The influence of particle size of Enogen Feed corn and conventional yellow dent corn on nursery and finishing pig performance, carcass characteristics and stomach morphology

Enogen Feed corn is a variety developed by Syngenta Seeds (Downers Grove, IL) that has been genetically modified to contain an α-amylase enzyme trait (SYT-EFC). Originally, Enogen feed corn was developed for the ethanol industry due to its reduction in viscosity of the corn mash, thus eliminating the need to add a liquid form of the α-amylase enzyme. However, there is a potential application for Enogen Feed corn to be used in livestock diets due to the increase in α-amylase enzyme potential to increase starch digestibility. A more common method of increasing starch digestibility in corn is to finely grind it to reduce particle size. This increases the surface area and allows for greater interaction with digestive enzymes. We hypothesized that pigs fed Enogen feed corn potentially could achieve similar gain:feed ratio (G:F) at larger particle sizes than conventional corn because of the differences in starch digestibility. In experiment 1, a total of 360 pigs (DNA 200 × 400, Columbus, NE; initially 6.6 ± 0.1 kg BW) were used with five pigs per pen and 12 pens per treatment. Treatments were arranged in a 2 × 3 factorial with main effects of corn source (Enogen Feed corn or conventional yellow dent corn) and ground corn particle size (300, 600, or 900 µm). Overall, there was a corn source × particle size interaction (linear, P = 0.027) for G:F. There was no effect due to particle size when pigs were fed conventional yellow dent corn, but in pigs fed Enogen Feed corn, G:F increased with decreasing particle size. Neither corn source nor particle size affected (P > 0.05) overall average daily gain (ADG) or average daily feed intake (ADFI). In experiment 2, a total of 323 pigs (241 × 600; DNA, Columbus, NE; initially 50.0 ± 1.3 kg) were used with nine pigs per pen and six pens per treatment. Treatments were identical as experiement 1. Overall, corn source had no effect on finishing pig ADG, ADFI or G:F. For corn particle size, ADG and G:F increased (linear, P < 0.014) and ADFI decreased (P = 0.043) as particle size decreased. For stomach morphology, there was a tendency for a corn source × particle size interaction (P = 0.055) for keratinization score with keratinization increasing linearly (P = 0.001) as particle size of the corn decreased for yellow dent corn with no change in keratinization score as particle size decreased for Enogen Feed corn. In summary, reducing corn particle size improved G:F with no major differences observed between corn sources for overall pig performance.

A Meta-Analysis to Understand the Relationship between Pig Body Weight and Variation from Birth to Market

Simple Summary

Understanding and managing variation in live weight within a pig population is key for swine producers to avoid economic penalties at processing plants. The objective of this meta-analysis was to determine the relationship between coefficient of variation (CV) and standard variation (SD) as a function of body weight for pigs and develop equations to predict CV and SD of a population of pigs from birth to market weight. Results reveal that there is a quadratic relationship between variation and body weight. Coefficient of variation decreases as live weight increases, but the slope is less pronounced as body weights became greater. Conversely, SD increases quadratically as body weight (BW) increases, with a less pronounced slope when BW is high within the population. Thus, the equations developed can be an effective tool for producers to predict normal BW variation within a group of pigs, which can then aid in the development of marketing strategies for finishing pigs.

Abstract

This meta-analysis aims to understand the changes in pig body weight (BW) variation from birth to market and develop prediction equations for coefficient of variation (CV) and standard deviation (SD) as a function of BW. Standard deviation is the measure of dispersion of a set of values from the mean and CV is the SD expressed as a percentage of the mean. Data collected from 16 papers and data sets yielded 117,268 individually weighed pigs with sample size ranging from 120 to 4108 pigs. Polynomial regression analysis was conducted separately for each variation measurement. The resulting prediction equations (CV (%) = 20.04 − 0.135 × (BW) + 0.00043 × (BW)², R² = 0.79; SD = 0.41 + 0.150 × (BW) − 0.00041 × (BW)², R² = 0.95) suggest that there is a quadratic decreasing relationship between the CV of a population and BW, the slope gets smaller as mean BW increases from birth to market. A quadratic increasing relationship is observed for SD, with slope being smaller as mean BW of pigs increases from birth to market. These prediction equations can be used by swine producers to estimate expected CV and SD of BW among a population of pigs.

Effects of dietary chromium propionate and space allowance on performance and carcass responses of growing-finishing pigs

In a 72-d trial, 256 pigs (Line 600 × 241, DNA Columbus, NE) were used to determine the effect of dietary Cr (Cr propionate; Kemin Industries, Des Moines, IA) and physical space restriction on performance and carcass characteristics of finishing pigs. Pens were blocked by initial weight and randomly assigned to treatments with eight pigs per pen and eight pens per treatment. Treatments were arranged in a 2 × 2 factorial with main effects of Cr (control and Cr propionate, 200 µg/kg added Cr) and space allowances (0.91 m²/animal: normal and 0.63 m²/animal: restricted). Pigs were fed in three dietary phases and pigs were weighed approximately every 14 d throughout the study. Feed efficiency was calculated as both a standard gain to feed ratio and as an adjusted G:F ratio at a common final bodyweight. There were no evidence of space allocation × Cr interactions for any measured responses (P > 0.05). Space restriction decreased (P < 0.001) daily weight gain, final body weight, hot carcass weight, and daily feed intake, but increased carcass yield (P = 0.009) and decreased backfat depth (P = 0.003). Feed efficiency was greater for pigs provided a normal space allowance when adjusted for a common final bodyweight (P = 0.021), although no evidence of a difference was observed for unadjusted G:F (P = 0.687). Adding Cr to the diet reduced G:F on both an adjusted and unadjusted basis (P ≤ 0.021). There was marginally significant evidence that pigs provided Cr had lower average daily gain (P = 0.079) and final bodyweight (P = 0.056) compared to pigs not provided added Cr. There was marginally significant evidence that Cr resulted in greater backfat depth (P = 0.069), although no evidence of a difference in other carcass parameters were observed (P > 0.10). These results demonstrated that there were no interactions between Cr propionate and space allocation, illustrating that under the conditions of this study Cr propionate did not provide an advantage in growth performance or carcass characteristics in either adequate or restricted space allocation.

