Effects of reducing the standardized ileal digestible lysine and tryptophan to lysine ratio to slow growth of finishing pigs

The COVID-19 global pandemic greatly affected pork processing plants in the United States. These pork processing plants were forced to either temporarily close or operate at reduced capacity due to the increased number of health-related employee absences. Because finishing pigs could not be timely marketed, methods to reduce growth performance were required to keep pigs from becoming too heavy at slaughter weight. Therefore, our objective was to determine the extent that reducing dietary standardized ileal digestible (SID) Lys and Trp:Lys ratio would slow finishing pig ADG in a commercial setting. A total of 1,080 finishing pigs (327 × 1050, PIC; initially 32.3 kg) were used in a 119-d growth trial. Pigs were allotted by initial body weight (BW) and randomly assigned to 1 of 4 dietary treatments in a completely randomized block design with 27 pigs per pen and 10 pens per treatment. Three dietary regimes were formulated to contain either 100, 90, or 80% of the estimated SID Lys requirement for pigs in this facility, with a SID Trp:Lys ratio of 19%, with the exception of the last dietary phase formulated to 17% SID Trp:Lys. Seven different dietary phases were fed. The SID Lys concentrations in the 100% diets were: 1.10, 1.01, 0.91, 0.83, 0.79, 0.71, or 0.67% SID Lys from 32 to 40, 40 to 51, 51 to 72, 72 to 85, 85 to 98, 98 to 112, and 112 to 130 kg, respectively. A fourth regime was formulated to 80% SID Lys with a SID Trp:Lys ratio of 16% (80–16% SID Trp:Lys) throughout all phases. Overall from d 0 to 119, ADG (linear, P < 0.001), final BW (linear, P < 0.001), and G:F decreased (linear, P = 0.087) as SID Lys decreased from 100 to 80% of the estimated requirement. Pigs fed the 80–16% SID Trp:Lys diets had an additional decrease in ADG (P < 0.05) and G:F (P < 0.10) compared with pigs fed 80% of the SID Lys requirement with the normal Trp:Lys ratio. The reduction in SID Lys (from 100 to 80%) and reduction in SID Lys and Trp:Lys ratio resulted in an 8.6 and 11.7 kg, respectively, decrease in final BW compared with pigs fed Lys and Trp at the requirement (100%). This study provides alternatives for pork producers to reduce growth rate of finishing pigs.

PSIV-9 Effect of Increasing the Level of a Modified Corn Protein on Nursery Pig Growth Performance, Feed Efficiency, and Fecal Dry Matter

A total of 360 barrows (DNA Line 200×400; initially 6.1±0.05 kg) were used in a 38-d study to evaluate the effects of increasing levels of a modified corn protein product on nursery pig growth performance and fecal dry matter. Upon arrival to the nursery research facility, pigs were randomly assigned to pens (5 pigs/pen) and pens were randomly allotted to 6 dietary treatments (12 pens/treatment). Experimental diets were fed in 2 phases. Phase 1 (d 0-10) diets were formulated to contain 3, 6, 9, 12, or 15% of a modified corn protein or 6% enzymatically treated soybean meal (ESBM). Additions of the modified protein product and ESBM were reduced by 50% for phase 2 (d 10 to 25) diets and were: 1.5, 3.0, 4.5, 6.0, 7.5, and 3.0%, respectively. Nutrient loading values were provided by the supplier and diets were formulated to maximize L-Lysine HCl while keeping SID Lys:CP and SID AA:Lys similar across treatments. A common phase 3 diet was fed from d 25-38. During the experimental period (d 0-25), ADG (quadratic, P = 0.030) and ADFI (quadratic, P = 0.036) increased, and G:F worsened (linear, P = 0.006) as the amount of modified corn protein increased. For the overall experiment (d 0-38), ADG (quadratic, P = 0.028) and ADFI (quadratic, P = 0.032) increased then decreased and G:F tended to decrease (linear, P = 0.066) with increasing modified corn protein. There was a marginally significant treatment×day interaction (quadratic, P = 0.064) where fecal DM tended to increase (P = 0.051) on d 25 as the level of the modified corn protein was increased, but no evidence for change on d 10 (P > 0.10). These data suggest that the modified corn protein tested in this trial may be an alternative protein source to consider for nursery pig diets, when fed up to 12% in phase 1 and 6% in phase 2.

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53 Evaluating the Efficacy of Boot Baths with Wet and Dry Disinfectants for Porcine Epidemic Diarrhea Virus and Porcine Reproductive and Respiratory Syndrome Virus

Maintaining biosecurity between barns is challenging. Boot baths, either wet or dry, can be implemented to limit pathogen spread. The objective was to evaluate the efficacy of boot baths using wet or dry disinfectants for porcine epidemic diarrhea virus (PEDV) and porcine reproductive and respiratory syndrome virus (PRRSV). Treatments included 1) control, 2) wet disinfectant (Synergize, Neogen, Lexington, KY), and 3) dry disinfectant (Traffic C.O.P., PSP, LLC, Rainsville, AL). Prior to disinfection, 0.5 mL of both PRRSV (~1×105 TCID50/mL) and PEDV (~1×105 TCID50/mL) was placed onto a new boot with a layer of autoclaved corn dust and allowed to dry for 15 minutes. After the mixture dried, the boot was put on and stepped into its respective boot bath. After 3 seconds, the boot was lifted out of the bath and stepped onto a stainless-steel coupon to simulate walking through a facility. Both boot and coupon were allowed to dry for 1 minute before swabs were taken from both surfaces. Samples were analyzed in a duplex PCR at the Kansas State Veterinary Diagnostic Laboratory. Cycle threshold values were analyzed using SAS GLIMMIX v 9.4 (SAS, Inc., Cary, NC). There was no evidence of a treatment×surface×virus interaction (P > 0.10). The interaction between treatment×surface impacted (P < 0.05) the quantity of detectable RNA. The control had greater concentration of virus on the coupon than the boot. The reverse was true for boots treated with wet disinfectant, where the boot had a greater concentration of virus than the coupon. Treatment×virus also impacted detectable RNA (P < 0.05), where wet and control boots had greater quantities of PEDV RNA than PRRSV. There was no detectable virus when dry disinfectant was used. For this trial, dry disinfectant was the most efficacious in reducing the viral RNA on both boots and subsequent surfaces; however, further research in commercial settings is warranted.

