Mike D. Tokach

Colibacillosis in nursery pigs, caused by Escherichia coli (ETEC, EPEC, and STEC pathotypes), remains a major economic concern in the swine industry. This study evaluated the effects of in-feed or in-water chlortetracycline (CTC) administration on the fecal prevalence of virulence genes and pathotypes associated with colibacillosis. A total of 1296 weaned piglets (21 days old) were allocated to 48 pens (16 pens/treatment; 27 piglets/pen) and assigned randomly to no CTC, in-feed CTC, or in-water CTC groups. CTC was administered from days 0 to 14. Fecal samples from five piglets per pen on days 0, 14, and 28 were enriched, screened by 11-plex PCR, cultured for pathotypes, and tested for CTC susceptibility and tetracycline resistance genes. None of the 360 fecal samples or 3267 E. coli isolates were positive for bfpA or aggA. Prevalence of estB (96.9%) and astA (92.8%) was highest. ETEC was the dominant pathotype (41.2%), with astA (29%) and estB (21.9%) as predominant enterotoxin genes. CTC administration had no significant effect on fecal prevalence of virulence genes or pathotypes (p > 0.05). stx2 and STEC were detected only at day 28, all harboring stx2e. All pathotypes were CTC-resistant, with tetA as the predominant resistance gene.

Antimicrobial Resistance (AMR) in bacteria is a growing public health concern in the US and around the world threatening the continual use of antimicrobials. In pigs, the oral route, either in-feed or in-water, is by far the most common route of administration of antimicrobials. Because the distribution of the antibiotic in the gut and the dosages are different, the impact of in-feed vs. in-water administration of antibiotics on the prevalence of pathogens, such as Salmonella, and the development of AMR are likely to be different. Therefore, a study was conducted to compare in-feed vs. in-water administrations of chlortetracycline (CTC) and/or tiamulin on the fecal prevalence and AMR profiles of Salmonella in nursery piglets. A total of 1296 weaned piglets, housed in 48 pens (27 piglets per pen), were assigned randomly to six treatment groups: Control (no antibiotic), in-feed CTC, in-water CTC, in-feed tiamulin, in-water tiamulin, or in-feed CTC and tiamulin. Fecal samples (n = 1440) were collected randomly from five piglets from each pen during the pre-treatment (days 7, 0), treatment (days 7, 14), and post-treatment (days 21, 28) phases. Salmonella enterica isolation and identification were completed by culture and PCR methods. The microbroth dilution method with Sensititre^TM (ThermoFisher Scientific, Lenexa, KS, USA) plates was used to determine the antimicrobial susceptibility and resistance of Salmonella strains. The susceptibility and resistance were interpreted based on the Clinical and Laboratory Standards Institute guidelines. The overall prevalence of Salmonella was 3.0% (43/1440). All isolates belonged to Salmonella enterica subsp. enterica serovar Typhimurium. Salmonella isolates were susceptible to azithromycin and resistant (100%) to ampicillin, streptomycin, sulfisoxazole, tiamulin, and tetracycline. Neither antibiotic, CTC or tiamulin, nor the route of administration, in-feed or in-water, had an effect (p > 0.05) on the occurrence of resistant Salmonella in the feces of piglets.

Antimicrobial resistance (AMR) in bacteria is a major public health concern in the US and around the world. Campylobacter is an important foodborne pathogen that resides in the gut of pigs and is shed in feces, with the potential to be transmitted to humans. In pigs, the oral route, either in-feed or in-water, is by far the most common route of administration of antimicrobials. Because the distribution of the antibiotic in the gut and the dosages are different, the impact of in-feed vs. in-water administration of antibiotics on the development of AMR is likely to be different. Therefore, a study was conducted to compare in-feed vs. in-water administrations of chlortetracycline (CTC) and/or tiamulin on fecal prevalence and AMR profiles of Campylobacter among weaned nursery piglets. A total of 1,296 weaned piglets, allocated into 48 pens (27 piglets per pen), were assigned randomly to six treatment groups: Control (no antibiotic), in-feed CTC, in-water CTC, in-feed tiamulin, in-water tiamulin, or in-feed CTC and tiamulin. Fecal samples were collected randomly from 5 piglets from each pen during the pre-treatment (days 0, 7), treatment (days 14, 21), and post-treatment (days 28, 35) phases. Bacterial isolations and species identifications were conducted by culture and PCR, respectively. The microbroth dilution method with Sensititre^TM plates was used to determine the antimicrobial susceptibility and resistance of Campylobacter isolates. The results on resistance were interpreted based on the European Committee on Antimicrobial Susceptibility Testing (EUCAST) epidemiological cutoff values for Campylobacter. The overall prevalence of Campylobacter was 18.2% (262/1440). Speciation of Campylobacter isolates by PCR indicated the prevalence of only two species: Campylobacter hyointestinalis (17.9%; 258/1440) and C. coli (0.3%; 4/1440). Campylobacter isolates were resistant to tetracycline (98.5%), ciprofloxacin (89.3%), and nalidixic acid (60.3%). Neither the antibiotic nor the route of administration had an effect (p > 0.05) on the prevalence of AMR Campylobacter in the feces of piglets.

