Compensatory gain based on lysine level in finishing pigs after being fed lysine deficient 97% corn diets for 3 or 6 wk

The objective of this experiment was to evaluate increasing the concentration of lysine on the compensatory gain of finishing pigs during their recovery period after being fed a 97% corn holding diet for 3 or 6 wk. One thousand six hundred and eighty pigs with a starting body weight of 73.5 ± 2.2 kg were blocked by starting body weight and assigned to a nested arrangement. Twenty replicates of seven treatments were comprised of two restriction lengths [3 weeks (3 wk) vs. 6 weeks (6 wk)], and three lysine concentrations during recovery (Lys:ME same as control:100; control + 10%: 110; control + 20%: 120) plus one control (CONT) that remained nutrient unrestricted. Pen weight and feed intake were recorded on days 0, 21, 41, and at marketing. Whole pens were marketed when the pen average met 130 kg and carcass measurements were collected. Data were analyzed by pen with the fixed effects of restriction length and lysine within restriction length. Nutrient restriction lowered (P < 0.01) average daily gain (ADG) compared to control, with 1.2, 0.4, and 0.5 kg for control, 3 wk, and 6 wk treatments, respectively. Restricted pigs showed decreased feed intake while restricted. After the respective restriction period, pigs were allowed a recovery diet until market. Previously restricted pigs had 16.7% and 27.3% greater (P < 0.01) ADG over control pigs for 3 and 6 wk treatments, respectively, in the first 3-wk of recovery. The lysine concentration in the recovery diet impacted (P < 0.01) the ADG with pigs allowed the highest lysine concentration having a 10% greater ADG than pigs fed the lower Lys:ME concentrations, for both restriction treatments. The increase in ADG was not paralleled by an increase in feed intake over control, thus, there was an improvement (P < 0.01) in gain to feed ratio in the recovery period. Control pigs reached market weight (131.5 kg) on experiment day 49 while pigs fed corn diets for 3 wk or 6 wk were slower to market (57 and 69 days, respectively; P < 0.01). Restricted pigs had greater backfat (CONT: 1.47, 3 wk: 1.55, 6 wk: 1.65 cm; P < 0.01), and decreased loin depth (CONT: 7.32, 3 wk: 7.03, 6 wk: 6.61 cm, P < 0.02) which was also impacted (P < 0.01) by lysine concentration. In conclusion, the use of restrictive diets reduced ADG and increased days to market. The use of recovery diets in which the Lys:ME ratio was greater than control pigs, resulted in increased compensatory growth.

The evaluation of the supplementation of vitamin A, beta-carotene, and oxidized beta-carotene in prepubertal gilts

Finishing pigs (N = 224; 28.66 ± 1.90 kg bodyweight) were randomly assigned across 56 pens of either four barrows or gilts, and assigned to one of four diets: control (7,656 IU vitamin A/kg), control supplemented with vitamin A (4.36 ppm, Rovimix A 1000, DSM, Parsippany, NJ, US), control supplemented with beta-carotene (163.28 ppm, Rovimix β-Carotene 10%, DSM, Parsippany, NJ, US), or control supplemented with oxidized beta-carotene (40 ppm; 10% active ingredient, Avivagen, Ottawa, ON, Canada). Pigs and feeder weights were obtained at the start of the study (d 0), and end of each phase (d 21, 42, and 63). A subset of gilts had a blood sample taken via jugular venipuncture on d 0, a blood sample and vaccinations of Lawsonia intracellularis and porcine circovirus type 2 on d 18, a blood sample and booster vaccination of porcine circovirus type 2 on d 39, a blood sample on day 60, and a final blood sample on day 63. Gilts were euthanized at the end of the study to obtain a liver (entire right lobe) and a jejunum sample (15.24 cm at 10% of length). Additionally, the second and fourth right anterior mammary were collected to assess anterior mammary tissues. Data were analyzed in SAS 9.4 (Statistical Analysis System, Cary, NC) via GLIMMIX procedure. Oxidized beta-carotene supplementation increased (P = 0.02) average daily gain across phases over vitamin A supplementation, although there were no differences (P = 0.18) in the body weight of pigs. There was no effect (P > 0.05) of diet on plasma or hepatic retinol, IgG or IgM levels, or immune cell presence in developing mammary tissue. Supplemented vitamin A tended (P = 0.05) to increase the mRNA abundance of retinol binding protein in the jejunum, but other mRNA abundance for genes (alcohol dehydrogenase class 1, lecithin retinol acyltransferase phosphatidylcholine-retinol O-acyltransferase, and beta-carotene oxygenase 1) were not affected (P > 0.05) by dietary treatments. A diet by time interaction (P = 0.04) was noted for the circovirus sample-to-positive ratio, where vitamin A supplementation had the best ratio compared to other diets. Analyzed titer levels for the circovirus vaccine had an interaction (P < 0.01) for diet by time, where vitamin A supplementation had the highest titer at the end of the study. Thus, pigs supplemented with oxidized beta-carotene had an improved average daily gain over vitamin A supplemented pigs, but pigs supplemented with vitamin A seemed to have an improved immune status.

Evaluation of oxidized beta-carotene on sow and piglet immune systems, sow reproductive performance, and piglet growth

This study aimed to determine if supplementation of oxidized-beta carotene (OxC-Beta) improved sow reproductive performance, litter growth performance, vitamin A status, and ability to alter immune cells abundance in sows and piglets, subsequent litter performance, and nursery growth performance. At approximately d 60 of gestation and through the lactation period, 194 sows (blocked by parity) were assigned to a common gestation diet or the common diet supplemented with 80 ppm oxidized beta-carotene (OxC-Beta, Aviagen, Ottawa, ON, Canada). A subset of sows (n = 54 per treatment) were sampled for blood and body weight recorded at the beginning of the study, farrowing, and weaning. A blood sample was taken from a subset of piglets at birth and weaning, and all piglet weights were recorded. Blood was analyzed for vitamin A as retinol concentrations and immunoglobulin G (IgG) and immunoglobulin M (IgG) levels were assessed from the sow's blood. Twelve pigs (n = 6 per treatment) were euthanized at birth and weaning. The livers were collected and analyzed for the Kupffer cell phagocytic activity through flow cytometry. Whole blood was analyzed via flow cytometry for cluster of differentiation (CD335, CD8, and CD4). Colostrum during farrowing and milk at weaning were analyzed for IgG and IgA concentrations. Data were analyzed via SAS 9.4 using MIXED and frequency procedures where appropriate. No differences (P > 0.05) between dietary treatments were observed in sow reproductive performance, feed intake, wean to estrus interval, or piglet growth performance. No differences (P > 0.05) were observed in the plasma or liver for vitamin A. No differences (P > 0.05) were observed in the composition of the colostrum or milk. No immunological differences (P > 0.05) were observed in the piglets' liver and blood or sow antibodies in colostrum and milk. The supplementation of OxC-Beta did (P < 0.05) decrease IgM and tended (P < 0.10) to decrease IgG in sow plasma. No differences (P > 0.05) were observed in the reproductive performance of subsequent litter information from the sows. Gilt litter weaning weight and feed intake were reduced (P < 0.05) compared to sow performance. In conclusion, the supplementation of OxC-Beta at 80 ppm from d 60 of gestation through lactation does not affect the reproductive performance of sows, litter growth performance, vitamin A status, piglet immune status, and antibodies or composition in colostrum and milk.

Evaluation of branched-chain amino acid interactions in 10 to 20 kg nursery pigs using a central composite design

Two groups of 240 pigs (PIC 337 × 1050, PIC Genus, Hendersonville, TN) were used to investigate the interactions between leucine, isoleucine, and valine on the growth performance of approximately 10 to 20 kg nursery pigs. At weaning, pigs were placed into 40 pens with three barrows and three gilts per pen and fed a common diet for 3 wk. On day 21 postweaning, pens were randomly assigned to 1 of 15 dietary treatments in a central composite design. Diets were formulated to various levels of standardized ileal digestible (SID) Leu, Ile, and Val by supplementing L-Leu, L-Ile, and L-Val. Levels of the branched-chain amino acids, expressed as ratios to SID Lys, ranged from 98% to 180%, 46% to 64%, and 51% to 78% for Leu, Ile, and Val, respectively. Diets were formulated to be iso-Lys, isonitrogenous, and isocaloric. Pig weights and feed intake were measured for the 21-d experiment to calculate average daily gain (ADG), average daily feed intake (ADFI), and feed efficiency (G:F). Growth performance data were analyzed using the lm() function in R version 4.2.2 (R Core Team, 2022). The second-order polynomial model included the linear and quadratic effects of Leu, Ile, and Val, their three two-way interactions, and initial body weight. Pen was the experimental unit, and parameters were considered significant at P ≤ 0.10. A linear and quadratic effect of Val was observed for ADG and G:F (P < 0.001). There was an interaction between Leu and Ile for ADG (P = 0.069) and G:F (P = 0.032), where increasing Leu and decreasing Ile, and the inverse, improved ADG and G:F. However, growth and efficiency were negatively impacted as Leu and Ile increased in the diet. There was an interaction between Leu and Val for ADFI (P = 0.060), where Leu negatively impacted feed intake at low levels of Val but had little impact as Val increased above NRC (2012) recommendations. In conclusion, Val linearly and quadratically impacted ADG and G:F, regardless of Leu and Ile levels in the diet, while ADG and G:F were reduced with high levels of Leu and Ile, which was resolved as either Leu or Ile was reduced. Furthermore, ADFI was negatively impacted by increased Leu when Val was below NRC (2012) recommendations but was not affected by Leu at higher Val levels. Together, the results of this experiment emphasize the complexity of amino acid metabolism in nursery pigs and the importance of considering potential interactions among amino acids when conducting requirement studies.

The effects of dietary essential fatty acid ratios and linoleic acid level in grow-finish pigs

The objective of this study was to investigate the effects of dietary linoleic acid level and the ratio of linoleic acid:linolenic acid (LA:ALA) on the growth performance, expression of genes associated with lipid metabolism, and inflammatory status of grow-finish pigs. A total of 300 growing pigs (body weight [BW] = 41.1 ± 6.3 kg) were randomly assigned to either a high (30 g/kg; HLA) or low (15 g/kg; LLA) dietary linoleic acid level with a high (23:1; HR), moderate (13:1; MR) or low (4:1; LR) dietary LA:ALA in a 2 × 3 factorial design. Diets were fed across three 28-d phases and were balanced for dietary metabolizable energy. Pigs were housed five pigs per pen in single-sex pens. Blood samples were collected on days 0, 21, 42, and 84, and synovial fluid was collected from the hock joint on days 0 and 84 for inflammatory marker analysis. Data were analyzed as repeated measures using PROC MIXED (SAS 9.4) with initial BW as a covariate, pen as the experimental unit, and LA level, LA:ALA, sex, phases, and their interactions as fixed effects. Compared to HLA, LLA pigs tended to have increased BW at days 56 and 84 (P = 0.088). There was no effect of LA × LA:ALA for growth performance. For the overall days 0 to 84 growth period, pigs fed HR had increased ADG compared to MR, with pigs receiving LR performing intermediate of MR and HR. Gilts receiving HR diets had increased day 84 BW compared to gilts receiving the low and moderate LA:ALA (P = 0.006), which was a result of improved overall days 0 to 84 ADG compared to gilts receiving the MR diets (P = 0.023). Barrows fed LR had improved BW on day 56 compared to MR and HR and higher final BW compared to HR, with MR performing intermediately (P = 0.006). This was a result of greater days 0 to 84 ADG (P = 0.023). Overall, C-reactive protein (CRP), tumor necrosis factor-α (TNFα), and interleukin-6 were reduced in the plasma of pigs over time (P ≤ 0.037). Across all treatments, CRP and TNFα were reduced in the hock and carpus synovial fluid on day 84 vs. day 0 (P ≤ 0.049). In conclusion, LA:ALA ratios utilized in this study can be fed at varying linoleic acid levels without impacting growth or inflammation. Additionally, LA:ALA ratios can differentially impact the growth of gilts and barrows.

