Effects of Conditioning Temperature and Pellet Mill Die Speed on Pellet Quality and Relative Stabilities of Phytase and Xylanase

The objective of this experiment was to determine the effect of conditioning temperature and die speed on pellet quality and enzyme stability of phytase and xylanase. Treatments were initially arranged as a 2 × 3 factorial of conditioning temperature (165 and 185°F) and die speed (127, 190, and 254 rpm); however, when conditioning at 185°F it was not possible to pellet at 127 rpm. Thus, data were analyzed in 2 different segments using the GLIMMIX procedure of SAS. First, linear and quadratic contrasts were utilized to test the response to increasing die speed at 165°F. Second, the data were analyzed as a 2 × 2 factorial of conditioning temperature (165 and 185°F) and die speed (190 and 254 rpm). Treatments were arranged in a completely randomized design and replicated 3 times. Diets were conditioned for approximately 30 s and pelleted with a 3/16 in. diameter × 1 3/4 in. effective length die at a rate of 5 ton/h. Pellet durability index (PDI) was determined using the tumble box and Holmen NHP 100 methods. Samples of the unconditioned mash (M), conditioned mash (CM), and pellets (P) were collected and analyzed for phytase and xylanase concentration. Relative enzyme stabilities were expressed as CM:M and P:M. Stabilities expressed as P:M were used an indication of enzyme stability through the entire pelleting process. Diets conditioned at 165°F showed no evidence of difference in phytase or xylanase P:M stability when decreasing die speed from 254 to 127 rpm. However, when conditioning diets at 165°F, decreasing die speed increased (linear, P \u3c 0.001) PDI. There was no conditioning temperature × die speed interaction for overall xylanase P:M stability or PDI. However, there was a conditioning temperature × die speed interaction (P \u3c 0.01) for phytase P:M stability. When conditioning diets at 185°F, increasing die speed decreased phytase P:M stability. However, when conditioning at 165°F, increasing die speed did not influence phytase P:M stability. For main effects of conditioning temperature, increasing temperature improved (P \u3c 0.001) PDI with no evidence of difference for xylanase P:M stability. For the main effects of die speed (254 vs. 190 rpm), decreasing die speed decreased (P \u3c 0.001) the P:M xylanase stability, but there was no evidence of difference for PDI. The results of this trial indicate that die speed should be taken into consideration when evaluating enzyme stability of both phytase and xylanase as pellet mill models may be operating at different speeds. Additionally, increasing conditioning temperature will improve PDI, but may result in decreased phytase stability

Assessment of Soy-Based Imports into the US and Associated Foreign Animal Disease Status

Soy-based products are known to pose a viable risk to US swine herds because of their ability to harbor and transmit virus. This study evaluated soy imports into the US as a whole and from foreign animal disease positive (FAD+) countries to determine which products are being imported in the highest quantities and observe potential trends in imports from FAD+ countries. Import data were accessed through the United States International Trade Commission website (USITC DataWeb) and summarized using R (version 4.0.2, R core team, Vienna, Austria). Twenty-one different Harmonized Tariff Schedule (HTS) codes were queried to determine quantities (US tons, T) and breakdown of different soy product types being imported into the US from 2015 to 2020. A total of 78 different countries exported soy products to the US in 2019 and 2020, with top contributors being Canada (602,377 T and 530,759 T, respectively), India (438,563 T and 474,678 T, respectively), and Argentina (134,610 T and 87,602 T, respectively). In 2020, soy oilcake (641,846 T) was imported in the largest quantities, followed by organic soybeans (297,838 T) and soy oil (148,190 T). Of the 78 countries, 46 had cases of FAD reported through the World Organization for Animal Health (OIE) World Animal Health Information Database (WAHIS). Top exporters of soy products to the US from FAD+ countries in 2019 and 2020 were India (438,563 T and 474,678 T, respectively), Argentina (134,610 T in 2019), and Ukraine (44,415 T and 62,162 T, respectively). A system to monitor the sourcing of these products into the US and the end usage would allow for a greater understanding of the risk of these products to domestic swine herds

Summary of Methodology Used in Enterotoxigenic Escherichia coli (ETEC) Challenge Experiments in Weanling Pigs and Quantitative Assessment of Observed Variability