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104 Effect of Mat Feeding on the Growth Performance and Morbidity and Mortality of Pigs After Weaning

Three experiments were conducted using 9,403 pigs to determine the effect of mat feeding on growth performance and morbidity and mortality of pigs after weaning. At weaning, pigs were randomized to 96 pens (48 feeders) with 30 to 35 pigs/pen. Feeder (2 pens) was the experimental unit. For each experiment, mat feed was provided 3 times daily for 10 d and was included in calculation of post-weaning ADFI and G:F. In Exp. 1, treatments consisted of mat verses no mat feeding. Overall, mat fed pigs tended to have decreased (P = 0.056) ADG compared with the control, which resulted in decreased (P < 0.026) final body weights. No differences were observed in ADFI or G:F. However, mat fed pigs had reduced total mortality and removals (P = 0.019). In Exp. 2, treatments were arranged in a 2×2 factorial with main effects of diet form (pellet or crumble) and mat feeding (without or with). Overall, no interactions between diet form and mat feeding were observed. No differences were observed in growth performance by mat feeding. However, pigs receiving pelleted feed had decreased overall ADFI (P = 0.013) and increased G:F (P < 0.001). Differences in total mortality and removals were not significant. In Exp. 3, treatments consisted of mat feeding small (0.32 cm) or large (1.27 cm) pellets, or no mat feeding. No differences were observed in overall ADG or G:F; however, mat fed pigs had increased ADFI (P < 0.05), regardless of pellet size. Differences in total mortality and removals were not significant. When combining removal and mortality data for the 3 experiments, mat fed pigs had fewer total removals (P = 0.025) compared with the control. In summary, mat feeding has limited effects on growth performance of pigs after weaning; however, mat feeding may encourage earlier feed intake reducing the fall out rate of pigs as indicated by the decreased removals.

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129 The Effect of Live Yeast and Yeast Extracts Included in Lactation and Nursery Diets on Nursery Pig Growth Performance

Two experiments were conducted to determine the impact of diets with yeast-based direct fed microbials (DFM) in nursery pigs weaned from sows fed lactation diets with or without yeast additives. Treatment descriptions for both experiments are reviewed in Table 1. There was no evidence of sow and nursery treatment interactions for either experiment (P > 0.05). In Exp. 1, 340 weaned pigs, initially 5.1 kg ± 0.02, were used to evaluate previous sow treatment (control vs yeast additives; Phileo by Lesaffre, Milwaukee, WI) and nursery diets with or without DFM. Treatments were a 2×2 factorial with main effects of sow treatment and nursery treatment (control vs. yeast-based pre- and probiotic diet) with 5 pigs/pen and 17 replications/treatment. Progeny from sows fed yeast additives had increased (P < 0.05) ADG from d 0-24 and d 0-45. However, pigs that were fed yeast additives for the first 24 d in the nursery tended to have decreased d 0-45 ADG (P = 0.079). In Exp. 2, 330 weaned pigs, initially 5.8 kg ± 0.03, were used to evaluate diets with combinations of DFM. Treatments were arranged in a 2×3 with main effects of sow (same as Exp. 1) and nursery treatment with 6 pigs/pen and 8 to 10 replications/treatment. From d 0-10 post-weaning, progeny of sows fed yeast additives had increased (P < 0.05) ADG and G:F. From d 24-38 when pigs were fed common diets with no added yeast-based products, ADG for pigs previously fed DFM2 was greater (P < 0.05) than control. In conclusion, feeding sows yeast during lactation improved offspring nursery growth performance in both studies. Interestingly, feeding live yeast and yeast extracts reduced nursery pig performance in Exp. 1; however, feeding DFM 2 improved growth later in the nursery in Exp. 2.

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242 Effects of Providing a Liquid Sensory Attractant to Suckling Pigs in Lactation and After Weaning on Post-Weaning Pig Performance

A total of 28 litters corresponding with 355 nursery pigs were used in a 42-d trial to determine the effect of a liquid sensory attractant (BlueLite Pro2Lyte; TechMix Global; Stewart, MN) pre- and post-weaning on the feed intake and growth of pigs after weaning. Treatments were arranged in a 2x2x2 factorial with main effects of: 1) pre-weaning treatment (without/with attractant), 2) post-weaning treatment (without/with attractant), and 3) body weight category (light/heavy). Litters that received liquid attractant pre-weaning were provided approximately 88 mL per d, divided into 2 applications, sprayed on the underline of sows for 2-d beginning the morning after farrowing and 2-d prior to weaning. In total, pigs received attractant for 4-d pre-weaning. After weaning, pens of pigs that received liquid attractant were offered approximately 56 mL per d, divided into 3 applications, sprayed on the feed in the feeder pan for 3-d post-weaning. Overall, pre and post-weaning liquid sensory attractant did not have a significant effect (P > 0.10) on growth performance of pigs after weaning. For the percentage of pigs that lost weight by d 3 after weaning, a 3-way interaction was observed (P = 0.016). Sensory attractant pre- or post-weaning reduced the percentage of heavyweight pigs that lost weight after weaning; however, for lightweight pigs, providing the attractant only pre-weaning increased the percentage of pigs that lost weight after weaning. Additionally, a greater percentage of heavyweight pigs lost weight on d 3 (P = 0.007) and d 7 (P = 0.051) compared with lightweight pigs. In summary, liquid sensory attractant application pre- and post-weaning had limited effects on the growth performance of pigs; however, varying responses were observed for the percentage of pigs that lost weight immediately after weaning. Strategies to reduce the number of pigs that lose weight after weaning warrant further investigation.