Effects of increasing standardized ileal digestible lysine during gestation on reproductive performance of gilts and sows

Limited information is available on lysine requirement estimates of modern, high-producing gestating sows Therefore, the objective of this study was to evaluate the effects of increasing standardized ileal digestible (SID) lysine during gestation on piglet birthweight and reproductive performance of gilts and sows. A total of 936 females (498 gilts, 438 sows; Camborough®, PIC, Hendersonville, TN) were group-housed (approximately 275 females per pen) and individually fed with electronic sow feeders. Females were moved from the breeding stall to pens on d 4 of gestation and allotted to one of four dietary treatments on d 5. Dietary treatments included increasing SID lysine intake (11.0, 13.5, 16.0, and 18.5 g/d). Gilts (parity 1) and sows (parity 2+) received 2.1 and 2.3 kg (22.2 and 24.3 MJ net energy per day) of feed throughout the entire gestation period, respectively. Dietary treatments were achieved by different blends of low (0.48% SID lysine) and high (0.88% SID lysine) lysine diets, prepared by changing the amount of corn and soybean meal in these two diets. Female weight and backfat were recorded on d 4 and 111 of gestation. Individual piglet weight was obtained within 12 h of birth on litters from 895 females. Final weight, and calculated maternal BW, body lipid, and body lean at d 111 of gestation increased (linear, P < 0.01) for gilts and sows as SID lysine increased. There was no evidence for differences in final backfat depth. Average total born for gilts and sows was 15.3 and 16.0 pigs with no evidence for differences among treatments. The percentage of pigs born alive increased (P = 0.01) with increasing SID lysine intake for sows, but not in gilts as a result of a treatment by parity group interaction (P = 0.04) for percentage of stillborn pigs. Increasing SID lysine intake during gestation did not affect the percentage of mummified fetuses, total born, or birthweight of piglets born alive in this study. In addition, increasing SID lysine intake during gestation did not affect subsequent reproductive performance. In conclusion, increasing dietary SID lysine intake in gestation increased female BW, without changing backfat depth. The minimal effects on female reproductive performance and piglet birthweight suggest that 11 g/day of SID lysine intake appears to be adequate for gestating gilts and sows; however, providing sows with 18.5 g/d SID lysine reduced (P = 0.01) stillbirth rate by 2.3 percentage points.

Determining the phosphorus release of GraINzyme phytase in diets for nursery pigs

The objective of this study was to determine the available P (aP) release curve for a new phytase source, GraINzyme Phytase (Agrivida Inc., Woburn, MA), which is expressed in corn containing an engineered Escherichia coli phytase called Phy02. Plant-expressed phytases are created by inserting phytase-encoding genes into plants resulting in their ability to produce seeds with increased concentrations of phytase. A total of 360 pigs (Line 200 × 400, DNA, Columbus, NE, initially 9.9 ± 0.19 kg) were used in a 21-d growth study. Pigs were weaned at approximately 21 d of age, randomly allotted to pens based on initial body weight (BW) and fed common starter diets. From days 18 to 21 postweaning, all pigs were fed a diet containing 0.11% aP. On day 21 postweaning, considered day 0 of the study, pens were blocked by BW and randomly allotted to one of eight dietary treatments with five pigs per pen and nine pens per treatment. Dietary treatments were formulated to include increasing aP derived from either an inorganic P source (0.11%, 0.19%, or 0.27% from monocalcium P) or increasing phytase (150, 250, 500, 1,000, or 1,500 FTU/kg). Diets were corn-soybean meal-based and contained 1.24% standardized ileal digestible Lys. On day 21 of the trial, one pig per pen (weighing closest to the mean pen BW) was euthanized and the right fibula was collected to determine bone ash using the nondefatted processing method. Overall (days 0 to 21), pigs fed increasing aP from inorganic P or phytase had increased (linear, P < 0.002) average daily gain (ADG), average daily feed intake (ADFI), and gain-to-feed (G:F; quadratic, P < 0.05). Bone ash weight (g) and percentage bone ash increased (linear, P < 0.001), with increasing inorganic P or added phytase. Based on the composition of the diets used in this study, the release equations developed for GraINzyme for ADG, G:F, bone ash weight, and percentage bone ash are as follows: aP = (0.255 × FTU)/(1299.969 + FTU), aP = (0.233 × FTU)/(1236.428 + FTU), aP = (45999.949 × FTU)/(462529200 + FTU), and aP = (0.272 × FTU)/(2576.581 + FTU), respectively.

Effect of mixing and feed batch sequencing on the prevalence and distribution of African swine fever virus in swine feed

It is critical to have methods that can detect and mitigate the risk of African swine fever virus (ASFV) in potentially contaminated feed or ingredients bound for the United States. The purpose of this work was to evaluate feed batch sequencing as a mitigation technique for ASFV contamination in a feed mill, and to determine if a feed sampling method could identify ASFV following experimental inoculation. Batches of feed were manufactured in a BSL-3Ag room at Kansas State University's Biosafety Research Institute in Manhattan, Kansas. First, the pilot feed manufacturing system mixed, conveyed, and discharged an ASFV-free diet. Next, a diet was manufactured using the same equipment, but contained feed inoculated with ASFV for final concentration of 5.6 × 10⁴ TCID₅₀ /g. Then, four subsequent ASFV-free batches of feed were manufactured. After discharging each batch into a collection container, 10 samples were collected in a double 'X' pattern. Samples were analysed using a qPCR assay for ASFV p72 gene then the cycle threshold (Ct) and Log₁₀ genomic copy number (CN)/g of feed were determined. The qPCR Ct values (p < .0001) and the Log₁₀ genomic CN/g (p < .0001) content of feed samples were impacted based on the batch of feed. Feed samples obtained after manufacturing the ASFV-contaminated diet contained the greatest amounts of ASFV p72 DNA across all criteria (p < .05). Quantity of ASFV p72 DNA decreased sequentially as additional batches of feed were manufactured, but was still detectable after batch sequence 4. This subsampling method was able to identify ASFV genetic material in feed samples using p72 qPCR. In summary, sequencing batches of feed decreases concentration of ASFV contamination in feed, but does not eliminate it. Bulk ingredients can be accurately evaluated for ASFV contamination by collecting 10 subsamples using the sampling method described herein. Future research is needed to evaluate if different mitigation techniques can reduce ASFV feed contamination.

