Effect of Fermenten on Nitrogen Metabolism and Ruminal Fermentation Profile of Angus Crossbred Steers

The objective of this study was to assess the effect of two inclusion rates of Fermenten (FER, Church & Dwight Co., Inc., Princeton, NJ) on ruminal fermentation profile, blood urea nitrogen (BUN) and apparent total tract digestibility of nutrients in Angus crossbred steers. Eight steers, fitted with ruminal cannulas, were randomly assigned to treatments in a switchback design. Steers were fed a basal diet (92% of the diet DM) comprised mainly of corn gluten feed, soybean hulls, and peanut hulls, and two different top-dressed premixes (8% of the diet DM) to achieve: 1) a final inclusion rate of FER of 4% in the diet DM (4% FER), or 0% inclusion rate of FER (CTL). Diets were isocaloric (69% TDN) and similar in RDP content (6.5% of diet DM), and were individually fed at 2.8% of BW/d. Individual intake was recorded using the GrowSafe System. Samples of ruminal fluid and blood were collected for 24 h, before feeding (0 h) and every 3 h, to determine ruminal pH, NH₃-N and VFA concentrations, and serum concentrations of BUN. Apparent total tract digestibility of nutrients was measured using indigestible NDF as an internal marker. Data were analyzed using the MIXED Procedure of SAS with steer as the experimental unit. Ruminal pH, VFA and concentrations of NH₃-N and BUN were analyzed as repeated measures using the MIXED procedure of SAS. There was a tendency (P = 0.09) for a treatment × time interaction for ruminal pH. Steers in the 4% FER treatment had increased concentrations of butyrate (P = 0.01) and a tendency (P = 0.06) for decreased concentrations of acetate. Steers receiving 4% FER had decreased intake of all nutrients (P < 0.05), as well as a decreased DMI as percent of BW (P = 0.03). Apparent total tract nutrient digestibility was similar between treatments (P > 0.05), except for CP, which was greater for 4% FER treatment (P = 0.012). Nitrogen metabolism was similar between treatments; there was no difference on ruminal NH₃-N (P = 0.97) or BUN (P = 0.95) concentrations. Decreased intake may hinder possible effects of FER on ruminal fermentation parameters, N metabolism, and nutrient digestibility.