INFLUENCE OF WHOLE SOYBEANS ON DIGESTIBIL ITY AND ENERGY CONTENT OF ROUGHAGE IN RATIONS FOR RUMINANTS

Whole, untreated soybeans were added in raising amounts of 8.5 % (trea tment II) and 17.1 % i. DM (treatment III) to rations either with fres h grass, grass silage, hay or maize silage. The soybeans had mean cont ents (i. DM) of fat of 21 %, of crude protein of 42 % and of crude fib er of 9.5 %. In 4 experimental periods with 12 sheep each (n = 48) the digestibility and the energy content of the total rations were measur ed. Besides the soybean-supplied rations each roughage were fed to she ep without soybeans, too (control, treatment I). The addition of soybe ans to the grass products (grass, grass silage, hay) clearly increased the digestibility of the organic matter of the total rations in avera ge about 1.3 % (treatment II) and 3.2 % (treatment III), respectively. The reason for this increase was a significantly higher digestibility of the total fat beginning with 42 % in average of treatment I to 70 % to 75 % of the treatments II and III with soybeans. The digestibilit y of the fiber fractions of rations with grass products were not influ enced by the addition of soybeans. The energy contents (MJ NEL, MJ ME) of the total rations significantly increased about 4 % to 7 % in trea tment II and 10 % to 16 % in treatment III. On the other hand, the add ition of soybeans to maize silage diminished the digestibility of the organic matter of the total rations about 2 % (treatment II) and 3 % ( treatment III), respectively. Thereby the digestibility of the fiber f raction was impaired, while the digestibility of the total fat didn't change scarcely. The energy contents of the maize silage rations suppl ied with soybeans didn't increase. Using the difference method mean di gestibilities of the organic matter, fat, crude fiber and N-free extra ct of the soybeans were calculated with values of 88.1 %, 89.5 %, 75.7 % and 89.4 %, respectively. The energy contents of the soybeans were 16.3 MJ ME and 10.2 MJ NEL per kg DM.