Comparison of actual and predicted amino acid contents in the duodenal digesta of dairy cows

Abstract

RICHTER, M., TŘINÁCTÝ, J., KŘÍŽOVÁ, L.: Comparison of actual and predicted amino acid contents in the duodenal digesta of dairy cows. Acta univ. agric. et silvic. Mendel. Brun., 2010, LVIII, No. 5, pp. 313-320 In this experiment on three dairy cows with the ruminal and duodenal T-cannulas, the actual and predicted amino acid (AA) profi les of the protein fraction fl owed to the small intestine were compared. The prediction was calculated by two methods: with the use of mean published AA profi le of microbial protein and of experimentally determined one. The actual AA profi le of digesta protein was corrected for glycine (Gly) of bile origin. In comparison to the published AA profi le of microbial protein the use of the actual one did not contribute to an improvement of prediction accuracy (mean prediction error: 7.36 vs. 7.54 %, respectively). Inaccurate determination of AA composition of undegraded feed protein and the insuffi cient correction for Gly of bile origin were the probable sources of the residual variability. amino acids, dairy cow, duodenum, microbial protein, prediction

Nutrient digestibility and endogenous protein losses in the foregut and small intestine of weaned dairy calves fed calf starters with conventional or enzyme-treated soybean meal

“…Reference AA profiles found in the literature were used for each of the digesta proteins. For the endogenous protein flow to the duodenum, the average of the mean AA profile of adult cows (Larsen et al, 2000;Richter et al, 2010) and growing goats (Zhou et al, 2008(Zhou et al, , 2009 was used, whereas only that of the adult cow (Larsen et al, 2001) was used for the flow to the distal ileum. For MCP, the AA profile of ruminal microbial protein (83.5% bacteria + 16.5% protozoa) as detailed by Sok at al.…”

“…Assuming that most of the true digestion of OM occurred in the rumen (Ipharraguerre et al, 2002), less Coefficients applied to the total flow of CP to estimate the flows of undigested dietary, microbial, and endogenous protein at the duodenum and ileum of weaned calves were estimated by multiple regression analysis and χ 2 distance according with Duvaux et al (1990). For the endogenous protein flow at the duodenum, the mean AA profile of adult cows (Larsen et al, 2000;Richter et al, 2010) and growing goats (Zhou et al, 2008(Zhou et al, , 2009 was used, whereas only that of the adult cow (Larsen et al, 2001) was used for the flow at the ileum. For microbial N, the AA profile as detailed reviewed by Sok et al (2017) was used for both sites, and the AA profile of the diets was used as reference for dietary undigested protein at both sites as well.…”