Třináctý J., Šustala M., Homolka P., Chládek G. (2001): Alfalfa hay crude protein intestinal digestibility determined by nylon bag and nylon capsule methods. In: Book of Abstracts of the 52nd Annual Meeting of the European Association for Animal Production, No. 7 (2001), 26-29 August 2001, p.91. ABSTRACT: A nylon bag method was performed on three dry cows fitted with rumen cannulas. The bags were made of nylon with pore size of 42 -m. The internal size of bag was 5 x10 cm. Each bag contained 0.7 g of good quality alfalfa hay ground through a sieve of 2 mm. The degradability parameters were drawn by fitting the curves to the equation P=a+b(1-e ), k=5%h. The trial with nylon capsules method was performed on three dairy cows (average yield 17.5 kg of milk per day) without any cannulas. Two hemispheres of the nylon capsules were made of the same material as the nylon bags. The capsule shape was lenticular, external diameter of 10 mm, internal diameter of 8 mm. The average weight of the alfalfa hay in one capsule was 0.0152 g. In each of the two periods 150 of capsules were inserted into one cow orally as a paper bolus. The average recovery of capsules was 85.9% (s.e. 2.03), the average time of capsules passage through the tract was 47.2 h (s.e. 5.60). ED value in rumen was 81.1% (s.e. 0.45). The value of digestibility evaluated by nylon capsule method in total tract was 95.5% (s.e.0.21). The calculated value of intestinal digestibility of rumen escape protein was 76.3%. This study was supported by GAČR (523/99/1529).