Effects of feeding diets containing low crude protein and coarse wheat bran as alternatives to zinc oxide in nursery pig diets

Two experiments were conducted to determine the effects of crude protein (CP) level in diets containing coarse wheat bran (CWB) with or without pharmacological levels of Zn (provided by zinc oxide: ZnO) on growth performance and fecal DM of nursery pigs. In experiment 1, 360 barrows (Line 200 × 400, DNA, Columbus, NE, initially 5.6 kg) were allotted to 1 of 6 dietary treatments from d 0 to 21 after weaning with 5 pigs per pen and 12 pens per treatment. Treatments included a positive control diet (21% CP) with 3,000 mg/kg Zn in phase 1 and 2,000 mg/kg in phase 2; negative control (21% CP) with 110 mg/kg added Zn, and 4 diets containing 4% CWB and 110 mg/kg added Zn formulated to contain 21%, 19.5%, 18%, or 16.5% CP. The 2 control diets and 21% CP CWB diet contained 1.40% standardized ileal digestible (SID) Lys in phase 1 and 1.35% SID Lys in phase 2, while the 19.5%, 18%, and 16.5% CP diets contained 1.33, 1.25 and 1.20% Lys, respectively, in both phases. Pigs fed the positive control diet containing pharmacological ZnO had increased (P < 0.05) ADG and G:F compared with the negative control and the 21% CP CWB diet. Reducing CP (concurrently with SID Lys) in diets containing CWB decreased ADG and G:F (linear, P = 0.002); however, fecal DM increased (linear, P = 0.005). In experiment 2, two groups of 300 and 350 pigs, initially 7.0 and 6.2 kg, respectively, were used with 5 pigs per pen and 26 pens per treatment. The objective was to determine if adding back essential AA would improve growth performance of pigs fed the low CP diets. All dietary treatments were fed for 13 days, contained 4% CWB, and consisted of: (1) positive control with 2,000 mg/kg of Zn and 21% CP (1.35% SID Lys); (2) no ZnO and 21% CP; and 3 diets with no ZnO formulated to 18% CP and (3) 1.2% SID Lys; (4) 1.35% SID Lys by the addition of feed grade amino acids (AA), and (5) diet 4 with non-essential amino acids (NEAA; Gly and Glu). Pigs fed 21% CP with ZnO had increased (P = 0.001) ADG compared to those fed 18% CP (1.35% SID Lys) with high levels of feed grade amino acids or those fed the reduced SID Lys (1.2%) diet. Overall, G:F was improved (P < 0.001) for pigs fed 21% CP diets and those fed the 18% CP diet with NEAA compared to pigs fed 1.2% SID Lys and pigs fed high levels of feed grade amino acids. Fecal DM was increased for pigs fed the reduced SID Lys diet. In summary, pharmacological levels of Zn improve pig growth performance, but reducing CP (and subsequently SID Lys) decreased nursery pig growth performance.

138 Effects of Increasing Soybean Meal in Corn-based Diets on Growth Performance of Late-finishing Pigs

Two experiments were conducted to determine the effects of increasing levels of soybean meal (SBM) replacing feed grade amino acids in corn or corn-dried distillers grains with solubles (DDGS)-based diets on growth performance of late finishing pigs. In both experiments, there were 22 to 27 pigs per pen and 14 pens per treatment. Average length of the experiments was 35 (Exp. 1) and 29 days (Exp. 2). Diets were balanced to contain 0.70% SID Lys and 2,667 or 2,610 kcal NE/kg for Exp. 1 and 2, respectively. Minimum amino acid ratios relative to Lys were: Ile, 55; Met&Cys, 60; Thr, 65; Trp, 19.5, and Val, 70. Dietary crude protein ranged from 10.1 to 15.2 for Exp. 1 and 13.6 to 19.4 for Exp. 2. The statistical model considered fixed effects of treatment, linear and quadratic contrasts, and random effect of block. In Exp.1, 1,793 pigs (L337×1050, PIC; initially 104.9 ± 1.4 kg) were fed corn-based diets and pens of pigs were assigned to 1 of 5 dietary treatments with increasing SBM from 5 to 20%. Overall, average daily gain (ADG) and gain-to-feed (G:F) increased (linear; P &lt; 0.05) as SBM increased with the greatest improvement observed as SBM increased from 5 to 8.75%, with little improvement thereafter. In Exp. 2, 1,827 pigs (L337×1050, PIC; initially 97.9 ± 1.1 kg) were used in a similar study as Exp. 1, but all diets contained 25% DDGS and SBM levels increased from 0 to 16%. Overall, G:F and final bodyweight of pigs marginally improved (linear and quadratic, respectively; P &lt; 0.10) as SBM increased, with the greatest performance observed when diets contained 8% SBM. These results suggest that increasing SBM up to 8% at the expense of feed grade amino acids in corn or corn-DDGS-based diets improved ADG or G:F in late-finishing pigs.

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PSVI-4 Efficacy of Medium Chain Fatty Acids and Fatty Acid-based Feed Additives as a Mitigation Strategy Against Porcine Epidemic Diarrhea Virus and Porcine Reproductive and Respiratory Syndrome Virus

