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A total of 288 pigs (PIC 327 × 1050; initially 11.1 ± 0.1 kg, and day 40 of age) were used in a 21-d growth trial to determine the available P (aP) release curve for a novel source of 6-phytase (Natuphos E 5,000 G; BASF Corporation, Florham Park, NJ). Natuphos E is a bacterial derived 6-phytase of which the phytase gene is assembled from a hybrid of phytase-producing bacteria and produced through the fermentation of Aspergillus niger. Pigs were randomly allotted to pens at weaning. From day 15 to 18 postweaning, a common corn-soybean meal diet containing 0.12% aP was fed to all pigs to acclimate them to a P-deficient diet. On day 0 of the experiment (day 19 after weaning), pens were allotted in a randomized complete block design to one of eight treatments. There were four pigs per pen and nine pens per dietary treatment. Pigs were fed a corn-soybean meal-based diet formulated to 1.25% standardized ileal digestible Lys. Experimental diets were formulated to contain 0.73% Ca and increasing aP supplied by either monocalcium P (0.12%, 0.18%, and 0.24% aP) or from increasing phytase (150, 250, 500, 750, and 1,000 phytase unit [FTU]/kg) added to the 0.12% aP diet. Analyzed phytase concentrations were 263, 397, 618, 1,100, and 1,350 FTU/kg, respectively. On day 21 of the study, one pig per pen was euthanized and the right fibula was collected for bone ash and percentage bone ash calculations. From day 0 to 21, increasing P from monocalcium P or phytase improved (linear, P< 0.01) ADG and G:F. Bone ash weight and percentage bone ash increased (linear, P< 0.01) with increasing monocalcium P or phytase. When formulated phytase values and percentage bone ash are used as the response variables, aP release for up to 1,000 FTU/kg of Natuphos E 5,000 G phytase can be predicted by the equation: aP release = 0.000212 × FTU/kg phytase.

A total of 1,143 pigs (PIC 337 × 1050, initially 25.1 ± 0.03 kg BW) were used in a 111-d study to determine the effects of copper sulfate (CuSO4; Prince Agri-Products, Quincy, IL) or tribasic copper chloride (TBCC; IntelliBond C; Micronutrients, Indianapolis, IN) on growth performance, carcass characteristics, and pen cleanliness. Pens of pigs were allotted to 1 of 6 dietary treatments, balanced on average pen weight in a randomized complete block design with 25 to 28 pigs per pen and 7 replications per treatment. Treatments included a corn–soybean meal–based diet (corn-soy), a high-by-product diet with 30% distillers dried grains with solubles and 15% bakery meal (by-product diet), and the by-product diet with 75 or 150 mg/kg added Cu from CuSO4or TBCC. All diets contained 20 mg/kg Cu from CuSO4in the trace mineral premix. At the conclusion of the trial, a digital photo of each pen was taken to allow 3 independent observers to score manure texture and buildup and to assess pen cleanliness prior to power washing. Furthermore, the time required to power wash each pen was also measured. Overall, pigs fed the by-product diet tended to have increased ADFI (P= 0.083) and had decreased G:F (P= 0.005) compared to those fed the corn-soy diet. No Cu source × level interactions or Cu source differences were observed (P> 0.05). From d 0 to 71, pigs fed increasing Cu had increased (quadratic, P< 0.05) ADG, d 71 BW, and ADFI. From d 71 to 111, pigs fed increasing Cu tended to have increased ADFI (linear, P= 0.068) and decreased G:F (quadratic, P= 0.056). Overall (d 0 to 111), increasing Cu increased (linear, P< 0.01) ADG, final BW, and ADFI (quadratic, P= 0.026). Hot carcass weight increased (linear, P= 0.023) by 2.4 kg with increasing Cu. Increasing Cu also increased loin depth (linear, P= 0.019) and percentage lean (quadratic, P= 0.024). Manure buildup and wash time (s/pen) increased (P< 0.05) for by-product diet pens compared to corn-soy pens; however, neither wash time nor pen cleanliness were influenced by added Cu. In summary, increasing dietary Cu in high-by-product diets improved growth and feed intake, resulting in increased final BW and HCW for pigs fed both Cu sources, without influencing pen wash time.

Porcine epidemic diarrhea virus (PEDV) is a heat-sensitive virus that has devastated the U.S. swine industry. Because of its heat sensitivity, we hypothesized that a steam conditioner and pellet mill mimicking traditional commercial thermal processing may mitigate PEDV infectivity. Pelleting, a common feed processing method, includes the use of steam and shear forces, resulting in increased temperature of the processed feed. Two thermal processing experiments were designed to determine if different pellet mill conditioner retention times and temperatures would impact PEDV quantity and infectivity by analysis of quantitative reverse transcription PCR and bioassay. In Exp. 1, a 3 · 3 · 2 factorial design was used with 3 pelleting temperatures (68.3, 79.4, and 90.6°C), 3 conditioning times (45, 90, or 180 s), and 2 doses of viral inoculation (low, 1 · 102tissue culture infectious dose50(the concentration used to see cytopathic effect in 50% of the cells)/g, or high, 1 · 104tissue culture infectious dose50/g). Noninoculated and PEDV-inoculated unprocessed mash were used as controls. The low-dose PEDV–infected mash had 6.8 ± 1.8 cycle threshold (Ct) greater (P< 0.05) PEDV than the high-dose mash. Regardless of time or temperature, pelleting reduced (P< 0.05) the quantity of detectable viral PEDV RNA compared with the PEDV-inoculated unprocessed mash. Fecal swabs from pigs inoculated with the PEDV-positive unprocessed mash, regardless of dose, were clinically PEDV positive from 2 to 7 d (end of the trial) after inoculation. However, if either PEDV dose of inoculated feed was pelleted at any of the 9 tested conditioning time · temperature combinations, no PEDV RNA was detected in fecal swabs or cecum content. Based on Exp. 1 results, a second experiment was developed to determine the impact of lower processing temperatures on PEDV quantity and infectivity. In Exp. 2, PEDV-inoculated feed was pelleted at 1 of 5 conditioning temperatures (37.8, 46.1, 54.4, 62.8, and 71.1°C) for 30 s. The 5 increasing processing temperatures led to feed with respective mean Ct values of 32.5, 34.6, 37.0, 36.5, and 36.7, respectively. All samples had detectable PEDV RNA. However, infectivity was detected by bioassay only in pigs from the 37.8 and 46.1°C conditioning temperatures. Experiment 2 results suggest conditioning and pelleting temperatures above 54.4°C could be effective in reducing the quantity and infectivity of PEDV in swine feed. However, additional research is needed to prevent subsequent recontamination after pelleting as it is a point-in-time mitigation step.

The addition of dietary fat has been shown to increase HCW and carcass yield in pigs fed low-fiber corn-soy diets; however, data on added fat in high-fiber, low-energy diets is less available. Therefore, the potential for dietary fat to ameliorate the negative effect high-fiber diets have on carcass yield during the last 3 wk before slaughter is of high importance. This experiment was conducted to determine the interactive effects of 30% distillers dried grains with solubles (DDGS) and 5% added fat fed before slaughter on growth performance and carcass characteristics. A total of 1,258 pigs in 2 groups (initially 105.8 ± 0.1 kg BW; group 1 PIC 337 × 1,050; group 2 PIC 327 × 1,050) were used in a 20-d experiment. All pigs were fed a common diet with 30% DDGS until 20 d before slaughter. Then, all pens were weighed and allotted to treatments with 20 replicate pens per treatment. Dietary treatments were arranged in a 2 × 2 factorial with 2 diet types (corn-soybean meal–based with or without 30% DDGS) and added fat (0 or 5%; group 1 = tallow; group 2 = choice white grease). Diets were formulated to a constant standardized ileal digestible Lys:NE ratio. There were no treatment × group interactions for any response criteria. Thus, data for the 2 groups were combined for analysis. Overall, there was a tendency for a diet type × added fat interaction for ADG (P= 0.054), whereas this was significant for G:F (P= 0.008). This was a result of 5% added fat increasing ADG and G:F to a greater magnitude for pigs fed the diet containing 30% DDGS (8.6 and 10.4%, respectively) than for pigs fed the corn-soy diet (2.0 and 2.9%, respectively). Although diet type did not affect final live BW, pigs fed the diet containing DDGS had decreased HCW and carcass yield (P< 0.05). Adding 5% fat did not affect carcass yield. In conclusion, adding 5% fat to finishing pig diets containing 30% DDGS approximately 20 d before slaughter improved ADG and G:F but did not overcome the reduction in carcass yield from feeding DDGS.

A total of 2,100 pigs (PIC 327 × 1050; initially 31.2 kg BW) were used in a 118-d trial to determine the effects of pellet or meal feeding regimens on finishing pig growth performance, stomach morphology, and carcass characteristics. Pens of pigs were balanced by initial BW and randomly allotted to 1 of 6 dietary treatments (14 pens/treatment with 25 pigs/pen). Pens were sorted by gender allowing for 7 barrow pens and 7 gilt pens per treatment. The same corn–soybean meal–based diets containing 15% dried distillers' grains with solubles were used for all treatments and fed in 5 phases. Phases were fed from d 0 to 28, 28 to 56, 56 to 84, 84 to 98, and 98 to 118. The 6 treatments included a meal or pelleted diet fed from d 0 to 118, a meal diet fed from d 0 to 70 followed by pellets from d 70 to 118, a pelleted diet fed from d 0 to 70 followed by a meal diet from d 70 to 118, or pellets and meal rotated every 2 wk starting with meal or pellets. On d 110, 4 pigs from each pen were harvested and stomachs collected, from which a combined ulcer and keratinization score was determined for each pig. Overall, there were no differences in ADG across feeding regimens. Pigs fed meal throughout had the greatest (P< 0.05) ADFI, whereas pigs fed pellets throughout had the lowest (P< 0.05), with all other treatments intermediate (P< 0.05). Pigs fed pelleted diets throughout had the greatest (P< 0.05) G:F, whereas pigs fed meal throughout had the worst G:F (P< 0.05), with all other treatments intermediate (P< 0.05). When pelleted diets were fed for the last 58 d or for the entire trial, the incidence of ulceration and keratinization increased (P< 0.05), whereas pigs fed meal for the last 58 d had a lower incidence (P< 0.05), with all other treatments intermediate (P< 0.05). Feeding pellets throughout increased (P< 0.05) the number of pigs removed per pen compared with all other treatments. Pig removals were determined by an on-site farm manager when pigs were at risk due to weight loss, health, or animal welfare concerns and needed to be separated from the general population. There were no differences for any carcass characteristics measured including HCW, carcass yield, backfat depth, loin depth, and percentage lean. In conclusion, feeding pelleted diets improved G:F but increased stomach ulceration and pig removals; however, rotating pellets and meal diets provided an intermediate G:F response and moderated stomach ulcerations compared with feeding only pellets.

