THE EFFECT OF CHEMICALLY TREATED GRAINS ON RUMINAL FERMENTATION

Trials were conducted to study changes in the chemical composition of grains treated with sodium hydroxide (3% and 5% NaOH for wheat and bar ley, resp.) and the effect of their feeding on some parameters of rumi nal fermentation (pH, NH3, acetic, propionic, butyric and lactic acid) and on nutrient digestibility in situ in cattle. Wheat and barley gra in treatment with sodium hydroxide increased water and ash contents an d decreased contents of fat, fiber and nitrogen-free extract in both g rains. In trial 1, heifers received daily rations consisting of hay (5 -6 kg) and concentrate mixture supplement (1 kg), which contained 20% of NaOH treated barley and 39% of NaOH treated wheat. Taking into acco unt the time dependence since feeding, the level of ruminal fermentati on - pH, total and individual volatile fatty acids, did not show any s ignificant changes after feeding NaOH treated grains at a low concentr ation of nutrients (13% dry matter met by concentrate) to heifers. Tri al 2 included 24 dairy cows divided into three groups. Silage, hay and concentrate mixture supplement (4.5 kg) were the basic ingredients of daily ration for the first group. The second group received daily rat ion identical with that for the first group, but a part of concentrate mixture was replaced by NaOH treated wheat (45%). Daily ration for th e third group consisted of green forage, silage, hay and a part: of co ncentrate mixture was replaced by NaOH treated wheat (45%) similarly l ike in the second group. Following the above replacement of concentrat e mixture by NaOH treated wheat and a high level of nutrition (25% of dry matter met by concentrate) in winter ration (2nd group) and in tra nsition ration (3rd group), dairy cows tended to show a decrease in to tal volatile fatty acids, acetic and propionic acids, a significant de crease in butyric acid (P < 0.01) and a significant increase in lactic acid (P < 0.01 and P < 0.001, reap.) in relation to full replacement of concentrate by concentrate mixture. Heifers with fistulas fed hay w ere used in trial 3. Nylon bags were taken out from the rumen in 3, 6, 9 and 24 hours. The values of dry matter digestibility and digestibil ity of all nutrients in ground wheat are significantly higher at ail t ime intervals if compared with the values for NaOH treated whole wheat grains, which together with the results of ruminal fermentation confi rms a shift of nutrient and starch digestion from ruminal fermentation to enzymatic digestion. Incubation in whole grains;was also a reason for lower nutrient digestibility in situ in NaOH treated wheat. No hea lth disorders of animals were observed after long-time feeding of NaOH treated grain supplement.