The effects of dietary essential fatty acid ratios and energy level on growth performance, lipid metabolism, and inflammation in grow-finish pigs

The objective of this study was to investigate the effects of dietary metabolizable energy (ME) level and the ratio of linoleic acid:α-linolenic acid (LA:ALA) on the growth performance, lipid metabolism, circulatory and joint inflammatory status, and synovial fluid proteome of grow-finish pigs. A total of 224 pigs (BW = 41.5 ± 6.1 kg; PIC Genus 337 × 1050, Hendersonville, TN) were randomly assigned to either a high (3.55 Mcal/kg; HE) or low (3.29 Mcal/kg; LE) ME dietary treatment with a high (23:1) or low (12:1) LA:ALA in a 2 × 2 factorial arrangement. Diets were fed across three 28-d phases. Pigs were housed either four barrows or four gilts per pen. Blood samples were collected on days 0, 21, 42, and 84. Synovial fluid was collected from the hock and carpus joints on days 0 and 84. Liver and adipose tissue samples were collected on day 84. Data were analyzed as repeated measures using PROC MIXED (SAS 9.4) with pen as the experimental unit and energy level, essential fatty acid ratio, sex, phase, and their interactions as fixed effects. Compared to LE, HE increased days 28, 56, and 84 body weight (BW; P = 0.005). For the overall period, HE increased average daily gain (ADG) compared to LE (P < 0.001) and improved feed efficiency (P = 0.001), while LE increased feed intake compared to HE (P < 0.001). Gilts receiving diets with low LA:ALA had similar final BW to barrows receiving a low LA:ALA at days 28, 56, and 84 (P = 0.024), resulting from improved overall days 0-84 ADG compared to gilts receiving the high LA:ALA (P = 0.031). In the liver, HE decreased the mRNA abundance of acetyl CoA carboxylase (ACACA; P = 0.004), cluster of differentiation 36 (P = 0.034), and tended to decrease fatty acid synthase (FASN; P = 0.056). In adipose tissue, HE decreased ACACA (P = 0.001) and FASN (P = 0.017). Plasma inflammatory markers C-reactive protein (CRP) and tumor necrosis factor-α (TNFα) were reduced on day 84 compared to day 0 (P ≤ 0.014). In the hock and carpus synovial fluid, LE tended to reduce CRP and TNFα (P ≤ 0.096). Hock and carpus synovial fluid CRP were also reduced on day 84 compared to day 0 (P = 0.001). Age of the pig impacted serum and hock synovial fluid protein abundance, but not energy level, LA:ALA, or their interactions (P < 0.05). To conclude, the high and low LA:ALA ratios utilized in this study can be fed at varying energy levels without impacting growth. Additionally, LA:ALA ratios can differentially impact the growth of barrows and gilts.

The impact of floor space allowance and dietary energy level on finishing pigs, from 65 to 120 kg, on growth performance

The objective of this experiment was to evaluate the impact of lowering floor space allowance in finishing hogs from 65 to 120 kg when fed high- vs. low-energy diets on growth performance. Eighty-eight mixed-sex pens with 24 ± 1 pigs per pen were randomly assigned by weight in a complete block design to one of eight treatments in a 2 × 4 factorial arrangement with two energy levels: low (LE, 3267 ± 15 kcal/kg) vs. high (HE, 3389 ± 15 kcal/kg) accomplished through fat inclusion; and four floor space allowances: 0.6, 0.63, 0.65, and 0.67 m²/pig. Assigned floor space was accomplished by moveable gates in the rear of the pen which were adjusted at each pig removal until the marketing phase. Pen weight was measured at days 0, 29, and 48, with feed disappearance measured at days 29 and 48 to calculate average daily gain (ADG), average daily feed intake (ADFI), and gain-to-feed ratio (GF). Data were analyzed by pen (SAS 9.4, Cary, NC), as repeated measures, with the fixed effects of floor space allowance, dietary energy level, and the interaction between floor space allowance and energy level. For the overall experiment, decreased floor space had no effect (P > 0.1) on ADG, ADFI, or GF. Energy had a significant effect (P < 0.01) on ADFI (3.17 vs. 3.12 kg for LE and HE, respectively) and GF (0.35 and 0.36 for LE and HE, respectively), and tended to impact (P = 0.08) ADG (1.12 vs. 1.13 kg, for LE and HE, respectively). In conclusion, reducing space allowance from 0.67 m² down to 0.6 m² did not affect the growth performance of pigs from 65 to 120 kg. Pigs fed LE consumed more than the HE diets but had generally similar growth and no difference in body weight.

The impact of essential fatty acid ratios and unsaturated to saturated fat ratio on growth performance of grow-finish pigs and estrus detection of gilts

The objective of this study was to investigate the effects of dietary unsaturated and saturated fat ratio (U:S) and the ratio of linoleic and linolenic acid (LA:ALA) on the growth performance of grow-finish pigs and estrus detection of gilts. A total of 240 pigs with initial body weight (BW) 54.4 ± 5.5 kg were randomly assigned to a high (>1.8; HUS) or low (<1.0; LUS) U:S in combination with a high (20:1), moderate (12:1), or low (4:1) LA:ALA in a 3 × 2 factorial arrangement. Dietary ratios were achieved using blends of choice white grease, beef tallow, corn oil, flaxseed oil, or palm kernel oil. Diets were fed across three phases and balanced for energy and LA. Pigs were housed across 60 pens with either four gilts or four barrows per pen. On day 49, 1 gilt per pen was moved to individual housing at approximately 154 d of age for evaluation of reproductive characteristics. Data were analyzed as repeated measures using PROC MIXED (SAS 9.4; SAS Inst., Cary, NC) with pen as the experimental unit and U:S, LA:ALA, sex, and their interactions as fixed effects. Initial BW was fit as a covariate. Within each phase, there were no differences in BW, daily gain (ADG), feed intake (ADFI), or feed efficiency (G:F) for U:S, LA:ALA, or their interaction when averaged across sex (P ≥0.128). Gilt feed efficiency was improved during the second phase compared to barrows; however, feed efficiency was not different between barrows and gilts during the first and third phases; resulting in a similar feed efficiency between sexes for the overall period (P = 0.523). Compared to HUS, gilts receiving LUS had higher ADFI overall (P = 0.018), which translated into improved G:F for HUS gilts (P = 0.011). Overall, gilts receiving the 20:1 diet tended to have improved G:F compared to 12:1 (P = 0.086). ADG was improved in pigs fed diets formulated with unsaturated fat sources to a 20:1 LA:ALA, regardless of sex. Detection of first estrus by 235 d of age in gilts was not impacted by U:S or LA:ALA (P ≥ 0.356). In conclusion, feeding differing dietary U:S and LA:ALA ratios impacts growth of growing pigs, particularly improving feed efficiency of gilts fed diets with unsaturated fat sources or a 20:1 LA:ALA. Further investigation into the physiological mechanisms differentially affecting gilt growth when fed varying dietary LA:ALA is warranted to understand the impact on reproductive outcomes.

Effect of benzoic acid with or without a Bacillus-based direct-fed microbial on the performance and carcass merit of grow-finish pigs

Two hundred and forty barrows and gilts (DNA 600 × 241, DNA Genetics, Columbus, NE) with an initial body weight (BW) of 35.5 ± 4.2 kg were sorted into split-sex pens, blocked by initial body weight, and randomly allocated to one of three dietary treatments with eight pigs per pen and ten pens per treatment. Dietary treatments included a standard diet (CON), CON plus 0.3% benzoic acid (BA; VevoVitall, DSM Nutritional Products, Parsippany, NJ), and CON plus 0.3% BA and 0.025% Bacillus-based direct-fed microbial (BA+DFM; PureGro, DSM Nutritional Products, Parsippany, NJ). The experimental diets were fed in four feeding phases. Pigs were weighed and feed intake measured at the beginning and end of each phase for the calculation of average daily gain (ADG), average daily feed intake (ADFI), and feed efficiency (G:F). In addition, ultra-sound was utilized at the conclusion of the trial on day 81 for measurements of backfat and loin eye area. Data were analyzed as repeated measures in SAS 9.4 (SAS Institute, Cary, NC) with fixed effects of treatment, phase, sex, and block included in the model. Pen was the experimental unit, and results were considered significant if P ≤ 0.05 and a tendency if 0.05 < P ≤ 0.10. Overall, pigs fed BA had increased ADFI compared to pigs fed CON (2.88 vs. 2.75 kg, P = 0.015), while pigs fed BA + DFM had similar ADFI compared to pigs fed CON or BA (P ≥ 0.279). There was a tendency for an effect of dietary treatment on ADG (P = 0.063), where pigs fed BA tended to grow faster than pigs fed CON (1.11 vs. 1.08 kg, P = 0.051); however, there were no differences in feed efficiency between treatments (P = 0.450). Additionally, there was no evidence of an effect of dietary treatment on pig BF or LEA (P ≥ 0.334). In conclusion, supplementing 0.3% benzoic acid to grow-finish pigs stimulated feed intake, but did not affect efficiency, or carcass merit.

