The objective of this study was to evaluate the effects of water-delivered, direct-fed microbials (DFM) or organic acids on intestinal morphology and active nutrient absorption in weanling pigs after deliberate Salmonella infection. Pigs (n = 88) were weaned at 19 ± 2 d of age and assigned to 1 of the following treatments, which were administered for 14 d: 1) control diet; 2) control diet + DFM (Enterococcus faecium, Bacillus subtilis, and Bacillus licheniformis) in drinking water at 109 cfu/L for each strain of bacteria; 3) control diet + organic acid-based blend (predominantly propionic, acetic, and benzoic acids) in drinking water at 2.58 mL/L; and 4) control diet + 55 mg/kg carbadox. Pigs were challenged with 1010 cfu Salmonella enterica var Typhimurium 6 d after commencement of treatments. Pigs (n = 22/d) were harvested before Salmonella challenge and on d 2, 4, and 8 after challenge. Duodenal, jejunal, and ileal mucosal tissues were sampled for measurement of villus height and crypt depth. Jejunal tissue was sampled for determination of active nutrient absorption in modified Ussing chambers. Duodenal villus height was greater in pigs fed in-feed antibiotic before infection (P < 0.05). Jejunal crypts were deeper in DFM- and acid-treated pigs on d 4 after infection compared with all other treatments (P < 0.05). Salmonella infection resulted in a linear decrease in phosphorus (P < 0.001) and glucose (P < 0.05) active transport, and an increase (P < 0.001) in glutamine uptake immediately after challenge. Salmonella infection reduced basal short-circuit current (Isc); however, water-delivered DFM or organic acid treatments caused greater basal Isc on d 2 after challenge than did carbadox. Carbachol-induced chloride ion secretion was greatest in negative control pigs before infection (P < 0.01) and DFM-treated pigs (P < 0.05) after infection. In conclusion, both the DFM and acidification treatments induced increases in basal active ion movement and jejunal crypt depth, which could be interpreted as responses consistent with increased Salmonella pathology, but none of the additives markedly affected intestinal absorptive and secretory function in response to Salmonella challenge.

In the original article, some necessary information was omitted from Table 1.The label "ADFI, kg/d" should have been included in the first column to describe the third and fourth rows of data.The corrected table is shown below.

Pigs (n = 88) weaned at 19 ± 2 d of age were used in a 14-d study to evaluate the effects of water-delivered direct-fed microbials (DFM) or organic acids on growth, immune status, Salmonella infection and shedding, and intestinal microbial populations after intranasal inoculation of Salmonella Typhimurium (10(10) cfu/pig). Pigs were challenged with Salmonella 6 d after commencement of water treatments. Treatments were 1) control diet; 2) control diet + DFM (Enterococcus faecium, Bacillus subtilis, and Bacillus licheniformis) in drinking water at 10(9) cfu/L for each strain of bacteria; 3) control diet + an organic acid-based blend (predominantly propionic, acetic, and benzoic acid) in drinking water at 2.58 mL/L; and 4) control diet + 55 mg/kg of carbadox. Serum samples were taken on d 6, 8, 10, and 14 for determination of tumor necrosis factor α (TNFα) concentrations. Fecal samples were taken on d 0, 5, 7, and 11 for determination of Salmonella shedding and enumeration of coliforms. Pigs were euthanized on d 6, 8, 10, and 14. Intestinal and cecal tissue and digesta and mesenteric lymph nodes were sampled and analyzed for Salmonella. Duodenal, jejunal, and ileal mucosal scrapings were sampled for measurement of mucosal TNFα concentrations. Water delivery of DFM prevented a decline in ADG on d 2 to 6 postchallenge compared with the negative control (P < 0.05). Coliform counts tended to be greater (P = 0.09) in the cecum of the DFM treatment group on d 2 postinfection compared with the negative control and acid treatment groups. However, Salmonella prevalence in the feces, gastrointestinal tract, or lymph nodes was not affected by water delivery of acids or DFM. Serum and mucosal TNFα concentrations were not affected by treatment throughout the study with the exception of ileal concentrations on d 4 postchallenge, which were greater in the negative control group compared with all other treatments (P < 0.05). The in-feed antibiotic was the only treatment that reduced Salmonella prevalence and this was localized to the cecum on d 8 postinfection. In conclusion, the DFM and organic acid treatments used in this study offered little or no benefits to pigs infected with Salmonella and should not be considered under the constraints of this study as viable alternatives to in-feed antibiotics in a pathogen challenge situation.