A of subsample of 448 growing pigs (PIC 327 × 1050) weaned from 52 sows fed varying dietary vitamin D regimens were used in a split-plot design to determine the effects of maternal and nursery dietary vitamin D on growth performance. Sows were previously administered diets containing vitamin D as vitamin D3(800, 2,000, or 9,600 IU/kg) or as 25(OH)D3(50 µg [or 2,000 IU vitamin D equivalent]/kg from HyD; DSM Nutritional Products, Parsippany, NJ). Once weaned, pigs were allotted to pens on the basis of previous maternal vitamin D treatment, and then pens were randomly assigned to 1 of 2 nursery vitamin D dietary regimens (2,000 IU of vitamin D3/kg or 50 µg 25(OH)D3/kg). Pigs remained on nursery vitamin D treatments for 35 d, and then they were provided common finishing diets until market (135 kg). Growing pig serum 25(OH)D3suggested that maternal dietary vitamin D influenced (P< 0.001 at weaning) serum concentrations early after weaning, but nursery vitamin D regimen had a larger impact (P< 0.001) on d 17 and 35 postweaning. Overall growth performance was not influenced by nursery vitamin D dietary treatments. From d 0 to 35 in the nursery, pigs from sows fed increasing vitamin D3had increased (quadratic, P< 0.003) ADG and ADFI, but G:F was similar regardless of maternal vitamin D regimen. Also, pigs from sows fed 50 µg/kg of 25(OH)D3had increased (P= 0.002) ADG compared with pigs weaned from sows fed 800 IU of vitamin D3. Throughout finishing (d 35 postweaning until 135 kg), ADG was increased (quadratic, P= 0.005) and G:F was improved (quadratic, P= 0.049) with increasing maternal dietary vitamin D3. Also, pigs from sows fed 50 µg/kg of 25(OH)D3had increased (P= 0.002) ADG compared with pigs weaned from sows fed 800 IU of vitamin D3. Carcass data were collected from a subsample population separate from that used for the growth performance portion of the study, and a total of 642 carcasses from progeny of sows fed the varying dietary vitamin D treatments were used. Live BW of pigs at marketing and HCW were heavier (P< 0.030) for pigs from sows previously fed 25(OH)D3compared with pigs from sows fed 9,600 IU of vitamin D3. Overall, pigs from sows fed 2,000 IU of vitamin D3grew faster after weaning compared with pigs from sows fed 800 or 9,600 IU of vitamin D3. Pigs from sows fed 25(OH)D3hag greater ADG compared with pigs from sows fed 800 IU of vitamin D3, and they had increased final BW and HCW compared with pigs from sows fed 9,600 IU of vitamin D3.

In Exp. 1, 56 gestating sows (PIC 1050; 35 d postinsemination) were used in a 30-d trial to determine serum 25(OH)D3response to increasing concentrations of dietary vitamin D3. Sows were randomly allotted to 1 of 7 dietary D3treatments (200, 800, 1,600, 3,200, 6,400, 12,800, or 25,600 IU of added D3per kilogram of complete diet) with 8 sows per treatment. Increasing D3increased (quadratic; P< 0.001) serum 25(OH)D3with the response depicted by the prediction equation: serum 25(OH)D3, ng/mL = 35.1746 + (0.002353 × dietary D3, IU/d) − (0.0000000156 × dietary D3, IU/d2). In Exp. 2, 112 sows and their litters were used to determine the effects of dietary vitamin D regimen on sow performance, subsequent preweaning pig performance, neonatal bone and muscle characteristics, and serum vitamin metabolites. Sows were allotted to 1 of 4 dietary treatments 3 to 5 d following breeding: 800, 2,000, or 9,600 IU of D3per kilogram of the diet or 50 µg of 25(OH)D3(2,000 IU of D3equivalent from Hy-D, DSM Nutritional Products, Parsippany, NJ) per kilogram of diet. There were 25 to 27 sows per treatment. Increasing dietary D3increased (linear, P= 0.001) serum 25(OH)D3of sows on d 100 of gestation, at farrowing, and at weaning. Increasing D3in sow diets increased piglet serum 25(OH)D3at birth (linear, P= 0.001) and weaning (quadratic, P= 0.033). Sows fed 50 µg of 25(OH)D3/kg had intermediate (P< 0.004) serum 25(OH)D3concentrations on d 100 of gestation, at farrowing, and at weaning compared with sows fed 2,000 IU of D3/kg and sows fed 9,600 IU of D3/kg. Pigs from sows fed 50 µg of 25(OH)D3/kg had greater serum 25(OH)D3compared with pigs from sows fed 2,000 IU of D3/kg, but at weaning, serum 25(OH)D3concentrations were similar. Also, pigs from sows fed 9,600 IU of D3/kg had greater (P= 0.011) serum 25(OH)D3at birth and weaning compared with pigs from sows fed 50 µg of 25(OH)D3/kg. Maternal performance, litter characteristics, neonatal bone ash content, and neonatal muscle fiber characteristics were largely unaffected by the dietary vitamin D treatments. Overall, D3and 25(OH)D3are both useful at increasing serum 25(OH)D3concentrations, but more D3(on an equivalent IU basis) is needed to achieve similar serum 25(OH)D3responses compared with feeding 25(OH)D3. Concentration of maternal vitamin D supplementation in lactation impacted milk transfer of the vitamin more so than the form of the vitamin, as evidence by the weaned pig serum 25(OH)D3concentrations.

ABSTRACT: A total of 1,092 finishing pigs (initially 36.3 kg) were used in a 117-d study to evaluate the impact of initial floor space allowance and removal strategy on the growth of pigs up to 140 kg BW. There were 4 experimental treatments with 14 pens per treatment. The first treatment provided 0.91 m2per pig (15 pigs/pen). The other 3 treatments initially provided 0.65 m2per pig (21 pigs/pen) with 3 different removal strategies. The second treatment (2:2:2) removed the 2 heaviest pigs from pens on d 64, 76, and 95 when floor space allowance was predicted to be limiting. Treatment 3 (2:4) removed the 2 heaviest pigs on d 76 and the 4 heaviest pigs on d 105. Treatment 4 (6) removed the heaviest 6 pigs on d 105. All pigs remaining in pens after removals were fed to d 117. Overall (d 0 to 117), pigs initially provided 0.91 m2of floor space had increased (P< 0.05) ADG compared to pigs in pens on the 2:4 or 6 removal strategy, but ADG was not different compared with pigs on the 2:2:2 removal strategy. Total BW gain per pen was greater (P< 0.05) for pens initially stocked at 0.65 m2compared to pens initially stocked at 0.91 m2. Feed usage per pen was less (P< 0.05) for pens initially stocked at 0.91 m2compared to pens initially providing 0.65 m2of floor space and on removal strategies; however, feed usage per pig was greater (P< 0.05) for pigs initially stocked at 0.91 m2compared to pigs initially stocked at 0.65 m2and on removal strategies. Feed usage, on a pig or pen basis, was less (P< 0.05) for pigs on the 2:2:2 removal strategy compared to pigs on the 2:4 or the 6 removal strategy. Income over feed and facility cost (IOFFC) was less (P< 0.05) for pigs initially provided 0.91 m2compared to pigs initially provided 0.65 m2and on removal strategies. Also, IOFFC was less (P< 0.05) for pigs on the 2:2:2 compared to the 2:4 and 6 removal strategies. In conclusion, increasing the floor space allowance or the time points at which pigs are removed from the pen improved the growth of pigs remaining in the pen; however, IOFFC may be reduced because fewer pigs are marketed from each pen (pigs stocked at 0.91 m2throughout the study) or from reducing total weight produced (2:2:2 removal strategy).

A 300-d study was conducted to evaluate storage stability of 4 commercially available phytase products under varied environmental conditions. Products used were: 1) Quantum Blue G (AB Vista, Plantation, FL), 2) Ronozyme Hi Phos GT (DSM Nutritional Products, Parsippany, NJ), 3) Axtra Phy TPT (Dupont, Wilmington, DE), and 4) Microtech 5000 Plus (Guangdong Vtr Bio-Tech Co., Ltd., Guangdong, China). Products were stored as pure forms, in a vitamin premix, or a vitamin trace mineral (VTM) premix. Pure products were stored at -20°C, 4°C, 22°C, or 35°C (75% humidity). Vitamin and VTM premixes were stored at 22°C or 35°C (75% humidity). Samples were stored in open-topped paper bags and sampled on d 30, 60, 90, 120, 210, and 300. Stability was determined as the amount of residual phytase activity (% of initial) at each sampling point. For the pure forms, all interactive and main effects of phytase product, time, and storage temperature were significant (P <0.05). From d 30 to 300, products had similar reductions in phytase activity at the 3 highest temperatures; however, Quantum Blue G, Ronozyme HiPhos GT, and Axtra Phy TPT had reduced (P <0.05) phytase activity as compared to Microtech 5000 at -20°C. In general, as storage time increased, residual phytase activity decreased (P <0.05) regardless of product and storage temperature. When product was stored at 4°C and 22°C, phytase activity was greater than that of product stored at -20°C or 35°C, and Microtech 5000 Plus had greater (P <0.05) stability regardless of time and temperature as compared to the other 3 products. For vitamin and VTM premixes, a time × temperature × product interaction (P <0.05) was observed. When stored at 22°C, Axtra Phy TPT and Microtech 5000 Plus had reduced residual phytase activity (P <0.05) when compared to the other 2 products; however, when stored at 35°C Axtra Phy had even further reduced (P <0.05) activity than the other 3 products regardless of which form the products were stored in. From d 30 to 300 Axtra Phy TPT and Microtech 5000 Plus had the lowest (P <0.05) residual phytase activity when compared to the others regardless of storage form or temperature. Phytase products stored in VTM premix had decreased (P <0.05) residual phytase activity when compared to pure products and vitamin premixes. In conclusion, phytase stored for longer than 90 to 120 d, at both high (35°C) and low (-20°C) temperatures when in pure form or as a VTM premix had reduced residual phytase activity.

Two experiments were conducted to characterize the progression of deoxynivalenol (DON)-induced growth suppression and to investigate algae-modified montmorillonite clay (AMMC) as a means to alleviate the effects of DON in nursery pigs. In both experiments, naturally DON-contaminated wheat was used to produce diets with desired DON levels. In Exp. 1, 280 barrows and gilts (10.0 ± 0.2 kg BW) were used in a 28-d experiment arranged in a 2 × 2 + 1 factorial design with 8 replicates per treatment. The 5 treatments consisted of 2 positive control (PC) diets with DON below detection limits and with or without 0 or 0.50% AMMC and 3 negative control (NC) diets with 5 mg/kg of DON and containing 0, 0.25, or 0.50% AMMC. No DON × AMMC interactions were observed. Overall, pigs fed DON had decreased (P< 0.001) ADG and final BW regardless of AMMC addition. Feeding DON-contaminated diets elicited the most severe depression (P< 0.001) in ADFI and G:F from d 0 to 3, remaining poorer overall (P< 0.01) but lessening in severity as exposure time increased. Pigs fed DON diets had greater (P< 0.05) within pen BW variation (CV) on d 28. Although the addition of 0.50% AMMC to diets restored (P< 0.05) ADFI from d 14 to 21 to levels similar to the PC, no other differences were observed for AMMC inclusion. In Exp. 2, 360 barrows (11.4 ± 0.2 kg BW) were used in a 21-d experiment with 9 dietary treatments arranged in a 3 × 3 factorial design with DON and AMMC inclusion as main effects. There were 8 replicate pens per treatment. Treatments consisted of 3 PC diets without DON, 3 low-DON (1.5 mg/kg DON) NC diets, and 3 high-DON (3 mg/kg DON) NC diets with 0, 0.17, or 0.50% AMMC incorporated at each DON level. No DON × AMMC interactions were observed. As DON level increased, ADG and final BW decreased (quadratic, P< 0.05), driven by decreased (quadratic, P< 0.01) ADFI and poorer (quadratic; P< 0.05) G:F. At both 1.5 and 3 mg/kg DON, reductions in ADG were most marked from d 0 to 7 (15 to 22% lower) and were least distinct from d 14 to 21 (5 to 6% lower). Incorporating AMMC at increasing levels had no effect on ADG, ADFI, G:F, or final BW. Overall, these experiments reinforce DON effects on feed intake but also indicate that the effects of DON on G:F may be more severe than previously thought. Furthermore, some pigs appear to develop tolerance to DON, as effects on ADFI and G:F lessen over time. However, the addition of AMMC did not offset the deleterious effects of DON.