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157 Effects of Standardized Ileal Digestible Lysine Level on Growth Performance in 75 to 130 Kg DNA Finishing Pigs

Two studies were conducted to estimate the SID Lys requirement for growth and feed efficiency of 70-130-kg DNA finishing pigs. In Exp. 1, 616 pigs (600×241, DNA; initially 76.4±1.25 kg) were used from 70-100-kg and in Exp. 2, 679 pigs (600×241, DNA; initially 103.8±1.32 kg) were used from 100-130 kg. Pens of pigs were blocked by BW and randomly allotted to dietary treatments with 8-10 pigs/pen in a randomized complete block design. Diets were corn-soybean meal based and SID Lys increased by increasing soybean meal and feed-grade amino acids while maintaining minimum ratios for other amino acids. From 70-100 kg, ADG, G:F, Lys intake/d, and Lys intake/kg of gain all increased, (linear, P < 0.05) with increasing SID Lys. From 100-130 kg, ADG, Lys intake/d, and Lys intake/kg of gain increased (linear, P < 0.05) with increasing SID Lys, while G:F increased (quadratic, P = 0.032). At current ingredient and pig prices, there were no statistical differences in income over feed cost (IOFC) from 70-100 kg. From 100-130 kg, increasing SID Lys increased (quadratic, P = 0.001) IOFC. A broken-line linear (BLL) model predicted optimal ADG at 0.83% SID Lys, while a quadratic polynomial (QP) model predicted a requirement of 0.90% for G:F from 75-100 kg. A QP model predicted maximum IOFC at 0.78% SID Lys from 75-100 kg. From 100-130 kg, BLL models predicted optimal ADG and G:F at 0.64 and 0.59% SID Lys, respectively. A QP model predicted maximum IOFC at 0.64% SID Lys. In summary, these results suggest the optimal SID Lys level for 75-100 kg DNA finishing pigs for growth performance is between 0.83 and 0.90% SID Lys, and 0.78% SID Lys for maximum IOFC. The optimal SID Lys level in 100-130 kg DNA finishing pigs depends upon the response criteria, with growth performance and IOFC maximized between 0.59 and 0.64% SID Lys.

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PSVIII-1 Evaluating the Efficacy of Acidifiers Used in Nursery Diets in Reducing Bacterial Loads in Both Non-Inoculated and Inoculated Complete Feed

Acidifiers are used in nursery pig diets to reduce the incidence of diarrhea, improve growth performance, and act as a feed preservative. The objective was to evaluate whether acidifiers were able to reduce bacteria presence in non-inoculated feed and reduce bacteria growth in feed inoculated with Escherichia coli and Enterococcus faecium. Each culture media was arranged in a 2×5 factorial with 2 phases and 5 diets. The diets were 1) control – no antibiotics, 2) ZnO (Phase 1: 3,000 ppm Zn and Phase 2: 2,000 ppm Zn), 3) formic acid at 0.7% of the diet (Amasil-NA; BASF Corp. Florham, NJ), 4) glycerol monolaurate – GML at 0.18% of the diet (Natural Biologics, Newfield, NY), and 5) FORMI-3G at 1.0% of the diet (Addcon Gmbh, Bitterfeld-Wolfen, Germany). Non-inoculated feed was plated onto Aerobic Count, E. coli/Coliform, and Enterobacteriaceae petrifilm (3M, St. Paul, MN). Inoculated feed was initially contaminated with E. coli or E. faecium and allowed to incubate prior to plating on MacConkey. There was no difference (P > 0.05) in quantity of bacteria for the diets inoculated with E. coli. There was no difference (P > 0.05) between the diets inoculated with E. faecium for phase 1; however, the formic acid diet had reduced (P < 0.05) quantities of bacteria compared with control, ZnO, and GML diets. The control and ZnO phase 1 non-inoculated diets had reduced (P < 0.05) quantities of aerobic bacteria, coliforms, and Enterobacteriaceae compared with GML. In phase 2 only the control had reduced (P < 0.05) quantities of Enterobacteriaceae compared with the ZnO and formic acid diets. Formic acid was able to reduce E. faecium quantities in phase 2, while the control and ZnO had decreased overall bacterial loads in phase 1.

PSVI-20 Effects of Adding Potassium Bicarbonate to Diets with High or and Low Crystalline Lysine as a Way to Influence DCAD on Finishing Pig Growth Performance

This experiment was conducted to evaluate the effect of balancing dietary cation-anion difference (DCAD), via added potassium bicarbonate (KHCO3), in diets containing low or high levels of L-Lys HCl on growth performance of growing-finishing pigs. A total of 1,944 pigs (PIC L337 × 1050, initially 35.2±0.85 kg) were used in a 120-d study. Pens of pigs were blocked by BW and randomly allotted to 1 of 4 dietary treatments in a randomized complete block design arranged in a 2×2 factorial with main effects of KHCO3 (0 vs 0.4%), and L-Lys HCl level (low vs. high), with 27 pigs/pen and 18 replicates/treatment. Diets were corn-soybean meal-based and formulated in 4 dietary phases (d 0-20, 30-58, 58-86, and 86-120). Diets were formulated in each phase such that the diet containing a low level of L-Lys HCl (0.14-0.21% depending on phase) without KHCO3, had similar calculated DCAD as the diet containing a high level of L-Lys HCl (0.36 to 0.43% depending on phase) with KHCO3. The DCAD for these 2 treatments were approximately 230, 200, 184, and 169 mEq/kg (phase 1, 2, 3, 4, respectively). The diets with low levels of L-Lys HCl with KHCO3 had the greatest DCAD in each phase (approximately 50 mEq/kg above the low L-Lys HCl without KHCO3 diet), while the diet with a high level of L-Lys HCl without KHCO3 had the least DCAD (approximately 50 mEq/kg below the high L-Lys HCl with KHCO3 diet). Overall, there was no evidence (P > 0.10) for a KHCO3 × L-Lys HCl interaction or main effect for any observed growth responses or carcass characteristics. The results of this study suggest that supplementing KHCO3 to finishing pig diets with either high or low levels of L-Lys HCl and the corresponding changes in DCAD values did not impact growth performance or carcass characteristics.

