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Barrows (n = 360; 200×400, DNA; initial BW = 6.5 ± 0.04 kg) were used in a 42-day study to evaluate clay-based binders or an in-feed antimicrobial on growth performance and biological measurements including fecal and blood analysis in nursery pigs. Pigs were weaned at approximately 21-day of age and randomly allotted to 1 of 4 dietary treatments in a completely randomized design. There were 5 pigs per pen and 18 replications per treatment. Dietary treatments were corn-soybean meal-based and fed in two phases from d 0 to 9 (Phase 1) and 9 to 21 (Phase 2) after weaning. Either clay-binders (Proteck, 0.40% of the diet; Nutriquest, Mason City, IA; Protect-8 Plus, 0.10% of the diet; Essential Ag Solutions, Sioux Falls, SD), or an antimicrobial (0.04% of the diet; Avilamycin (Kavault); Elanco, Greenfield, IN) were added to the control diet to create the experimental treatments. A common phase 3 diet was fed to all pigs from d 21 to 42. Overall (d 0 to 42), pigs fed Avilamycin had increased (P < 0.05) final BW, ADG and ADFI compared with all other treatments. There was evidence that frequency of fecal scores with softer feces increased over time (P < 0.001), with d 21 having the greatest frequency of diarrhea and soft feces (Table). Fecal E. coli colony count was less (P < 0.001) on d 21 compared with d 9 (2.04 vs. 4.03 Log10, respectively). For fecal myeloperoxidase (MPO), concentrations were less (P < 0.05) on d 21 compared with d 6 and 9 (0.014, 0.059, and 0.045 nmole·min-1·mL-1, respectively). For fecal DM, pigs fed Avilamycin had decreased (P < 0.05) DM percentage compared with all other treatments. Fecal DM percentage was greater (P < 0.05) on d 6 and 9 compared with d 21 (26.64, 27.63, and 24.88%, respectively). Correlation coefficients were used to further characterize the relationships between biological measurements in the nursery period. There was a strong negative correlation between fecal DM and score (P < 0.001) on d 6, 9, and 21 indicating that as fecal DM increased, the score became closer to 0, representing a firmer fecal sample. Fecal DM on d 6 and fecal DM on d 9 were negatively correlated with ADG from d 0 to 9 meaning that as growth rate increased, fecal DM decreased. In summary, pigs fed Avilamycin had increased BW, ADG, and ADFI compared with those fed the 2 clay-based additives or the control diet. There were no treatment effects on fecal score, fecal MPO, or blood measurements. However, fecal consistency was softer and fecal E. coli colony count and MPO had lower concentrations on d 21 compared with samples collected earlier in the nursery phase. [ABSTRACT FROM AUTHOR]

The objective of this trial was to determine the influence of live yeast supplementation (LY) and temperature exposure (TEMP) on the ruminal fermentation characteristics of steers receiving a grower diet. The effects of LY and TEMP were investigated using a 2 x 2 crossover design that spanned five periods. Eight Angus crossbred steers (365 ± 32 kg) were randomly split into pairs and housed in four outdoor pens outfitted with an individualized feeding system. Animals were limit fed a grower diet (DIET) at 1.2% SBW with no live yeast supplementation (NOY) or a grower diet top-dressed with 10 g live yeast/d for 14 days (1.2 × 1012 CFU/d). On days 13 and 14, animals were subjected to one of two TEMP conditions, thermoneutral (TN; 18.4 ± 1.1°C, 57.6 ± 2.8 % RH) or heat stress (HS; 33.8 ± 0.6°C, 55.7 ± 2.7 % RH), in two side-by-side, single-stall open-circuit, indirect respiration calorimetry chambers. Data were analyzed using a random coefficients model. Carryover effects were examined and removed from the model if not significant (P > 0.05). There was no effect of DIET, TEMP, or DIET×TEMP (P > 0.05) on ruminal pH, redox, ciliated protozoa count, acetate, butyrate, total VFA, and ruminal ammonia concentrations. Similarly, the acetate to propionate ratio was not influenced by DIET, TEMP, or DIET × TEMP (P = 0.190). Propionate concentration was the greatest in animals in TN conditions receiving LY (P = 0.008). Compared to HS+NOY, HS+LY (P = 0.003) and TN+LY (P = 0.043) had greater ruminal enumerations of Fusobacterium necrophorum. This suggests LY (P = 0.010) provided a favorable environment for F. necrophorum during heat stress. Live yeast supplementation did not improve overall ruminal fermentation during heat stress. Additional research is required to better understand the dynamic relationship between live yeast and temperature exposure. [ABSTRACT FROM AUTHOR]