In 2006, the USDA Natural Resources Conservation Service (NRCS) Conservation Innovation Grant program funded a project to develop the infrastructure for the systematic development and implementation of the USDA-NRCS Feed Management (FM) Conservation Practice Standard 592 (CPS 592). The overall goal of CPS 592 is to encourage adoption of FM practices that can have a positive impact on soil, water, and air quality. Implementation documents, templates, decision aid tools, and supporting fact sheets were developed for the species of beef, dairy, poultry, and swine. Specific objectives of the project were to 1) assist USDA-NRCS staff and agricultural professionals to increase their understanding of FM and its impacts on environmental sustainability of livestock and poultry operations, 2) improve the proficiency of agricultural professionals in the development and implementation of a FM plan as part of a Comprehensive Nutrient Management Plan, 3) provide the American Registry of Professional Animal Scientists with certification exams, and 4) provide methodology on how to assess the financial implications of different ration strategies on whole-farm nutrient balance and economics of use of manure nutrients at agronomic rates. Implementation of CPS 592 is described for the states of California, Maryland, Pennsylvania, and Wisconsin.

The main objective of the present investigation was to study the impact of fermentation of cereals on the degradation of polysaccharides and other macronutrients in the small intestine and total tract of growing pigs. Eight pigs (initial BW, 34.5 ± 0.9 kg) were used in a replicated 4 × 4 Latin square design. Pigs were cannulated and housed individually in metabolism pens during sample collection. The 4 cereal-based diets were nonfermented liquid barley (NFLB), nonfermented liquid wheat (NFLW), fermented liquid barley (FLB), and fermented liquid wheat (FLW). The fermented feeds were prepared by storing the dietary cereals (barley and wheat) and water [1:2.75 (wt/wt)] in a closed tank at 25 °C for 2 d, after which 50% of the volume was removed and replaced with an equal amount of fresh cereals and water after each afternoon meal. At the time of feeding (0730 and 1430 h), the remaining dietary ingredients were added. Water was added to the dry nonfermented feeds [1:1 (wt/wt)] immediately before feeding. The fermentation process reduced the amount of DM in both cereals (P<0.001), whereas the amount of DM was similar (P=0.626) between the fermented cereals. There was an interaction of cereal and treatment for ileal flow of DM (P=0.014), OM (P=0.013), and protein (P=0.006), which were less in pigs fed the NFLB than the FLB diets, but unchanged in pigs fed the NFLW and FLW diets. Conversely, the ileal flow of protein was similar (P=0.605) in pigs fed the barley diets (average, 47.5 ± 1.7 g/kg of DMI) and increased with the FLW diet compared with the NFLW diet (43 vs. 35 g/kg of DMI, respectively). Ileal fat and CH(2)O digestibilities were 7.6 (P=0.002) and 8.9% (P<0.001) greater, respectively, when pigs were fed wheat compared with the barley-based diets, and the ileal digestibility of CH(2)O was greater when pigs were fed the fermented than nonfermented diets (86.5 vs. 84.5%, respectively; P<0.001). Fermentation reduced (P<0.0001) the fecal excretion of DM, OM, and protein in pigs fed the barley diet, but not when fed the wheat-based diet (P=0.305). Fermentation had no effect (P=0.243) on the fecal digestibility of nonstarch polysaccharides in either of the cereals but their digestibility was 10.0% greater (P<0.001) in pigs fed wheat than the barley-based diets. In conclusion, fermentation of cereal before feeding altered the dietary composition and influenced flow and composition of polysaccharides and other macronutrients at the ileum and in feces to a larger extent for barley than wheat.