Recent research has demonstrated that swine viruses can be transmitted via feed. Chemical feed additives have been suggested for the mitigation of these viruses in complete feed. Therefore, the objective of this study was to evaluate the efficacy of a commercially available formaldehyde-based feed additive, medium chain fatty acid blend (MCFA), and commercially available fatty acid-based products for mitigation of porcine epidemic diarrhea virus (PEDV) and porcine reproductive and respiratory syndrome virus (PRRSV) in a feed matrix. Treatments consisted of: 1) non-treated positive control, 2) 0.33% commercial formaldehyde-based product (Sal Curb; Kemin Industries, Inc.; Des Moines, IA), 3) 0.5% MCFA blend (1:1:1 ratio of C6:0, C8:0, and C10:0, Sigma Aldrich, St. Louis, MO), 4) 0.25%, 5) 0.5%, or 6) 1% of commercial dry mono and diglyceride-based product (Furst Strike; Furst-McNess Company, Freeport, IL), 7) 0.25%, 8) 0.5%, or 9) 1% of commercial dry mono and diglyceride-based product (Furst Protect; Furst-McNess Company, Freeport, IL), 10) 0.25%, 11) 0.5%, or 12) 1% dry mono and diglyceride-based experimental product (Furst-McNess Company, Freeport, IL) with 3 replications/treatment. Treatments were applied to complete swine feed before inoculation with 106 TCID50/g of feed with PEDV or PRRSV. Post inoculation feed was held at ambient temperature for 24 h before being analyzed via qRT-PCR. The analyzed values represent the cycle threshold. Formaldehyde and MCFA decreased (P &lt; 0.05) the detectable RNA of PEDV and PRRSV compared to all other treatments. Furst Strike, Furst Protect, and the experimental product did not significantly impact detectability of PEDV or PRRSV RNA. In conclusion, MCFA and formaldehyde treatments are effective at reducing detection of RNA from PEDV and PRRSV in feed.

264 Effects of Low Dietary Crude Protein Diets Containing Coarse Wheat Bran as an Alternative to Zinc Oxide in Nursery Pig Diets

An experiment was conducted to determine the effect of reduced crude protein (CP) in diets containing coarse wheat bran (CWB) without pharmacological levels of Zn (ZnO) on growth performance and fecal dry matter (DM) of nursery pigs. A total of 650 pigs (DNA 241′600; initially 6.6 kg), were used with 5 pigs/pen and 26 replicate pens/treatment. Pens were assigned to 1 of 5 treatments in a RCB design based on BW. Treatments were fed for 13-d, contained 4% CWB, and consisted of: 1) diet with pharmacological ZnO (2,000 mg/kg Zn) and 21% CP formulated to 1.35% standardized ileal digestible (SID) Lys; 2) a diet with 110 ppm added Zn and 21% CP (1.35% SID Lys); 3) a diet with 110 ppm added Zn formulated to 18% CP (1.20% SID Lys); 4) an 18% CP diet with 110 ppm added Zn formulated to 1.35% SID Lys by the addition of increased levels of feed grade amino acids; and 5) diet 4 with addition of non-essential amino acids (NEAA; glycine and glutamic acid). Data were analyzed using the lmer function in R. Overall, pigs fed 21% CP with ZnO had increased (P &lt; 0.05) ADG compared to those fed 18% CP (1.35% SID Lys) with high levels of feed grade amino acids or those fed the reduced SID Lys (1.2%) diet. Gain-to-feed ratio was increased (P &lt; 0.05) for pigs fed 21% CP diets and those fed the 18% CP diet with NEAA compared to pigs fed 1.2% SID Lys and pigs fed high levels of feed grade amino acids. Fecal DM was increased (P &lt; 0.05) for pigs fed reduced SID Lys diet. In conclusion, reducing CP (subsequently SID Lys) in diets without ZnO decreased growth performance but increased fecal DM.

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140 Influence of Enogen Feed Corn and Conventional Yellow Dent Corn in Pelleted or Meal-based Diets on Finishing Pig Performance and Carcass Characteristics

Previous research has indicated that starch gelatinization during the pelleting process is greater for Enogen® Feed corn compared to conventional yellow dent corn. Increasing starch gelatinization in the pellet increases the starch digestibility in the pig, which potentially leads to increased growth rate. Therefore, the objective of this study was to determine the effects of feeding Enogen Feed corn in meal or pellet form on finishing pig growth performance and carcass characteristics. A total of 288 pigs (53.0 ± 0.5 kg) were used with 8 pigs/pen and 9 pens/treatment in a 72-d study. Treatments were arranged in a 2×2 factorial with main effects of corn source (Enogen Feed corn or conventional yellow dent corn) and diet form (meal or pellet). Main effects of corn source and diet form as well as their interactions were tested. Pelleting parameters were established with a target conditioner temperature of 82.2°C and corn moisture of 13 to 14%. When pelleting the diets, the conditioning temperature for conventional yellow dent corn averaged 68.4°C and Enogen Feed corn averaged 67.7°C. The hot pellet temperature for conventional yellow dent corn averaged 75.1°C and 75.8°C for Enogen feed corn. For overall performance (d 0 to 72), no interactions between corn source and diet form were observed (P &gt; 0.05). There was a tendency (P &lt; 0.10) for slightly improved average daily gain (ADG) and gain:feed ratio (G:F) for pigs fed conventional yellow dent corn compared to those fed Enogen Feed corn. Pigs fed pelleted diets had increased (P &lt; 0.001) ADG, G:F, and hot carcass weight compared to pigs fed meal diets. In summary, feeding pelleted diets to finishing pigs increased ADG and G:F compared to those fed meal-based diets. There were no major differences observed between corn sources or interactions between corn source and diet form on growth performance.

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165 Effects of Digestible Lysine Level on Growth Performance and Economics of Grow-finish Pigs

A total of 2,124 barrows and gilts (PIC 1050′DNA 600, initially 48.9 kg) were used in a 32-d study to determine the optimal dietary standardized ileal digestibility (SID) Lys level in a commercial setting. Pigs were randomly allotted to 1 of 5 dietary treatments with 24 to 27 pigs/pen and 16 replications/treatment. Similar number of barrows and gilts were placed in each pen. Diets were fed over 3 phases (48.9 to 58.6, 58.6 to 70.9, and 70.9 to 80.8 kg respectively). Dietary treatments were corn-soybean meal-based and contained 10 (phase 1 and 2) or 5% (phase 3) distillers dried grains with solubles. Diets were formulated to 85, 95, 103, 110, or 120% of the current Pig Improvement Company (PIC, Hendersonville, TN) SID Lys gilt recommendations with phase 1 SID Lys levels of 0.90, 1.01, 1.09, 1.17 and 1.27%, phase 2 levels of 0.79, 0.87, 0.94, 1.03, and 1.10%, and phase 3 levels of 0.71, 0.78, 0.85, 0.92, and 0.99%, respectively. Dose response curves were evaluated using linear (LM), quadratic polynomial (QP), broken-line linear (BLL), and broken-line quadratic (BLQ) models. For each response variable, the best-fitting model was selected using the Bayesian information criterion. Overall (d 0 to 32), increasing SID Lys increased (linear, P&lt; 0.001) BW, ADG, G:F, Lys intake/d, and Lys intake/kg of gain. Modeling margin over feed cost (MOFC), BLL and QP estimated the requirement at 105.8% and 113.7% respectively. In summary, while growth increased linearly up to 120% of the PIC current feeding level, the optimal MOFC was 106% to 114% depending on the model used.