Post-weaning diarrhea in pigs can be caused by the F4 or F18 strains of enterotoxigenic Escherichia coli (ETEC). To evaluate interventions for ETEC, experimental infection via a challenge model is critical. To our knowledge, there is a lack of explanation for the variability in responses observed across ETEC challenge studies. Our objective was to quantitatively summarize the responses and variability among recent ETEC challenge studies and develop a tool for sample size calculation. The most widely evaluated response criteria across ETEC challenge studies are growth performance, fecal consistency and bacterial shedding, intestinal morphology, and immune responses. Factors that contribute to the variability seen across studies include the type of ETEC studied, dose and timing of inoculation, and the number of replications. Generally, a reduction in average daily gain (ADG) and average daily feed intake (ADFI) are seen following an ETEC challenge, as well as a rapid increase in diarrhea. Fecal bacterial shedding is a common indicator of ETEC infection, but the responses seen across the literature are not consistent due to differences in bacterial enumeration procedures. Emphasis should also be placed on the piglet’s immune response to ETEC, which is commonly assessed by quantifying levels of immunoglobulins and pro-inflammatory cytokines. Again, there is variability in these responses across published work. Small intestinal morphology is drastically altered following infection with ETEC and appears to be a less variable response criterion to evaluate. While there is a large degree of variability across ETEC challenge experiments, we have provided a quantitative summary of these studies, and a Microsoft Excel-based tool was created to help calculate sample sizes for future studies

Effects of different diet alternatives to replace the use of pharmacological levels of zinc on growth performance and fecal dry matter of weanling pigs

A total of 300 weanling pigs (Line 400 × 200, DNA, Columbus, NE, initially 4.83 kg) were used in a 46-d trial to evaluate the effects of different nutritional strategies to replace pharmacological levels of Zn, provided by zinc oxide (ZnO), in nursery diets on growth performance and fecal dry matter (DM). Six treatments with 10 replicate pens per treatment and 5 pigs per pen were used. Diets consisted of: (1) positive control (ZnO providing 3,000 mg/kg added Zn from d 0 to 7 and 2,000 mg/kg added Zn from d 8 to 25 and 21% crude protein, CP); (2) negative control (NC; no added ZnO); (3) NC plus 1.2% Na diformate; (4) NC with 4% coarse ground wheat bran; (5) NC but formulated to 18% CP; and (6) the combination of NC with 18% CP, 1.2% Na diformate, and 4% coarse ground wheat bran. The diets formulated to 18% CP contained 1.2% standardized ileal digestible (SID) Lys from d 0 to 25, whereas the 21% CP diets contained 1.4% SID Lys from d 0 to 7 and 1.35% SID Lys from d 7 to 25. From d 25 to 46, all pigs were fed a common diet. From d 0 to 7, no differences in any variables were observed between treatments. From d 7 to 25, pigs fed the diet with added ZnO had greater (P < 0.01) average daily gain (ADG) and average daily feed intake (ADFI) than all other treatments. Pigs fed the diet formulated to 18% CP had decreased (P < 0.01) ADG when compared with pigs fed the other diets. From d 25 to 46, no previous treatment effects on ADG or gain to feed ratio (G:F) were observed. Overall (d 0 to 46), pigs fed the diet with added ZnO from d 0 to 25 had greater (P < 0.01) ADG, ADFI, and final body weight than pigs fed added Na Diformate, or 4% coarse ground wheat bran, or with the 18% CP diet, or with pigs fed the combination of the additives intermediate. There was no evidence for differences in overall G:F. Pigs fed the NC diet had the lowest fecal DM and highest fecal scores (P < 0.05), indicating the greatest incidence of loose stools. Pigs fed added ZnO had greater fecal DM than pigs fed the NC, 4% added wheat bran, or 18% CP diets, or with pigs fed the combination of additives intermediate (P < 0.01). These results suggest that adding pharmacological levels of Zn from ZnO improves nursery pig performance and increases DM content of feces when compared with pigs fed diets with either Na diformate, 4% course wheat bran, or 18% CP alone. However, a combination of all three alternatives appeared to be additive and partially restored growth performance similar to adding pharmacological levels of Zn

