EFFECT OF THE NH3 TREATMENT TO SUGAR-CANE STRAW ON RUMEN FERMENTATION AND N-CONTENT IN THE RUMEN

Six rumen cannulated Holstein bulls were used in a completely randomized design with two treatments and three replications to determine the effect of ammonium on sugar cane straw in rumen fermentation, total N content (tN) and ammonium in the rumen. The treatments consisted of supplying straw treated with ammonium (TS) or non-treated (NTS) ad libitum and 3 kg of a home feed as supplement. Data were analysed according to a linear model where treatment, sampling time, animals within the treatment and treatment x hour interaction were evaluated. The treatment with ammonium to the straws increased (P < 0.01) DM and tN consumption. Treatment x sampling time interaction was not significant for total and individual VFA nor for pH or tN in the rumen. VFA concentration was 81.2 and 71.1 meq/litre for TS and NTS, respectively and did not differ between them. Molar proportion of butyric acid decreased with TS (P < 0.05) compared with NTS while acetate and propionate did not differ between treatments. The content of tN in the liquid rumen was higher for TS (64.3 mg/dl) compared to NTS (32.6 mg/dl). There was a treatment x sampling time interaction for ammonium in the rumen. It is concluded that NH3 in straws improves DM and tN consumption and propitiates more adequate amounts Of NH3 in the rumen so as to obtain adequate developments of microorganisms in digestion.