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PSII-13 Effect of Body Weight, Body Temperature, and Blood Glucose on the Survivability of Pull Pigs After Removal

A total of 988 nursery pigs were used to determine the effect of body weight, body temperature, and blood glucose on the survivability of pull pigs after removal. At weaning, pigs were transported to a 24,000 head hotel-style nursery and placed in rooms based on sow source. Over a 4-week period post-placement, every other pig removed from the general population for welfare considerations (lameness, sick, or fallback) were tagged, weighed, and their body temperature and blood glucose measured. Mortality was tracked through the end of the nursery or approximately 38 d post-placement. Data were analyzed as a completely randomized design with room as a random effect. The predictor variables of body weight, body temperature, and blood glucose were categorized into biologically significant categories and LSMeans were determined using a binary model with mortality as the outcome. Pigs with a body weight under 4.5 kg at removal had increased mortality rate (32.4%; P< 0.001) compared with pigs with a body weight between 4.5 and 5.4 kg (20.8%) or greater than 5.4 kg (14.6%) at removal. Pigs with a body temperature below 38.6°C or above 39.7°C at removal had increased mortality rate (33.4 or 26.8%, respectively; P < 0.001) compared with pigs with a body temperature between 38.6 and 39.7°C (17.7%) at removal. Pigs with a blood glucose greater than 120 mg/dL at removal had increased mortality rate (43.5%; P < 0.001) compared with pigs with a blood glucose less than 70 mg/dL (23.0%) or between 70 and 120 (17.9%) at removal. In summary, pull pigs with low bodyweight, high or low body temperature, or high blood glucose had decreased survivability. The results of this study indicate that there are metabolic differences between nursery pigs at the time of removal and that these differences may influence survivability.

61 Persistence and Distribution of African Swine Fever Virus in Feed and Feed Mill Environment Over Time After Manufacture of Experimentally Inoculated Feed and Subsequent Manufactured Batches of Feed

To reduce the risk of feed-based pathogens causing disease, some feed manufacturers quarantine high-risk ingredients before their inclusion in feed. Data exists that confirms this practice is effective, but there is no information about swine pathogen survival in mill environments. This objective of the study was to determine survival of African swine fever virus (ASFV) in swine feed and mill surfaces. A pilot-scale feed mill manufactured a batch of ASFV-free feed (Batch 1), followed by a batch inoculated with ASFV (5.6×104 TCID50/gram; Batch 2). Then 4 subsequent ASFV-free batches were manufactured (Batch 3-6). After each batch,10 feed samples were aseptically collected in a double ‘X’ pattern. During feed manufacturing, 24 steel coupons were placed on the floor of the manufacturing area and feed dust settled on them during the milling process and overnight. Feed samples and steel coupons were stored at room temperature. Three of each were randomly selected and analyzed for ASFV DNA on d 1, 3, 7, 14, 28, 60, 90, and 180. The interaction of batch and day impacted (P = 0.023) the number of genomic copies detected per gram of feed. There were no differences of genomic copies/g in early batches; but the quantity of detectable ASFV decreased with increasing storage time after collection. In Batches 4-6, the greatest quantity of ASFV was detected on d 1, but the lowest quantity was detected on d 7, 60, and 28 or 180 for Batches 5, 6, and 7, respectively. There was no evidence (P = 0.433) of ASFV degradation on environmental coupons over the 180-d storage period. This study found that quarantine time can help reduce, but not eliminate ASFV in feed over time. However, ASFV survives on feed manufacturing surfaces for at least 180 d. Additional research is necessary to evaluate the viability of detected virus to cause illness.

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141 Evaluation of a Fermented Corn Protein Source on Growth Performance of Nursery Pigs

Two experiments were conducted to determine if fermented corn protein (FCP) can serve as a replacement to enzymatically treated soybean meal (ESBM) in 6.0 to 15.8 kg or as a replacement for soybean meal in 12.1 to 24.7 kg pig nursery diets. In Exp. 1, 350 barrows (initially 6.0 kg) were randomly allotted to 5 treatments with 5 pigs/pen and 14 replications/treatment. Dietary treatments were arranged in a 2×2 + 1 factorial with a control diet or diets with 5 or 10% FCP or ESBM. Newly weaned pigs were fed phase 1 diets for 10-d followed by phase 2 diets for 21-d. There were no interactions throughout the experiment. Overall (d 0-31), pigs fed increasing FCP had decreased (linear, P ≤ 0.026) ADG and ADFI with no differences in G:F, whereas increasing ESBM had no effect on growth performance (Table). Pigs fed ESBM had increased (P ≤ 0.034) ADG and G:F compared with pigs fed FCP with no effect on ADFI. In Exp 2, 350 pigs (initially 12.1 kg) were randomly assigned to pens with 5 pigs/pen and 14 replications/treatment. On d 24 after weaning (d 0 of trial), pens of pigs were weighed and assigned to 5 dietary treatments. Dietary treatments were arranged in a 2×2 + 1 factorial with a control diet or diets with 10 or 20% FCP with either high or low Val+Ile:Leu ratios. There were no interactions observed throughout the experiment. Overall (d 0-21), ADG, ADFI, and G:F worsened (linear, P < 0.001) as FCP increased. High Val+Ile:Leu ratios improved (P = 0.017) G:F compared with low Val+Ile:Leu ratios with no effect on ADG and ADFI. In summary, using FCP to replace ESBM for nursery pigs weighing 6.0 to 15.8 kg had decreased growth performance. Increasing concentrations of FCP in diets for pigs weighting 12.1 to 24.7 kg worsened growth and increasing Val+Ile:Leu ratios only improved G:F.