Evaluation of Corn Protein Source on Feed Intake Preference in Nursery Pigs

A total of 180 pigs (241 × 600, DNA; initially 17.0 ±1.6 lb) were used to determine feed intake preference from various corn protein sources. A series of 5-day preference trials were used with two diets offered within each comparison with feeder location rotated daily within each pen. Feed consumption was used to determine preference between each diet comparison. There were 6 replicates of each diet comparison. The corn protein sources utilized in this experiment included: fermented corn protein, high protein distillers dried grains with solubles (HPDDGs), whole stillage solids (approximately 2/3 content of fermented corn protein), and thin stillage solids (approximately 1/3 content of fermented corn protein). Fermented corn protein and HPDDGs were included in the diet at 15% as a replacement for corn. Whole stillage solids and thin stillage solids were included in the diet at 10% and 5%, respectively, as a replacement to corn to match its contribution in fermented corn protein. The control diet was a standard nursery diet. Diet comparisons included: 1) Control vs. Fermented corn protein; 2) Whole stillage solids vs. Fermented corn protein; 3) Thin stillage solids vs. Fermented corn protein; 4) HPDDGs vs. Fermented corn protein; 5) Control vs. Whole stillage solids; 6) Control vs. Thin stillage solids. For comparison 1, pigs preferred (P \u3c 0.001) the control diet by consuming 82.5% of their intake with this diet compared with the diet containing fermented corn protein. For comparison 2, there was no difference (P \u3e 0.05) in feed consumption of diets containing whole stillage solids and the fermented corn protein. For comparison 3, pigs preferred (P = 0.001) the diet containing thin stillage solids by consuming 75.8% of their intake with this diet compared to the diet containing fermented corn protein. There was no difference when comparing fermented corn protein and whole stillage solids, but thin stillage solids had a higher percentage intake than fermented corn protein. Therefore, it is likely that whole stillage solids are the component of fermented corn protein that negatively affect feed consumption

Effects of Standardized Ileal Digestible Lysine Level on Growth Performance in 230 to 285 lb DNA Finishing Pigs

The objective of this study was to estimate the SID Lys requirement for growth and feed efficiency of 230- to 285-lb DNA finishing pigs. A total of 679 barrows and gilts (600 × 241, DNA; initial BW of 228.8 ± 2.9 lb) were used in two separate studies lasting 21- and 28-d, respectively. Pens of pigs were blocked by BW and randomly allotted to 1 of 6 dietary treatments with 8 to 10 pigs per pen in a randomized complete block design. A similar number of barrows and gilts were placed in each pen. Dietary treatments were corn-soybean meal-based and formulated to 0.43, 0.50, 0.57, 0.64, 0.71, and 0.79% SID Lys, with 12 replications for the 0.43, 0.50, 0.57, 0.71, and 0.79% SID Lys treatments, and 11 replications for the 0.64% SID Lys treatment. Increasing SID Lys increased (linear, P = 0.043) ADG, and improved (quadratic, P = 0.020) feed efficiency, resulting in pigs fed the diet containing 0.71% SID Lys having the greatest final BW and most optimum F/G. At high and low ingredient and pig prices, increasing SID Lys increased (quadratic, P = 0.004) IOFC. The broken-line linear model to maximize ADG predicted that there was no further improvement past 0.64% SID Lys. For F/G, the broken-line linear model predicted that there was no further improvement past 0.59% SID Lys. At high ingredient and pig prices, the quadratic polynomial model for IOFC predicted maximum economic return at 0.64% SID Lys. Additionally, at low ingredient and pig prices, the quadratic polynomial model for IOFC predicted maximum economic return at 0.62% SID Lys. In summary, the optimal SID Lys level for DNA finishing pigs from 230- to 285-lb depends upon the response criteria, with growth performance maximized between 0.59 to 0.64% SID Lys. Economic responses were maximized between 0.62% SID Lys and 0.64% SID Lys

Effects of Standardized Ileal Digestible Lysine Level on Growth Performance in 120 to 170 lb DNA Finishing Pigs