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PSIV-14 Influence of Feed Grade Amino Acid Inclusion Level in Late Nursery and Grower Diets Fed to Pigs from 10 to 35 Kg

A total of 912 pigs (PIC TR4 × (Fast LW × PIC L02)) were used in a 43-d trial to evaluate the influence of feed grade amino acid levels in late nursery and grower diets containing 30% dried distillers grains with solubles (DDGS) on growth performance. Pigs were randomly assigned to pens (19 pigs per pen) and pens were randomly allotted in weight blocks to 1 of 4 dietary treatments with 12 pens per treatment. Treatment diets were fed in 2 phases from 10 to 19.5 kg and 19.5 to 35 kg with digestible lysine at 1.31 and 1.15%, respectively). Predetermined orthogonal contrasts were used to evaluate linear or quadratic effects based on percentage of digestible lysine from intact protein versus feed grade lysine. Dietary treatments contained low, medium, high, or very high levels of feed grade amino acids with L-lysine added at 0.25, 0.40, 0.55, and 0.70% of the diet, respectively, with all other amino acids added as needed to meet minimum ratios relative to lysine (60% Ile; 58% Met and Cys; 65% Thr; 19% Trp; 72% Val). Overall, from d 0 to 43, there was an increase (quadratic, P&lt; 0.020) in average daily gain (ADG) and average daily feed intake (ADFI) with pigs fed increasing levels of feed grade amino acids having the greatest gain and feed intake at the medium and high inclusion of feed grade amino acids, respectively. For overall gain:feed (G:F), pigs fed the medium level of feed grade amino acids had improved G:F (P=0.002) compared to pigs fed the high and very high feed grade amino acids with the pigs fed the low feed grade amino acids intermediate. In summary, feeding pigs medium levels of feed grade amino acids resulted in increased ADG and G:F during the late nursery and grower period.

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PSVI-8 Meta-regression Analysis to Determine the Relationship Between Growing Pig Body Weight and Variation

The swine industry has been constantly evolving to select animals with improved performance traits and to minimize variation in body weight (BW) in order to meet packer specifications. Therefore, understanding variation presents an opportunity for producers to find strategies that could help reduce, manage, or deal with variation of pigs in a barn. A systematic review and meta-analysis was conducted by collecting data from multiple studies and available data sets in order to develop prediction equations for coefficient of variation (CV) and standard deviation (SD) as a function of BW. Information regarding BW variation from 16 papers was recorded to provide approximately 204 data points. Together, these data included 117,268 individually weighed pigs with a sample size that ranged from 104 to 4,108 pigs. A random-effects model with study used as a random effect was developed. Observations were weighted using sample size as an estimate for precision on the analysis, where larger data sets accounted for increased accuracy in the model. Regression equations were developed using the nlme package of R to determine the relationship between BW and its variation. Polynomial regression analysis was conducted separately for each variation measurement. When CV was reported in the data set, SD was calculated and vice versa. The resulting prediction equations were: CV (%) = 20.04 – 0.135 × (BW) + 0.00043 × (BW)2, R2=0.79; SD = 0.41 + 0.150 × (BW) - 0.00041 × (BW)2, R2 = 0.95. These equations suggest that there is evidence for a decreasing quadratic relationship between mean CV of a population and BW of pigs whereby the rate of decrease is smaller as mean pig BW increases from birth to market. Conversely, the rate of increase of SD of a population of pigs is smaller as mean pig BW increases from birth to market.

PSIII-15 Effect of the Pelleting Process on Diet Formulations with Varying Levels of Crystalline AA and Reducing Sugars on Nursery Pig Growth Performance

A total of 360 pigs (DNA 200×400; initially 11.3 kg) were used in an 18-d study to determine the effect of pelleting diets with or without increased concentrations of free amino acids (AA) and reducing sugars (RS) on pig growth performance. There were 9 replications/treatment and 5 pigs/pen. Treatments were arranged in a 2×2×2 factorial with main effects of diet form (mash vs. pellet), crystalline AA (low vs. high), and RS (low vs. high) provided by dried distillers grain with solubles and bakery meal included at 20% and 15%, respectively. Diets were pelleted to achieve a conditioning temperature of 86.7°C using a 22.4 kW pellet mill equipped with a 4.7 x 34.9-mm die. Data were analyzed as a CRD using the GLIMMIX procedure of SAS. There were no 3-way interactions observed. For the main effect of feed form, ADFI decreased (P=0.001) and G:F and caloric efficiency improved (P=0.001) in pigs fed pelleted diets compared to mash diets. For the main effect of crystalline AA, pigs fed diets with high crystalline AA had increased (P&lt; 0.024) ADFI compared to those fed diets with low crystalline AA. For the main effect of RS, pigs fed high RS diets had decreased (P&lt; 0.041) ADG, ADFI, G:F, and caloric efficiency compared to those fed low RS. In conclusion, there was no evidence of interactions between treatments, indicating that increasing amounts of crystalline AA and RS did not influence the response to pelleted diets. Pigs fed the high RS diets had reduced feed intake which resulted in reduced gain and improved feed and caloric efficiency.