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PSV-5 Effects of Benzoic Acid and an Essential Oils Blend on Detection of Swine Viruses in Inoculated Swine Feed and Premix

Feed has been shown to harbor viable viruses over an extended period. This study investigated the use of benzoic acid (BA) and an essential oils blend (EO) to mitigate the presence of porcine epidemic diarrhea virus (PEDV), porcine reproductive and respiratory syndrome virus (PRRSV), and Senecavirus A (SVA) in a complete diet (Exp. 1) and a vitamin premix (Exp. 2). Experiment 1 consisted of a control with no additive, 0.5% BA, 0.5% BA and 200 ppm EO, 0.3% BA and 120 ppm EO, and 0.25% BA and 100 ppm EO. Feed samples were inoculated with PEDV, PRRSV, and SVA. For Exp. 2, the control contained no additive, and treatment had 2.68% EO included to mitigate PEDV. Inoculated feed or premix was stored at room temperature with sampling points at 2, 5, and 15 d post-inoculation (dpi). Samples were analyzed using triplex qRT-PCR to detect changes in RNA quantities for all viruses. Detectible PRRSV in the feed demonstrated a quadratic decrease over time (P = 0.038). A significant treatment × day interaction was observed in the feed for both PEDV (P = 0.008) and SVA (P < 0.001). The 0.5% BA treatment had greater (P < 0.05) amounts of detectible PEDV on d 2 and 5 and decreased detectible PEDV on d 15 compared with control. The 0.5% BA treated feed demonstrated decreased (P < 0.05) detectable SVA at 2 dpi but greater detectible SVA at 15 dpi compared with control. Both PEDV and SVA demonstrated viral degradation over time. The use of the EO in the vitamin premix had no evidence of main or interactive effects. In conclusion, 0.5% BA decreased PEDV at 15 dpi, but BA and EO mitigation in this model did not provide consistent evidence for increased viral degradation. However, time decreased detectability of all three viruses.

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PSVI-1 Effect of Dietary Sodium and Pharmacological Zinc Levels on Growth Performance of Nursery Pigs

A total of 360 pigs (initially 5.7±0.2 kg) were used to determine the effect of pharmacological levels of Zn and dietary Na concentration on nursey pig growth performance. The experiment compared NRC (2012) and European CVB (2020) Na estimates for this weight range (0.35% and 0.24%, respectively), with or without added Zn from ZnO. At weaning, pigs were randomly allotted to pens (6 pigs/pen) and fed a common diet for 7 d. On d-7 after weaning (d-0 of trial), pigs were assigned to 6 dietary treatments with 10 replications/treatment. Dietary treatments were arranged in a 2×3 factorial with main effects of Zn (0 or 2,000 ppm from ZnO) and Na (0.13, 0.24, or 0.35% from salt). All diets contained 110 ppm of Zn from the trace mineral premix. Following a 14-d experimental period, pigs were fed a common phase 3 diet for 21-d. There were no Zn×Na interactions for ADG or ADFI (P >0.05). From d 0-14, adding dietary ZnO or increasing Na increased (linear, P < 0.05) ADG and ADFI. An interaction for G:F (linear, P = 0.019) was observed where increasing Na up to 0.35% improved G:F when pharmacological levels of Zn were fed, but pigs fed diets without ZnO had a quadratic response (P =0.024) with maximum G:F at 0.24% dietary Na. From d 14-35 and overall, an interaction was observed (linear, P < 0.05) for G:F. Within the interaction, pigs previously fed diets without ZnO observed a linear decrease in G:F as Na level increased (linear, P =0.001), but pigs previously fed diets with ZnO observed no difference in G:F with increasing Na. In summary, increasing dietary Na and the addition of 2,000 ppm Zn from ZnO independently improved daily gain and feed intake in nursery pigs, but an improvement in G:F from increasing Na up to 0.35% was only observed when pharmacological ZnO was present.

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PSVI-5 Effects of Added Vitamin Levels on Growth Performance of Finishing Pigs

A total of 1,080 mixed sex growing-finishing pigs (337 × 1050, PIC; initially 28.7 ±0.39 kg) were used in a 123-d growth trial to determine the effects of vitamin concentrations on finishing pig growth performance and carcass characteristics. Pens of pigs were assigned to 1 of 2 treatments in a completely randomized design. There were 20 replicate pens/treatment and 27 pigs/pen. The experimental diets were corn-soybean meal-based and were fed in 4 phases from 28 to 50, 50 to 73, 73 to 100 and 100 to 133 kg. Pigs were fed 1 of 2 levels of a vitamin premix (control and high) that contained: 1,653,468 IU vitamin A acetate; 661,387 IU vitamin D, vitamin E (17,637 mg dl-α-tocopheryl acetate), 1,323 mg vitamin K (menadione), 13.2 mg vitamin B₁₂, 19,842 mg niacin, 11,023 mg pantothenic acid, and 3,307 mg riboflavin per kg. The amount per phase was 1.36, 1.13, 0.91 and 0.07%, respectively, for the control with the added amount doubled for the high vitamin fortification. Overall, (day 0 to 123), there was no evidence for difference (P > 0.10) in ADG, ADFI and G:F. Also, no statistical difference was found (P > 0.10) for final BW, HCW or any carcass characteristic. In conclusion, the level of vitamins used in this study did not influence growth and carcass traits in finishing pigs.

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168 Evaluation of Increasing Dietary Threonine to Lysine Ratio in Corn-Soybean Meal Diets with and Without Dried Distillers Grains with Solubles (DDGS) on Growth Performance of Grow-Finish Pigs

A total of 2,160 pigs (PIC 337×1050; initial BW 35.1 kg) were used in a 112-d growth trial to evaluate the effects of normal or high SID Thr:Lys ratio in diets with and without DDGS on growth performance. Pigs were assigned to pens (27 pigs per pen) in a randomized complete block design by BW with 20 replications per treatment. Pens of pigs were allotted to 1 of 4 dietary treatments arranged in a 2×2 factorial with main effects of dietary Thr level (Normal vs High) and DDGS (with or without). Treatment diets were formulated in 4 phases from 35 to 57, 57 to 82, 82 to 105, and 105 to 136 kg BW. Diets with high DDGS were formulated to include 40% DDGS in phase 1 and 2, 30% in phase 3, and 15% in phase 4. Normal Thr diets were formulated to contain 61, 62, 63, and 65% SID Thr:Lys ratios for the 4 dietary phases, respectively. High Thr diets had SID Thr:Lys ratios of 67, 68, 69 and 72%, respectively. There were no (P>0.10) DDGS×Thr interactions. For the overall period (d 0 to 112), pigs fed diets without DDGS had increased (P < 0.001) ADG and BW, and reduced (P < 0.001) ADFI leading to improved (P < 0.001) G:F. There was no evidence for difference (P > 0.10) between diets with normal or high SID Thr:Lys ratio regardless of DDGS inclusion. In summary, the addition of high levels of DDGS reduced ADG and increased ADFI, which resulted in poorer G:F and lighter final BW, regardless of the dietary SID Thr:Lys ratio. These results indicate that addition of an insoluble fiber source, such as corn DDGS, does not increase the Thr:Lys requirement of finishing pigs.