Ractopamine (RAC) is a feed ingredient for use in finishing pigs that increases pork carcass muscle protein and improves production efficiency. A mathematical analysis of the environmental effects of increased rate of gain, improved feed efficiency, and increased carcass leanness was conducted, and for the analysis, it was assumed that RAC was implemented in all finishing pig diets in the United States at 5 or 10 mg/kg of diet, while producing the same amount of pork protein that is currently being produced. The average responses to 5 or 10 mg/kg RAC fed for the last 28 d before market included a 5.3 or 5.9% increase in carcass protein percentage, a 0.31 or 0.81% increase in carcass yield, a 12.0 or 10.9% increase in ADG, a 0.5 or 2.5% reduction in ADFI, and a 9.3 or 14.3% improvement in G:F, respectively, and approximately 3 fewer days to market. Using these assumptions, the current amount of pork could be produced with 5.3 or 6.3% fewer pigs. Because of improved efficiency and the reduction in animal numbers, 2.8 or 3.4 billion fewer kilograms (equivalent to 0.29 or 0.35 million hectares) of corn and 0.16 or 0.34 billion fewer kilograms (equivalent to 0.059 or 0.127 million hectares) of soybeans would be needed for pork production each year, respectively. This reduction in cropland acreage would lead to an annual reduction of 79 or 97.4 million kilograms of fertilizer, 0.8 or 1.05 million kilograms of pesticides (herbicides and insecticides), and 184 or 233 billion liters of water, respectively. In conclusion, the implementation of RAC in swine diets results in a reduced natural resource demand for pork production and improved environmental stewardship.

Animal manure is a significant source of environmental pollution and manure dilution in barn cleaning and slurry storage is a common practice in animal agriculture. The effect of swine manure dilution on releases of four pollutant gases was studied in a 30-day experiment using eight manure reactors divided into two groups. One group was treated with swine manure of 6.71% dry matter and another with manure diluted with water to 3.73% dry matter. Ammonia release from the diluted manure was 3.32mgmin−1m−2 and was 71.0% of the 4.67mgmin−1m−2 from the undiluted manure (P<0.01). Because the ammonia release reduction ratio was lower than the manure dilution ratio, dilution could increase the total ammonia emissions from swine manure, especially in lagoons with large liquid surface areas. Carbon dioxide release of 87.3mgmin−1m−2 from the diluted manure was 56.4% of the 154.8mgmin−1m−2 from the undiluted manure (P<0.01). Manure dry matter was an important factor for carbon dioxide release from manure. No differences were observed between the treatments (P>0.05) for both hydrogen sulfide and sulfur dioxide releases. Therefore, dilution could also significantly increase the total releases of hydrogen sulfide and sulfur dioxide to the environment because dilution adds to the total manure volume and usually also increases the total gas release surface area.

SUMMARY A 2-year experiment was conducted to study the effects of .2 or .5% salt (NaC1) in growing- finishing swine diets and aerobic (oxidation ditch) or anaerobic (deep pit) liquid waste systems on swine performance and waste nutri- ent composition. Neither dietary salt content nor waste han- ding system affected pig gains or feed conver- sion. Waste from pigs fed .5% salt contained higher sodium levels than waste from pigs fed .2% salt. During the study, the sodium level increased in the waste pits beneath pigs fed the .5% salt diet, whereas the sodium level in the waste pits beneath pigs fed the .2% salt diet remained relatively constant. Aerobically treated waste contained lower dry matter and higher dissolved oxygen concen- trations, had higher pH and temperature on a wet basis, and lower ammonium nitrogen and higher nitrate nitrogen, potassium and sodium concentrations on a dry weight basis that anaerobic waste. The average percentage of ammonium nitrogen to total Kjeldahl nitrogen was 42% in aerobic pits, 53% in anaerobic pits, 45.5% in waste from pigs fed .5% salt diets and 49.5% in waste from pigs fed .2% salt diets. Copper and phosphorus levels in wastes were directly related to the dry matter content of the waste. Sodium and potassium concentra- tions (dry weight basis) were higher in aerobi-