The effect of benzoic acid with or without a direct-fed microbial on the nutrient metabolism and gas emissions of growing pigs

Twenty-four gilts (PIC 337 × 1050, PIC Genus, Hendersonville, TN) with an initial body weight (BW) of 33.09 ± 1.33 kg were used to investigate the effects of benzoic acid (BA) and a Bacillus-based direct-fed microbial (DFM) on the nutrient metabolism and manure gas emissions of growing pigs. Pigs were blocked by BW, placed into metabolism stalls, and randomly assigned to one of four dietary treatments: basal control (PC), low nitrogen (NC), PC plus 0.3% BA (PC+BA; VevoVitall, DSM Nutritional Products), and PC plus 0.3% BA and 0.025% DFM (PC+BA+DFM; PureGro, DSM Nutritional Products). Pigs were fed a common diet from day 0 to 14, and the experimental diets were fed in two phases (day 14 to 28 and day 28 to 53). The experiment consisted of four collection periods, with each period subdivided into two subperiods to collect samples for gas emissions and nutrient balance. Firstly, manure samples were collected for 72 h. Twice daily, urine and feces were weighed, and urine pH was measured. After each period, manure was subsampled and taken to the lab to measure gas emissions. Secondly, urine and feces were quantitatively collected for 96 h to allow for measurement of nutrient digestibility (ATTD) and retention. Data were analyzed as repeated measures in SAS 9.4 (SAS Inst., Cary, NC) with fixed effects of treatment, collection period, and block. Pig was the experimental unit, and results were considered significant at P ≤ 0.05 and a tendency at 0.05 < P ≤ 0.10. Pigs fed PC+BA had the greatest ADG compared to pigs fed NC (P = 0.016), with intermediate ADG for pigs fed PC or PC+BA+DFM (P ≥ 0.148). The ATTD of dry matter, gross energy, P, and N did not differ between treatments (P ≥ 0.093). However, the ATTD of Ca was reduced in pigs fed PC+BA+DFM compared to pigs fed PC+BA (P = 0.012). Pigs fed PC+BA or NC excreted less urinary N compared to PC and PC+BA+DFM (P ≤ 0.034), which contributed to greater nitrogen retention in PC+BA compared to PC (P = 0.016). Furthermore, decreased manure pH from pigs fed PC+BA or NC resulted in lower ammonia (NH₃) emissions compared to pigs fed PC+BA+DFM or PC. There was no effect of dietary treatment on manure hydrogen sulfide, methane, or carbon dioxide emissions. In conclusion, supplementing 0.3% BA improved N retention and reduced manure pH and NH₃ emissions, similar to feeding pigs low N, but improved the ADG of pigs when compared to feeding a low N diet.

The validation of the existence of the entero-mammary pathway and the assessment of the differences of the pathway between first and third parity sows

Forty sows (PIC Camborough 1050) from a single farm were randomly selected at 112 days of gestation to evaluate if gut bacteria transverse the blood system of the sow to deposit gut microbiota into colostrum for piglet gut inoculation via the entero-mammary pathway. Fourteen first-parity gilts and twenty third-parity sows were used for the study. At the time of farrowing, colostrum, fecal samples and blood samples were collected to evaluate the presence of bacteria in each sample. Colostrum and blood samples were processed via centrifugation to separate the immune cell fraction. Total deoxyribonucleic acid (DNA) was extracted from fecal, colostrum and white blood cell fractions. 16S ribosomal ribonucleic acid (rRNA) gene amplicon sequencing was conducted at the Iowa State University DNA Facility (Ames, IA) to further characterize the bacterial and archaeal taxa present within each sample. Data were analyzed using Mothur and using R v4.0.3 (R Core Team, 2020). The experimental unit was the sow. Tables were generated to demonstrate the relative abundances of bacteria and archaea present in each type of sample and also identify organisms differentially abundant between sample types. Firmicutes was the most abundant phylum in colostrum and fecal samples and Tenericutes had the greatest abundance in blood comparative to other phyla. Further evaluation of the classification of bacteria present demonstrated that a few genera of bacteria are present in all three samples. Clostridum_sensu_stricto 1 was present in high relative abundance in colostrum and in moderate abundance in the feces while also being present within the blood. Other genera present in all three sample types includes Ruminococcus and Mycoplasma. In conclusion, the data suggest that there are bacteria present in all three locations of the sow at the time of farrowing and that first parity sows have different microbial populations than third parity sows.

183 Circulating Biomarkers and Leukocyte Profiles in Agalactic Sows

Agalactia is characterized by reduced milk production after farrowing, resulting in economic losses due to increased piglet mortality. Although a variety of management factors have been associated with the etiology of agalactia, a specific causative mechanism has not been identified. Since clinical signs of agalactia develop in the days following farrowing, the objective of the current study was to determine if periparturient immune cell profiles and circulating biomarkers are predictive of future agalactia. Blood samples and litter weights were collected from sows (n = 374) within 24-36 hours after farrowing (timepoint 1) and sows were subsequently monitored for symptoms of agalactia and gaunt piglets. When a sow was designated as agalactic (n = 36) blood samples and litter weights were collected again (timepoint 2) and also from a parity matched healthy control sow (n = 46) of the same day of lactation. Agalactia diagnosis occurred on average 9.25 ± 2.67 d after farrowing. Average daily gain (ADG) of piglets from agalactic sows was 55% less (P &lt; 0.01) than ADG of piglets from controls. Additionally, piglet mortality was substantially greater (P &lt; 0.01) in litters from agalactic sows compared with controls. Circulating immune cells and metabolites were determined. Cholesterol, blood urea nitrogen, and globulin were increased 22.3, 17.8, and 34.1%, respectively, in agalactic compared with control sows at timepoint 2 (P ≤ 0.01). Aspartate aminotransferase tended to increase in agalactic sows compared with control at timepoint 1 (P = 0.08). No differences in immune cell profiles were observed between agalactic and control sows at either timepoint (P ≥ 0.14). Collectively, these data suggest metabolic changes are occurring in sows experiencing agalactia compared with healthy herd mates, but that very few of the metrics analyzed at timepoint 1 predicted future agalactia. This project was supported by Zoetis; TI-07023.

PSVII-8 The Impact of Dietary Essential Fatty Acids Ratios and Unsaturated:Saturated Ratio on Growth Performance of Grow-Finish Pigs

The objective was to investigate the effects of dietary unsaturated:saturated fat ratio (U:S) and the fatty acid ratio of linoleic acid:linolenic acid (n6:n3) on growth performance of grow-finish pigs. A total of 240 pigs with initial body weight (BW) 54.4±5.5kg were randomly assigned to a high (&gt; 1.8; HUS) or low (&lt; 1.0; LUS) U:S ratio with a high (20:1), moderate (12:1) or low (4:1) n6:n3 in a 3×2 factorial design (n = 10). Diets were fed across 3 phases and balanced for energy and linoleic acid. Pigs were housed 4 pigs per pen and separated by sex. Data were analyzed as repeated measures using SAS (9.4) with pen as the experimental unit and U:S ratio, n6:n3 ratio, sex, and their interactions as fixed effects. Initial BW was fit as a covariate. Within each phase, there were no differences in BW, daily gain (ADG), feed intake (ADFI) or feed efficiency (G:F) for U:S, n6:n3, or their interaction (P &gt; 0.10). For the overall period, there was a U:S×n6:n3 interaction for ADG (P &lt; 0.05) with pigs receiving LUS×12:1 (1.19kg/d) having increased ADG compared with pigs receiving HUS×12:1 (1.12kg/d). There was no effect of sex (P &gt; 0.10) for G:F within each phase; however, overall, gilts had improved G:F compared with barrows (P &lt; 0.05). Compared with HUS, gilts receiving LUS had greater ADFI overall (P &lt; 0.05; 2.84 vs. 2.70kg), which translated into improved G:F for HUS gilts (P &lt; 0.05; 0.40 vs 0.39). Overall, gilts receiving the 20:1 diet tended to have improved G:F compared with 12:1 (P &lt; 0.10; 0.40 vs 0.39). The dietary U:S ratio impacted overall ADG of pigs fed the 12:1 ratio when averaged across sex; however, there was no significant sex × U:S × n6:n3 interaction. A low U:S ratio can also increase feed intake of gilts; however, this did not result in improved ADG.

185 The Validation of the Existence of the Entero-Mammary Pathway and the Assessment of the Differences of the Pathway Between Gilts and Sows

Forty sows (PIC Camborough 1050) from a single farm were randomly selected at 112 d of gestation to evaluate if gut bacteria transverse the blood system of the sow to deposit gut microbiota into colostrum for piglet gut inoculation via the entero-mammary pathway. Fourteen first-parity gilts and twenty third-parity sows were used for the study. At the time of farrowing, colostrum, fecal samples and blood samples were collected to evaluate the presence of bacteria in each sample. Colostrum and blood samples were processed via centrifugation to separate the immune cell fraction. Total deoxyribonucleic acid (DNA) was extracted from fecal, colostrum and white blood cell fractions. 16S ribosomal ribonucleic acid (rRNA) gene amplicon sequencing was conducted at the Iowa State University DNA Facility (Ames, IA) to further characterize the bacterial and archaeal taxa present within each sample. Data were analyzed using Mothur and using R v4.0.3 (R Core Team, 2020). The experimental unit was the female. Tables were generated to demonstrate the relative abundances of bacteria and archaea present in each type of sample and also identify organisms differentially abundant between sample types. Firmicutes was the most abundant phylum in colostrum and fecal samples and Tenericutes had the greatest abundance in blood comparative to other phyla. Further evaluation of the classification of bacteria present demonstrated that a few genera of bacteria are present in all 3 samples. Clostridum_sensu_stricto 1 was present in high relative abundance in colostrum and in moderate abundance in the feces while also being present within the blood. Other genera present in all 3 sample types includes Ruminococcus and Mycoplasma. In conclusion, the data suggests that there are bacteria present in all 3 locations of the sow at the time of farrowing and that gilts have different microbial populations than sows.

105 The Impact of Lowering Floor Space Allowance and Dietary Energy Level on Finishing Pigs, from 65 Kg to Market, on Growth Performance

The objective of this experiment was to evaluate the impact of reducing floor space allowance in finishing hogs with a starting body weight (BW) of 65 ± 2 kg when fed high versus low energy diets on growth performance. Mixed-sex pens (n=88) with 24 ± 1 pigs per pen were blocked by starting BW to a randomized complete block design with eight treatments. These eight treatments formed a 2 x 4 factorial arrangement with 2 energy levels: low (LE, 3270 ±19 kcal/kg ME) vs. high (HE, 3392 ±19 kcal/kg ME) accomplished through fat inclusion; and 4 floor space allowances: 0.60, 0.63, 0.65, 0.67 m2 per pig. Assigned floor space was adjusted by moveable gates in the rear of the pen, which were corrected at each pig removal until the marketing phase. Pen weight and feed disappearance were measured for 2 phases at d 0, 29, and 48 to calculate average daily gain (ADG), average daily feed intake (ADFI), and gain to feed ratio (GF). Data were analyzed by pen (SAS 9.4, Cary, NC) with the repeated measure of phase, and the fixed effects of floor space allowance, dietary energy, and the interaction between. For the overall trial, decreased floor space had no effect (P &gt; 0.1) on ADG, ADFI, or GF (0.36, for all). Energy had a significant effect (P &lt; 0.01) on ADFI (3.17 vs 3.12 kg for LE and HE, respectively) and GF (0.35 and 0.36 for LE and HE, respectively), and tended to impact ADG (1.12 vs 1.13 kg, for LE and HE, respectively; P = 0.08). In conclusion, lowering floor space allowance from 0.67 m2 down to 0.60 m2 did not affect the growth performance of pigs starting at 65 kg. Pigs fed HE diets had 2.86% better GF compared with pigs fed LE diets, however had similar growth and body weight.