Feed additives have shown benefits throughout the literature in improving grow–finish pigs’ growth performance and carcass characteristics. However, the results have not been well summarized. Therefore, this review summarizes the available research (402 articles) on 14 feed additive categories fed to grow–finish pigs. The categories were acidifiers, betaine, Cr, conjugated linoleic acids, Cu, direct-fed microbials, carbohydrases, proteases, phytases, multi-enzymes, essential oils, L-carnitine, yeasts, and Zn. Qualified articles were collected and selected based on inclusion and exclusion criteria from online databases. The percentage difference for each response variable between the treatment and control group was calculated and summarized. Most results were positive for each feed additive; however, the magnitude of improvement varied, and most were not statistically significant. For ADG, DFM, Cu, L-carnitine, and multi-enzymes showed relatively large positive effects (>2.1% improvement) across a reasonable number of articles. Acidifiers, betaine, CLA, multi-enzymes, DFM, L-carnitine, and yeasts showed relatively large positive effects (>2.5% improvement) on improving G:F. Moreover, except for betaine, Cr, CLA, and L-carnitine, most feed additives showed little and non-significant effects on BF thickness (<1.7% improvement). This review provides a descriptive analysis for commonly used feed additives in the hope of better understanding feed additives’ effects on grow–finish pigs.

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

COVID-19 has provided global challenges to almost every industry. Among these challenges were positive cases of COVID-19 in employees at swine processing facilities, leading to temporary, or extended, shutdown of the facilities ( Millet et al., 2020). In the United States, processing capacity is closely aligned with the number of pigs produced such that packing facility shutdowns or slowdowns rapidly results in a backlog of pigs needing to be harvested. Thus, there was no place for the pigs to go that were ready for market. Swine processing under federal inspection began to decrease in late March 2020 ( Figure 1; USDA, 2020). The lowest weekly harvest occurred from April 27 to May 2, 2020, which represented a decrease of approximately 45% of normal slaughter capacity.

Fumonisin contamination in corn is an emerging issue in animal feed production. Fumonisin disrupts the metabolism of sphingolipids and reduces growth performance. This experiment was conducted to determine the effect of feeding fumonisin-contaminated corn on growth performance and sphinganine (SA) to sphingosine (SO) ratios of 9 to 28 kg pigs. A total of 350 pigs, were used with 5 pigs/pen and 14 pens/treatment. Dietary treatments contained fumonisin-contaminated corn (50 mg/kg of fumonisin B1 + B2) blended with low fumonisin corn (10 mg/kg of fumonisin B1 + B2) to provide dietary fumonisin concentrations of 7.2, 14.7, 21.9, 32.7, and 35.1 mg/kg. From day 0 to 28, increasing fumonisin concentration decreased (linear, p < 0.001) average daily gain, average daily feed intake (linear, p = 0.055), and gain:feed ratio (linear, p = 0.016). Although these response criteria tested linear, the greatest reduction in performance was in pigs fed with 32.7 and 35.1 mg/kg of fumonisin (B1 + B2). Increasing fumonisin concentration increased the serum SA:SO ratio (linear, p < 0.001) on day 14 and 28. In summary, for 9 to 28 kg nursery pigs, increasing fumonisin linearly decreased average daily gain and gain:feed ratio. However, despite the linear response, diets containing up to 21.9 mg/kg of fumonisin did not have as dramatic a decrease in growth performance as those fed more than 32.7 mg/kg. Further research is warranted to determine the effect of fumonisin concentrations between 21.9 and 32.7 mg/kg.

