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

Six rumen cannulated Holstein bulls were used in a completely randomiz ed 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 su pplying straw treated with ammonium (TS) or non-treated (NTS) ad libit um 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 treatme nt with ammonium to the straws increased (P < 0.01) DM and tN consumpt ion. Treatment x sampling time interaction was not significant for tot al 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 T S (P < 0.05) compared with NTS while acetate and propionate did not di ffer between treatments. The content of tN in the liquid rumen was hig her for TS (64.3 mg/dl) compared to NTS (32.6 mg/dl). There was a trea tment x sampling time interaction for ammonium in the rumen. It is con cluded that NH3 in straws improves DM and tN consumption and propitiat es more adequate amounts Of NH3 in the rumen so as to obtain adequate developments of microorganisms in digestion.