60 Evaluation of Fat Sources and Inclusion Rate with the Supplementation of Vitamin A or Beta-Carotene in Nursery Pigs

The objective of this study was to evaluate the effect of fat inclusion level and fat source with supplementation of either vitamin A (ROVIMIX A 1000; DSM; NJ) or beta-carotene (ROVIMIX β-Carotene 10%; DSM; NJ) on growth performance and vitamin A, D, and E status of nursery pigs (n = 216; 5.81 ± 0.92 kg). The study was a 3 X 2 factorial with main effects being no fat, 3% saturated fat (choice white grease), or 3% unsaturated fat (soybean oil) and supplemented with either 4 mg/kg vitamin A or 40 mg/kg beta-carotene. Pigs were randomly assigned to mixed sex pens and dietary treatments. Blood samples from 1 pig per pen were taken at the beginning and end of the study to evaluate vitamin status. All data were analyzed using PROC GLIMMIX in SAS 9.4 with pen as the experimental unit. Repeated measures were utilized for growth performance as well as vitamin status. There were no significant differences (P &gt; 0.05) for average daily feed intake, average daily gain, gain to feed ratio, and body weight throughout the study. There were no significant differences (P &gt; 0.05) in the vitamin status at either the start or end of the study, although there is a significant time difference (P &lt; 0.05) for each of the vitamins. There was a three-factor interaction (P &lt; 0.05) for diet X sex X time for vitamin D. Vitamin A and D values were greater at the end of the study than at the beginning, but vitamin E values were less at the end of the study than at the beginning. In general, fat inclusion level, a type, or type of vitamin A source supplementation did not affect the growth performance nor the status of vitamin A, D, or E in the nursery pig.

161 The Impact of Sex, Birth Weight, and Nutrient Density on the Growth Restriction and Compensatory Gain of Finishing Hogs After a Three- or Six-Week Period of Nutrient Restriction

The objective of this analysis was to investigate the effect of pig phenotype on growth restriction and compensatory ability after receiving a nutrient-deficient (97% corn) diet for 3 or 6 weeks. Sixteen hundred and sixty mixed-sex pigs (DNA Genetics, Columbus, NE) were tagged with radio frequency identification tags (LeeO, Prairie Systems, Spencer, IA) at birth with litter information and body weight (BW) measured at birth, weaning, and the end of the nursery phase. At a starting BW of 73.5 ± 2.2 kg, pigs were blocked by BW to 140 pens and assigned to a 2:3:1 factorial. The seven treatments were comprised of a combination of 2 restriction lengths (3 weeks vs. 6 weeks) and 3 lysine inclusion levels at re-alimentation (Lys:ME of 100%, 110%, or 120% of the genetic margin over feed curve), and a control that remained nutrient unrestricted. Individual BW was measured on trial d 0, 21, 41, and market to calculate individual average daily gain (ADG) for each phase. Percent change in ADG between each phase was calculated using the previous ADG of each pig. Observational analysis was conducted in SAS 9.4 (Cary, NC) with pig as the observational unit. When fed the restrictive diet, gilts had a greater reduction in ADG (P &lt; 0.01) than barrows (64 vs. 59 % decrease in ADG from previous period). Furthermore, pigs with lower birth weight, thus lighter starting trial weight, had a greater decrease (P &lt; 0.01) in growth in response to nutrient restriction. Validating the biological requirements of finishing pigs, animals with a greater lysine requirement, gilts, and lighter weight pigs had a more severe reduction in growth than those with a decreased lysine requirement.

PSVII-2 Effects of Oxidized Beta-Carotene on Sow Reproduction and Piglet Growth Performance

As reproductive performance of sows in the commercial U.S. sow herd continues to improve, advancing the impact of gestation and lactation diet supplementation is critical. Beginning on d 60 of gestation through lactation, sows (blocked by parity) were assigned to a standard gestation diet (n = 88), or the standard diet supplemented with 80 ppm OxC-beta (n = 90) provided by Avivagen (Ottawa, ON, Canada) to determine if the supplementation of OxC-beta improves sow reproductive performance, litter growth performance, and alters the abundance of immune cells in sows and piglets. Blood samples were taken from a subset of sows (n = 54 per treatment) at the start of the study, at farrowing, and at weaning; and also, on a subset of piglets at birth and weaning. Also, at birth and weaning, 12 pigs (n = 6 per treatment) were euthanized, and livers were collected and subjected to flow cytometry to analyze phagocytic activity of the Kupfer cells. CD335, CD8, and CD4 populations within whole blood were assessed via flow cytometry. Colostrum at farrowing and milk at weaning were collected for analysis of IgG and IgA. Data were analyzed via SAS 9.4 using PROC GLIMMIX. No differences (P &gt; 0.05) between dietary treatments were observed in sow reproductive performance, sow feed intake, wean to estrus interval, or piglet growth performance. No differences (P &gt; 0.05) were observed for vitamin A in the plasma or liver. No immune differences (P &gt; 0.05) were observed in the piglet’s liver and blood nor sow antibodies in colostrum and milk. Subsequent litter information was obtained from the sows, and no differences (P &gt; 0.05) were observed in reproductive performance. Overall, there were no differences in sow reproductive performance, litter growth performance, and the immune system of sows and piglets of sows supplemented OxC-beta.

55 The Effect of Feeding 0.3% Benzoic Acid to Growing Pigs, Alone or in Combination with a Direct-Fed Microbial, on Nutrient Metabolism and Manure Composition and Emissions Compared with a Low Protein Diet

Twenty-four gilts (PIC 337X1050, PIC Genus, Hendersonville, TN) with initial bodyweight (BW) 33.09±1.33kg were used to investigate the effects of benzoic acid (BA), with or without a Bacillus-based direct-fed microbial (DFM), on the nutrient metabolism and gas emissions of growing pigs. Pigs were blocked by BW, placed into metabolism stalls, and randomly assigned to 1 of 4 dietary treatments: control (PC), low nitrogen (NC), PC plus 0.3% BA (VevoVitall, DSM Nutritional Products), and PC plus 0.3% BA and 0.025% DFM (PureGro, DSM Nutritional Products). The 54-d experiment consisted of 4 collection periods, with each period subdivided into 2 sub-periods to measure manure gas emissions and nutrient balance and digestibility. Gas emissions sub-periods lasted 72h. Twice daily, urine and feces were weighed, and urine pH was measured. Urine and feces were stored together and, after 5 d of storage, manure was subsampled and taken to the lab for gas emissions measurements. Urine and feces were quantitatively collected for 96h to measure nutrient digestibility (ATTD), excretion, and retention. Data were analyzed as repeated measures in SAS. Pig was the experimental unit, and results were significant at P ≤ 0.05. Pigs fed BA had greater ADG (922g/d) than pigs fed NC (849g/d), with intermediate ADG for PC (882g/d) or BA+DFM (906g/d). The ATTD of DM, GE, and CP was similar among treatments; however, pigs fed BA or NC excreted less nitrogen in urine than PC and BA+DFM, resulting in greater nitrogen retention in BA compared with PC. Decreased manure pH from pigs fed BA or NC resulted in lower NH3emissions compared with BA+DFM or PC. Manure H2S, CH4, and CO2 emissions were similar among treatments. In conclusion, BA improved nitrogen retention and reduced manure pH and ammonia emissions similarly to feeding low crude protein but improved ADG when compared with a low crude protein diet.

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160 The Compensatory Growth of Finishing Pigs Fed Increasing Dietary Lysine Following a Period of Nutrient Restriction

The objective of this experiment was to evaluate the degree of compensatory gain in finishing hogs when fed increasing levels of lysine during the re-alimentation period after being fed a restrictive 97% corn diet for 3 or 6 weeks. One hundred and forty mixed-sex pens (DNA Genetics, Columbus, NE) with a starting body weight of 73.5 ± 2.2 kg were blocked by starting bodyweight and assigned to a 2:3:1 factorial. Twenty replicates of seven treatments were comprised of 2 restriction lengths [3 weeks (3W) vs. 6 weeks (6W)], and 3 lysine inclusion levels at re-alimentation (Lys:ME: 100%, 110%, or 120% of the genetic margin over feed curve), and a control that remained nutrient unrestricted. Pen weight and feed disappearance were recorded at trial day zero and every 3-weeks until market. Whole pens were marketed when the average met 130 kg to evaluate the full re-alimentation period. Data were analyzed by pen (SAS 9.4, Cary, NC) with the fixed effects of restriction length and lysine level nested within restriction length. Control pigs were market weight (130 kg) on d 49 while pigs fed corn diets for 3 weeks or 6 weeks were significantly slower to market (57 and 69 d, respectively; P &lt; 0.01). Overall average daily gain was significantly different between the control, 3W, and 6W groups (Control: 1.17, 3W: 0.99, 6W: 0.82; P &lt; 0.01). Furthermore, overall average daily gain was significantly influenced by the lysine inclusion level during re-alimentation (Control: 1.17, 3W/100%: 0.98, 3W/110%: 0.99, 3W/120%: 1.01, 6W/100%: 0.81, 6W/110%: 0.83, and 6W/120%: 0.84 kg/d; P &lt; 0.03). In conclusion, the use of 97% corn diets significantly reduced average daily gain and increased days to market. However, the use of diets in which the Lys:ME was greater than genetic recommendations after a period of nutrient restriction, resulted in increased compensatory growth.

PSVII-1 Sample Handling and Vitamin Analysis

Vitamins are crucial for day-to-day function in the body. They are often collected in studies to ensure that the body is functioning normally, but the ways in which these samples are collected are inconsistent. Therefore, the objective of this study was to evaluate differences in sampling collection methods. A total of 4 blood tubes (2 serum and 2 plasma) were collected from 8 finishing pigs (n = 4 gilts and barrows). One blood tube of each type was either exposed to light or wrapped in foil before processing for analysis took place. Livers were taken from 6 gilts, sectioned, and those sections were either frozen immediately or placed at 1 of 3 temperatures (room temperature, 4oC, or -20oC) for 3, 6, or 12 hours before freezing to assess degradation of vitamins within the tissue. Blood was assessed for vitamins A, D, and E while liver was assessed for vitamins A and E with data analyzed by PROC GLIMMIX. There was a significant difference (P &lt; 0.05) for the interaction of blood tube type and light exposure for vitamin D in the blood and a tendency (P &lt; 0.10) for the interaction of blood tube type and light exposure for vitamin A in the blood. Furthermore, there were sex effects (P &lt; 0.05) for vitamin D and (P &lt; 0.10) vitamin A with barrows having higher vitamin statuses than gilts. There were no differences (P &gt; 0.10) for the interaction of blood tube type and light exposure for vitamin E in the blood, or the amount of degradation of vitamins A and E in the liver. In conclusion, factors such as sex, blood tube type, and light, can influence vitamin concentration in biological samples.