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111 Evaluation of Dietary Mycotoxin Control Strategies on Nursery Pig Growth Performance and Blood Measures

A total of 4,318 pigs (337×1050, PIC; initially 6.5±0.08kg) were used in a 35-d trial to evaluate dietary mycotoxin control strategies on nursery pig performance and blood measures. Pigs were weaned at 21-d of age and randomly allotted to 1 of 5 dietary treatments. A total of 160 pens were used with 80 double-sided 5-hole stainless steel fence line feeders, with feeder serving as the experimental unit. For each feeder, 1 pen contained 27 gilts and 1 pen contained 27 barrows. There were 16 replications/treatment. A common phase 1 diet was fed in pelleted form for 7-d prior to treatment diets. Experimental treatments were fed from d 7 to 42 after weaning (d0 to 35 of study) and included a low deoxynivalenol (DON) diet (1.12±0.623 mg/kg), high DON diet (2.34±1.809 mg/kg), high DON+ sodium metabisulfite (SMB), high DON+ 1 of 2 mitigating products; Technology1, or Technology1+. Technology1 and 1+ are comprised of clays, yeast cell wall components and a blend of plant extracts. Technology1+ also contains SMB. Overall (d0 to 35), pigs fed high DON had decreased (P < 0.05) final BW, ADG, and ADFI compared with low DON. Additionally, pigs fed high DON+SMB had increased (P<0.05) ADG compared with all other treatments. An increase (P < 0.05) in G:F was observed in pigs fed high DON+SMB or high DON+Technology1+ compared with low DON or high DON+Technology1 with high DON intermediate. Analysis of dried blood spots collected on d 35 revealed pigs fed high DON or high DON+Technology1 had increased (P < 0.05) DON concentrations compared with low DON with high DON+SMB and high DON+Technology1+ intermediate. In summary, pigs fed high DON had reduced performance compared with low DON. Sodium metabisulfite supplementation to high DON led to ADG and G:F that exceeded low DON, whereas Technology1+ resulted in similar ADG and improved G:F compared with low DON.

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246 Awardee Talk: Evaluating the Impact of Essential Fatty Acids in Lactation Diets on Sow and Litter Performance

Two experiments were conducted to evaluate the effects of supplemental fat sources providing low and high essential fatty acids (EFA) in lactation diets on sow reproductive performance, piglet growth and survivability, and colostrum and milk composition. In Exp. 1, mixed parity sows (n = 91) were allotted to 5 experimental treatments arranged in a 2×2 + 1 factorial. Treatments were corn-soybean meal-based diets that contained no added fat or diets with 3% added fat as either beef tallow or soybean oil starting on d 107 or 112 of gestation. Sows were provided low EFA [linoleic acid (LA) and α-linolenic acid (ALA)] in diets without supplemental fat or with beef tallow or high EFA with soybean oil. Results confirmed that providing fat sources with high EFA can increase colostrum and milk LA and ALA content, regardless of pre-farrow time of diet consumption. However, supplemental fat did not influence litter growth performance (P > 0.05). In Exp. 2, mixed parity sows (n = 3,451) were assigned to 4 corn-soybean meal-wheat-based lactation diets with 0.5 (Control) or 3% choice white grease (CWG), 3% soybean oil (SO), or a combination of 3% soybean oil and 2% choice white grease (Combination) at d 112 of gestation to provide diets with low or high EFA. Lactation ADFI increased (P < 0.05) for sows fed the Combination and CWG diets compared with sows fed the Control or SO diet. Sows fed Combination and SO diets had greater (P < 0.05) LA and ALA intake, LA and ALA in colostrum and milk, litter weaning weights, and litter ADG than sows fed 0.5 or 3% CWG. Sow EFA intake did not affect (P > 0.10) piglet survivability or subsequent sow reproductive performance. In conclusion, increased LA and ALA intake provided by SO during lactation increased overall litter growth and weaning weights but did not affect piglet survivability or subsequent performance.

PSIV-17 The Effect of Live Yeast and Yeast Extracts Included in Lactation Diets on Sow and Litter Performance and Antimicrobial Susceptibility of Sow Fecal Escherichia Coli

Eighty sows (Line 241; DNA Genetics) were used to evaluate the effect of feeding live yeast and yeast extracts to lactating sows on sow and litter performance and antimicrobial resistance (AMR) patterns of sow fecal Escherichia coli. Sows were blocked by farrowing group, BW, and parity on d 110 of gestation and allotted to 1 of 2 dietary treatments. Dietary treatments consisted of a standard lactation diet or a diet that contained yeast-based pre- and probiotics (0.10% Actisaf Sc 47 HR+ and 0.025% SafMannan; Phileo by Lesaffre, Milwaukee, WI). Diets were fed from d 110 of gestation until weaning. A tendency (P = 0.073) was observed for increased feed intake through lactation when sows were fed yeast additives compared with the control (5.65 vs 5.90 kg/d). There was no evidence (P > 0.10) that treatment influenced any other sow or litter performance criteria. Fecal samples were collected from the first farrowing group (27 sows) to determine AMR patterns of E. coli upon entry into the farrowing house and at weaning. Microbroth dilution method was used to determine the minimal inhibitory concentrations (MIC) of E. coli isolates to 14 different antimicrobials. An interaction (P = 0.026) of diet × sampling day was observed for cefoxitin where fecal E. coli showed no evidence of treatment differences (P = 0.237) in MIC values at entry, but sows fed the control diet had lower (P = 0.035) MIC values at weaning compared with sows fed yeast additives. There were no diet main effects (P > 0.10) on the AMR of fecal E. coli. There was an increased (P < 0.02) trend towards resistance for 11 of the 14 antimicrobials over time (Table 1). In conclusion, feeding live yeast and yeast extracts tended to increase feed intake during lactation but did not influence sow or litter performance and had minimal impact on AMR of fecal E. coli during lactation.