Two experiments were conducted to test the effects of wheat source and particle size in meal and pelleted diets on finishing pig performance, carcass characteristics, and diet digestibility. In Exp. 1, pigs (PIC 327 · 1050; n= 288; initially 43.8 kg BW) were balanced by initial BW and randomly allotted to 1 of 3 treatments with 8 pigs per pen (4 barrows and 4 gilts) and 12 pens per treatment. The 3 dietary treatments were hard red winter wheat ground with a hammer mill to 728, 579, or 326 μm, respectively. From d 0 to 40, decreasing wheat particle size decreased (linear, P< 0.033) ADFI but improved (quadratic, P< 0.014) G:F. From d 40 to 83, decreasing wheat particle size increased (quadratic, P< 0.018) ADG and improved (linear, P< 0.002) G:F. Overall from d 0 to 83, reducing wheat particle size improved (linear, P< 0.002) G:F. In Exp. 2, pigs (PIC 327 · 1050; n= 576; initially 43.4 ± 0.02 kg BW) were used to determine the effects of wheat source and particle size of pelleted diets on finishing pig growth performance and carcass characteristics. Pigs were randomly allotted to pens, and pens of pigs were balanced by initial BW and randomly allotted to 1 of 6 dietary treatments with 12 replications per treatment and 8 pigs/pen. The experimental diets used the same wheat–soybean meal formulation, with the 6 treatments using hard red winter or soft white winter wheat that were processed to 245, 465, and 693 μm and 258, 402, and 710 μm, respectively. All diets were pelleted. Overall, feeding hard red winter wheat increased (P< 0.05) ADG and ADFI when compared with soft white winter wheat. There was a tendency (P< 0.10) for a quadratic particle size · wheat source interaction for ADG, ADFI, and both DM and GE digestibility, as they were decreased for pigs fed 465-μm hard red winter wheat and were greatest for pigs fed 402-μm soft white winter wheat. There were no main or interactive effects of particle size or wheat source on carcass characteristics. In summary, fine grinding hard red winter wheat fed in meal form improved G:F and nutrient digestibility, whereas reducing particle size of wheat from approximately 700 to 250 μm in pelleted diets did not influence growth or carcass traits. Finally, feeding hard red winter wheat improved ADG and ADFI compared with feeding soft white winter wheat.

A total of 480 pigs (PIC 327 · 1050; initially 48.7 ± 2.3 kg) were used to determine the interactive effects of supplemental Cu, Zn, and ractopamine HCl (RAC) on finishing pig growth performance, carcass characteristics, and antimicrobial susceptibility of enteric bacteria. Treatments were arranged in a 2 · 2 · 2 factorial with the main effects of added Cu (CuSO4; 0 vs. 125 mg/kg Cu), Zn (ZnO; 0 vs. 150 mg/kg Zn), and RAC (0 vs. 10 mg/kg during the last 28 d prior to marketing). All diets contained 11 mg/kg Cu and 73 mg/kg Zn from the trace mineral premix. Pens of pigs were balanced and blocked on initial BW and then randomly allotted to 1 of the 4 mineral treatment diets. At 28 d prior to marketing, pens within each block and mineral treatment were randomly assigned to receive either 0 or 10 mg/kg RAC in addition to the mineral treatment. Adding either Cu or Zn alone did not improve ADG or ADFI yet resulted in numerical improvements in overall G:F and caloric efficiencies, but improvements were not additive (Cu · Zn, P= 0.057, P= 0.068, and P= 0.064 for G:F and caloric efficiency on a ME and NE basis, respectively). Ractopamine improved (P< 0.001) overall ADG, G:F, and caloric efficiency, thereby increasing final BW by 3% with no change in ADFI. Ractopamine also increased (P< 0.001) HCW, percentage carcass yield, G:F, loin depth, and percent fat-free lean and decreased (P= 0.014) backfat. Adding Zn or Cu alone to diets containing RAC numerically improved percent yield and HCW G:F, but this effect was absent when the Cu or Zn was added to the control diet or when Cu and Zn were fed in combination in RAC diets (Cu · Zn · RAC, P= 0.011 and P= 0.018 for yield and HCW G:F, respectively). Fecal samples were collected on d 0 and at the conclusion of the finishing period (d 90) for bacterial isolation and antimicrobial susceptibility determinations according to Clinical and Laboratory Standards Institute minimal inhibitory concentrations breakpoints. Enterococcusspp. and Escherichia coliisolates displayed varying levels of resistance to certain antibiotics prior to initiation of treatments on d 0. Resistance to most antibiotics decreased (P< 0.05) over time or was stable for those that had a low baseline percentage of resistance. Neither Zn nor RAC adversely affected antimicrobial resistance. However, extended feeding of 125 mg/kg Cu throughout the finishing period seems to decrease enterococcal susceptability to tetracycline, tylosin, and quinupristin/dalfopristin.

A total of 160 finishing pigs (PIC 327 × 1050; initially 45.6 kg) were used in an 84-d experiment to evaluate the effects of dietary fat source and feeding duration on growth performance, carcass characteristics, and carcass fat quality. There were 2 pigs per pen with 8 pens per treatment. The 10 dietary treatments were a corn–soybean meal control diet with no added fat and a 3 × 3 factorial with main effects of fat source (4% tallow, 4% soybean oil, or a blend of 2% tallow and 2% soybean oil) and feeding duration (d 0 to 42, 42 to 84, or 0 to 84). The control corn–soybean meal diet was fed in place of added fat diets when needed for duration treatment purposes. On d 0, 1 pig was identified in each pen and fat biopsy samples of the back, belly, and jowl were collected on d 0, 41, and 81 for fatty acid analysis. At the conclusion of the study, all pigs were harvested, carcass characteristics were determined, and back, belly, and jowl fat samples were collected for analysis. Overall (d 0 to 84), there were no differences among pigs fed the different fat sources for growth and carcass characteristics; however, pigs fed diets with added fat for the entire study had improved (P= 0.036) G:F compared with pigs fed the control diet without added fat. Pigs fed supplemental fat throughout the entire study also had improved (P< 0.05) ADG and G:F as well as heavier d-84 BW (P= 0.006) compared with pigs fed additional fat during only 1 period. Adding fat for the entire study increased (P= 0.032) backfat and tended to reduce (P= 0.079) the fat free lean index compared with pigs fed the control diet without added fat. Added fat also increased (P< 0.05) the iodine value (IV) when compared with pigs fed the control diet. Increasing the feeding duration of soybean oil lowered MUFA and increased PUFA concentrations for all fat depots, whereas these values remained relatively unchanged by the addition of tallow (duration × fat source interactions, P< 0.05). Our study failed to show any feeding period × fat source interactions (P< 0.05) in fatty acid composition or IV for jowl fat, whereas this interaction occurred for belly fat and backfat, which would indicate a longer turnover rate for jowl fat. In conclusion, feeding additional fat improved ADG and G:F; however, feeding soybean oil for an increased duration, either alone or in combination with tallow, negatively affected the fatty acid composition and IV of different fat depots.

The objective of this study was to determine the effects of AA and energy intake during late gestation on piglet birth weight and reproductive performance of high-performing (14.5 total born) gilts and sows housed under commercial conditions. At d 90 of gestation, a total of 1,102 females (PIC 1050) were housed in pens by parity group (gilts or sows) with approximately 63 gilts and 80 sows in each pen, blocked by BW within each pen, and each female was randomly assigned to dietary treatments within BW block. Dietary treatments consisted of combinations of 2 standardized ileal digestible (SID) AA intakes (10.7 or 20.0 g/d SID Lys and other AA met or exceeded the NRC [2012] recommendations) and 2 energy intakes (4.50 or 6.75 Mcal/d intake of NE) in a 2 × 2 factorial arrangement. Data were analyzed using generalized linear mixed models specified to recognize pen as the experimental unit for parity and the individual female as the experimental unit for dietary treatments. Results indicate an overall positive effect of high energy intake on BW gain during late gestation, although this effect was more manifest under conditions of high, as opposed to low, AA intake (interaction, P< 0.001). Furthermore, the magnitude of BW gain response to increased energy intake was greater (P< 0.001) for sows compared with gilts. Sows fed high energy intake had a reduced probability of piglets born alive (P< 0.004) compared with those fed low energy, but no evidence for differences was found in gilts. This can be explained by an increased probability (P= 0.002) of stillborns in sows fed high energy intake vs. sows fed low energy intake. There were no evidences for differences among dietary treatments in litter birth weight and individual piglet birth weight of total piglets born. However, individual born alive birth weight was approximately 30 ± 8.2 g heavier (P= 0.011) for females fed high, as opposed to low, energy intake. Furthermore, piglets born alive were approximately 97 ± 9.5 g heavier (P< 0.001) for sows than for gilts. Preweaning mortality was decreased (P= 0.034) for females fed high AA intake compared with females fed low AA intake regardless of energy level. In conclusion, 1) BW gain of gilts and sows depended not only on energy but also on AA intake, 2) sows fed increased amount of energy had an increased stillborn rate, and 3) increased energy intake during late gestation had a positive effect on individual piglet birth weight with no evidence for such an effect for AA intake.

Advanced methods for dose–response assessments are used to estimate the minimum concentrations of a nutrient that maximizes a given outcome of interest, thereby determining nutritional requirements for optimal performance. Contrary to standard modeling assumptions, experimental data often present a design structure that includes correlations between observations (i.e., blocking, nesting, etc.) as well as heterogeneity of error variances; either can mislead inference if disregarded. Our objective is to demonstrate practical implementation of linear and nonlinear mixed models for dose–response relationships accounting for correlated data structure and heterogeneous error variances. To illustrate, we modeled data from a randomized complete block design study to evaluate the standardized ileal digestible (SID) Trp:Lys ratio dose–response on G:F of nursery pigs. A base linear mixed model was fitted to explore the functional form of G:F relative to Trp:Lys ratios and assess model assumptions. Next, we fitted 3 competing dose–response mixed models to G:F, namely a quadratic polynomial (QP) model, a broken-line linear (BLL) ascending model, and a broken-line quadratic (BLQ) ascending model, all of which included heteroskedastic specifications, as dictated by the base model. The GLIMMIX procedure of SAS (version 9.4) was used to fit the base and QP models and the NLMIXED procedure was used to fit the BLL and BLQ models. We further illustrated the use of a grid search of initial parameter values to facilitate convergence and parameter estimation in nonlinear mixed models. Fit between competing dose–response models was compared using a maximum likelihood–based Bayesian information criterion (BIC). The QP, BLL, and BLQ models fitted on G:F of nursery pigs yielded BIC values of 353.7, 343.4, and 345.2, respectively, thus indicating a better fit of the BLL model. The BLL breakpoint estimate of the SID Trp:Lys ratio was 16.5% (95% confidence interval [16.1, 17.0]). Problems with the estimation process rendered results from the BLQ model questionable. Importantly, accounting for heterogeneous variance enhanced inferential precision as the breadth of the confidence interval for the mean breakpoint decreased by approximately 44%. In summary, the article illustrates the use of linear and nonlinear mixed models for dose–response relationships accounting for heterogeneous residual variances, discusses important diagnostics and their implications for inference, and provides practical recommendations for computational troubleshooting.