106 Evaluation of a Novel Wet/Dry Feeder in Finishing Pigs

Approximately 1,200 pigs (DNA 241×600, Columbus, NE) at approximately 20 kg were randomly allocated into sixty pens (20 pigs/pen) within 3 treatments to evaluate different feeder styles (conventional dry feeder (Dry), PigEasy (PE) wet/dry (PigEasy, Templeton, IA), or Crystal Springs(CS) wet/dry (Crystal Springs, Brandt, SD). Diets for the study were standard, commercial, mash diets that met the growth requirements for the pigs (NRC, 2012). Pigs were allowed 1 week of acclimation to the respective feeder style before the initiation of the study. Pigs were weighed at the beginning of the trial and at each phase change (approximately every 3 to 4 weeks) until market. Feed disappearance was recorded for each phase for the calculation of average daily gain (ADG), average daily feed intake (ADFI), and feed conversion (G:F). Carcass information was collected by treatment to assess carcass metrics. Data were analyzed by pen, with the fixed effect of feeder type, and using repeated measures (SAS, Cary, NC) for the evaluation of ADG, ADFI, GF. The use of either wet/dry feeder compared with a dry feeder resulted in improved ADFI and body weight and a reduced G:F over time (P &lt; 0.02). At the time of market, pigs on wet/dry feeders were approximately 9 kg heavier compared with a standard dry feeder (121.05, 130.64 and 129.28 kg, respectively; P &lt; 0.01). From d0 until time of first market, both wet/dry feeders had significant differences in ADG, ADFI, and GF compared with the dry feeder (Table 1). The use of a wet/dry feeder resulted in significantly higher backfat (1.54, 1.78 and 1.77 cm, respectively; P &lt; 0.01) compared with the dry feeder. The use of a wet/dry feeder compared with a dry feeder resulted in improved average daily feed intake and daily gain, but reduced G:F and carcass merit compared with the dry feeder. There were no significant differences in performance between the 2 different wet/dry feeders.

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134 Water- and Feed-Based Arginine Impacts on Gut Integrity in Weanling Pigs

Two hundred and forty newly weaned pigs (PIC, Hendersonville, TN) were used to determine if supplementing with additional arginine either in the water or in the feed, and the combinations thereof, improved intestinal integrity and growth performance in the nursery. Three pigs (21 ± 2 d) per pen for a total of 80 pens, within 4 water lines, were randomly assigned to 1 of 3 arginine-dietary treatments across the 20 pens for a 4×3 factorial. With 4 water treatments: 0, 4, 8 and 12% Arg and 3 dietary treatments: basal level, 1.55 and 1.75% SID Arg. Pigs and feeders were weighed at the d0, d7 (water and diet change), d21 (diet change), and d41. Eighty pigs were euthanized at d7, for ileum evaluation of villus height and crypt depth. Remaining pigs were then taken off the arginine-water treatment portion of the experiment, and fed the diets formulated to contain 3 different levels of dietary arginine. Data were analyzed by pen as repeated measures (SAS 9.4). Feeding additional arginine resulted in an improvement (basal: 20.35, 1.55: 22.22, 1.75: 20.93 kg; P = 0.04) in pig body weight compared with basal. No interaction was detected when using arginine in the water and feed simultaneously, on piglet performance. The use of 8% arginine in the water resulted in a reduction in crypt depth (0:132.54, 4:140.70, 8:117.28, 12:131.99; P &lt; 0.01) and 4% Arg reduced total villous height:crypt depth ratio (0:2.50, 4:2.09, 8:2.56, 12:2.43; P &lt; 0.02). The feeding of arginine resulted in an improvement in final body weight of the pigs; however, there were no differences in intestinal villi when Arg is added to the feed. However, the use of Arg in the water resulted in an improvement in intestinal villi, but no phenotypical change in piglet growth in the nursery.

184 Correlating Microbial Community Membership of Cervical Fluid, Vagina and Feces in Post-Partum Sows

Postpartum metritis, or the inflammation of the uterus after parturition, is often a direct result of bacterial infection and considered to contribute to agalactia / dysgalactia in multiple species. Diagnosing metritis has included evaluation of vaginal and cervical fluid (CF) discharge for signs of infection (i.e., purulent discharge, strong odor, and discoloration). Metritis in sows results in economic losses for the swine industry due to increased numbers of sows requiring repeat inseminations to establish pregnancy, longer weaning to estrus intervals, association with increased abortions, and is also linked to agalactia. This study aimed to compare the microbial communities of the CF, the vaginal cavity, and feces from sows shortly after parturition, to identify similarities and differences in relative microorganism abundance between these body sites. Fecal and vaginal swabs were collected from 82 sows within 24-36 hours post-parturition. Additionally, CF was collected from each sow and classified based on color and consistency. Extraction of DNA was performed from all 246 samples and used for 16S rRNA gene Illumina MiSeq sequencing. Sequence analysis was conducted using MOTHUR (V1.43.0). No changes in CF microbial community composition or structure were determined related to CF color but differences (P &lt; 0.05) were detected relative to CF consistency. Taxa were compared across body sites to identify correlated phylotypes using CoNet (V1.1.1). The abundances of several phylotypes harboring metritis-relevant pathogens were correlated with common commensal microorganisms across body sites (including Fusobacterium, Streptococcus, Escherichia, and Staphylococcus) suggesting interactions between these body sites exist. This work provides initial insights into postpartum sow CF microbial communities, and the interconnectedness with the vaginal and fecal microbiota. This project was supported by Zoetis (TI-07021).

Innovative strategies for managing swine welfare during the COVID-19 pandemic in Iowa

Coronavirus Disease 2019 (COVID-19) was declared a global pandemic on March 11, 2020 by the World Health Organization and its impact on animal agriculture in the United States was undeniable. By April, COVID-19 resulted in the simultaneous closure or reduced operations of many meat processing plants in the upper Midwest, leading to supply chain disruptions. In Iowa, the leading pork production and processing state, these disruptions caused producer uncertainty, confusion, and stress, including time-sensitive challenges for maintaining animal care. The Iowa Resource Coordination Center (IRCC) was quickly created and launched by the Iowa Department of Agriculture and Land Stewardship (IDALS). The IRCC included public representation from the Iowa Pork Producers Association (IPPA), Iowa Pork Industry Center (IPIC), and Iowa State University Extension and Outreach, and private partners including producers, veterinarians, and technical specialists. Supporting swine welfare, the IRCC provided information on management strategies, dietary alterations to slow pig growth, alternative markets, on-farm euthanasia, and mass depopulation under veterinary oversight. In a crisis, Iowa created a model that reacted to producers’ pragmatic, mental and emotional needs. This model could be quickly replicated with an introduction of foreign animal disease.

13 Innovative Strategies for Managing Swine Welfare During Natural Disasters

Coronavirus Disease 2019 (COVID-19) was declared a global pandemic on March 11, 2020, by the World Health Organization. By April 2020, COVID-19 resulted in the simultaneous closure or reduced operations of many processing plants in the upper Midwest, which quickly resulted in supply chain disruptions. Iowa is the leading pork production and processing state, and these disruptions caused producer uncertainty, confusion, and stress, including time-sensitive challenges for maintaining animal care. The Resource Coordination Center (RCC) was quickly created and launched from the Iowa Department of Agriculture and Land Stewardship. The RCC had strategic collaborations with public representation from the Iowa Pork Producers Association, Iowa Pork Industry Center, and Iowa State University Extension and Outreach, and private partners through producers, veterinarians, and technical specialists. The RCC’s mission was four-fold: (1) implement appropriate actions to ensure the health and safety of RCC members, stakeholders, and the public, (2) evaluate and reassess appropriate actions as needed for continuity of pork production operations, (3) provide information to pork producers during supply chain disruptions, and (4) maintain a safe and abundant pork supply for consumers. The command structure included Incident Commanders, Command Staff, and four Section Chiefs whom worked with their respective experts. Sections covered (1) operations, (2) planning, (3) logistics, and (4) finance and administration. As it related to animal welfare, the RCC provided information on management decisions, dietary alterations to slow pig growth, pig movement to increase living space, alternative markets, on-farm euthanasia and mass depopulation. Veterinary oversight was continually maintained. A manual was created to provide up-to-date information to inform producer decisions and aid. Although originally created for swine, the RCC also assisted poultry, cattle and sheep producers. In a crisis, Iowa created a model that reacted to producer’s pragmatic and emotional needs. This model could be replicated for any emergency by other states.

206 An Investigation into the Role of Dietary Essential Fatty Acids Ratios and Energy Level on Growth Performance, Inflammation, and Joint Health of Grow-finish Pigs

The objective of this study was to investigate the effects of dietary metabolizable energy level and the ratio of linoleic acid:linolenic acid (n6:n3) on the growth performance and inflammatory status of grow-finish pigs. A total of 240 growing pigs (BW = 41.5 ± 6.1 kg) were randomly assigned to either a high (3.55 Mcal/kg; HE) or low (3.29 Mcal/kg; LE) energy dietary treatment with a high (23:1) or low (12:1) n6:n3 in a 2 x 2 factorial design (n = 16). Diets were fed across three 28-day phases and were balanced for linoleic acid inclusion. Pigs were housed 4 pigs per pen. Blood samples were collected on weeks 1, 3, 6, and 12 of the study. Synovial fluid was collected from the hock joint on weeks 1 and 12 for inflammatory marker analysis. The pen was the experimental unit and data were analyzed as repeated measures using PROC MIXED (SAS 9.4) with energy, ratio, and the interaction as fixed effects. Compared to LE, pigs receiving HE had increased BW (P &lt; 0.05) at d28 (73.0 vs. 69.9kg), d56 (105.0 vs. 100.7kg), and d84 (135.3 vs. 129.9kg). For the overall period, HE had increased ADG compared to LE (1.10 vs. 1.06kg; P &lt; 0.05) and improved G:F (0.41 vs. 0.37; P &lt; 0.05), while LE increased ADFI compared to HE (2.88 vs. 2.72kg; P &lt; 0.05). There was no effect of ratio or energy ratio interaction for growth performance. C-reactive protein tended to be reduced in hock synovial fluid of pigs receiving LE (1854.3 vs. 2277.3ng/mL; P &lt; 0.10). Across all treatments, CRP was reduced in the synovial fluid and plasma in week 12 compared to week 1 (P &lt; 0.05). In conclusion, dietary n6:n3 ratio did not impact growth performance or CRP response regardless of energy level.