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100 The Impact of Dietary Analyzed Ca to P Ratios and Standardized Total Tract Digestible P to Net Energy Ratios on Growth Performance, Bone, and Carcass Characteristics of Pigs

A total of 2,184 pigs (initially 12.4 kg) were used to evaluate effects of varying analyzed Ca:P ratios at 2 levels of standardized total tract digestible (STTD) P:NE. Pens of pigs (26 pigs/pen) were assigned to 6 dietary treatments in a randomized complete block design with 14 pens/treatment. Diets consisted of 2 levels of STTD P:NE: PIC recommendation (1.8, 1.62, 1.43, 1.25, 1.10, 0.99 g STTD P/Mcal NE from 11-22, 22-40, 40-58, 58-81, 81-104, 104-129 kg, respectively) or 75% of the PIC recommendation, and 3 analyzed Ca:P ratios: 0.90:1, 1.30:1, and 1.75:1. Diets were corn-soybean meal-based and contained phytase (Quantum Blue G, AB Vista, Marlborough, UK; 500 to 210 FTU/kg with release values from 0.13 to 0.07% STTD P). There was a Ca:P×STTD P:NE interaction (P < 0.05) observed for ADG, G:F and final BW. For ADG and final BW, when feeding 75% of PIC STTD P recommendation, increasing analyzed Ca:P ratio decreased ADG and final BW (linear, P< 0.001). But when feeding at PIC STTD P recommendation, increasing the analyzed Ca:P ratio tended to improve ADG and final BW (linear, P< 0.10). For G:F, when feeding 75% of PIC STTD P recommendation, increasing analyzed Ca:P ratio tended to decrease G:F (linear, P < 0.10), whereas in pigs fed diets that met PIC STTD P recommendations, increasing analyzed Ca:P ratio tended to improve G:F in a quadratic (P < 0.10) manner. Pigs fed at PIC STTD P recommendations had increased ADG, final BW, and G:F compared with pigs fed 75% of PIC STTD P recommendations (P < 0.001). In summary, pigs fed at PIC STTD P recommendations had improved overall ADG and G:F compared with pigs fed diets at 75% PIC STTD P recommendations. Additionally, increasing analyzed Ca:P ratio reduced ADG and G:F when STTD P was below PIC recommendations, but had marginal impacts when adequate STTD P was fed.

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PSI-2 Effect of Gruel Feeding and Oral Dextrose on the Survivability of Pigs After Weaning

Two experiments were conducted using 3,087 (Exp. 1) and 988 (Exp. 2) pigs to determine the effect of gruel feeding (Exp. 1) and oral glucose (Exp. 2) on pig survivability after weaning. Upon arrival to the nursery, the smallest 10% of pigs were selected and randomly placed in designated pens with 61 to 108 pigs/pen. Pens of small pigs were assigned to 1 of 2 treatments in a completely randomized design. Treatment consisted of gruel feeding 2 or 4 times/day for 14-d post-placement. At each gruel feeding, approximately 1.13 kg of solid feed was added to a round Rotecna bowl (Rotecna S.A., Agramunt, Spain) located at the front of the pen. Water was added at a decreasing rate over time. From d 0 to 5, 6 to 10, and 11 to 14 the ratio of water to feed was 3:1, 1:1, and 1:3, respectively. In Exp. 2, every other pig removed from general population or pens of small pigs for welfare considerations received a single 10 mL oral dose of a 50% dextrose solution and were placed in sick/fallback pens. All removed pigs were tagged and blood glucose measured prior to and 30 min after entering sick/fallback pens. Overall, gruel feeding small pigs 2 or 4 times/day for 14-d post-placement did not influence (P > 0.10) mortality from weaning to the end of gruel feeding (3.78 vs 4.25%, respectively). Likewise, dextrose administration did not influence (P > 0.10) pig mortality after removal to approximately d 38 after weaning (21.4 vs 23.4% respectively), even though blood glucose increased (P < 0.001) in those administered dextrose (11.4 vs 19.1 mg/dL). In summary, gruel feeding 4 times/d or providing sick/fallback pigs glucose supplementation does not improve survivability of pigs after weaning. More research is needed using alternative protocols to understand the value of gruel feeding on pig survival post-weaning.

103 Effect of Floor Feeding Creep Feed on the Growth Performance and Morbidity and Mortality of Pigs After Weaning

A total of 264 litters corresponding to 2,497 nursery pigs were used in a 40-d trial to determine the effect of floor feeding pelleted creep feed or lactation feed on the growth performance and morbidity and mortality of pigs after weaning. Treatments were applied in the farrowing house for 4-d prior to weaning and consisted of a control (no creep), standard (0.32 cm) creep pellet, large (1.27 cm) creep pellet, or sow lactation feed in meal form. For each treatment, approximately 227 g of creep feed per day equally divided into 2 feedings was provided on the mat in farrowing stalls. At weaning, pigs were transported to the nursery facility and randomized to pen within creep feeding treatment. A total of 96 pens (48 feeders) were used, with one barrow pen and one gilt pen per feeder. Thus, feeder (2 pens) was the experimental unit. There were 26 pigs per pen and 12 replications per treatment. During week 1 post-weaning, pigs fed standard or large pellet creep feed had increased (P < 0.001) ADG compared with pigs fed sow lactation feed or no creep feed. This was not driven by improved ADFI but rather G:F (P < 0.001). No differences in growth performance were observed throughout the remainder of the nursery period. Overall, on a per pig placed basis, pigs fed large pellet creep feed had increased ADG (P < 0.05) and improved G:F (P < 0.05) compared with pigs fed sow lactation feed, with the other 2 treatments intermediate. This response was a direct reflection of decreased (P < 0.05) total mortality and removals for pigs fed large pellet creep feed. In summary, floor feeding large pellet creep feed starting 4-d preweaning improved nursery pig growth performance and fallout rates compared with creep feeding sow lactation feed, with standard pellet creep feed or no creep feed having an intermediate effect.