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94 The Effects of Dietary Crude Protein, Acidifier, and Pharmacological Levels of Zinc on Growth Performance of Nursery Pigs

Weanling pigs (n = 360, DNA 200 × 400, initially 5.90 kg) were used to evaluate pharmacological levels of Zn (ZnO), diet acidification (sodium diformate; Addcon, Bitterfeld-Wolfen, Germany), and crude protein (18 or 21% CP) on pig performance. At weaning, pigs were assigned to treatments with 5 pigs/pen and 9 pens/treatment. Treatments were arranged in a 2×2×2 factorial with main effects of Zn (110 mg/kg from d 0 to 21 or 3,000 mg/kg from d 0 to 7, and 2,000 mg/kg from d 7 to 21), diet acidification (without or with 1.2% sodium diformate), and dietary CP (21 or 18%). The 21% CP diets were formulated to 1.40 and 1.35% SID Lys in phase 1 and 2, respectively, and 18% CP diets were formulated to 1.20% SID Lys. Experimental diets were fed from d 0 to 21 with a common diet from d 21 to 42. Fecal samples were collected weekly to determine fecal dry matter (DM). Data were analyzed using R Studio as a RCBD. From d 0 to 21, ADG and G:F increased (P &lt; 0.05) for pigs fed pharmacological Zn, and sodium diformate. Overall, ADG tended (P ≤ 0.069) to increase for pigs fed added Zn or sodium diformate. Pigs fed 21% CP had increased (P &lt; 0.05) ADG and G:F from d 0 to 21 and overall G:F compared with those fed 18% CP. Feeding 18% CP diets increased fecal dry matter on d 7 when pharmacological Zn and sodium diformate were not in the diet (Zn×acidifier×CP interaction, P &lt; 0.05). From d 21 to 42, there was no evidence of difference in growth performance. In conclusion, reducing CP without acidification increased fecal DM when pharmacological Zn were not in the diet, but had little effect when it was in the diet. Adding sodium diformate and pharmacological Zn independently improved nursery pig growth performance.

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28 In-feed or In-water Antibiotic Administration Did Not Influence the Fecal Prevalence and Antimicrobial Susceptibility Profiles of Salmonella in Piglets

A total of 1,296 weaned piglets were used in a 35-d study to assess the impact of in-feed vs in-water administrations of chlortetracycline (CTC) and or tiamulin on prevalence and antimicrobial resistance (AMR) profiles of Salmonella enterica. Piglets were allocated to 48 pens (27 pigs per pen) and pens were assigned randomly to six treatment groups: control (no antibiotic), in-feed CTC, in-water CTC, in-feed tiamulin, in-water tiamulin, and in feed CTC and tiamulin. Fresh fecal samples were collected randomly from 5 of 27 piglets from each pen on days -7, 0 (pre-treatment), 7, 14 (treatment), 21, and 28 (post-treatment). Salmonella isolation and identification were done by enrichment, plating on selective medium, and species confirmation of putative colonies by PCR. Antimicrobial susceptibility and resistance of the isolates were determined using premade antibiotic panel (SensititreTM CMV3AGNF and BOPO7F) and results were interpreted based on the Clinical and Laboratory Standards Institute guidelines. All Salmonella isolates were identified as serotype Typhimurium. The overall prevalence of Salmonella was 3.0% (43/1,440) with no treatment effect (P &gt; 0.05). All isolates were resistant (100%) to tetracycline and tiamulin. Additionally, the isolates were resistant to ampicillin (100%), streptomycin (100%), sulfisoxazole (100), ciprofloxacin (95.4%) and nalidixic acid (74.4%). Only a few isolates were resistant to trimethoprim/sulphamethoxazole (4.7%), ceftriaxone (7.0%), and ceftiofur (7.0%). PCR assays indicated the presence of tetB gene in all isolates, while 11 (25.6%) and 4 (9.3%) isolates were positive for tetD and tetA genes, respectively. Neither in-feed nor in-water administration of CTC or tiamulin impacted the fecal prevalence and antimicrobial susceptibility of Salmonella in nursery piglets.

PSIV-15 Influence of Particle Size of Enogen Feed Corn and Conventional Yellow Dent Corn on Lactating Sow Performance

A total of 107 sows (Line 241; DNA, Columbus, NE) across 4 batch farrowing groups were used to evaluate the effects of corn source and particle size on sow and litter performance. Treatments were arranged in a 2×2 factorial with main effects of corn source (Enogen® Feed corn (Syngenta Seeds, Downers Grove, IL) or conventional yellow dent corn) and ground corn particle size (600 or 900 µm). Sows were blocked by parity and BW upon arrival to the farrowing house. There were approximately 27 sows per treatment, sow was considered the experimental unit, dietary treatment was a fixed effect, and sow group and block were used as random effects. Main effects of corn source and particle size as well as their interactions were tested. From farrowing to weaning, there was a tendency for a source×particle size interaction (P=0.065) for sow BW change. Sows fed 900 µm Enogen Feed corn had decreased BW loss compared to sows fed other treatments which were similar in BW loss. There was a source×particle size interaction (P=0.048) for lactation ADFI with sows fed 900 µm conventional yellow dent corn having lower feed intake than the sows fed 600 µm conventional yellow dent corn, whereas sows fed 900 µm Enogen Feed corn had greater feed intake compared to the sows fed 600 µm Enogen Feed corn. There was a tendency for a particle size main effect (P&lt;0.10) for litter ADG (2,849 vs 2,635 g/d) and total litter gain (45.7 vs 42.3 kg), with sows fed corn ground to 600 µm having increased litter ADG and total litter gain compared to sows fed corn ground to 900 µm. In summary, there were few differences in sow or litter characteristics among corn sources. Reducing particle size of both corn sources tended to increase litter ADG and weaning weights.

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184 Evaluation of Aviplus on Growth Performance of Nursery and Growing-finishing Pigs

A total of 1,215 pigs (L337×1050, PIC, Hendersonville, TN) were used in a 156-d wean-to-finish experiment. Pigs were weaned at 21 d of age and placed in pens based on initial body weight (BW) with 27 pigs/pen. There were three dietary treatments including a: 1) control; 2) pigs fed diets containing AviPlus (micro-encapsulated sorbic and citric acids and synthetic thymol and vanillin botanicals; Vetagro Inc., Chicago, IL) during the nursery and finisher phases; or 3) pigs fed AviPlus during the nursery but not the finishing phase. AviPlus was included at 2.72 kg/ton from d 0 to 21, 0.90 kg/ton from d 21 to 42, and 0.45 kg/ton from d 42 to 156. Thus, there were 15 control pens and 30 Aviplus pens in the nursery and 15 pens for the 3 treatments in the finisher phase. On d 42, pigs were transported as intact pens to the finishing facility. Data were analyzed as a RCBD with pen as experimental unit. For the overall nursery period (d 0 to 42), pigs fed AviPlus had improved (P &lt; 0.05) G:F, with no evidence of difference (P &gt; 0.05) for d 42 BW, ADG, or ADFI. For the overall finishing period (d 42 to 156) and overall experimental period (d 0 to 156), there was no evidence of difference (P &gt; 0.05) for BW, ADG, ADFI, or G:F. There was no evidence of difference (P &gt; 0.05) observed for mortality and removals during the nursery, finisher, or overall. In summary, providing AviPlus during the nursery improved nursery G:F, but there was no effect on overall wean-to-finish performance.