204 An Investigation into the Role of Dietary Essential Fatty Acids Ratios and Linoleic Acid Level on Growth Performance and Inflammation of Grow-finish Pigs

The objective was to investigate the effects of dietary linoleic acid level and the ratio of linoleic acid:linolenic acid (n6:n3) on the growth performance and inflammatory status of grow-finish pigs. A total of 300 growing pigs (BW = 41.1 ± 6.3 kg) were randomly assigned to either a high (30 g/kg; HLA) or low (15 g/kg; LLA) linoleic acid level with a high (20:1; HR), moderate (12:1; MR) or low (4:1; LR) n6:n3 in a 2 x 3 factorial design. Diets were fed across three 28-day phases and were balanced for dietary metabolizable energy. Pigs were housed 5 pigs per pen. Blood samples were collected on weeks 1, 3, 6, and 12, and synovial fluid was collected from the hock joint on weeks 1 and 12 for inflammatory marker analysis. Data were analyzed as repeated measures using PROC MIXED (SAS 9.4) with initial body weight as a covariate, pen as the experimental unit, and linoleic acid level, ratio, and their interaction as fixed effects. Compared to HLA, LLA pigs had increased BW (P &lt; 0.05) at d56 (103.2 vs. 101.3kg) and tended to have increased BW at d84 (P &lt; 0.10; 129.1 vs. 127.8kg). Pigs receiving LR tended to have higher d84 BW compared to MR (P &lt; 0.10; 129.1 vs. 127.3kg). There was no effect of linoleic acid ratio interaction for growth performance. In phase 2, pigs receiving LR had higher feed intake (P &lt; 0.05) compared to MR. Pigs receiving HR performed intermediate of LR and MR. Overall, C-reactive protein was reduced in the plasma of pigs receiving HLA (P &lt; 0.05; 19.3 vs. 26.2mg/mL). Across all treatments, CRP was reduced in synovial fluid and plasma in week 12 vs. week 1 (P &lt; 0.05). In conclusion, LLA and a low ratio of n6:n3 improved final pig BW, and HLA is potentially beneficial in improving inflammation.

PSIV-12 Evaluation of the Effect of Benzoic Acid with or Without a Direct Fed Microbial on the Performance and Health of Growing and Finishing Pigs

The objective of this study was to determine if benzoic acid in combination of a direct fed microbial could improve grow-finish performance in swine. Three hundred and twenty (DNA 600 X 241, DNA Genetics, Columbus, NE) barrows and gilts were used to evaluate the effect of benzoic acid (BA; VevoVitall, DSM Nutritional Products, Parsippany, NJ) with or without a direct fed microbial (DFM; PureGro, DSM Nutritional Products, Parsippany, NJ) on the growth performance of pigs from approximately 35 to 125 kg. Pigs were sorted by sex, randomly placed into complete blocks, and equalized by weight (40 pens total). Pigs were fed a common diet for 11 days. Following acclimation, pens were assigned to one of four dietary treatments: standard commercial (PC), 85% PC SID lysine and lowered crude protein (NC), PC plus BA (BA at 0.3% inclusion), and PC plus BA and DFM (BA+DFM at 0.3 and 0.025% inclusion, respectively). Ultrasound was conducted to evaluate body composition on day 81. Data were analyzed using PROC MIXED in SAS with pen as the experimental unit. Results were considered significant at P≤0.05 and a trend at P &gt;0.05 and P≤0.10. Pigs fed BA had increased ADG compared to pigs fed PC (1.11 vs. 1.07 kg/d, P=0.02) and NC (1.11 vs. 1.07 kg/d, P=0.01), and similar ADG compared to pigs fed BA+DFM (1.11 vs. 1.09, P=0.21). G:F in pigs fed BA tended to be higher compared to pigs fed NC (0.175 vs. 0.172, P=0.06), and similar compared to pigs fed PC (0.175 vs. 0.176, P=0.51) and BA+DFM (0.175 vs. 0.174, P=0.73). There was a tendency in therapeutic intervention frequency across treatments (P=0.07). In conclusion, reducing lysine and crude protein levels resulted in poorer feed efficiency and BA resulted in increased gain in growing and finishing pigs from approximately 35 to 125 kg.

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Nutritional approaches to slow late finishing pig growth: implications on carcass composition and pork quality

Although pork producers typically aim to optimize growth rates, occasionally it is necessary to slow growth, such as when harvest facility capacity is limited. In finishing pigs, numerous dietary strategies can be used to slow growth so pigs are at optimal slaughter body weights when harvest facility capacity and/or access is restored. However, the impact of these diets on pork carcass quality is largely unknown. Thus, this study aimed to evaluate the efficacy of dietary strategies to slow growth in late finishing pigs and evaluate their effects on carcass composition and pork quality. Mixed-sex pigs (n = 897; 125 ± 2 kg BW) were randomly allotted across 48 pens and assigned to 1 of 6 dietary treatments (n = 8 pens/treatment): (1) Control diet representative of a typical finisher diet (CON); (2) diet containing 3% calcium chloride (CaCl2); (3) diet containing 97% corn and no soybean meal (Corn); (4) diet deficient in isoleucine (LowIle); (5) diet containing 15% neutral detergent fiber (NDF) from soybean hulls (15% NDF); and (6) diet containing 20% NDF from soybean hulls (20% NDF). Over 42 d, pen body weights and feed disappearance were collected. Pigs were harvested in 3 groups (14, 28, and 42 d on feed) and carcass data collected. From the harvest group, 1 loin was collected from 120 randomly selected carcasses (20 loins/treatment) to evaluate pork quality traits. Overall, ADG was reduced in CaCl2, Corn, and 20% NDF pigs compared with CON pigs (P < 0.001). However, ADFI was only reduced in CaCl2 and 20% NDF pigs compared with CON (P < 0.001). Feed efficiency was reduced in CaCl2 and Corn pigs compared with CON (P < 0.001). Hot carcass weights were reduced in CaCl2 pigs at all harvest dates (P < 0.001) and were reduced in Corn and 20% NDF pigs at days 28 and 42 compared with CON pigs (P < 0.001). In general, CaCl2 and 20% NDF diets resulted in leaner carcasses, whereas the Corn diet increased backfat by 42 d on test (P < 0.05). Loin pH was reduced and star probe increased in CaCl2 pigs compared with CON pigs (P < 0.05); no treatments differed from CON pigs regarding drip loss, cook loss, color, firmness, or marbling (P ≥ 0.117). Overall, these data indicate that several dietary strategies can slow finishing pig growth without evidence of behavioral vices. However, changes to carcass composition and quality were also observed, indicating quality should be taken into consideration when choosing diets to slow growth.

89 Nutrition and Feeding of the Modern Hyperprolific Sow

Over the last 25 years, the sow has developed to have a leaner body mass to address the need for leaner, fast growing offspring. The leaner body mass results in a female that biologically can have a lower feed intake. Furthermore, the number of pigs born per litter and milk production have also increased during the same timeframe. Much research has been conducted over the years to investigate the amino acid and energy requirements of both the lactating and gestating sow; however, application of the research has resulted in varied responses. The varied responses can be related to sow health, environmental influences, litter growth rates, and anticipated body reserve changes during lactation. Furthermore, calculations associated with the regression of reproductive tissue after farrowing can complicate the analysis of amino acid requirements. This presentation will discuss some of the recent research associated with feeding the modern sow, potentially challenging some of the differences in data, and offering some thoughts on looking towards the next 25 years of sow production.

176 Evaluation of a novel threonine source for nursery pig diets

Four hundred and eighty (PIC 337 X 1050, PIC Genus, Hendersonville, TN) pigs were used to evaluate a novel threonine source (ThrPro, CJ America-Bio, Fort Dodge, IA) for nursery pigs from approximately 7 kg to 20 kg. At weaning, pigs were sorted by gender and fed a common diet for one week. Upon completion of the first week, pigs were sorted into randomized complete blocks, equalized by weight, within 16 replications. Pigs were allocated to one of three dietary treatments: positive control (POS)-SID LYS:THR 0.60, negative control (NEG)-SID LYS:THR ≤0.46 and alternative threonine source (TEST)-SID LYS:THR 0.60. All other nutrients met or exceeded the NRC (2012) recommendations. Growth and intake data were analyzed using PROC MIXED procedure in SAS. The experimental unit was the pen. During the first 14 days, pigs fed TEST had similar ADG (0.417 vs. 0.414 kg/d, P=0.81) and G:F (0.977 vs. 1.030, P=0.18) compared to POS, and increased ADG (0.417 vs. 0.387 kg/d, P=0.01) and G:F (0.977 vs. 0.898, P=0.05) compared to NEG. Over days 14-28, pigs fed TEST had similar ADG (0.523 vs. 0.532 kg/d, P=0.49) and G:F (0.712 vs. 0.707, P=0.71) compared to POS, and increased ADG (0.523 vs. 0.479 kg/d, P=0.002) and G:F (0.712 vs. 0.627, P&lt; 0.0001) compared to NEG. Overall (d 0 to 28), pigs fed TEST had similar ADG (0.466 vs. 0.474 kg/d, P=0.48) and G:F (0.808 vs. 0.816, P=0.55) compared to POS, and increased ADG (0.466 vs. 0.433 kg/d, P=0.002) and G:F (0.808 vs. 0.725, P&lt; 0.0001) compared to NEG. ADFI was not significantly different across treatments for the entirety of the study. In conclusion, the replacement of L-threonine with a novel threonine source resulted in similar growth performance in nursery pigs from approximately 7 kg to 20 kg.

46 Novel creep area heat source impact on pre-wean mortality occurrence

Pre-wean mortality (PWM) is a multifaceted problem facing the US swine industry. The objective of this study was to compare the occurrence of mortality and age of piglets between a novel heat source (HS; semi-enclosed heated microclimate; SEHM) and a conventional heat lamp setup. This study was conducted in two rooms at a 1,000 head commercial sow farm. Treatments were blocked by sow parity group (SPG; young, prime, and geriatric) over six farrowing cycles. Litters were cross fostered within HS treatment at 1 day of age. PWM, was the experimental unit, data were collected from the farm’s farrowing records and production accounting system. Age of the mortalities was categorized into four phases of lactation (PL) over the 20 d lactation (d0 to d3, d4 to d7, d8 to d11, and d12 to d20). Overall, there were 220 recorded instances of mortality. Data were analyzed in a CRBD using a PROC MIXED model in SAS (v9.4, SAS Inst., Cary, NC) and reported as LSMEANS with standard errors. The model included farrowing cycle as a random effect and the following fixed effects: HS, SPG, PL, HS*SPG, and HS*PL. Overall average PWM was 8.60%±0.80 for SEHM and 10.0%±0.70 for the heat lamps. There was no effect (P &gt;0.05) of HS or HS*PL on PWM occurrence. There were significant effects of SPG (P=0.026), PL (P=0.05), and HS*SPG (P=0.036) on PWM occurrence. These data suggest that the HS type did not have an impact on the mortality rate or the timing of the mortality, indicating the mortalities that occurred had no relationship to HS. A limitation of this data set is the low sample size, thereby limiting the detection ability for this interaction. Further research into the impact of the HS is needed to expand the data set and to explore other popular HS effects on PWM.