Two experiments were conducted to determine the effects of pelleting, diet type (fat and fiber level), and withdrawal of dietary fiber and fat before marketing on growth performance, carcass yield, and carcass fat iodine value (IV) of finishing pigs. Each experiment used 288 pigs (initially 49.6 and 48.5 kg BW, respectively) with 6 dietary treatments arranged as 2 × 3 factorials. In Exp. 1, main effects were diet form (meal vs. pellet) and diet regimen. Diet regimens were 1) a low-fiber, low-fat (corn–soybean meal) diet from d 0 to 81, 2) a high-fiber, high-fat (30% dried distillers grains with solubles [DDGS] and 19% wheat middlings [midds]) diet from d 0 to 64 followed by the low-fiber, low-fat diet from d 64 to 81 (fiber and fat withdrawal), and 3) the high-fiber, high-fat diet fed from d 0 to 81. Pigs fed pelleted diets had increased (P< 0.05) ADG and G:F compared with those fed meal diets. Pigs fed pelleted diets had increased belly fat IV (2.9 mg/g) compared with those fed meal diets, with a greater increase when fed high-fiber, high-fat diets throughout the entire study (interaction, P< 0.05). Pigs fed the low-fiber, low-fat diet throughout had increased (P< 0.001) G:F compared with pigs fed the other 2 treatments. Pigs fed low-fiber, low-fat diets throughout the study or pigs withdrawn from high-fiber, high-fat diets had increased (P< 0.001) carcass yield compared with pigs fed high-fiber, high-fat diets throughout. In Exp. 2, treatment main effects were diet form (meal vs. pellet) and diet type (corn–soybean meal–based control, the control with 30% DDGS and 19% midds, or the control diet with 3% corn oil). The diet containing corn oil was calculated to produce carcass fat IV similar to diets containing DDGS and midds. Overall, pigs fed pelleted diets had increased (P< 0.05) ADG, G:F, and belly fat IV (1.3 mg/g) compared with those fed meal diets. Pigs fed the diets containing DDGS and midds had decreased (P< 0.05) ADG, carcass yield, and HCW compared with pigs fed the control or corn oil diets and decreased (P< 0.001) G:F compared with pigs fed added corn oil. Belly IV was greatest (P< 0.001) for pigs fed diets with DDGS and midds and lowest for pigs fed the control diet, with pigs fed the corn oil diets intermediate. In conclusion, pelleting diets improves pig ADG (approximately 3%) and G:F (approximately 6%); however, a novel finding of this study is that pelleting diets fed to finishing pigs also increases belly fat IV.

Three experiments were conducted to determine the effects of feeder adjustment and diet form on growth performance of nursery (Exp. 1 and 2) and finishing (Exp. 3) pigs. Treatments were arranged as a 2 × 3 factorial with the main effects of feeder adjustment and diet form. The 2 feeder adjustments were a narrow and wide feeder adjustment (minimum gap opening of 1.27 and 2.54 cm, respectively). The 3 diet forms were meal, poor-quality pellets (70% pellets and 30% fines for Exp. 1 and 2 and 50% pellets and 50% fines for Exp. 3), and screened pellets with minimal fines (3 to 10%). In Exp. 1, 210 pigs (initially 11.9 kg BW) were used in a 21-d trial with 7 pigs per pen and 5 pens per treatment. No feeder adjustment × diet form interactions were observed. There were no differences in ADG, ADFI, or G:F due to feeder adjustment. Pigs fed the meal diet had increased (P< 0.05) ADG and ADFI compared with pigs fed the poor-quality or screened pellets. Pigs fed meal or poor-quality pellets had decreased (P< 0.05) G:F compared with pigs fed screened pellets. In Exp. 2, 1,005 nursery pigs (initially 14.1 kg BW) were used in a 28-d trial with 26 to 28 pigs per pen and 6 pens per treatment. Pigs fed from the narrow feeder adjustment had decreased (P< 0.05) ADG and ADFI compared with pigs fed from the wide adjustment with no differences in G:F. Pigs fed the meal diet had decreased (P< 0.05) ADG compared with pigs fed poor-quality or screened pellets. Pigs fed meal or poor-quality pellets had decreased (P< 0.05) G:F compared with pigs fed screened pellets. In Exp. 3, 246 pigs (initially 56.8 kg BW) were used in a 69-d trial with 5 pens per treatment and 6 or 7 pigs per pen. Overall, ADFI decreased (P< 0.05) and G:F increased (P< 0.05) for pigs fed from the narrow adjusted feeders compared with the wide adjustment with no differences in ADG. Overall, pigs fed meal diets tended to have decreased (P< 0.10) ADG and had decreased (P< 0.05) G:F compared with pigs fed screened pellets; ADG and G:F in those fed poor-quality pellets were intermediate. Feeding meal or poor-quality pellets increased (P< 0.05) ADFI compared with pigs fed screened pellets. In conclusion, feeding nursery pigs from a wide feeder gap may increase ADG and ADFI with no negative effects on G:F. For finishing pigs, reducing feeder gap reduced feed disappearance and improved G:F. In all experiments, the greatest G:F improvements from pelleting were observed when the percentage of fines was minimized.

Two experiments were conducted to estimate the standardized ileal digestible (SID) Trp:Lys ratio requirement for growth performance of nursery pigs. Experimental diets were formulated to ensure that lysine was the second limiting AA throughout the experiments. In Exp. 1 (6 to 10 kg BW), 255 nursery pigs (PIC 327 × 1050, initially 6.3 ± 0.15 kg, mean ± SD) arranged in pens of 6 or 7 pigs were blocked by pen weight and assigned to experimental diets (7 pens/diet) consisting of SID Trp:Lys ratios of 14.7%, 16.5%, 18.4%, 20.3%, 22.1%, and 24.0% for 14 d with 1.30% SID Lys. In Exp. 2 (11 to 20 kg BW), 1,088 pigs (PIC 337 × 1050, initially 11.2 kg ± 1.35 BW, mean ± SD) arranged in pens of 24 to 27 pigs were blocked by average pig weight and assigned to experimental diets (6 pens/diet) consisting of SID Trp:Lys ratios of 14.5%, 16.5%, 18.0%, 19.5%, 21.0%, 22.5%, and 24.5% for 21 d with 30% dried distillers grains with solubles and 0.97% SID Lys. Each experiment was analyzed using general linear mixed models with heterogeneous residual variances. Competing heteroskedastic models included broken-line linear (BLL), broken-line quadratic (BLQ), and quadratic polynomial (QP). For each response, the best-fitting model was selected using Bayesian information criterion. In Exp. 1 (6 to 10 kg BW), increasing SID Trp:Lys ratio linearly increased (P <0.05) ADG and G:F. For ADG, the best-fitting model was a QP in which the maximum ADG was estimated at 23.9% (95% confidence interval [CI]: [<14.7%, >24.0%]) SID Trp:Lys ratio. For G:F, the best-fitting model was a BLL in which the maximum G:F was estimated at 20.4% (95% CI: [14.3%, 26.5%]) SID Trp:Lys. In Exp. 2 (11 to 20 kg BW), increasing SID Trp:Lys ratio increased (P <0.05) ADG and G:F in a quadratic manner. For ADG, the best-fitting model was a QP in which the maximum ADG was estimated at 21.2% (95% CI: [20.5%, 21.9%]) SID Trp:Lys. For G:F, BLL and BLQ models had comparable fit and estimated SID Trp:Lys requirements at 16.6% (95% CI: [16.0%, 17.3%]) and 17.1% (95% CI: [16.6%, 17.7%]), respectively. In conclusion, the estimated SID Trp:Lys requirement in Exp. 1 ranged from 20.4% for maximum G:F to 23.9% for maximum ADG, whereas in Exp. 2 it ranged from 16.6% for maximum G:F to 21.2% for maximum ADG. These results suggest that standard NRC (2012)recommendations may underestimate the SID Trp:Lys requirement for nursery pigs from 11 to 20 kg BW.

The objective of this study was to determine the effects of feeding sorghum dried distillers grains with solubles (DDGS) in grain sorghum– or corn-based diets on pig growth performance, carcass characteristics, and carcass fat quality. A total of 288 finishing pigs (BW 58.8 ± 4.43 kg; Line TR 4 × 1050, PIC, Hendersonville, TN) were used in a 73-d study. Pigs were allotted to 1 of 6 dietary treatments with 6 pens of 8 pigs per treatment. Treatments included grain sorghum–based diets with 0%, 15%, 30%, or 45% sorghum DDGS (29.0% CP, 7.2% ether extract); a grain sorghum–based diet with 30% corn DDGS (25.7% CP, 8.7% ether extract); and a corn-based diet with 30% corn DDGS. The diets were formulated to 0.95%, 0.83%, and 0.71% standardized ileal digestible Lys in phases 1, 2, and 3, respectively, and were not balanced for energy. On d 73, a subsample of 72 pigs (1 barrow and 1 gilt/pen) was harvested at Kansas State University's Meats Laboratory. Carcass traits were calculated, as well as 10th-rib LM color, marbling and firmness, and fat color score. Fat samples from the 10th rib were collected and analyzed for fatty acid profile, which was used to calculate iodine value (IV). The remaining pigs were transported to a commercial packing plant (Triumph Foods, St. Joseph, MO) for carcass measurement and jowl IV determinations. Overall, increasing the dietary sorghum DDGS reduced (linear, P< 0.01) ADG and increased (linear, P< 0.01) back fat IV. Pigs fed increasing sorghum DDGS had decreased 10th-rib fat a* (less red) and b* (less yellow; P< 0.01 and 0.06, respectively). No differences were observed in growth performance or back fat IV among pigs fed corn- or grain sorghum–based diets with 30% corn DDGS. Pigs fed the grain sorghum–based diet with 30% corn DDGS had fat color that was more yellow (b*; P< 0.03) than that of pigs fed the grain sorghum–based diet with 30% sorghum DDGS. Pigs fed the grain sorghum–based diet with 30% sorghum DDGS also had decreased back fat IV (P< 0.01) and fat that was whiter (L*; P< 0.02) than that of those fed the grain sorghum–based diet with corn DDGS. Pigs fed grain sorghum with 30% sorghum DDGS had lower (P< 0.01) back fat IV than pigs fed corn with 30% corn DDGS. Feeding a grain sorghum–based diet with increasing sorghum DDGS reduces ADG when diets are not balanced for energy but, when fed at 30% of the diet, produces firmer pork fat than feeding a corn-based diet with 30% corn DDGS, which may be preferred for pork export markets.

Data from 41 trials with multiple energy levels (285 observations) were used in a meta-analysis to predict growth performance based on dietary NE concentration. Nutrient and energy concentrations in all diets were estimated using the NRC ingredient library. Predictor variables examined for best fit models using Akaike information criteria included linear and quadratic terms of NE, BW, CP, standardized ileal digestible (SID) Lys, crude fiber, NDF, ADF, fat, ash, and their interactions. The initial best fit models included interactions between NE and CP or SID Lys. After removal of the observations that fed SID Lys below the suggested requirement, these terms were no longer significant. Including dietary fat in the model with NE and BW significantly improved the G:F prediction model, indicating that NE may underestimate the influence of fat on G:F. The meta-analysis indicated that, as long as diets are adequate for other nutrients (i.e., Lys), dietary NE is adequate to predict changes in ADG across different dietary ingredients and conditions. The analysis indicates that ADG increases with increasing dietary NE and BW but decreases when BW is above 87 kg. The G:F ratio improves with increasing dietary NE and fat but decreases with increasing BW. The regression equations were then evaluated by comparing the actual and predicted performance of 543 finishing pigs in 2 trials fed 5 dietary treatments, included 3 different levels of NE by adding wheat middlings, soybean hulls, dried distillers grains with solubles (DDGS; 8 to 9% oil), or choice white grease (CWG) to a corn-soybean meal-based diet. Diets were 1) 30% DDGS, 20% wheat middlings, and 4 to 5% soybean hulls (low energy); 2) 20% wheat middlings and 4 to 5% soybean hulls (low energy); 3) a corn-soybean meal diet (medium energy); 4) diet 2 supplemented with 3.7% CWG to equalize the NE level to diet 3 (medium energy); and 5) a corn-soybean meal diet with 3.7% CWG (high energy). Only small differences were observed between predicted and observed values of ADG and G:F except for the low-energy diet containing the greatest fiber content (30% DDGS diet), where ADG and G:F were overpredicted by 3 to 6%. Therefore, the prediction equations provided a good estimation of the growth rate and feed efficiency of growing-finishing pigs fed different levels of dietary NE except for the pigs fed the low-energy diet containing the greatest fiber content.

