| Popis: |
The objective of this experiment was to evaluate craft brewing side streams of trub, hops and yeast mix (THYM) as a potential feedstuff and replacement for monensin in growing beef cattle rations. British-cross steers (n = 45, initial BW = 732 ± 58kg) were stratified by BW and randomly assigned to 1 of 15 pens (3 head/pen). Treatment diets were randomly assigned to pen and consisted of a corn silage based total mixed ration (TMR) with no supplementation (CON; 70.99% TDN, 12.25% CP), supplementation with monensin (MON; 22g/907kg ration, dry matter basis) or supplementation with the brewery side streams (THYM; 70.95% TDN, 12.49% CP, 2.65% THYM, dry matter basis). Steers were adjusted to a TMR for 14 d prior to a 63 d collection period. Body weight and serum urea nitrogen (SUN) were measured on d 0 and every 21 d thereafter. Rumen fluid was collected via esophageal/rumen tube at d 42 and 63 for short chain fatty acid analysis (SCFA). Data were analyzed using the MIXED procedure of SAS 9.4 (Cary, NC) with treatment as the main effect and using repeated measures. Average daily gain and dry matter intake did not differ among treatments (P = 0.40 and P = 0.96, respectively), but a tendency was noted for THYM to have greater average gain:feed than the CON treatment. SUN concentrations were least on d 0 (P < 0.01) but did not differ among treatments at any time (P =0.11). On d 42, THYM had a greater (P = 0.05) A:P than MON. Concentrations of propionic and valeric acid were greater (P < 0.05) for CON than THYM on d 63, while SCFA concentrations tended to be greater (P = 0.08) for CON than THYM. THYM also tended to have a greater A:P on d 63 than CON. Interpretation of the data indicates that inclusion of THYM in growing cattle rations has no negative impact on animal performance. |