The BW growth of 1,385 barrows and gilts was evaluated from d-21 weaning to 130 kg BW. The pigs were assigned to a 2×2 factorial arrangement of treatments. The pigs were fed a series of either standard corn- and soybean meal-based control diets or low nutrient excretion nutrient-dense (LNE-ND) diets from 1 wk postweaning to 130 kg BW and assigned to rooms with either deep pit or pull plug-recharge manure storage treatments. The pigs were weighed at weaning, at 7 and 14 d postweaning, and at approximately 2-wk intervals from 28 d postweaning to a mean BW of 130 kg. Mixed model nonlinear equations including pig-specific random effects were evaluated for the generalized Michaelis-Menten function. The serial postweaning BW data were fitted to a mixed model generalized Michaelis-Menten equation. Relationships of weaning BW to late finishing BW and days to 125 kg BW were different for each dietary treatment. Late finishing BW and days to 125 kg BW had nonlinear relationships with weaning BW for pigs fed the LNE-ND diets and had linear relationships for pigs fed the control diets. The predicted changes in subsequent BW of the LNE-ND diets per kilogram of change in weaning BW were greater for pigs with the lightest weaning BW than for pigs with average to above-average weaning BW. Across both dietary treatments, pigs with greater weaning BW and greater early postweaning ADG required fewer days to achieve target market BW.

Two experiments were conducted to determine the effects of feeding a corn- and soybean meal-based diet (control) or a low nutrient excretion (LNE) diet, formulated with reduced dietary CP and additional synthetic AA, low phytic acid corn, and phytase, on pig growth performance during the grower (BW=32 to 77 kg) and finisher (BW=78 to 126 kg) periods and on carcass and bone characteristics at slaughter. Pigs (32+/-1.3 kg of BW, Exp. 1; 6.7+/-0.27 kg of BW, Exp. 2) were blocked by sex and BW and randomly allotted to a control or LNE diet. Pigs were housed in 4 rooms during the nursery period and in 2 rooms during the grower and finisher periods, with individual and identical ventilation systems. Pigs were phase fed 3 nursery diets for 5 wk (Exp. 2) and phase fed 2 grower and 2 finisher diets for 16 wk (Exp. 1 and 2). Pigs were housed 4 or 5 pigs/pen with 9 pens x sex(-1) x treatment(-1) during the nursery period and 4 or 5 pigs/pen with 5 pens x sex(-1) x treatment(-1) in the grower phase and 2 or 3 pigs/pen in the finisher phase. Individual BW and pen feed disappearance were recorded weekly in the nursery period and every 2 wk in the grower-finisher period. Pigs were scanned ultrasonically at d 34 of the nursery period and wk 8 and 16 of the grower-finisher period to determine backfat depths and LM area. Ten pigs x sex(-1) x treatment(-1) were slaughtered at wk 16 of each experiment to determine carcass characteristics. Overall growth performance was not different during each experiment. However, nursery G:F (control=0.65; LNE=0.60), grower ADG (Exp. 1 and 2), and grower G:F (Exp. 2) were reduced (P<0.05) when the LNE diets were fed. Diet had no effect on 10th-rib carcass data in either experiment. Metatarsal bone ash percentage was reduced (P<0.05) when the LNE diets were consumed in both experiments. Feeding LNE diets resulted in the maintenance of overall growth performance, bone variables, and carcass characteristics. However, further refinements are still required in the nursery and grower phases of pig production to optimize LNE diet use by the swine industry.