Data from existing literature were used to generate equations to predict finishing pig back, belly, and jowl fat iodine values (IV) and an experiment was conducted to evaluate these equations. The final database included 24, 21, and 29 papers for back, belly, and jowl fat IV, respectively. For experiments that changed dietary fatty acid composition, initial (INT) diets were defined as those fed before the change in diet composition and final (FIN) diets were those fed after. The predictor variables tested were divided into 5 groups: 1) diet fat composition (dietary percent C16:1, C18:1, C18:2, C18:3, EFA, unsaturated fatty acids, and IV product) for both INT and FIN diets, 2) day feeding the INT and FIN diets, 3) ME or NE of the INT and FIN diet, 4) live performance criteria (initial BW, final BW, ADG, ADFI, and G:F), and 5) carcass criteria (HCW and backfat thickness). The PROC MIXED procedure of SAS (SAS Inst., Inc., Cary, NC) was used to develop regression equations. Evaluation of models with significant terms was then conducted based on the Bayesian information criterion. The optimum equations to predict back, belly, and jowl fat IV were backfat IV = 84.83 + (6.87 × INT EFA) – (3.90 × FIN EFA) – (0.12 × INT days) – (1.30 × FIN days) – (0.11 × INT EFA × FIN days) + (0.048 × FIN EFA × INT days) + (0.12 × FIN EFA × FIN days) – (0.0060 × FIN NE) + (0.0005 × FIN NE × FIN days) – (0.26 × backfat depth); belly fat IV = 106.16 + (6.21 × INT EFA) – (1.50 × FIN days) – (0.11 × INT EFA × FIN days) – (0.012 × INT NE) + (0.00069 × INT NE × FIN days) – (0.18 × HCW) – (0.25 × backfat depth); and jowl fat IV = 85.50 + (1.08 × INT EFA) + (0.87 × FIN EFA) – (0.014 × INT days) – (0.050 × FIN days) + (0.038 × INT EFA × INT days) + (0.054 × FIN EFA × FIN days) – (0.0066 × INT NE) + (0.071 × INT BW) – (2.19 × ADFI) – (0.29 × backfat depth). Dietary treatments from the evaluation experiment consisted of a corn–soybean meal control diet with no added fat or a 3 × 3 factorial arrangement with main effects of fat source (4% tallow, 4% soybean oil, or a blend of 2% tallow and 2% soybean oil) and feeding duration (d 0 to 42, 42 to 84, or 0 to 84). The back, belly, and jowl fat IV equations tended to overestimate IV when observed IV were less than approximately 65 g/100 g and underestimate belly fat IV when actual IV are greater than approximately 74 g/100 g or when the fat blend was fed from d 0 to 84 or 42 to 84. Overall, with the exceptions noted, the regression equations were an accurate tool for predicting carcass fat quality based on dietary and pig performance factors.

Four experiments were conducted to investigate the effects of deoxynivalenol (DON) from naturally contaminated dried distillers grains with solubles (DDGS) and the efficacy of feed additives in nursery pig diets. In Exp. 1, 180 pigs (10.3 ± 0.2 kg BW) were fed 1 of 5 diets for 21 d. Diets were 1) Positive Control (PC; < 0.5 mg/kg DON), 2) Negative Control (NC; 4 mg/kg DON), 3) NC + 0.10% Biofix (Biomin Inc., Herzogenburg, Austria), 4) NC + 0.15% Cel-can (VAST Inc., Mason City, IA) and 0.50% bentonite clay, and 5) NC + 0.25% Defusion Plus (Cargill Animal Nutrition, Minneapolis, MN). Pigs fed the NC diet had poorer (P< 0.01) ADG than those fed the PC. Pigs fed Defusion Plus had improved (P< 0.03) ADG over those fed NC, whereas pigs fed Biofix or Cel-can with bentonite clay had reduced ADG (P< 0.01) compared with those fed PC. In Exp. 2, 340 pigs (11.7 ± 0.1 kg BW) were fed 1 of 8 diets for 21 d. Diets were 1) PC (< 0.5 mg/kg DON), 2) Low NC (1.5 mg/kg DON), 3) Low NC + 0.15% Biofix, 4) Low NC + 0.30% Biofix, 5) High NC (3.0 mg/kg DON), 6) High NC + 0.30% Biofix, 7) High NC + 0.45% Biofix, and 8) Diet 7 with 5% added water. Increasing the DON level reduced (linear; P< 0.05) ADG, ADFI, and pig BW, and Biofix did not improve performance. In Exp. 3, 1,008 pigs (12.5 ± 0.3 kg BW) were fed 6 treatments for 24 d. Diets were 1) PC ( < 0.5 mg/kg DON), 2) NC (3 mg/kg DON), 3) NC + 0.25% Defusion, 4) NC + 0.50% Defusion, 5) Diet 3 with supplemental nutrients, and 6) Diet 5, pelleted. Pigs fed the NC had decreased (P< 0.01) ADG and ADFI, but adding Defusion improved (linear; P< 0.04) ADG and ADFI over pigs fed NC. Pelleting improved (P< 0.01) both ADG and G:F, resulting in ADG above PC pigs. In Exp. 4, 980 pigs (12.0 ± 0.3 kg BW) were fed 1 of 7 diets in a 28-d trial in a 2 · 3 + 1 factorial arrangement. The 7 treatments were based on 3 diets fed in meal or pellet form: 1) PC (< 0.5 mg/kg DON), 2) NC (3 mg/kg DON), and 3) NC + 0.25% Defusion. Treatment 7 was Diet 3 with supplemental nutrients in pellet form. No interactions were observed between pelleting and Defusion. Pigs fed the NC had decreased (P< 0.01) ADG and ADFI, and pelleting improved (P< 0.01) ADG to PC levels, driven by improved (P< 0.01) G:F. Adding nutrients or Defusion had no effect. Overall, these studies show that Defusion and pelleting can help overcome some of the negative effects of DON, whereas other feed additives and additional nutrients do not.

Two experiments were conducted to determine the effects of increasing the dietary Zn content on growth performance, carcass characteristics, plasma Zn, and ileal mucosal inflammation mRNA expression of finishing pigs fed diets containing ractopamine HCl (RAC; Elanco Animal Health, Greenfield, IN). In Exp. 1, 312 pigs (327 × 1050; PIC, Hendersonville, TN; 94 kg BW) were used in a 27-d study. There were 2 pigs per pen and 26 pens per treatment. Treatments included a corn–soybean meal diet (control; 0.66% standardized ileal digestible [SID] Lys); a diet (0.92% SID Lys) with 10 mg/kg RAC; and the RAC diet plus 50, 100, or 150 mg Zn/kg from ZnO or 50 mg Zn/kg from a Zn AA complex (ZnAA; Availa-Zn; Zinpro, Eden Prairie, MN). All diets also contained 83 mg Zn/kg from ZnSO4in the trace mineral premix. Pigs fed the RAC diet without added Zn had increased (P< 0.05) ADG, G:F, HCW, carcass yield, and loin weight compared with pigs fed the control diet. Increasing Zn from ZnO in diets containing RAC tended to increase (linear, P= 0.067) G:F and loin weight (quadratic, P= 0.064). Pigs fed diets with 50 mg Zn/kg from ZnAA tended to have increased (P= 0.057) ADG compared with pigs fed the RAC diet. In Exp. 2, 320 pigs (327 × 1050; PIC; 98 kg BW) were used in a 35-d study. There were 2 pigs per pen and 20 pens per treatment. Treatments included a control diet (0.66% SID Lys); a diet (0.92% SID Lys) with 10 mg/kg RAC; or the RAC diet plus 75, 150, and 225 mg Zn/kg from ZnO or ZnAA. All diets also contained 55 mg Zn/kg from ZnSO4from the trace mineral premix. Pigs fed the RAC diet had increased (P< 0.05) ADG, G:F, HCW, loin depth, percentage lean, and liver weight compared with pigs fed the control diet. No Zn level or source effects or level × source interactions were observed for growth performance. A Zn level × source interaction (quadratic, P= 0.007) was observed in liver Zn concentrations. This resulted from liver Zn concentrations plateauing at 150 mg Zn/kg when ZnO was supplemented, while there was a linear increase when using ZnAA. Increasing Zn in diets containing RAC increased (linear, P< 0.05) plasma Zn on d 18 and 32. The expression of IL-1β was increased (P= 0.014) in mucosa of pigs fed the RAC diet compared with those fed the control diet. Expression of IL-1β decreased (linear, P= 0.026) in the mucosa of pigs fed increasing added Zn. In conclusion, adding Zn to diets containing RAC resulted in a trend for improved growth performance of pigs in 1 of 2 experiments. Also, additional Zn increased plasma Zn and reduced IL-1β.

A total of 576 mixed-sex pigs (PIC 327 × 1,050; initial BW = 55.8 ± 5.5 kg) were used to determine the effects of corn dried distillers grains with solubles (DDGS) and wheat middlings (midds) withdrawal 24 d before harvest in diets without or with ractopamine HCl (RAC) on growth performance, carcass characteristics, and carcass fat quality. From d 0 to 49, pigs were fed a corn-soybean meal–based diet (CS) or a diet high in unsaturated fat and crude fiber provided by 30% DDGS and 19% wheat midds (HFF) and not balanced for energy. On d 49, pens of pigs previously fed CS diets remained on the CS diet. Half of the HFF-fed pigs were switched to the CS–based diets, which served as the withdrawal regimen. Finally, half of the HFF-fed pigs remained on the same HFF diet. All 3 regimens were fed without or with 10 mg/kg RAC. There were 12 pens per treatment with 8 pigs per pen. No significant diet regimen × RAC interactions were observed. From d 0 to 49, pigs fed the CS diet had increased (P< 0.001) ADG and G:F compared with pigs fed the HFF diet. Overall (d 0 to 73), pigs fed the CS diets throughout had greater (P< 0.001) ADG and G:F than those fed the HFF diets throughout. Pigs fed the withdrawal diets had greater (P= 0.014) ADG, but similar G:F to those fed the HFF diets throughout. Pigs fed the CS diets throughout had greater (P= 0.025) carcass yield compared with pigs fed the HFF diets throughout, with those fed the withdrawal diets intermediate. Pigs fed RAC had greater (P< 0.001) ADG, G:F, and carcass yield (P= 0.061than pigs not fed RAC. Jowl, backfat, belly, and leaf fat iodine value (IV) were lowest (P< 0.001) for pigs fed the CS diets, highest (P< 0.015) for those fed HFF diets throughout, and intermediate for pigs fed the withdrawal diet. There were no differences in either full or rinsed intestine or organ weights between pigs that were fed CS diets throughout and pigs fed the withdrawal diet; however, pigs fed the HFF diets throughout the study had increased (P =0.002) rinsed cecum and full large intestine weights (P= 0.003) compared with the pigs fed the withdrawal diets. Withdrawing the HFF diet and switching to a CS diet for the last 24 d before harvest partially mitigated negative effects on carcass yield and IV often associated with high-fat, high-fiber ingredients such as DDGS and wheat midds. Feeding RAC for the last 24 d before market, regardless of dietary regimen, improved growth performance and carcass yield.

