No abstract

To evaluate the effects of lactylate and Bacillus subtilis on growth performance, complete blood cell count, and microbial changes, 264 weaning pigs were assigned to four treatments (1) control (Con) basal diets that met the nutrient requirement for each phase, (2) 0.2% lactylate (LA), (3) 0.05% Bacillus subtilis strains mixtures (BM), or (4) the combination of LA and BM (LA+BM) added to the control basal diet at their respective inclusion rates in each of the three phases. Dietary lactylate tended to increase weight gain, significantly increased feed intake, and reduced fecal total E. coli and enterotoxigenic E. coli counts during Phase 1. Pigs fed Bacillus subtilis had a greater gain to feed ratio (G:F) during Phases 1 and 2. Pigs fed lactylate had an increased peripheral absolute neutrophil count on D14 but a decreased eosinophil percentage. Pigs fed Bacillus subtilis had an elevated peripheral total white blood cell count at study completion. The addition of lactylate increased microbiota richness, reduced E. coli, and increased Prevotella, Christensenellaceae, and Succinivibrio. Bacillus subtilis supplementation-enriched f_Ruminococcaceae_unclassified and S24-7_ unclassified had positive relationships with feed efficiency. Collectively, these findings suggested that lactylate can be added to diets to balance gut microbiota and improve growth performance during the early postweaning period. The combination of lactylate and Bacillus subtilis strains exerted a synergic effect on the growth performance of nursery pigs.

Fresh forage crops have traditionally been preserved by fermentation, either based on the spontaneous fermentation by epiphytic lactic acid bacterial populations or driven by the addition of lactic acid bacteria inoculant cultures. Although this method of preservation is effective at retarding the spoilage and pathogenic bacteria it does not eliminate these organisms from the forage. Spore-forming and other bacteria are often able to survive the low pH and organic acid levels in the fermented forages and outgrow during feed-out and in the animal. The purpose of this research was to understand the levels and diversity of pathogens in silage systems as an important prerequisite to develop effective ways to control them. From February 2016 to December of 2019, 866 corn silage samples and 577 haylage samples were collected from 457 US dairy farms across 27 states to assess the pathogenic levels in silage. Results indicate the clostridia levels in the haylage samples averaged 9.4 x 103 cfu/g with a range of less than 10 cfu/g to 4.1 x 106 cfu/g. Corn silage had a significantly lower level of clostridia (p<0.05) averaging 2.3 x 103 cfu/g. Clostridium perfringens was the dominant species identified in both haylage and corn silage and accounted for more than 60% of all the clostridia isolates. The other major clostridia species identified were C. beijerinckii, Paraclostridium bifermentens and C. butyricum. E. coli levels were also determined in the haylage and corn silage samples. In haylage, the average E. coli level was 2.1 x 104 cfu/g and ranged from less than 10 cfu/g to 2.5 x 106 cfu/g and were significantly higher (p<0.05) than levels detected in corn silage (average of 5.4 x 101 cfu/g). Further work is underway to determine the source of these pathogens and methods of controlling through the fermentation process.

A Bacillus probiotic administered to sows was evaluated to determine the effect on their litters and subsequent pig growth response during the nursery phase. The study included 500 sows (250 sows/trt) fed a control or treatment diet with two Bacillus subtilis strains administered at 3.7x105 CFU/g of feed beginning three days after mating. Pigs (n=1,100) weaned from the sow phase were divided into 44 pens (22 pens/trt) and fed a common diet to determine the effect of sow treatment on post-weaning growth performance. Fecal samples were collected from a subset of sows (25/trt) at d112 of gestation and d19 of lactation, and from two pigs/pen in the nursery on d3 post-weaning for microbial enumeration. A blood sample was obtained from two pigs/pen on d3 and serum cytokines and the acute phase protein, α-1-acid glycoprotein (AGP) were quantified. Data were analyzed using the MIXED procedure of SAS; sow/litter and pen served as the experimental unit. Litter weaning weights did not differ, but Escherichia coli counts were lower (P≤0.05) on d112 in fecal samples from sows fed Bacillus compared to control sows. Lactic acid bacteria counts were greater (P≤0.01) on d3 post-weaning in pigs weaned from sows fed Bacillus compared to control pigs. Nursery pigs weaned from sows fed the Bacillus probiotic had greater (P≤0.01) ADG and G/F during Phase1 (d 0-11), greater (P≤0.01) ADG and ADFI during Phase3 (d 23-37) and were 0.91 kg heavier (P≤0.01) at the end of the nursery phase (d 51) compared to pigs from control sows. The administration of Bacillus to sows resulted in lower AGP (P≤0.05) and greater tumor necrosis factor-α (P=0.08) serum concentrations on d3 post-weaning and reduced (P≤0.05) the percentage of nursery pigs removed from the trial and placed in invalid pens compared to pigs from control sows. These data indicate that a Bacillus probiotic improves sow health and the lactation environment and has a substantial impact on the subsequent productivity of their progeny.

The objective of this research was to determine the influence of long-term supplementation (258 d) of a direct fed microbial (DFM) and yeast cell wall (YCW) product used alone or in combination on growth performance, dietary net energy utilization, and carcass characteristics in beef steers finished under climatic conditions in the Northern Plains (NP). Single-sourced Charolais × Red Angus steers [n=256; body weight = 246 ± 1.68 kg] were blocked by pen location in a 2 × 2 factorial arrangement of DFM and YCW. Steers were administered a series of diets common to the NP and administered ractopamine hydrochloride (RH; 300 mg/kg) the last 28 d of the finishing phase. Steers were vaccinated and poured at processing and individually weighed on d 1, 14, 42, 77, 105, 133, 161, 182, 230 and 258. Temperature-humidity index (THI) was calculated during RH supplementation. For 98% of the experiment, the THI was lower than 72 and thus cattle were not under high-ambient temperature. On d 1, 2, 21 and 22 of RH supplementation, respiration rates (RR) and panting scores (PS) were determined before and after AM and PM feedings (0700 h, 1100 h, 1400 h, and 1700 h). A DFM+YCW interaction was noted for the proportion of steers categorized as PS 2.0 at 1100 h on d 21 (P = 0.03) and RR on d 21 at 1400 h (P = 0.02). Control steers had a greater proportion of PS 2.0 compared to DFM or YCW steers (P ≤ 0.05), while DFM+YCW steers did not differ from others (P ≥ 0.05); DFM+YCW steers had greater (P < 0.05) RR compared to DFM steers, while control and YCW steers did not differ from others (P ≥ 0.05). No DFM+YCW interactions or main effects (P ≥ 0.05) were observed for cumulative growth performance measures. However, YCW steers had 2% lower (P = 0.04) dry matter intakes compared to steers not fed YCW. No DFM+YCW interactions or main effects (P ≥ 0.05) were observed for carcass traits or liver abscess severity. However, a DFM+YCW interaction (P < 0.05) was noted for the distribution of USDA yield grade (YG) 1 and Prime carcasses. Control steers had a greater proportion (P < 0.05) of YG 1 carcasses compared to other treatments. DFM+YCW steers had a greater proportion (P < 0.05) of USDA Prime carcasses compared to DFM or YCW, but were similar to control steers, which were also similar to DFM or YCW. Overall, the use of DFM and YCW alone or in combination had minimal effects on growth performance, carcass traits, and heat stress measures in steers finished in NP climatic conditions.