280 Effects of metabolizable energy and standardized ileal digestible lysine levels on lactating sow and litter performance

The objective was to determine the effects of metabolizable energy (ME) and standardized ileal digestible (SID) lysine (Lys) levels on lactating sows and litter performance. A total of 600 sows (Camborough; PIC, Hendersonville, TN) were blocked by parity (P1, P2, P3+) on d 112 of gestation and allotted to 1 of 6 treatments arranged in a 2 x 3 factorial with the main effect of ME (3.2 and 3.4 Mcal/kg) and SID Lys (0.70, 0.85, and 1.00 %). Corn-soybean meal-based diets were fed from farrowing until weaning (d 21±2.3). Litters were cross-fostered until 48-h after farrowing to equalize litter size. Sows were weighed at d 112 of gestation and at weaning. Litter size and weight were collected at 24-h post-farrow and weaning. Daily feed intake was recorded from 48-h post-farrow until weaning. Data were analyzed using the GLIMMIX procedure of SAS with sow as the experimental unit. There was no evidence of interaction between ME and SID Lys for any response criteria. There was no evidence for an ME effect on sow performance. There was a quadratic effect (P&lt; 0.05) of SID Lys on sow average daily feed intake, with the greatest intake at 0.85% SID Lys. Increasing SID Lys levels increased sow BW change (linear, P&lt; 0.05). Litters from sows fed 3.4 Mcal of ME/kg had greater (P&lt; 0.05) daily gain compared to those from sows fed 3.2 Mcal of ME/kg. Increasing SID Lys levels increased (linear, P&lt; 0.05) litter weight at weaning and piglet daily gain. Wean-to-estrus interval, percentage of sows bred after weaning, total born on the subsequent parity, litter size at weaning, and percent of piglet removals were not influenced by dietary treatments. In summary, increasing ME levels did not affect sow performance, but improved litter and piglet daily gain. Increasing SID Lys levels improved both litter and sow performance.

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11 Understanding today’s sow and challenging ourselves for the future

The impact of maternal influence across all species on lifelong health and performance is a topic that while recognized as important in the past was not heavily explored until more recently. Over the years, production has focused on sow nutrition and its role in improving birth weights and weaning weights. Today’s sow has approximately 3 more pigs per litter compared to sows 12 years ago and is producing more milk than that of a sow a quarter of a century ago (Nielsen et al. 2018; Rosero, et al, 2016). The biological challenges of supporting the increased total born and milk production, the change in the genetics and lean mass of the sow, along with the environmental challenges such as disease, temperature and social interactions have created an ever changing dynamic that has the potential to influence the sow’s nutritional demands, but also complicates the interpretation of data generated in sow facilities. Along with the increase in total born, other issues such as pelvic organ prolapses and agalactia have also started to increase. While little is known at this time as to the causative nature of these conditions, the goal to quickly resolve such challenges has become absolute. Furthermore, many wonder what else is on the horizon for the modern day sow? Researchers are working to better understand the basis of sow to piglet interaction in terms of immunology, microbiome hereditability and progeny wean to finish performance alongside those working to better understand nutritional requirements to improve longevity of the female. The presentation will focus on these aspects associated with predicting issues for the sows and proactively addressing these concerns along with exploring knowledge advancements and aligning them with sow performance and production.

Effects of feeding melatonin during proestrus and early gestation to gilts and parity 1 sows to minimize effects of seasonal infertility1

This study tested whether supplemental melatonin given to mimic the extended nighttime melatonin pattern observed in the higher fertility winter season could minimize infertility during summer and fall in swine. Exogenous melatonin was fed during periods coinciding with follicle selection, corpus luteum formation, pregnancy recognition, and early embryo survival. Experiments were conducted at a commercial farm in 12 sequential replicates. In Exp. 1a, mature gilts (n = 420) that had expressed a second estrus were assigned by weight to receive once daily oral Melatonin (MEL, 3 mg) or Control (CON, placebo) at 1400 h for 3 wk starting before insemination at third estrus. In Exp. 1b, parity 1 sows (n = 470) were randomly assigned by lactation length to receive MEL or CON for 3 wk, starting 2 d before weaning. Follicles, estrus, pregnancy, and farrowing data were analyzed for the main effects of treatment, season (4-wk periods), and their interaction. Environmental measures were also analyzed for reproductive responses. In Exp. 1a, there was no effect (P > 0.10) of MEL on age at third estrus (203 d), follicle size after 7 d of treatment (5.0 mm), estrous cycle length (22.6 d), return to service (9.2%), farrowing rate (FR, 80.0%), or total born pigs (TB, 13.6). However, there was an effect of season (P = 0.03) on number of follicles and on gilts expressing estrus within 23 d of the previous estrus (P < 0.005). In Exp. 1b, there was no effect of MEL (P > 0.10) on follicle measures, wean to estrous interval, FR (84.0%), or TB (13.0). But MEL (73.5%) reduced (P = 0.03) estrous expression within 7 d of weaning compared with CON (82.0%) and season (P = 0.001) decreased FR by ~14.0% during mid summer. Also, gilts and parity 1 sows exposed to low light intensity (<45 lx) during breeding had reduced conception (-8%) and farrowing (-15%) rates, compared with higher light intensity. Similarly, high temperatures (>25 °C) during breeding also reduced gilt conception rates by 7%. Although there was clear evidence of seasonal fertility failures in gilts and sows, MEL treatment did not improve fertility in gilts and reduced estrus in parity 1 sows. It is possible that differences in lighting and thermal environments before breeding could explain the differential response to MEL in sows and gilts.

Pilot-Scale Assessment of a Novel Farrowing Creep Area Supplementary Heat Source

Simple Summary

Pre-weaning mortality (PWM) causes major economic and productivity losses for the US swine industry. This pilot-scale study evaluated a novel semi-enclosed heated microclimate (SEHM) as a supplementary heat source for farrowing creep areas. Six farrowing cycles (from January to July 2019) were studied in two rooms with 24 farrowing stalls per room. Six SEHMs (each SEHM covers two stalls) were randomly distributed in each room and compared to heat lamps (HLs) for productivity and electricity usage. Data were collected on 113 (SEHM) and 101 litters (HL), and there was no statistically significant difference for average daily gain and weaning weight. There was a tendency for significance of PWM (p = 0.08). A significant difference (p = 0.02) was noted in the PWM attributed to over-lay mortalities, SEHM = 4.05% (± 0.76%) compared to HL = 6.04% (± 0.78%). The SEHM averaged 3.25 kWh d⁻¹ (2.91, 3.59 kWh d⁻¹; 95% CI), which was significantly different (p < 0.01) from the HL equivalent with 125 W bulbs (6 kWh d⁻¹). Based on only electrical savings, payback was estimated at 74 farrowing cycles, or at 12 cycles y⁻¹, 6.1 years. The SEHM demonstrated promising pilot-scale results for increasing productivity and decreasing electricity usage compared to conventional HLs.

Abstract

Pre-weaning morality (PWM) is attributed to a poor creep area microclimate and causes major economic and productivity losses for the US swine industry. Piglets need supplementary heat to overcome a high surface area to body weight ratio and minimal thermoregulation. A pilot-scale study was conducted to evaluate a semi-enclosed heated microclimate (SEHM) as a supplementary heat source for farrowing creep areas over six farrowing cycles (from January to July 2019) in two rooms with 24 farrowing stalls in each room. Six SEHMs (each SEHM covers two stalls) were randomly distributed to each room and compared to heat lamps (HLs) for productivity and electricity usage. Data from 113 (SEHM) and 101 litters (HL) showed no significant difference between treatments in average daily gain (p = 0.26), 252.4 ± 8.0 g hd⁻¹ d⁻¹ (SEHM) and 260.3 ± 8.1 g hd⁻¹ d⁻¹ (HL) and PWM (p = 0.08), 9.67% ± 0.82% (SEHM) and 12.04% ± 0.87% (HL). However, a significant difference (p = 0.02) was noted in the PWM attributed to over-lay mortalities, 4.05% ± 0.76% (SEHM) compared to 6.04% ± 0.78% (HL). The SEHM electricity averaged 3.25 kWh d⁻¹ (2.91, 3.59 kWh d⁻¹; 95% CI), which was significantly different (p < 0.01) from the HL equivalent (125 W bulb; 6 kWh d⁻¹).

Effect of timing of relocation of replacement gilts from group pens to individual stalls before breeding on fertility and well-being

Variation in gilt fertility is associated with increased replacement and reduced longevity. Stress before breeding is hypothesized to be involved in reduced fertility. This study tested the timing of gilt relocation from pens to individual stalls before breeding on fertility and well-being. The experiment was performed in replicates on a commercial research farm. After detection of first estrus, gilts ( = 563) were assigned to treatment for relocation into stalls 3 wk (REL3wk), 2 wk (REL2wk), or 1 wk (REL1wk) before breeding at second estrus. Subsets of gilts from each treatment ( = 60) were selected for assessment of follicles at second estrus. Data included interestrus interval, number of services, conception, farrowing, total born, and wean to service interval. Piglet birth weight was obtained on subsets of litters ( = 42/treatment). Measures of well-being included BW, backfat, BCS, lesions, and lameness from wk 1 after first estrus until wk 16. Gilt BW at wk 5 (158.4 kg) was not affected ( > 0.10) by treatment. Measures of BCS, lameness, and lesions at breeding and throughout gestation did not differ ( > 0.10). Treatment did not affect ( > 0.10) gilts expressing a normal interestrus interval of 18 to 24 d (83.4%) but did influence ( < 0.05) the proportion expressing shorter ( < 0.001) and longer ( < 0.001) intervals. Gilts in REL3wk had a shorter ( < 0.001) interestrus interval (20.7 d) than those in REL2wk and REL1wk (22.6 d). Gilts with shorter intervals ( = 24) had fewer total born while gilts expressing longer cycles ( = 65) had reduced farrowing rates. The number of services (1.9) and number of follicles (19.7) at breeding were not affected ( > 0.10) by relocation. There was no effect of treatment on farrowing rate (85.2%), born alive (12.6), or any litter birth weight measures ( > 0.10). The percentage of sows bred within 7 d after weaning (94.4%) was also not affected by treatment ( > 0.10). These results suggest that the timing of relocation before breeding had no effect on well-being or on the majority of gilts with normal estrous cycles and their subsequent fertility. However, a smaller proportion of the gilts exhibited shorter and longer interestrus intervals in response to relocation 1 or 3 wk before breeding. In cases where gilt fertility may be less than optimal, producers that relocate gilts from pens to stalls before breeding should evaluate interestrus interval as a response criterion.

Characterization of anti-porcine epidemic diarrhea virus neutralizing activity in mammary secretions

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Colostrum uptake is important for early establishment of lactogenic immunity.

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Neutralizing activity in milk and colostrum is associated with anti-spike IgA.

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Sow milk is a continuous supply of IgA with neutralizing activity.

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Temporal patterns of neutralizing antibody production in milk are variable.