A total of 126 gilts and sows (PIC 1050) and their litters were used to determine the effects of dietary vitamin E concentration and source on sow plasma, milk, and pig concentrations of α-tocopherol. Additionally, we estimated the bioavailability of D-α-tocopheryl acetate (D-α-TAc) relative to DL-α-tocopheryl acetate (DL-α-TAc) when fed in diets containing dried distillers grains with solubles (DDGS). The 6 dietary treatments included DL-α-TAc at 44 and 66 mg/kg and D-α-TAc at 11, 22, 33, and 44 mg/kg. From breeding to d 69 of gestation, sows were fed 2.0 kg/d of a diet containing 40% DDGS, 0.30 mg/kg added Se, and no added vitamin E. Vitamin E treatments were fed from d 70 of gestation through weaning. Plasma was collected from sows on d 69 and 100 of gestation, at farrowing, and at weaning. Colostrum and milk samples were also collected. Plasma from 3 pigs per litter and heart and liver samples from 1 pig per litter were collected at weaning. Plasma, milk, and tissues from 6 litters per treatment were analyzed for α-tocopherol. Although tissue, plasma, and milk concentrations of α-tocopherol were the primary response criteria of interest, sow and litter performance were measured. As expected, treatment effects were not observed for lactation feed intake, sow BW, or backfat measurements. A trend (P= 0.085) for a treatment effect on average pig BW at weaning was detected, with pigs nursing sows fed 44 mg/kg DL-α-TAc weighing less because of a younger weaning age. No other differences in litter performance were observed. As D-α-TAc increased in the diet, sow plasma, colostrum, and milk, pig plasma, and pig heart concentrations of α-tocopherol increased (linear, P< 0.03). Sows fed diets with 44 mg/kg D-α-TAc had increased (P< 0.03) plasma and colostrum and pig plasma concentrations of α-tocopherol compared with sows fed 44 mg/kg of DL-α-TAc. Sows fed 66 mg/kg DL-α-TAc also had greater (P= 0.022) plasma α-tocopherol at weaning than sows fed 44 mg/kg DL-α-TAc. Bioavailability coefficients for D-α-TAc relative to DL-α-TAc ranged from 1.9 to 4.2 for sow and pig plasma α-tocopherol, 2.9 to 3.6 for colostrum α-tocopherol, 1.6 for milk α-tocopherol, and 1.7 to 2.0 for pig heart and liver α-tocopherol. Overall, this study indicates the bioavailability for D-α-TAc relative to DL-α-TAc varies depending on the response criteria but is greater than the standard potency value of 1.36.

The effects of feed withdrawal time before slaughter on finishing pig carcass composition were evaluated in 2 studies. In Exp. 1, 728 pigs (BW = 128.9 ± 1.2 kg) were allotted to 1 of 4 treatments in a randomized design with number of pigs per pen and location within barn balanced across treatment. The 4 treatments were feed withdrawal times of 8, 24, 36, or 48 h and there were 12 replicate pens per treatment. Before feed withdrawal, pigs were fed a standard corn–soybean meal diet containing dried distillers grains with solubles (DDGS), bakery coproducts, and 5.0 mg/kg ractopamine HCl. Feed withdrawal time decreased (linear; P< 0.02) live weight, HCW, and backfat while increasing percentage yield (quadratic; P< 0.01) and fat-free lean index (FFLI; linear; P< 0.001). In Exp. 2, 843 pigs (BW = 125.4 ± 1.6 kg) were used to determine the impact of feed withdrawal on growth, carcass, blood lactate, and meat quality. There were 4 treatments: withholding feed for 8, 12, 24, or 36 h, with 10 replicates per treatment. Pigs were fed a common corn–soybean meal–based diet containing 20% DDGS and 5.0 mg/kg ractopamine HCl. Withholding feed decreased (linear; P< 0.001) live weight, ultimately resulting in decreased (P< 0.01) HCW. There were no differences in FFLI or backfat, but percentage yield (linear; P< 0.001) increased with longer withdrawal times. Carcass contaminations by stomach contents escaping from the oral cavity after shackling (leaking ingesta) or visible fecal contamination of the exterior of the carcass (runny bung) were also measured. Although withholding feed did not affect runny bung, it increased (linear; P< 0.001) the incidence of leaking ingesta, whereas blood lactate, visual color score, and purge loss were unaffected. Withholding feed increased 45-min pH (quadratic; P> 0.02) and ultimate pH (linear; P< 0.01) and increased (quadratic; P< 0.03) visual marbling score. Withholding feed decreased (linear; P< 0.001) feed intake, resulting in feed savings of up to 3 kg/pig. Although several heavyweight pigs were removed before trial commencement and the variable number of remaining pigs per pen may have influenced the response to feed withdrawal, the present data indicates that finishing pigs can experience between 24 and 36 h of feed withdrawal without negatively affecting carcass composition. However, the increased incidence of leaking ingesta beyond 12 h of feed withdrawal is concerning.

Two experiments were conducted to investigate the effects of sodium sulfate water and the efficacy of nonnutritive feed additives in nursery pig diets. In Exp. 1, 320 barrows (5.4 ± 0.1 kg BW and 21 d of age) were allotted to 1 of 8 treatments for 24 d in a 2 × 4 factorial with 2 levels of sodium sulfate water (control or 3,000 mg sodium sulfate/L added), and 4 dietary zeolite (clinoptilolite) levels (0, 0.25, 0.50, or 1%). Fecal samples were collected on d 5, 9, 16, and 23; visually scored for consistency (1 = firm and 5 = watery); and analyzed for DM. No interactions of sodium sulfate × zeolite were observed for any response criteria. Overall (d 0 to 24), pigs drinking sodium sulfate water had decreased (P< 0.01) ADG, ADFI, and G:F compared with pigs drinking control water. Pigs drinking sodium sulfate water also had increased (P< 0.01) fecal scores and lower (P< 0.04) fecal DM on d 5, 9, and 16 compared with pigs drinking control water. Increasing dietary zeolite increased (linear; P< 0.05) ADG and ADFI but had no effect on G:F. In Exp. 2, 350 barrows (5.7 ± 0.1 kg BW and 21 d of age) were allotted to 1 of 10 treatments in a 2 × 5 factorial for 21 d with 2 levels of sodium sulfate water (control or 2,000 mg sodium sulfate/L added) and 5 dietary treatments (control, 1 or 2% zeolite, 1% humic acid substance [HA], and 1% humic and fulvic acid substance [HFB]). Fecal samples were collected on d 5, 8, 15, and 21; visually scored for consistency (1 = firm and 5 = watery); and analyzed for DM. Overall (d 0 to 21), a water source × diet interaction was observed for ADG and G:F because pigs fed the 1% HA had decreased (P< 0.01) ADG and G:F when drinking sodium sulfate water compared with other treatments but increased ADG and G:F when drinking control water. Pigs drinking sodium sulfate water had decreased (P< 0.01) ADG and G:F and tended (P< 0.08) to have decreased ADFI compared with pigs drinking control water. Pigs drinking sodium sulfate water had increased (P< 0.01) fecal scores and decreased (P< 0.01) fecal DM on d 5 and 8. In conclusion, water high in sodium sulfate concentrations decreased growth performance and increased fecal moisture in newly weaned pigs. Although zeolite improved growth performance in the first experiment, it did not influence growth in the second study. The nonnutritive feed additives used in both experiments were unsuccessful in ameliorating the increased osmotic diarrhea observed from high sodium sulfate water.

A total of 1,480 pigs were used in 3 experiments to determine the effects of corn distillers dried grains with solubles (DDGS) varying in oil content on growth performance, carcass traits, and nutrient digestibility in finishing pigs. In Exp. 1, 1,198 pigs (PIC Line 337 × 1050; initially 46.1 kg) were allotted to a corn–soybean meal–based diet or diets with 20 or 40% of a 5.4% oil DDGS (29.5% CP, 8.9% ADF, and 21.8% NDF; as-fed basis) or a 9.6% oil DDGS (29.6% CP, 15.3% ADF, and 28.6% NDF; as-fed basis). From d 0 to 82, ADG was unaffected by DDGS source or level. However, increasing 5.4% oil DDGS decreased (linear, P< 0.01) G:F, whereas G:F did not change among pigs fed 9.6% oil DDGS (DDGS source × level interaction; P< 0.01). Regardless of DDGS source, carcass yield and HCW decreased (linear, P< 0.04) with increasing DDGS. Increasing DDGS increased jowl iodine value (IV), but the magnitude was greater in pigs fed the 9.6% oil DDGS compared with those fed 5.4% oil DDGS (DDGS source × level interaction; P< 0.01). In Exp. 2, 270 pigs (PIC Line 327 × 1050; initially 46.5 kg) were allotted a corn–soybean meal–based diet or diets with 20 or 40% of a 9.4% oil DDGS (29.4% CP, 19.6% ADF, and 34.5% NDF; as-fed basis) or a 12.1% oil DDGS (28.5% CP, 17.6% ADF, and 31.4% NDF; as-fed basis). From d 0 to 75, ADG increased and then decreased for pigs fed 9.4% oil DDGS but was unchanged for pigs fed 12.1% oil DDGS (quadratic interaction, P< 0.02). Increasing DDGS increased (linear, P< 0.01) jowl IV and tended (linear, P< 0.07) to increase G:F. Regardless of source, HCW and carcass yield decreased (linear, P< 0.05) as DDGS increased. In Exp. 3, nutrient digestibility of the 4 DDGS sources was determined using pigs fed either a corn-based basal diet (96.6% corn and 3.4% vitamins and minerals) or a DDGS diet with 50% basal diet and 50% DDGS. On an as-fed basis, corn contained 3,871 and 3,515 kcal/kg GE and DE, respectively. The 5.4, 9.6, 9.4, and 12.1% oil DDGS contained 4,347, 4,648, 4,723, and 4,904 kcal/kg (as-fed basis) GE and 3,417, 3,690, 3,838, and 3,734 kcal/kg DE, respectively (as-fed basis). Stepwise regression indicated that the oil (ether extract) content was the only significant variable to explain differences in energy content. The equations generated to predict DE and NE as a function of oil content on an as-fed basis were DE (kcal/kg) = 62.347 × ether extract (%) + 3,058.13 (n= 5, adjusted R2= 0.41) and NE (kcal/kg) = 115.011 × ether extract (%) + 1,501.01 (n= 5, adjusted R2= 0.86).