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156 Effects of Standardized Ileal Digestible Lysine Level on Growth Performance in 35 to 80 Kg DNA Finishing Pigs

Two studies were conducted to estimate the SID Lys requirement for growth and feed efficiency of 35-80-kg DNA finishing pigs. In Exp. 1, 608 pigs (600 × 241, DNA; initially 36.3±0.91kg) were used to estimate the SID Lys requirement from 35-55-kg. In Exp. 2, 700 pigs (DNA 600×241; initial BW of 53.2±0.86kg) were used to estimate the SID Lys requirement form 50-80-kg. Pens of pigs were blocked by BW and randomly allotted to 1 of 6 dietary treatments with 7-10 pigs/pen in a randomized complete block design with 12 replications per treatment. Diets were corn-soybean meal-based and SID Lys increased by increasing soybean meal and feed-grade amino acids while maintaining minimum ratios for other amino acids. Increasing SID Lys increased (linear, P < 0.05) ADG in both studies. From 50-80-kg, ADFI decreased, then increased (quadratic, P = 0.004) with increasing SID Lys. Feed efficiency improved, while Lys intake/d, and Lys intake/kg of gain increased (linear, P < 0.05, 35-55-kg; quadratic, P < 0.05, 50-80-kg) with increasing SID Lys. At current ingredient and pig prices, there were no statistical differences in income over feed cost (IOFC) from 35-55 kg. From 50-80-kg, increasing SID Lys increased (linear, P < 0.001) IOFC. Linear models resulted in the best fit for ADG, G:F and IOFC from 35-55-kg, with optimum performance at 1.20% SID Lys or greater. A quadratic polynomial model predicted a requirement of 0.97% SID Lys for optimum G:F from 50-80-kg. Meanwhile, a broken-line linear model predicted optimal IOFC at 0.76% SID Lys from 50-80-kg. In summary, these results suggest that the optimal SID Lys level for 35-55-kg DNA finishing pigs is at least 1.20%. The optimal SID Lys level for 50-80-kg DNA finishing pigs depends on the response criteria, with growth performance optimized at or above 0.97% SID Lys and IOFC maximized at 0.76% SID Lys.

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169 The Effect of Increasing Valine, Isoleucine, and Tryptophan:Lysine Ratios on Growth Performance and Carcass Characteristics of Pigs Fed Diets with High Leucine:Lysine

A total of 4,076 pigs (initially 39.3 kg) were used across 2 experiments to evaluate the effect of increasing ratios of Val, Ile, and Trp:Lys in corn-soybean meal-DDGS-based diets on pig growth performance and carcass characteristics. In both experiments, the 4 dietary treatments were: 1) high soybean meal and low feed grade amino acids (control), 2) low soybean meal and high feed grade amino acids, with Val:Lys, Ile:Lys, and Trp:Lys at 67, 55, and 18, respectively, (low ratio) 3) diet 2 except Val:Lys, Ile:Lys, and Trp:Lys increased to 72, 60, and 21, respectively, (medium ratio), and 4) diet 2 except Val:Lys, Ile:Lys, and Trp:Lys at 80, 65, and 23, respectively (high ratio). The Leu:lys levels for the diets with increased synthetic amino acids ranged from 135 to 146 for the 4 phases. All diets contained 30% DDGS until 100 kg BW, and then 20% DDGS until trial completion. Because there was no experiment × treatment interactions, data from both experiments were combined. Overall, ADG and ADFI increased (AA ratio; linear, P < 0.05) as Val, Ile, and Trp:Lys ratios increased from low to high. Pigs fed the control diet exhibited increased ADG compared with pigs fed low ratio diets, while pigs fed medium and high ratio diets performed intermediate. For carcass characteristics, pigs fed the control had increased (P < 0.05) percentage lean and loin depth compared with pigs fed the medium ratio diet, with pigs fed low and high ratio intermediate. Pigs fed the medium ratio diet had increased backfat depth compared with pigs fed the control, with pigs fed the low and high ratio intermediate (P < 0.05). In summary, the soybean meal level can be reduced, and synthetic amino acid levels increased in high DDGS diets as long as ratios of Val, Ile, and Trp to Lys are increased.

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57 Effect of Calcium Carbonate Level with or without Benzoic Acid on Weanling Pig Growth Performance, Fecal Dry Matter, and Blood Ca and P Concentrations

A total of 360 barrows (DNA Line 200×400; initially 6.2 ± 0.03 kg) were used in a 38-d study to evaluate the interactive effects of added dietary calcium carbonate and benzoic acid on nursery pig growth performance, fecal dry matter, and blood Ca and P concentration. Upon arrival to the nursery research facility, pigs were randomly assigned to pens (5 pigs/pen) and pens were allotted to 1 of 6 dietary treatments (12 pens/treatment). Dietary treatments fed from d 0 to 24 were formulated to provide 0.45, 0.90, or 1.35% calcium carbonate with or without 0.5% benzoic acid (VevoVitall, DSM Nutritional Products, Parsippany, NJ). Diets were fed in 3 phases with total Ca of 0.66, 0.83, or 1.00% Ca from d 0 to 10, and 0.54, 0.72, or 0.89% from d 10 to 24. A common diet was fed from d 24 to 38 (0.68% Ca). Serum Ca and P was analyzed on d 21. There were no calcium carbonate×benzoic acid interactions observed for any response criteria (P > 0.10). For the experimental period (d 0 to 24), there was a tendency for benzoic acid to improve ADG (P = 0.056) and ADFI (P = 0.071) with no influence on G:F (P>0.10). Increasing calcium carbonate linearly reduced (P < 0.05) G:F. For serum analysis, serum Ca increased (linear, P < 0.001) as the level of dietary calcium carbonate increased. There were no differences (P > 0.010) in fecal DM. For the overall study (d 0 to 38), pigs fed benzoic acid had increased ADG (P = 0.011) and ADFI (P = 0.030) and marginally improved (P = 0.096) G:F. Calcium carbonate level did not influence overall performance. This data suggests that lower levels of calcium carbonate may improve feed efficiency in early nursey period. Adding benzoic acid to the diet for nursery pigs increased ADG and ADFI, and tended to increase G:F regardless of the calcium carbonate level.

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