Knowledge about release mechanisms of pollutant gases from animal manure is important for modeling and predicting gas release and emission, improving measurement accuracy, developing abatement technologies, and ensuring farm safety. This article presents research results oil release behaviors of ammonia (NH3), hydrogen sulfide (H2S), carbon dioxide (CO2), and sulfur dioxide (SO2) from swine manure. The study was conducted in a laboratory using 138 L laboratory reactors at 20 degrees C for 260 d. Gas release behaviors were investigated under transient conditions when manure was suddenly disturbed and under steady-state conditions at different reactor ventilation rates. Distinguishing release behaviors were observed and related to the different releases mechanisms of these gases. Convective mass transfer release governed NH3 release and influenced H2S and CO2 releases. Solubility of gases played all important role in the convective releases. Higher solubility was related to higher convective release. "Bubble-release" was dominant in the releases of H2S, SO2, and CO2. A new Bubble-release model was developed to explain release behavior characteristics related to these gases. Bubble-release was responsible for the reported phenomenon of "H2S Burst-release" that had been defined as sudden increases in H2S release by more than 100% as compared with previous releases in less than I h in deep-pit swine barns. Interactive release occurred among different gases via their different effects on the pH of surface manure. This study demonstrated that gas production in liquid manure and gas release from liquid medium into the immediate free air stream are two different processes that should be distinguished when addressing air pollution. Liquid manure containing dissolved gases and micro air bubbles serves as a reservoir before the gases tire released to the free air stream. A "Reservoir-effect" was found to be considerable in this study because it held gaseous H2S for about 10 d before H2S babbles started to release. Understanding gas release mechanisms call help to improve air quality sampling methodology. For example, to obtain accurate H2S emission factors at swine buildings, long-term monitoring with high-frequency (or continuous) and multipoint measurement is necessary to cope with temporal and spatial variations of the gas due to its Bubble-release behavior.

Two trials were conducted to determine the effect of microbial phytase (PHY) addition and low phytic acid (LPA) corn, on the nutrient digestibility and performance of growing beef steers. Four crossbred steers (initial BW = 345 ± 25 kg; Exp. 1) were used in a 4 × 4 Latin square design digestibility trial and were provided ad libitum access to 1 of 4 diets: 1) a normal corn and 15% corn silage diet (control diet), 2) diet 1 + PHY (control + PHY diet; 600 FTU/kg, where a FTU is the quantity of enzyme that liberates 1 µmol inorganic P/min from 0.005 mol/L sodium phytate at pH 5.5 and 37°C), 3) diet 1 with LPA corn replacing normal corn (LPA diet), and 4) diet 3 + PHY (LPA + PHY diet; 600 FTU/kg). Dietary P content was 0.38 to 0.40%, with no supplemental P added. Forty-eight crossbred steers (initial BW = 273 ± 6.9 kg; Exp. 2) were individually fed 4 diets: 1) a control diet; 2) a control + PHY diet; 3) diet 1 limit fed to 85% of ad libitum intake (limit-fed diet); and 4) the limit-fed diet + PHY. In Exp. 1, P digestibility, retention, and excretion were not affected (P > 0.05) by corn type or PHY. There was a trend (P < 0.10) toward increased N retention and decreased N excretion with PHY addition. In Exp. 2, overall, steers fed PHY in the diet had higher DMI (P < 0.03); however, PHY addition did not affect ADG or G:F. Inclusion of LPA corn tended to increase fecal Cu (P < 0.09) and S (P < 0.08) excretion (mg/d). Low-phytate corn and PHY supported similar performance and nutrient digestibility, but did not reduce P excretion in growing cattle diets.