Three experiments were conducted to compare the effects of a conventional dry (five 30.5-cm spaces 152.4 cm wide; Staco Inc., Schaefferstown, PA) vs. a wet–dry (double sided; each side = 38.1-cm space; Crystal Spring; GroMaster Inc., Omaha, NE) finishing feeder (Exp. 1 and 2) and to evaluate the effects of feeder design and dietary level of dried distillers' grains with solubles (DDGS; >10% oil; Exp. 3) on performance and carcass characteristics of finishing pigs. In Exp. 1, 1,186 pigs (32.1 kg BW) were used in a 69-d experiment. There were 26 to 28 pigs per pen and 22 pens per feeder design, and all pigs received the same diets in 4 phases. In Exp. 2, 1,236 pigs (28.7 kg BW) were used in a 104-d experiment, with 25 to 28 pigs per pen and 23 pens per feeder design, and all pigs received the same diets in 5 phases. Carcass measurements were obtained from 11 pens of each feeder design after harvest. In Exp. 3, 1,080 pigs (35.1 kg BW) were used in a 99-d 2 × 2 factorial with main effects of feeder design (dry vs. wet–dry feeders) and DDGS (20 vs. 60%) with 10 pens of 27 pigs per treatment and all diets fed in 4 phases. Jowl fat samples were collected from 2 pigs per pen for fatty acid analysis and iodine value (IV) determination. In all experiments, pigs fed with the wet–dry feeder had greater (P< 0.05) ADG, ADFI, and final BW. In Exp. 2 and 3, HCW and backfat depth were increased (P< 0.05) for pigs fed with a wet–dry feeder, but G:F and fat-free lean index (FFLI) were reduced. Jowl IV was also reduced (P< 0.05) with a wet–dry feeder in Exp. 3. Pigs fed 60% DDGS in Exp. 3 had decreased (P< 0.05) ADG, G:F, final BW, HCW, and backfat but increased jowl IV and a tendency (P< 0.07) toward greater FFLI regardless of feeder type. In conclusion, pigs fed with this specific type of wet–dry feeder had improved ADG and ADFI, poorer G:F, and increased backfat depth compared to pigs fed with a conventional dry feeder. The poorer growth performance and increased jowl IV of pigs fed diets with 60% DDGS was similarly exhibited for pigs fed on both feeders.

Four experiments were conducted to examine effects of dietary wheat middlings (midds), corn dried distillers grains with solubles (DDGS), and NE formulation on nursery pig performance and caloric efficiency. In Exp. 1, 180 nursery pigs (11.86 ± 0.02 kg BW and 39 d of age) were fed 1 of 5 diets for 21 d, with 6 pigs per pen and 6 replications per treatment. Diets were corn–soybean meal based and included 0, 5, 10, 15, or 20% wheat midds. Increasing wheat midds decreased (linear; P< 0.05) ADG and ADFI. Caloric efficiency improved (linear; P< 0.05) on both an ME (NRC, 1998) and NE (Sauvant et al., 2004) basis as dietary wheat midds increased. In Exp. 2, 210 pigs (6.85 ± 0.01 kg BW and 26 d of age) were fed 1 of 5 diets for 35 d, with 7 pigs per pen and 6 replications per treatment. Diets were corn–soybean meal based and contained 0, 5, 10, 15, or 20% wheat midds. Increasing wheat midds did not affect overall ADG or ADFI but decreased (quadratic; P< 0.013) G:F at 20%. Caloric efficiency for both ME and NE improved (quadratic; P< 0.05) as dietary wheat midds increased. In Exp. 3, 180 pigs (12.18 ± 0.4 kg BW and 39 d of age) were fed 1 of 6 experimental diets arranged in a 2 × 3 factorial with main effects of DDGS (0 or 20%) and wheat midds (0, 10, or 20%) for 21 d, with 6 pigs per pen and 5 replications per treatment. No DDGS × wheat midds interactions were observed, and DDGS did not influence ADG, ADFI, or G:F, but increasing dietary wheat midds decreased (linear; P< 0.05) ADG, G:F, and final BW. In Exp. 4, 210 pigs (6.87 kg BW and 26 d of age) were allotted to 1 of 5 dietary treatments, with 7 pigs per pen and 6 replications per treatment. Wheat middlings (0, 10, or 20%) were added to the first 3 diets without balancing for energy. In diets 4 and 5, soybean oil was added (1.4 and 2.8%) to 10 and 20% wheat midds diets to balance to the same NE as the positive control (0% wheat midds). Overall, no wheat midds × fat interactions occurred. Regardless of formulated energy value, caloric efficiency and G:F were poorer (P< 0.05) on an ME basis as wheat midds increased from 10 to 20% of the diet but did not change when calculated on an NE basis. Results of these experiments indicate that wheat midds may be fed up to 10 to 15% of the diet without negatively affecting nursery pig performance and with no interactive effects when fed in combination with DDGS. Also, formulating on an NE basis provided for similar performance with increasing dietary wheat midds compared with a corn–soybean meal control diet.

A total of 320 finishing pigs (PIC 327 × 1050; initially 98 kg) were used to determine the effects of adding Zn to diets containing ractopamine HCl (RAC) on muscle fiber type distribution, fresh chop color, and cooked meat characteristics. Dietary treatments were fed for approximately 35 d and consisted of a corn–soybean meal–based negative control (CON), a positive control diet with 10 mg/kg of RAC (RAC+), and the RAC+ diet plus 75, 150, or 225 mg/kg added Zn from either ZnO or Availa-Zn. Loins randomly selected from each treatment (n= 20) were evaluated using contrasts: CON vs. RAC+, interaction of Zn level × source, Zn level linear and quadratic polynomials, and Zn source. There were no Zn source effects or Zn source × level interactions throughout the study (P> 0.10). Pigs fed RAC+ had increased (P< 0.02) percentage type IIX and a tendency for increased (P= 0.10) percent type IIB muscle fibers. Increasing added Zn decreased (linear, P= 0.01) percentage type IIA and tended to increase (P= 0.09) IIX muscle fibers. On d 1, 2, 3, 4, and 5 of display, pork chops from pigs fed the RAC+ treatment had greater (P< 0.03) L* values compared to the CON. On d 0 and 3 of display, increasing added Zn tended to decrease (quadratic, P= 0.10) L* values and decreased (quadratic, P< 0.03) L* values on d 1, 2, 4, and 5. Pigs fed RAC+ had decreased (P< 0.05) a* values on d 1 and 4 of display and tended to have decreased (P< 0.10) a* values on d 0 and 2 compared to CON pork chops. Pork chops from the RAC+ treatment had a tendency for increased (P< 0.08) oxymyoglobin percentage compared to CON pork chops on d 1, 2, 4, and 5. On d 0, as dietary Zn increased in RAC+ diets, there was a decrease (linear, P< 0.01) in the formation of pork chop surface oxymyoglobin percentage. Metmyoglobin reducing ability (MRA) of pork chops on d 5 was decreased in the RAC+ group. Chops from pigs fed added Zn had increased (quadratic, P< 0.03) MRA on d 3 and 5 of the display period. There was a trend for increased (linear, P= 0.07) cooking loss with increasing Zn in RAC diets and treatments did not affect tenderness as measured by Warner-Bratzler shear force (P> 0.07). In conclusion, RAC+ diets produced chops that were lighter and less red but maintained a greater percentage of surface oxymyoglobin throughout a 5-d simulated retail display. Ractopamine reduced MRA at the end of the display period, but supplementing Zn to RAC diets restored MRA to near CON treatment levels at the end of the display period.

Five experiments were conducted to evaluate replacing fish meal, meat and bone meal, and poultry byproduct meal with crystalline AA for 7- to 12-kg pigs. In all experiments, pigs (PIC TR4 × 1050) were fed a common diet for 3 d postweaning, treatment diets for 14 d (d 0 to 14), and, again, a common diet for 14 d (d 14 to 28). Treatment diets were corn–soybean meal based and formulated to contain 1.30% standardized ileal digestible (SID) Lys. Experiment 1 evaluated replacing dietary fish meal with crystalline AA. For the 6 treatments, crystalline Lys, Met, Thr, Trp, Ile, Val, Gln, and Gly all increased to maintain minimum AA ratios as fish meal decreased (4.50, 3.60, 2.70, 1.80, and 0.90 to 0.00%). There was no difference in ADG, ADFI, or G:F among treatments, validating a low-CP, AA-fortified diet for subsequent experiments. Experiment 2 evaluated deleting crystalline AA from a low-CP, AA-fortified diet with 6 treatments: 1) a positive control similar to the diet validated in Exp. 1, 2) positive control with L-Ile deleted, 3) positive control with L-Trp deleted, 4) positive control with L-Val deleted, 5) positive control with L-Gln and L-Gly deleted, and 6) positive control with L-Ile, L-Trp, L-Val, L-Gln, and L-Gly deleted (NC). Pigs fed the positive control or Ile deleted diet had improved (P< 0.05) ADG and ADFI during d 0 to 14 compared with pigs fed diets with L-Trp or L-Val deleted or NC. Experiment 3 evaluated 6 treatments with total Lys:CP of 6.79, 6.92, 7.06, 7.20, 7.35, and 7.51%. Fish meal was adjusted as a source of dispensable N to achieve the target Lys:CP. There were no differences in growth performance among pigs fed different Lys:CP diets. Experiment 4 evaluated increasing SID Val:Lys with Val at 57.4, 59.9, 62.3, 64.7, 67.2, and 69.6% of Lys. Average daily gain and ADFI increased (quadratic, P< 0.01) and G:F improved (linear, P= 0.02) during d 0 to 14 as Val:Lys increased from 57.4 to 64.7%. Experiment 5 was a 2 × 3 factorial arrangement of treatments with main effects of low or high level of crystalline AA and 3 animal protein sources (fish meal, meat and bone meal, or poultry byproduct meal). Low- and high-crystalline AA diets contained 4.5 or 1% fish meal, 6 or 1.2% meat and bone meal, and 6 or 1% poultry byproduct meal, respectively. No AA × protein source interactions were observed. From d 0 to 14, no differences in growth performance among protein sources was found, whereas increasing crystalline AA improved (P= 0.04) ADG. In conclusion, crystalline AA can replace fish meal, meat and bone meal, and poultry byproduct meal when balanced for SID AA ratios of Met and Cys:Lys (58%), Thr:Lys (62%), Trp:Lys (16.5%), Val:Lys (65%), and Ile:Lys (52%).

Three studies were conducted to compare the effects of 4 different porcine intestinal mucosa products (PEP2, PEP2+, Peptone 50, and PEP-NS; TechMix Inc., Stewart, MN) with select menhaden fish meal (SMFM) on nursery pig performance. These intestine-derived mucosal ingredients are byproducts of heparin production, with a similar amount of mucosal protein, but differ based on the carriers with which they are co-dried. Enzymatically processed vegetable protein is the carrier for PEP2 whereas PEP2+ is co-dried with enzymatically processed vegetable proteins and biomass from crystalline AA production. Peptone 50 uses vegetable protein as its carrier while PEP-NS is co-dried with byproducts of corn wet milling and biomass from crystalline AA production. In Exp. 1, 300 weanling pigs (PIC 327 × 1050; initially 5.4 kg and 19 d of age) were allotted to 1 of 5 dietary treatments with 12 replications and 5 pigs per pen. Diets consisted of a negative control (NC) containing no specialty protein sources, NC with 4, 8, or 12% PEP2 in phases 1 (d 0 to 11) and 2 (d 11 to 25), and a positive control containing 4% spray-dried animal plasma (SDAP) in phase 1 and 4% SMFM in phase 2. From d 0 to 11, pigs fed SDAP had greater (P< 0.05) ADG and G:F than pigs fed PEP2. From d 11 to 25, increasing PEP2 increased (quadratic; P< 0.01) ADG and G:F, with the greatest response observed at 4%. In Exp. 2, 960 weanling pigs (Newsham GPK35 × PIC 380; initially 5.6 kg, and 20 d of age) were allotted to 1 of 5 dietary treatments with 32 pigs per pen and 6 replications per treatment. Diets included a control with 4.5% SDAP in phase 1 (d 0 to 7) and no specialty protein sources in phase 2 (d 7 to 21) or the control diet with 6% of the following: SMFM, PEP2+, Peptone 50, or PEP-NS. From d 0 to 21, pigs fed diets containing SMFM, PEP2+, or PEP-NS had greater (P< 0.05) ADG than pigs fed the control or 6% Peptone 50. In Exp. 3, 180 nursery pigs (PIC 327 × 1050; initially 6.4 kg and 28 d of age) were allotted to 1 of 5 dietary treatments with 5 pigs per pen and 6 replications per treatment. Treatment diets were fed from d 7 to 21 postweaning. Treatments consisted of a NC, NC with 3, 6, 9, or 12% PEP-NS, or NC with 6% SMFM. Overall, pigs fed increasing PEP-NS had improved (quadratic; P< 0.01) ADG and G:F, with the greatest improvement observed in pigs fed 6% PEP-NS, similar to those fed 6% SMFM. These results suggest PEP2, PEP2+, and PEP-NS can effectively replace SMFM in nursery pig diets.