Background: Two experiments were conducted to determine the effects of increasing amounts of soybean meal (SBM) in swine diets and estimate the energy value of SBM.Methods: A total of 2233 pigs (PIC 337 × 1050, Hendersonville, TN) and 3796 pigs (PIC 359 × C40), initially 11.0 kg and 17.6 kg body weight (BW), were used in Exp. 1 and 2, respectively. In Exp. 1, pigs were placed in 92 pens each containing 20 to 27 pigs. In Exp. 2, pigs were placed in 84 pens each containing 37 to 43 pigs. Treatments were assigned in a randomized complete block design with BW as the blocking factor. Dietary treatments consisted of 21%, 27%, 33%, or 39% SBM in Exp. 1 and 17.5%, 22%, 26.5%, 31%, 35.5%, or 40% SBM in Exp. 2, obtained by changing the inclusion rate of feed-grade amino acids and corn grain. For Exp. 1, representative samples of corn grain, SBM, and distillers dried grains with solubles were analyzed for total AA content prior to diet formulation. For Exp. 2, diets were formulated using NRC (2012) nutrient loadings. Treatment diets were fed for 21 and 22 d (Exp. 1 and 2) and there were 23 replicates in Exp. 1 and 14 replicates in Exp. 2. Pigs were weighed and feed disappearance measured weekly to calculate average daily gain (ADG), average daily feed intake (ADFI), gain-to-feed ratio (G:F), and caloric efficiency (CE). Data were analyzed with block as a random effect and treatment as a fixed effect, and contrasts were constructed to test the linear and quadratic effects of increasing SBM.Results: In Exp. 1, there was a tendency (linear,P = 0.092) for a decrease in ADFI as SBM increased. There was a tendency (P = 0.090) for a quadratic response for ADG, with a decrease in ADG observed with 39% SBM inclusion. Pigs fed diets with increasing SBM had a tendency (quadratic,P = 0.069) for an increase in G:F up to 33% SBM and an improvement (linear,P = 0.001; quadratic,P = 0.063) in CE with increasing SBM. Using CE to estimate the energy of SBM relative to corn, a value of 105.4% of corn energy or 2816 kcal/kg NE was determined using all data points. When removing the CE value of the 39% SBM treatment due to the quadratic tendency, SBM was estimated to have 121.1% of corn energy or 3236 kcal/kg NE. In Exp. 2, there was a decrease (linear,P = 0.001) in ADFI. Pigs fed increasing SBM had a tendency (linear,P = 0.065) for reduced ADG but an improvement (linear,P = 0.001) in G:F and CE as SBM increased. The energy value of SBM was estimated as 124.7% of corn energy or 3332 kcal/kg NE.Conclusions: The results suggest that feeding increasing levels of SBM improves G:F and CE. The energy value of SBM was estimated to be between 105% and 125% of corn, which is much greater than the NRC (2012) would indicate.

It is with great pleasure that we present the 2020 Swine Industry Day Report of Progress. This report contains updates and summaries of applied and basic research conducted at Kansas State University during the past year. We hope that the information will be of benefit as we attempt to meet the needs of the Kansas swine industry.

A total of 288 pigs (DNA 241 × 600; initially 117 lb) were used in a 72-d trial to evaluate the influence of Enogen Feed corn (Enogen, Syngenta Seeds, LLC; Downers Grove, IL) and conventional yellow dent corn in pelleted or meal diets on finishing pig performance and carcass characteristics. Pigs were randomly assigned to pens (8 pigs per pen) and pens were allotted by weight to 1 of 4 dietary treatments in a randomized complete block design with 9 pens per treatment. Treatments were arranged in a 2 × 2 factorial with main effects of corn source (Enogen Feed corn or conventional yellow dent) and diet forms (meal or pellet). Overall, from d 0 to 72, there was a tendency (P < 0.10) for a difference between corn source for average daily gain (ADG) and feed efficiency (F/G) with slightly improved performance for pigs fed conventional yellow dent corn. When diets were fed as pellets, ADG was increased (P = < 0.001) and F/G was improved (P = 0.001) compared to pigs fed meal diets. In summary, feeding pellets to pigs increased ADG and improved feed efficiency with no major differences between corn sources on growth performance.