The objective of this study was to estimate the SID Lys requirement for growth and feed efficiency of 120- to 170-lb finishing pigs. A total of 700 barrows and gilts (600 × 241, DNA; initial BW of 117.2 ± 1.89 lb) were used in two separate studies, each lasting 21-d. Pens of pigs were blocked by BW and randomly allotted to 1 of 6 dietary treatments with 8 to 10 pigs per pen in a randomized complete block design. A similar number of barrows and gilts were placed in each pen. Dietary treatments were corn-soybean meal-based and formulated to 0.65, 0.72, 0.79, 0.86, 0.93, and 1.00% SID Lys, with 12 replications per treatment. Increasing SID Lys increased (linear, P \u3c 0.001) ADG, with pigs fed 1.00% SID Lys having the greatest final BW. In addition, increasing SID Lys decreased (quadratic, P = 0.004) ADFI. Feed efficiency improved, while Lys intake/d, and Lys intake/kg of gain increased (quadratic, P \u3c 0.005), with increasing SID Lys. At both high and low ingredient and pig prices, feed cost/pig increased (quadratic, P \u3c 0.05) as SID Lys increased, while feed cost/lb of gain decreased (quadratic, P \u3c 0.001), with pigs fed 0.79% SID Lys having the lowest feed cost/lb of gain. At high and low feed prices, increasing SID Lys increased (linear, P \u3c 0.002) IOFC. A linear model resulted in the best fit for ADG and predicted that the maximum ADG response was beyond 1.00% SID Lys. For F/G, the quadratic polynomial model predicted a requirement of 0.97% SID Lys. At high ingredient and pig prices, the broken-line linear model to maximize IOFC predicted that there was no further significant improvement to IOFC past 0.76% SID Lys. Meanwhile, at low ingredient and pig prices the quadratic polynomial model predicted a requirement of 0.91% SID Lys to maximize IOFC, however, a similar fitting linear model predicted maximum IOFC response at greater than 1.00% SID Lys. In summary, the optimal SID Lys level for 120- to 170-lb finishing pigs depends upon the response criteria, with growth performance optimized at or greater than 0.97% SID Lys and IOFC maximized between 0.76 to 0.91% SID Lys

Effects of Added Potassium to Diets with High or and Low Crystalline Lysine on Finishing Pig Growth Performance

This experiment was conducted to evaluate the effect of balancing dietary cation-anion difference (DCAD) levels, via added potassium bicarbonate (KHCO3), to diets containing low or high levels of L-Lys HCL on growth performance of growing-finishing pigs. A total of 1,944 pigs (PIC L337 × 1050; initially 77.6 ± 1.88 lb BW) were used in a 120-d study to determine the effect of added potassium bicarbonate to diets containing low or high levels of crystalline lysine on growth performance and carcass characteristics of finishing pigs. Pens of pigs were blocked by BW and randomly allotted to 1 of 4 dietary treatments in a randomized complete block design arranged in a 2 × 2 factorial with main effects of KHCO3 (0 vs. 0.4%), and L-Lys HCl level (low vs. high). There were 27 pigs per pen and 18 replicates per treatment and a similar number of barrows and gilts placed in each pen. Treatment diets were corn-soybean meal-based and formulated in four dietary phases (approximately 80 to 130 lb, 130 to 185 lb, 185 to 230 lb, and 230 to 285 lb). Dietary treatments were formulated such that in each phase the diet containing a low level of L-Lys HCl without KHCO3 and the diet containing a high level of L-Lys HCl with KHCO3, had similar calculated DCAD values. Additionally, the diet with a low level of L-Lys HCl with KHCO3 was formulated to have the highest DCAD in each phase, while the diet with a high level of L-Lys HCl without KHCO3 was formulated to have the lowest DCAD. Overall, there was no evidence (P \u3e 0.10) for a KHCO3 × L-Lys HCl interaction or main effect for final BW or any observed growth response or carcass characteristics. The results of this study suggest that supplementing KHCO3 to finishing pig diets with either high or low levels of L-Lys HCl and the corresponding changes in DCAD values did not impact growth performance or carcass characteristics

