Estimation of Effectie N Degradability of Protein Supplements Using Nylon Bag Technique* Reddy E. Prasada, Arasad D. Anjaneya Department of Animal Nutrition, Andhra Pradesh Agricultural University, College of Veterinary Science, Tirupati-517502 (AP), India *Part of Ph.D. thesis submitted to the Andhra Pradesh Agricultural University, Hyderabad, by the first author. Online published on 21 January, 2012. Abstract The potential N degradability (p) of solvent extracted groundnut cake (SEGC), expellar processed groundnut cake (EPGC), cotton seed cake (CSC), safflower cake (SFC), tobacco seed cake (TSC), silk cotton seed cake (SCSC), niger seed cake (NSC) and sunflower seed cake (SFSC) has been reported. The ‘p’ value was calculated by the equation p=a + b(a–e-et) with ‘t’ representing incubation time and the constants ‘a’, ‘b’ and ‘c’ representing soluble N%, insoluble but degradable N% and the rate constant/h, respectively. For each protein supplement these constants were derived from incubation experiments conducted on rumen flstulatcd Ongolex Holstein Freisian bullocks using the nylon bag technique. Allowing for rate of passage (k or kd 0 05/h) the effective N defradablitiies according to Orskov and be kd McDonald Model (p=a + bc/c+k) and Miller model (dg=a (1–a)kd/kr+kd) were 30, 0.323; 20, 0.254, 18. 0.191; 61, 0.623; 43, 0.424; 78, 0.788; 33, 0.237 and 46, 0.416 for the SEGC, EPGC, CSC, SPC, TSC, SCSC, NSC and SFSC, respectively. The correlation (r=0.988) between N degradability values obtained by the two models was highly significant. The N degradability values of protein supplements will be quite useful in formulating concentrate mixtures for cattle. Top |