Forty-eight grower pigs were used to evaluate the effects of feeding low phytic acid (LPA) corn, LPA soybean meal, normal corn (NC), normal soybean meal (NSBM), and phytase on nutrient digestibility and excretion. Barrows were blocked by BW (initial BW=45.3+/-1.6 kg) and randomly assigned to 1 of 8 dietary treatments in a 2 x 2 x 2 factorial arrangement (6 pigs/treatment). Pigs were fed twice daily (0700 and 1700 h) at 3 times the ME requirement for maintenance. Phytase was added to the diet at 510 phytase units/kg of feed (where 1 phytase unit is the quantity of enzyme that liberates 1 mumol of inorganic P/min from 0.005 mol/L of sodium phytate at pH 5.5 and 37 degrees C), at the expense of corn starch, and all diets were formulated to provide 0.39% total P, 0.50% Ca, and 1.0% lysine with no supplemental inorganic P. Pigs were adapted to metabolism crates and dietary treatments for 7 d, followed by a 3-d total collection of urine and feces. Total fecal DM excreted, percentage of DM of feces, and percentage of DM digested were not different (P>0.53) among treatments. Fecal P excretion was reduced for pigs fed LPA corn vs. NC (2.85 vs. 3.24+/-0.119 g/d; P=0.024), for pigs fed LPA soybean meal vs. NSBM (2.79 vs. 3.30+/-0.119 g/d; P=0.007), for pigs fed phytase vs. nonphytase diets (2.80 vs. 3.29+/-0.119 g/d; P=0.009), and for pigs fed LPA corn, LPA soybean meal, and phytase vs. NC and NSBM without phytase (2.16 vs. 3.70+/-0.237 g/d; P<0.001). Phosphorus digestibility was increased for pigs fed diets containing LPA corn vs. NC (48.4 vs. 39.9+/-2.27%; P=0.012), for pigs fed phytase vs. nonphytase diets (48.4 vs. 39.9+/-2.27%; P=0.019), and for pigs fed the LPA corn, LPA soybean meal, and phytase diet vs. the NC and soybean meal diet (60.1 vs. 34.1+/-4.5%; P<0.001) and tended to be increased for pigs fed LPA soybean meal vs. NSBM (47.2 vs. 41.1+/-2.27%; P=0.075). Corn type and soybean meal type had no effect (P>0.11) on water-soluble P excretion. However, pigs fed diets containing phytase tended to excrete less total water-soluble P than those without phytase inclusion (1.99 vs. 2.27+/-0.099 g/d; P<0.066). This study demonstrates that feeding any combination of LPA corn, LPA soybean meal, and phytase was additive, significantly improving P digestibility and dramatically decreasing P excretion to reduce the potential impacts of P from pig manure on the environment.

Concentrated animal feeding operations (AFO) and many AFO are required to comply with state and federal environmental regulations specifically related to the protection of water quality. Most regulations are based on the need to account for and control nutrient flow on-farm to minimize buildup, leaching, and runoff of nutrients that may pose a risk to surface and ground water quality. Attempts to encourage the control of nutrient flow include the requirements for comprehensive nutrient management plans (CNMP), conservation practice plans, storm water pollution prevention plans, animal mortality management, and emergency action plans. The overall goal of the CNMP on a livestock and poultry farm is to sustain a whole farm nutrient mass balance. An extensive auditing and assessment program evaluates the status of nutrient management on-farm and develops an action plan to minimize water pollution. An annual audit and review checks the performance of the concentrated AFO and AFO on environmental stewardship and identifies areas needing improvement. Critical control points that need to be audited and assessed are 1) nutrients imported on-farm, 2) nutrients exported off-farm, 3) nutrient status of soils and water, 4) manure handling and storage facilities, 5) conservation practices, 6) runoff waste water control, 7) land application practices, 8) animal mortality practices, 9) record keeping system, 10) operation and maintenance plan, and 11) alternative treatment systems, if applicable. Professional animal scientists can contribute significantly to livestock and poultry producers by providing assessments and audits of nutrient management along with other qualified professionals in the development of CNMP.

