass grown at controlled temperatures

Abstract

Fodder oats (Avena sativa L, cv. Cooba) and Sudan grass (Sorghum sudanense cv. Greenleaf) were grown in pots in glasshouses with day/night temperatures of 27/22 and 21/16°C. Plants were harvested at the emergence of each leaf and at various stages after anthesis.

Growth rates and changes in dry matter content, nitrogen, cellulose and in vitro digestibility in oats were similar under both temperature regimes, but more primary leaf and less panicle were formed at the high temperatures. Development of Sudan grass was more rapid at the high temperatures, but production of main shoot, panicle and tillers was much less and the nitrogen contents and in vitro digestibilities were consistently lower than at the low temperatures.

Sudan grass produced much more dry matter than oats. Differences in composition were in general not large, though stem digestibility remained higher in Sudan grass after anthesis.

Tropical species, because of their efficiency of photosynthesis and water use, warrant further study of their nutritive value as forage crops in temperate regions.