Effects of Added Calcium Carbonate on Weanling Pig Growth Performance

A total of 695 barrows (DNA Line 200 × 400; initially 12.9 lb) were used in two groups in a 28-d study to evaluate the effects of added dietary calcium carbonate on phase 1 nursery pig growth performance and fecal dry matter. Upon arrival to the nursery research facility, pigs were randomly assigned to pens (5 pigs per pen) and pens were allotted to 1 of 5 dietary treatments with 27 or 28 pens per treatment. Dietary treatments were formulated to provide 0, 0.45, 0.90, 1.35, and 1.80% calcium carbonate added at the expense of corn. Analyzed Ca for treatment diets were 0.61, 0.80, 0.99, 1.15, and 1.37%, respectively. Standardized total tract P concentration was formulated to 0.58% in all diets. Diets were fed in two phases with treatment diets fed from weaning (d 0) to d 14 and a common phase 2 diet fed from d 14 to 28. Treatment diets were fed in both meal (group 1) and pellet (group 2) form. There was no evidence for treatment × group interaction observed, so data from both groups were combined. From d 0 to 14 (treatment period), ADG, d 14 BW, and F/G worsened (linear, P = 0.010) as calcium carbonate increased. There was no evidence for difference for ADFI (P \u3e 0.10). From d 14 to 28 (common period) and for the overall experiment (d 0 to 28), there was no evidence (P \u3e 0.10) for differences observed for any growth performance criteria. For fecal dry matter, there was a tendency (quadratic, P = 0.091) with the highest and lowest calcium carbonate diets having the highest dry matter. In summary, increasing dietary calcium carbonate from 0 to 1.80% decreases ADG and worsens feed efficiency in phase 1 nursery diets. Despite the linear response, the largest decrease was observed when calcium carbonate increased from 0.45 to 0.90% with no difference in performance thereafter. These data suggest that lower levels of calcium carbonate can be used than are typically added to phase 1 diets

Dietary Acid-Binding Capacity-4 Influences Nursery Pig Performance and Fecal Dry Matter

A total of 360 pigs (200 × 400 DNA; initially 12.9 lb) were used to evaluate the impact of increasing the acid-binding capacity-4 (ABC-4) of the diet on nursery pig performance and fecal dry matter (DM). At weaning, pigs were allotted to 1 of 6 dietary treatments. There were 5 pigs per pen and 12 replications per treatment. Pigs were fed experimental diets in two phases with phase 1 being from d 0 to 10 post-weaning followed by phase 2 from d 10 to 23. Diets were formulated with increasing ABC-4 levels ranging from 150 meq/kg (diet 1, low ABC-4) to 312 meq/kg (diet 5, high ABC-4) in phase 1 and 200 meq/kg (diet 1, low ABC-4) to 343 meq/kg (diet 5, high ABC-4) in phase 2. For diet 1, the low ABC-4 diets were formulated using specialty soy protein concentrate (AX3 Digest; Protekta; Newport Beach, CA) at 12.50 and 10.00% of the diet in phase 1 and 2, respectively. The low ABC-4 diet also utilized fumaric acid and formic acid at 0.50 and 0.48% of the diet, respectively for both phase 1 and 2. For diets 2 (medium low), 3 (medium), 4 (medium high), and 5 (high), increasing ABC-4 of the diet was achieved by progressively decreasing the level of acidifiers and replacing specialty soy protein concentrate with enzymatically treated soybean meal (HP 300; Hamlet Protein; Findlay, OH) on an SID Lys basis. Diets 1 through 5 were formulated without the inclusion of ZnO. For diet 6, a positive control diet was utilized which had the same formulation as the highest ABC-4 diet but with the addition of pharmacological levels of Zn from ZnO. Following phase 2, all pigs were placed on a common diet until d 38 of the study. In the experimental period (d 0 to 23) and overall (d 0 to 38), a quadratic response was observed (P ≤ 0.030) where BW and ADG were highest for pigs fed the medium low and medium ABC-4 diets. During the experimental period (d 0 to 23), pigs fed increasing ABC-4 levels had poorer (linear, P = 0.002) F/G. For overall F/G, a quadratic response was observed (P = 0.023) where F/G was most improved for pigs fed the medium low and medium ABC-4 levels. Pigs fed diets with ZnO had increased (P ≤ 0.038) ADG compared to pigs fed diets without ZnO during the experimental period and overall. In summary, pharmacological levels of Zn improved nursery pig performance as expected. The medium low and medium ABC-4 levels improved performance compared to higher ABC-4 levels, suggesting an optimal ABC-4 level of the diet for this study would be at or below 256 and 295 meq/kg in phase 1 and 2, respectively