PSVII-11 Fecal parameters as indicators of starch digestibility and feedlot performance of water buffaloes

Abstract

This study evaluated fecal parameters indicative of starch digestibility of water buffaloes (Bubalus bubalis) of three genetic groups (GG: Jafarabadi, Mediterranean, and Murrah). Seventy-eight non-castrated males [n = 26 of each GG; 200 kg of initial body weight (BW); 210 days of age] were used. Animals were finished in feedlot, receiving a diet rich in starch [38.76% in dry matter (DM) basis]. Samples of feces, diet offered, and orts were collected for digestibility test during 3 consecutive days. Diet samples were incubated in situ in the rumen of cannulated buffaloes. The remaining material was submitted to analysis to quantify the indigestible neutral detergent fiber levels. Fecal starch (FS) determination was performed by near infrared reflectance spectroscopy. Final BW (BW, kg), metabolic BW (BW0.75, kg0.75), average daily gain (ADG, kg/day), DM intake (DMI, in kg/day, and %BW) were recorded. Data were analyzed using MIXED and CORR procedure in SAS, with significance considered if P ≤ 0.05. Starch digestibility and FS concentration are not influenced by GG (P ≥ 0.23), unlike fecal DM and fecal pH (P ≤ 0.04; Table 1). Although weak, negative correlations were detected between FS and BW (r = -0.247; P = 0.05) and BW0.75 (r = -0.261; P =0.03), as well as between fecal DM and BW (r = -0.245; P = 0.05), ADG (r = -0.341; P < 0.01), DMI, kg/day (r = -0.374; P < 0.01), and DMI, %BW (r = -0.335; P < 0.01) variables. The results demonstrate that there are differences among GG of water buffaloes regarding fecal parameters. Furthermore, the high FS content and the low fecal pH may indicate the low capacity of water buffaloes to digest starch. Thus, the research results provide evidence that water buffaloes are not able to use high-grain diets, and fecal parameters proved to be potential tools to evaluate the feedlot performance of these animals.