Effect of different fibrous and nonfiber carbohydrate levels on nutrients digestibility of total mixed ration using in vivo in buffalo

Abstract In order to investigate the effect of different levels of NDF on chewing behavior and their relationship with ruminal acidity, 3 ruminally fistulated buffalo steers (average BW = 389.6 ±7.5 Kg) were allotted in a change over design in Agriculture and Natural Resource center of Uremia city of Iran. Two diets with 2 levels of NDF were used as treatments. First and second diets had 52 and 47 % of NDF, respectively. The experiment had two periods and each period’s take 15d for adaptation, 7d for sample collection and determination of nutrient digestibility and for determination of passage rate, 2d for measuring ruminal pH, and 3d for measuring chewing activity. Using Penn Stat Particle Separator (PSPS), distribution, geometric mean, its standard deviation and physically effective factor (pef) of diets were determined. Animals fed ad libitum at 09:00a.m and 21:00p.m. The time that spent for eating and rumination were optically recorded in 24h with 5 minutes intervals and total chewing activity calculated from sum of eating and rumination time. There were no significant differences between chemical composition, particles distribution, geometric mean, its standard deviation and physically effective factor (pef) of diets, dry matter intake (kg/d) and nutrients intake (NDF, ADF, NFC and crude protein) and their digestibility, but digestibility ADF, NDF and NFC decreased as content of fiber increased(P<0.05). Increasing NFC reduced ruminal pH at 0.5, 1.0, 4.5, 6.0 9.0 and 10.0 h post feeding (P<0.05). In addition, there were no significant differences on eating time, rumination time and total chewing activity between diets, but increased as NDF intake and peNDF>1.18 increased (P<0.05). Also, rumination time and total chewing activity over night decreased as NDF intake and peNDF>1.18 increased (P<0.05).