DIGESTIBILITY OF IN RUMEN UNDERGRADED CRU DE PROTEIN OF TREATED PROTEIN FEEDS IN POSTRUMINAL PART OF DIGESTIVE-TRACT OF RUMINANTS

The effective degradability and intestinal digestibility of CP of untr eated and with formaldehyde (F) treated sunflower press - cakes (SF), lucerne meal (LM) and field beans (FB) were measured on polycannulated bulls by ''in sacco'' and ''imobile bag'' methods. The feeds were tre ated by F solution in doses from 0.2; 0.4... to 2.0 g F per 100 g CP. The effective CP degradability after treatment was decreased significa ntly (for SF from 78 to 33%, LM from 73 to 62%, FB from 70 to 47% with max. dose of F). The effect of F was various on individual feeds. The intestinal digestibility of treated feeds, without previous incubatio n in the rumen, passed from abomasum to feaces has been influenced wit h doses of F non significantly. The digestibility of FB treated with d ose off was lower about 20% in the part duodenum feaces than in abomas um feaces. The digestibility in the part caecum - feaces for all teste d feeds has been decreasing with doses of F, similar as in the rumen. The intestinal digestibility of in rumen undegraded crude protein resi dues of SF has been influenced by the treatment positively. It increas ed from 43 to 82%. The effect of F on LM was very low. The digestibili ty has been changed from 75 to 80%.