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36 Evaluation of Compensatory Growth of 90-kg Finishing Pigs Previously Fed a Low Lysine Diet

A total of 346 pigs (241×600, DNA, Columbus, NE; initially 88.6 kg) were used in a 44-day trial to evaluate compensatory growth of pigs previously fed very low lysine diets. Two diets [control and corn (98% corn and 2% vitamins and minerals)] were arranged into 4 nutritional strategies. One group of pigs (control) was fed the control diet from d 0 to 44. The other three groups of pigs were fed the corn diet for 14, 21, or 28-d and then fed the control diet until day 44. The control and corn diets contained 0.70 and 0.18% standardized ileal digestible Lys, respectively. Pens were assigned to nutritional strategies in a randomized complete block design based on initial BW with 9 pens per treatment. On average, pigs fed the corn diet grew 49% slower than the control. Pigs previously fed the corn diet had 28% increased (P &lt; 0.05) ADG during the first week of switching to the control diet and 12% faster (P &lt; 0.05) ADG than the control for the rest of the trial. Despite this increase in ADG, final BW on d 44 was lower (P &lt; 0.05) compared to the control for pigs fed the corn diet for 21 or 28-d. From d 0 to 44, control pigs and pigs fed the corn diet for only 14-d had increased (P &lt; 0.05) ADG compared to pigs fed the corn diet for 21 and 28-d. Feed efficiency was decreased (P &lt; 0.05) when the corn diet was fed and increased (P &lt; 0.05) during the period of compensatory growth; however, overall G:F decreased (P &lt; 0.05) as pigs were fed the corn diet longer. The data suggest that compensatory growth was observed when pigs fed the corn diet for 21 or 28-d followed by the control diet within a 6-week-period, but overall growth performance was still reduced compared to the control.

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PSIV-16 Evaluation of Nutritional Strategies to Reduce Growth Rate of Pigs Beyond 90-kg Body Weight

A total of 356 pigs (241×600; DNA; Columbus, NE; initially 89.0 kg) were used in a 44-d trial to evaluate nutritional strategies to reduce growth rate. Three diets [control, Lys-deficient, and corn (98% corn and 2% vitamins and minerals)] were arranged into 4 nutritional strategies. The three diets contained 0.70, 0.50, and 0.18% standardized ileal digestible (SID) Lys, respectively, with all nutrients other than amino acids above requirement estimates. From d 0 to 28, pens received one of two diets (control or Lys-deficient). On d 28, pens either remained on their previous treatment or were fed the corn diet from d 28 to 44. Pens were assigned to nutritional strategies in a randomized complete block design based on initial body weight (BW) with 18 pens/treatment from d 0 to 28 and 9 pens/treatment from d 28 to 44. From d 0 to 28, pigs fed the Lys-deficient diet had decreased (P&lt; 0.001) ADG, G:F, and d 28 BW compared to pigs fed the control diet. From d 28 to 44, pigs fed the corn diet had decreased (P&lt; 0.05) ADG and G:F compared to pigs fed the control or Lys-deficient diets. Pigs fed the Lys-deficient diet for 44 days had decreased (P&lt; 0.05) ADG and G:F compared to pigs fed the control diet for 44 days. From d 0 to 44, pigs fed the Lys-deficient diet then corn diet had decreased (P&lt; 0.05) ADG, final BW, and G:F compared to all other treatments. Pigs fed the Lys-deficient diet for 44-d and pigs fed the control diet then corn diet had decreased (P&lt; 0.05) ADG, G:F, and final BW compared to pigs fed the control diet for 44-d. In summary, feeding strategies with lysine deficient diets allow producers to slow growth rate of finishing pigs; however, feed efficiency is also impaired.

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133 Influence of Particle Size of Enogen Feed Corn and Conventional Yellow Dent Corn on Nursery and Finishing Pig Performance, Carcass Characteristics and Stomach Morphology

Two studies evaluated the effect of particle size of Enogen® Feed corn (Syngenta Seeds, LLC, Downers Grove, IL) and conventional yellow dent corn on nursery and finishing pig performance, carcass characteristics and stomach morphology. In Exp. 1, 360 nursery pigs (DNA 200×400, Columbus, NE; initially 6.6±0.1 kg BW) were used with 5 pigs per pen and 12 pens per treatment. Treatments were arranged in a 2×3 factorial with main effects of corn source (Enogen Feed corn or conventional yellow dent corn) and ground corn particle size (300, 600, or 900 µm). Overall, there was a corn source×particle size interaction (linear, P = 0.027) for G:F ratio. There was no difference due to particle size when pigs were fed conventional yellow dent corn, but in pigs fed Enogen Feed corn, G:F increased with decreasing particle size. Neither corn source nor particle size affected (P &gt; 0.05) ADG or ADFI. In Exp. 2, 323 finishing pigs (241′600; DNA, Columbus, NE; initially 50.0±1.3 kg) were used with 8 or 9 pigs per pen and 6 pens per treatment. Treatments were arranged identical to Exp. 1. Overall, corn source did not elicit differences in ADG, ADFI or G:F (P &gt; 0.05). For corn particle size, ADG and G:F increased (linear, P ≤ 0.014) and ADFI decreased (P = 0.043) as particle size decreased. For carcass characteristics, there was a tendency (linear, P = 0.093) for increased HCW and increased (linear, P = 0.023) carcass yield as corn particle size decreased. For stomach morphology, there was a tendency for a corn source×particle size interaction (P = 0.055) for keratinization score with keratinization increasing linearly (P = 0.001) as particle size decreased for yellow dent corn with no change in keratinization score as particle size decreased for Enogen Feed corn. In summary, reducing corn particle size improved G:F with no major differences observed between corn sources for overall pig performance.

