In red steppe cattle with duodenal and ileocecal anastomoses when fed isoenergetic, isoprotein hay-concentrate rations with different levels of soluble protein (SR), the digestibility of dry matter (SR), crude ash (CW) and crude fat (CW) was studied separately in a complex stomach , small (TnK) and large (TsK) intestinal sections. Different amounts of RchSP in the rations were achieved by feeding grist from natural and roasted peas at a temperature of 105°C.
 When feeding the experimental ration with a reduced level of RchSP against the background of a decrease in the apparent intensity of digestion, which was manifested in a smaller amount of duodenal and ileocecal chyme, significant changes in the digestibility of SR, SZ and SZ were observed in the postruminal sections of the gastrointestinal tract. According to the general digestibility of SR in the entire alimentary canal and prestomach, in the small and large intestines, there were different directions and degrees of changes in the experimental and control diets. The digestibility of SZ, while being the same in the entire alimentary canal, differed most significantly between rations in the complex stomach and TsK, less so in TnK. On the experimental diet, absorption of dietary fiber in the small and large intestines was 18% lower. The actual level of digestibility of dietary fiber in the animal body did not correspond to the value determined by the formula "feed minus feces" and was 2 times higher in the control diet and 1.4 times higher in the experimental diet.
 The assimilation of dietary fiber in the studied rations in the alimentary canal had a multidirectional character and, in general, was lower in the experimental ration. The actual digestibility of dietary fiber, compared to the "visible" digestibility of the control diet, was 17% higher, and the experimental diet was 3% lower.