PSV-29 Impact of the use of a blend based on organic minerals and yeasts and road transport for 48 hours on the nutrient digestibility of grass-fed beef cattle.

Abstract The objective this study was investigate the effect of supplementation with a blend of live yeast, organic Cr and Se, and road transportation for 48 hours on the nutrient digestibility in Nellore steers fed forage. Nineteen Nellore steers, castrated and rumen cannulated (body weight (BW) = 400 kg ± 35 kg; age = 20 months) were blocked by BW and distributed in individual pens in a 2 x 2 factorial arrangement to investigate the combination of the following factors: 1) animals receiving supplementation containing organic Cr and Se and live yeast (ORG+YT; BEEF SAAC+, Alltech) or containing inorganic Se without added yeast (ING, inorganic source); 2) animals transported for 48 hours (TRANS) or animals not transported and fed regularly (NOTRANS). The 65 days of study were divided into: (1) acclimatization (-30d to -25d) and measurement of nutrient digestibility to be used as an independent covariate from -24d to -22d, (2) adaptation phase from -21d to -1d and (3) evaluation period from 2d to 33d. During the 0d to 2d half of the animals were subjected to road transport for 48 hours. Nutrient digestibility (DM, OM, CP, NDF and ADF) was evaluated on days 3d to 5d, 11d to 13d and 31d to 33d. Data were analyzed by ANOVA using PROC MIXED, SAS 9.4. All variables were analyzed as repeated measures over time using REPEATED procedure of SAS. Digestibility data during the experimental period were analyzed using nutrient digestibility measured between -24d to -22d as an independent covariate. Interaction between transportation × period was detected (P < 0.012) for DMD, OMD, CPD, NDFD and ADFD. TRANS increased DMD (681 vs. 614 g/kg; P = 0.024), OMD (694 vs. 631 g/kg; P = 0.025), CPD (765 vs. 730 g/kg; P = 0.075), NDFD (745 vs. 687 g/kg; P = 0.035) and ADFD (717 vs. 651 g/kg; P = 0.014) in the short period after transportation (3d to 5d). No differences were found at intermediate periods (11d to 13d; P > 0.215), but TRANS reduced DMD (502 vs. 560 g/kg; P = 0.045), OMD (534 vs. 591 g/kg; P = 0.043), CPD (554 vs. 598 g/kg; P = 0.014), NDFD (671 vs. 712 g/kg; P = 0.084) and ADFD (666 vs. 690 g/kg; P = 0.070) at long periods, such as 31d to 33d. Interaction between transport × period was detected (P < 0.001) for fecal excretion. TRANS reduced fecal excretion in the short term (1.87 vs. 2.33 kg; P = 0.010; 3d to 5d) and increased it in the long term (3.83 vs. 3.42 kg; P = 0.047; 31d to 33d). In conclusion, road transportation imposed in this study was able to impact nutrient digestibility in the short and long term.