29 Live Yeast and Yeast Extracts with and Without Pharmacological Levels of Zinc on Nursery Pig Growth Performance and Fecal Escherichia coli Antimicrobial Resistance

A total of 360 barrows (DNA 200×400; initially 5.6 kg) were used to evaluate yeast-based probiotics (Phileo by Lesaffre, Milwaukee, WI) in diets with or without pharmacological levels of Zn on growth and fecal Escherichia coli antimicrobial resistance (AMR). There were 5 pigs/pen and 18 pens/treatment. Dietary treatments were arranged in a 2×2 factorial with main effects of yeast pre- and probiotics (0 vs. 0.10% Actisaf Sc 47 HR+, 0.05% SafMannan, and 0.05% Nucleosaf in phase 1 then concentrations were lowered by 50% in phase 2) and pharmacological levels of Zn (110 vs. 3,000 mg/kg in phase 1 and 2,000 mg/kg in phase 2 provided by zinc oxide). Treatments were fed in two phases from d 0 to 7 and 7 to 21 with a common diet fed from d 21 to 42 post-weaning. There were no probiotics×Zn interactions. From d 0 to 21, pigs fed pharmacological Zn had increased (P &lt; 0.001) ADG and ADFI; however, there were no effects of added pre- and probiotics. Fecal samples were collected on d 4, 21, and 42 from the same three pigs/pen for AMR profiles and fecal dry matter (DM). On d 4, pigs fed pharmacological Zn had greater fecal DM (P = 0.043); however, no differences were observed on d 21 or 42. E. coli was isolated from fecal samples and species confirmation was accomplished by PCR detection of uidA and clpB genes. Microbroth dilution method using SensititreTM CMV3AGNF panel was used to determine antimicrobial susceptibilities of E. coli isolates to 14 different antimicrobials. There was no evidence for differences in AMR of fecal E. coli isolates to antibiotics by added pre- and probiotics or Zn. Results suggest that pharmacological levels of Zn stimulate intake and growth and improve fecal consistency in the nursery with no statistical response from added pre- and probiotics.

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214 Effects of Reducing Digestible Lysine and Tryptophan to Lysine Ratio on Growth Performance of Grow-finish Pigs

Due to packing plant closures or slow-downs, many producers needed to examine ways to reduce average daily gain (ADG) of finishing pigs. Therefore, a total of 1,080 pigs (L337 × 1050, PIC; initially 32.0 kg) were used in a 119-d trial to evaluate the effects of reducing dietary standardized ileal digestibility (SID) Lys and SID Trp:Lys ratio to slow growth of finishing pigs in a commercial setting. Pigs were randomly allotted in weight blocks to 1 of 4 dietary regimens with 27 pigs/pen and 10 replications/regimen. Pigs were fed a control regimen (100% of the estimated SID Lys requirement for pigs in this facility) formulated to contain 1.10, 1.01, 0.91, 0.83, 0.79, 0.71 and 0.67% SID Lys from 32 to 42, 42 to 51, 51 to 72, 72 to 85, 85 to 97, 97 to 112, and, 112 to 130 kg, respectively. Two other regimens contained 90 or 80% of the Lys estimate. These 3 regimes were formulated to a SID Trp:Lys ratio of 19% except for the last dietary phase that contained 17% SID Trp:Lys ratio. The fourth regimen contained 80% of the SID Lys estimate with 16% SID Trp:Lys in all phases. The statistical model included fixed effects of treatment, random effect of block, linear and quadratic effects of SID Lys and pairwise comparison of the two 80% treatments. Overall, decreasing SID Lys decreased (linear, P &lt; 0.01) ADG and final body weight (BW) and tended (P &lt; 0.10) to decrease gain:feed ratio (G:F). Reducing the Trp:Lys ratio decreased (P = 0.014) ADG and final BW compared to pigs fed diets with 80% SID Lys with higher SID Trp:Lys. In summary, decreasing SID Lys reduced ADG and feeding a reduced SID Trp:Lys ratio resulted in a further decrease in ADG of grow-finish pigs.

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245 Evaluation of Cellulose in Diets with and Without Added Zno on Nursery Pig Performance

A total of 1,296 pigs (PIC L337×1050; initially 4.8 kg) were used in a 42-d study to evaluate cellulose in diets with and without pharmacological levels of Zn on nursery pig performance. Our hypothesis was that added fiber (cellulose) may provide more benefit in diets without ZnO. Pens were assigned to 1 of 4 dietary treatments in a RCBD by BW with 27 pigs/pen and 12 pens/treatment. Dietary treatments were arranged in a 2×2 factorial with main effects of cellulose (0 vs 1%; J. Rettenmaier USA, Schoolcraft, MI) and Zn (200 vs. 3,000 mg/kg in phase 1 and 110 vs. 2,000 mg/kg in phase 2). Treatment diets were formulated in two phases fed from d 0 to 7 and 7 to 21 with a common diet fed from d 21 to 42 post-weaning. Pig weights and feed disappearance were collected weekly to determine ADG, ADFI, and G:F. On d 16 or 17, fecal samples were collected from 3 pigs/pen to determine fecal DM, and all pens were visually evaluated for fecal consistency. There were no Zn×cellulose interactions. For the experimental and overall period, pigs fed diets containing added Zn had increased (P &lt; 0.001) ADG, ADFI, G:F and BW while those that were fed cellulose had decreased (P &lt; 0.05) ADG. For fecal dry matter, there was no evidence for difference (P &gt;0.10) between any of the treatments but those fed added ZnO had visually firmer feces as evidenced by lower (P &lt; 0.001) fecal scores. When fed a common diet from d 21 to 42, pigs previously fed added ZnO had increased (P &lt; 0.001) ADG (502 vs. 523 g/d) and ADFI (697 vs. 734 g/d). In conclusion, there were no interactive effects between added cellulose and Zn; however, cellulose reduced ADG while the inclusion of pharmacological levels of Zn improved all growth criteria.

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