Porcine epidemic diarrhea virus (PEDV) causes a severe clinical enteric disease in suckling neonates with up to 100% mortality, resulting in devastating economic losses to the pork industry in recent years. Maternal immunity via colostrum and milk is a vital source to neonates of passive protection against diarrhea, dehydration and death caused by PEDV. Comprehensive information on neutralizing activity (NA) against PEDV in mammary secretions is critically important for assessing the protective capacity of sows. Therefore, the objectives of this study were to characterize anti-PEDV neutralizing activity in mammary secretions. Anti-PEDV NA was present in colostrum, milk and serum from PEDV-infected sows as determined both by immunofluorescence and ELISA-based neutralizing assays, with neutralization levels higher in colostrum and milk than in serum. The highest NA was observed in colostrum on day 1, and decreased rapidly in milk at day 3, then gradually declined from day 3 to day 19 post-farrowing. Notably, the NA in mammary secretions showed various patterns of decline over time of lactation that may contribute to variation in sow protective capacities. The kinetics of NA decline were associated with total IgA and IgG antibody levels. Neutralizing activity significantly correlated with specific IgA primarily to spike domain 1 (S1) and domain 2 (S2) proteins of PEDV rather than to specific IgG in colostrum. Subsequently, the NA in milk was mainly related to specific IgA to S1 and S2 during lactation.

Biofilm Formation by Neisseria gonorrhoeae

Studies were performed in continuous-flow chambers to determine whether Neisseria gonorrhoeae could form a biofilm. Under these growth conditions, N. gonorrhoeae formed a biofilm with or without the addition of 10 microM sodium nitrite to the perfusion medium. Microscopic analysis of a 4-day growth of N. gonorrhoeae strain 1291 revealed evidence of a biofilm with organisms embedded in matrix, which was interlaced with water channels. N. gonorrhoeae strains MS11 and FA1090 were found to also form biofilms under the same growth conditions. Cryofield emission scanning electron microscopy and transmission electron microscopy confirmed that organisms were embedded in a continuous matrix with membranous structures spanning the biofilm. These studies also demonstrated that N. gonorrhoeae has the capability to form a matrix in the presence and absence of CMP-N-acetylneuraminic acid (CMP-Neu5Ac). Studies with monoclonal antibody 6B4 and the lectins soy bean agglutinin and Maackia amurensis indicated that the predominate terminal sugars in the biofilm matrix formed a lactosamine when the biofilm was grown in the absence of CMP-Neu5Ac and sialyllactosamine in the presence of CMP-Neu5Ac. N. gonorrhoeae strain 1291 formed a biofilm on primary urethral epithelial cells and cervical cells in culture without loss of viability of the epithelial cell layer. Our studies demonstrated that N. gonorrhoeae can form biofilms in continuous-flow chambers and on living cells. Studies of these biofilms may have implications for understanding asymptomatic gonococcal infection.

Nontypeable Haemophilus influenzae strain 2019 produces a biofilm containing N-acetylneuraminic acid that may mimic sialylated O-linked glycans

Previous studies suggested that nontypeable Haemophilus influenzae (NTHI) can form biofilms during human and chinchilla middle ear infections. Microscopic analysis of a 5-day biofilm of NTHI strain 2019 grown in a continuous-flow chamber revealed that the biofilm had a diffuse matrix interlaced with multiple water channels. Our studies showed that biofilm production was significantly decreased when a chemically defined medium lacking N-acetylneuraminic acid (sialic acid) was used. Based on these observations, we examined mutations in seven NTHI strain 2019 genes involved in carbohydrate and lipooligosaccharide biosynthesis. NTHI strain 2019 with mutations in the genes encoding CMP-N-acetylneuraminic acid synthetase (siaB), one of the three NTHI sialyltransferases (siaA), and the undecaprenyl-phosphate alpha-N-acetylglucosaminyltransferase homolog (wecA) produced significantly smaller amounts of biofilm. NTHI strain 2019 with mutations in genes encoding phosphoglucomutase (pgm), UDP-galactose-4-epimerase, and two other NTHI sialyltransferases (lic3A and lsgB) produced biofilms that were equivalent to or larger than the biofilms produced by the parent strain. The biofilm formed by the NTHI strain 2019pgm mutant was studied with Maackia amurensis fluorescein isothiocyanate (FITC)-conjugated and Sambucus nigra tetramethyl rhodamine isocyanate (TRITC)-conjugated lectins. S. nigra TRITC-conjugated lectin bound to this biofilm, while M. amurensis FITC-conjugated lectin did not. S. nigra TRITC-conjugated lectin binding was inhibited by incubation with alpha2,6-neuraminyllactose and by pretreatment of the biofilm with Vibrio cholerae neuraminidase. Matrix-assisted laser desorption ionization-time of flight mass spectometry analysis of lipooligosaccharides isolated from a biofilm, the planktonic phase, and plate-grown organisms showed that the levels of most sialylated glycoforms were two- to fourfold greater when the lipooligosaccharide was derived from planktonic or biofilm organisms. Our data indicate that NTHI strain 2019 produces a biofilm containing alpha2,6-linked sialic acid and that the sialic acid content of the lipooligosaccharides increases concomitant with the transition of organisms to a biofilm form.

The effect of dietary soy daidzein on pig growth and viral replication during a viral challenge

Twelve replications of four littermate pigs from a porcine reproductive and respiratory syndrome (PRRS) naive herd were weaned (11 +/- 2 d of age) and penned individually in isolation rooms. Pigs were randomly allotted within litter to one of four dietary soy daidzein concentrations (0, 200, 400, or 800 ppm) to quantify the effect of daidzein on growth and immune response during a PRRS challenge. Daidzein was provided as the soy aglycone. At 27 +/- 2 d of age (4.9 +/- 1.4 kg BW), pigs were oronasally inoculated with 10(4.3) PRRS virus/mL from strain JA142 in a 2-mL dose. Blood was collected every 4 d from d 0 to 24 after inoculation and analyzed for serum PRRS virus, interferon, and alpha-1-acylglycoprotein (AGP) concentrations. Serum virus and interferon peaked at 10(5.3) virus/mL and 79% protection, respectively, at 4 d after inoculation and then declined steadily. Serum AGP concentration peaked at 12 d after inoculation. Each log increase in serum virus was associated with an increase in serum interferon, which resulted in a decrease of pig ADG and daily feed intake of 0.019 kg and 0.023 kg, respectively, in 5.8-kg pigs and a feed intake reduction of 0.024 kg in 12.5-kg pigs. Dietary daidzein additions did not (P > 0.3) alter the serum concentration after inoculation of PRRS virus (10(1.79), 10(1.94), 10(1.86), 10(1.93) virus/mL of serum) or AGP. Serum concentrations of interferon responded cubically (30.3, 28.9, 29.4, and 31.1% protection) as dietary daidzein concentrations increased; however, the magnitude of the response decreased over time. Dietary daidzein additions resulted in improvements in daily pig gain, daily feed intake, and gain/feed during periods of peak viremia (d 4 to 16 after inoculation), but not in periods when systemic virus concentrations were minimized (d 16 to 24 after inoculation), resulting in a daidzein x days after inoculation interaction. Based on these data, the magnitude of the growth responses that occur in pigs infected with a virus is quantitatively related to the animal's serum concentration of the virus and interferon, and dietary soy daidzein at 200 or 400 ppm is a weak enhancer of body growth in virally challenged pigs.

The effect of dietary soy genistein on pig growth and viral replication during a viral challenge

Twelve replications of four littermate pigs from a herd naive for porcine reproductive and respiratory syndrome (PRRS) were weaned (10 +/- 2 d of age) and penned individually in isolation rooms. Pigs were randomly allotted within litter to one of four dietary soy genistein concentrations (0, 200, 400, and 800 ppm) to quantify the effect of soy genistein on pig growth and virus replication during a viral challenge. Genistein was provided as the soy glycoside, genistin. At 29 +/- 2 d of age (4.9 +/- 1.4 kg BW), pigs were oronasally inoculated with 10(4.3) PRRS virus/mL from strain JA142 in a 2-mL dose. Blood was collected every 4 d from d 0 to 24 postinoculation and analyzed for serum PPRS virus, interferon activity, and alpha1-acylglycoprotein (AGP) concentrations. Serum virus and interferon peaked at 10(5) virus/mL and 57% protection, respectively, at 4 d postinoculation and then declined steadily. Serum AGP concentration peaked at 12 d postinoculation. Each log increase in serum virus was associated with a reduction of daily gain of 0.034 kg in 5.3-kg pigs and 0.004 kg in 11-kg pigs. As dietary genistein concentration increased, serum concentrations of PRRS virus decreased linearly (10(2.46), 10(2.26), 10(2.05), and 10(2.14) virus per milliliter of serum, P < 0.07) and interferon responded quadratically (28.4, 25.7, 22.8, and 30.9% protection, P < 0.06) independent of days postinoculation. The AGP concentrations increased (P < 0.01) quadratically with the magnitude of the response to dietary genistein maximized at 12 to 16 d postinoculation. Effects of dietary genistein on daily pig gain and feed intake were dependent on dietary genistein concentration and stage of viremia. Daily pig gains from d 0 to 24 postinoculation were improved as dietary genistein increased, but the magnitude of the response to dietary genistein concentration lessened as the serum virus concentrations were minimized resulting in a linear genistein x period interaction (P < 0.07). Daily feed intakes also were increased quadratically as genistein concentration increased. These data indicate that soy genistein at dietary concentrations of 200 to 400 ppm is an orally active immune modulator that enhances systemic serum virus elimination and body growth in virally challenged pigs.

Quantitative relationship of systemic virus concentration on growth and immune response in pigs

Ninety-six pigs from a herd naive for porcine reproductive and respiratory syndrome (PRRS) virus were weaned (10 +/- 3 d of age), penned individually in isolation rooms, and, at 29 +/- 4 d of age, oronasally inoculated with a 2-mL dose of 10(4.3) JA142 PRRS virus/ mL. Body weight; feed intake; and serum concentrations of PRRS virus, interferon, and alpha1-acylglycoprotein were determined for each pig every 4 d on d -8 to 24 postinoculation to quantify the effect of PRRS exposure on the immune response and growth of pigs. Another objective was to determine whether a quantitative relationship between a measure of systemic (serum) virus concentration and pig growth exists. Serum PRRS virus and interferon peaked at 10(5) virus/mL and 69% protection, respectively, at 4 d postinoculation and then declined steadily. Serum alpha1-acylglycoprotein concentration peaked at 12 d postinoculation. Pig weight gains and feed intake were reduced sharply in the initial 8 d postinoculation and to a lesser degree for 24 d postinoculation. The serum concentration of virus and to a lesser degree serum concentrations of interferon and alpha1-acylglycoprotein were quantitatively related to body weight gain and feed intake. The magnitude of the relationship was dependent on the stage of recovery from PRRS infection. Specifically, each log increase in serum virus concentration was associated with a reduction of 4-d pig gain and feed intake of .047 kg and .189 kg, respectively, in 5.5-kg pigs 4 d postinoculation and .085 kg and .036 kg, respectively, in 12.5-kg pigs at 20 d postinoculation. Based on these data, factors that minimize the systemic presence of a virus in pigs result in improvements in pig growth that are quantitatively related to the degree of systemic virus elimination or minimization.