J. Anim. Sci. Vol. 86, E-Suppl. 2/J. Dairy Sci. Vol. 91, E-Suppl. 1 693 Effects of enzyme additions to diets with cornand sorghumbased distillers dried grains with solubles on growth performance and nutrient digestibility in nursery and finishing pigs. C. Feoli*1, J. D. Hancock1, T. L. Gugle1, S. D. Carter2, and N. A. Cole3, 1Kansas State University, Manhattan, 2Oklahoma State University, Stillwater, 3USDA/ARS, Bushland, TX.

Weanling pigs with mean initial BW of 6.04 kg (Exp.1) and 5.65 kg (Exp. 2) and mean age at weaning of 18.2 d (Exp. 1) and 17.7 d (Exp. 2) were used in two 5-wk experiments (Exp. 1, n = 180; Exp. 2, n = 300) to evaluate the effects of an organic acid blend (Acid LAC, Kemin Americas Inc., Des Moines, IA) and an inorganic/organic acid blend (Kem-Gest, Kemin Americas Inc.) on weanling pig growth performance and microbial shedding. In Exp. 1, the 5 dietary treatments were 1) negative control, 2) diet 1 + 55 ppm carbadox, 3) diet 1 + 0.4% Acid LAC, 4) diet 1 + 0.2% Kem-Gest, 5) diet 1 + 0.4% Acid LAC and 0.2% Kem-Gest. In Exp. 2, the 6 dietary treatments were diets 1 through 4 corresponding to Exp. 1, plus 5) sequence 1: 0.4% Acid LAC for 7 d followed by 0.2% Kem-Gest for 28 d, and 6) sequence 2: 0.2% Kem-Gest for 7 d followed by 0.4% Acid LAC for 28 d. Pigs were housed at 6 (Exp. 1) or 10 (Exp. 2) pigs/pen. Treatments were fed throughout the experiment in 3 phases: d 0 to 7, d 7 to 21, and d 21 to 35. In Exp. 1, there were no differences (P > 0.05) in ADG, ADFI, or G:F among the dietary treatments at any time during the study. In Exp. 2, throughout the study, pigs fed carbadox (diet 2) and sequence 1 (diet 5) diets had the greatest ADG (d 0 to 35; 262, 294, 257, 257, 292, and 261 g/d, diets 1 through 6, respectively; P < 0.05), greater ADFI than all other acid treatments (P < 0.05), and tended to have greater ADFI than diet 1 (P < 0.10). Fecal pH, Escherichia coli concentrations, and Salmonella presence were determined at d 6, 20, and 34 for Exp. 1, and on d 32 for Exp. 2. For both experiments, there was no effect of treatment on the presence of fecal Salmonella (P > 0.10) at any sampling time. In Exp. 1, fecal E. coli concentrations for pigs fed the carbadox (P < 0.05) diet were greater than for pigs fed the combination diet with 0.4% Acid LAC and 0.2% Kem-Gest on d 34, and the pigs fed the negative control diet tended (P < 0.10) to have greater fecal E. coli concentrations than those fed the combination diet on d 34. In Exp. 2, fecal pH of pigs fed sequence 1 tended to be greater than fecal pH of pigs fed diet 1, diet 4, or sequence 2 (P < 0.10), but there was no dietary effect on fecal E. coli. In Exp. 1, growth performance of pigs fed the Acid LAC and Kem-Gest diets was similar to each other and to that of the carbadox-fed pigs. Adding the combination of 0.4% Acid LAC and 0.2% Kem-Gest to nursery pig diets reduced ADFI and pig growth rate. In Exp. 2, pigs fed the acid sequence of Acid LAC-Kem-Gest had similar growth performance to pigs fed carbadox, and this novel dietary acid sequence may have merit as a replacement for antibiotics in the nursery phase.