A total of 84 sows (PIC 1050) and their litters were used to determine the effects of supplementing maternal diet with vitamin D3on sow and pig performance, serum 25-hydroxyvitamin D3(25(OH)D3), milk vitamin D3, neonatal bone mineralization, and neonatal tissue vitamin D3. After breeding, sows were randomly assigned to 1 of 3 dietary vitamin D3treatments (1,500, 3,000, or 6,000 IU/kg of complete diets). Sows were bled on d 0 and 100 of gestation and at farrowing and weaning (d 21). Pig BW was recorded at birth and weaning, and serum was collected from 2 pigs/litter at birth, on d 10 and at weaning. A total of 54 pigs (18/treatment) were euthanized at birth and necropsied to sample bones and tissues. Sow and suckling pig performance and neonatal bone ash and bone density did not differ among maternal vitamin D3treatments; however, sow 25(OH)D3and milk vitamin D3increased (linear, P< 0.01) with increasing maternal vitamin D3supplementation. Piglet serum 25(OH)D3increased (quadratic, P< 0.03) with increased maternal vitamin D3. Neonatal kidney vitamin D3tended (quadratic, P= 0.08) to decrease with increasing maternal vitamin D3, but liver vitamin D3tended (linear, P= 0.09) to increase with increasing maternal vitamin D3. At weaning, a subsample of 180 pigs (PIC 327 × 1050) were used in a 3 × 2 split plot design for 35 d to determine the effects of maternal vitamin D3and 2 levels of dietary vitamin D3(1,800 or 18,000 IU/kg) from d 0 to 10 postweaning on nursery growth and serum 25(OH)D3. Overall (d 0 to 35), nursery ADG and G:F were not affected by either concentration of vitamin D3, but ADFI tended (quadratic, P< 0.06) to decrease with increasing maternal vitamin D3as pigs from sows fed 3,000 IU had lower ADFI compared with pigs from sows fed 1,500 or 6,000 IU/kg. Nursery pig serum 25(OH)D3increased with increasing maternal vitamin D3(weaning) on d 0 (linear, P< 0.01), and maternal × diet interactions (P< 0.01) were observed on d 10 and 21 because pigs from sows fed 1,500 IU had greater increases in serum 25(OH)D3when fed 18,000 IU compared with pigs from sows fed 3,000 IU. In conclusion, sow and pig serum 25(OH)D3, milk vitamin D3, and neonatal tissue vitamin D3can be increased by increasing maternal vitamin D3, and nursery pig 25(OH)D3can be increased by increasing dietary vitamin D3; however, sow and pig performance and neonatal bone mineralization was not influenced by increasing vitamin D3dietary levels.

A total of 288 mixed-sex pigs (PIC 327 × 1050; initially 68.9 kg BW) were used in a 67-d study to determine the effects of increasing medium-oil dried distillers grains with solubles (DDGS; 7.63% ether extract, 30.1% CP, 19.53% ADF, 36.47% NDF, and 4.53% ash; as-fed basis) on growth performance and carcass traits in finishing pigs. Treatments consisted of a corn–soybean meal control diet or the control diet with 15, 30, or 45% medium-oil DDGS. Diets were fed over 2 phases (69 to 100 and 100 to 126 kg) and were not balanced for energy. Diets were formulated to meet or exceed the AA, vitamin, and mineral requirements and contained constant standardized ileal digestible lysine levels within phase. Increasing medium-oil DDGS decreased (linear, P< 0.02) ADG and G:F. Average daily gain decreased approximately 2.3% for every 15% added medium-oil DDGS whereas G:F decreased approximately 1.3% with every 15% added DDGS. In addition, final BW, HCW, carcass yield, and loin-eye depth decreased (linear, P< 0.03) and jowl iodine value (IV) increased (linear, P< 0.001) with increasing medium-oil DDGS. Nutrient digestibility of the DDGS source was determined using pigs (initially 25.6 kg BW) that were fed either a corn-based basal diet (96.6% corn and 3.4% vitamins and minerals) or a DDGS diet, which was a 50:50 blend of the basal diet and medium-oil DDGS. There were 12 replications for each diet consisting of a 5-d adaptation period followed by 2 d of total fecal collection on a timed basis. Feces were analyzed for GE, DM, CP, crude fiber, NDF, ADF, and ether extract. On an as-fed basis, corn was analyzed to contain 3,871 and 3,515 kcal/kg GE and DE, respectively. Medium-oil DDGS was analyzed to contain 4,585 and 3,356 kcal/kg GE and DE, respectively (as-fed basis). Digestibility coefficients of the medium-oil DDGS were 70.3% DM, 82.9% CP, 61.4% ether extract, 77.4% ADF, 67.5% NDF, and 67.2% crude fiber. Caloric efficiency (ADFI × kcal energy intake/kg BW gain) was not different when expressed on a DE or a calculated ME or NE basis, which suggests that the energy values derived from the nutrient balance study were accurate. In conclusion, increasing dietary inclusion of medium-oil DDGS decreased ADG, G:F, final BW, HCW, and carcass yield and increased jowl fat IV relative to those fed a corn–soybean meal–based diet.

Samples of sorghum distillers dried grains with solubles (DDGS) were collected and analyzed to establish a nutrient database and evaluate the quality and consistency between and within 5 ethanol plants in Kansas and Texas. Each sample (n= 21) was analyzed for AA, DM, CP, crude fiber, crude fat, ash, NDF, ADF, trace minerals, and starch. Mean values (DM basis) were 0.88% Lys, 10.49% crude fat, 34.21% CP, and 4,722 kcal/kg GE. The standard deviations among sorghum DDGS plants were similar to those within plants for most nutrients. Results of these analyses were used to formulate diets for 2 nursery trials. The 2 experiments were conducted to determine the effects of adding sorghum DDGS (29.0% CP and 7.2% crude fat) to corn- or sorghum-based diets on nursery pig growth performance. In Exp. 1, 360 nursery barrows (6.8 kg and 26 d of age) were used in a 34-d study. Pigs were allotted to 1 of 8 dietary treatments with 5 pigs per pen and 9 pens per treatment. Treatments were arranged in a 2 × 4 factorial with main effects of grain source (corn vs. sorghum) and sorghum DDGS (0, 15, 30, or 45%). Diets were formulated to 1.30 and 1.25% standardized ileal digestible (SID) Lys in phases 1 and 2, respectively, but were not balanced for energy. Overall, there were no differences among pigs fed sorghum- or corn-based diets for ADG and ADFI; however, as sorghum DDGS increased from 0 to 45% of the diet, ADG decreased (linear, P< 0.01). There was a DDGS × grain source interaction (linear, P< 0.04) observed for G:F. In corn-based diets, pigs fed increasing sorghum DDGS had relatively similar G:F. However, in pigs fed sorghum-based diets, G:F was best for those fed 0% DDGS but was decreased in pigs fed 15, 30, or 45% sorghum DDGS. In Exp. 2, 180 nursery pigs (10.7 kg and 38 d of age) were used in a 21-d study with 6 pigs per pen and 5 pens per treatment. Treatments were arranged in a 2 × 3 factorial with main effects of grain source (corn vs. sorghum) and DDGS (0 vs. 30% corn or sorghum DDGS). Diets were formulated to 1.27% SID Lys and were not balanced for energy. Overall, there were no differences in ADG among pigs fed sorghum- or corn-based diets as well as no differences among pigs fed sorghum or corn DDGS. Pigs fed diets with 30% DDGS gained less (P< 0.03) than pigs fed basal diets. These results indicate sorghum can be a suitable replacement for corn in nursery pig diets, but increasing sorghum DDGS decreased ADG.

Four experiments were conducted to investigate the effects of varying concentrations of supplemental vitamin D3on pig growth, feed preference, serum 25-hydroxycholecalciferol [25(OH)D3] , and bone mineralization of nursing and weanling pigs. In Exp. 1, 270 pigs (1.71 ± 0.01 kg BW) were administered 1 of 3 oral vitamin D3dosages (none, 40,000, or 80,000 IU vitamin D3) on d 1 or 2 of age. Increasing oral vitamin D3increased serum 25(OH)D3on d 10 and 20 (quadratic, P< 0.01) and d 30 (linear, P< 0.01). No differences were observed in ADG before weaning or for nursery ADG, ADFI, or G:F. Vitamin D3concentration had no effect on bone ash concentration or bone histological traits evaluated on d 19 or 35. In Exp. 2, 398 barrows (initially 7 d of age) were used in a 2 × 2 split plot design to determine the influence of vitamin D3before (none or 40,000 IU vitamin D3in an oral dose) or after weaning (1,378 or 13,780 IU vitamin D3/kg in nursery diets from d 21 to 31 of age) in a 45-d trial. Before weaning (7 to 21 d of age), oral vitamin D3dose did not influence growth but increased (P< 0.01) serum 25(OH)D3at weaning (d 21) and tended (P= 0.08) to increase 25(OH)D3on d 31. Increasing dietary vitamin D3concentration from d 21 to 31 increased (P< 0.01) serum 25(OH)D3on d 31. Neither the oral vitamin D3dose nor nursery vitamin D3supplements influenced nursery ADG, ADFI, or G:F. In Exp. 3, 864 pigs (initially 21 d of age) were allotted to 1 of 2 water solubilized vitamin D3treatments (none or 16,516 IU/L vitamin D3provided in the drinking water from d 0 to 10) in a 30-d study. Providing vitamin D3increased serum 25(OH)D3concentrations on d 10, 20, and 30; however, vitamin D3supplementation did not affect overall (d 0 to 30) ADG, ADFI, or G:F. In Exp. 4, 72 pigs were used in a feed preference study consisting of 2 feed preference comparisons. Pigs did not differentiate diets containing either 1,378 or 13,780 IU vitamin D3/kg but consumed less (P< 0.01) of a diet containing 44,100 IU vitamin D3/kg compared with the diet containing 1,378 IU vitamin D3/kg. Overall, these studies demonstrate that supplementing vitamin D3above basal concentrations used in these studies is effective at increasing circulating 25(OH)D3, but the supplement did not influence growth or bone mineralization. Also, concentrations of vitamin D3of 44,100 IU/kg of the diet may negatively affect feed preference of nursery pigs.

A total of 264 pigs (initially 41.0 kg BW) were used in a 90-d study to determine the effects of lowering dietary fiber before market on pigs fed high dietary fiber [provided by wheat middlings (midds) and distillers dried grains with solubles (DDGS)] on growth performance, carcass characteristics, carcass fat quality, and intestinal weights of growing-finishing pigs. Pens of pigs were randomly allotted by initial BW and sex to 1 of 6 treatments with 6 replications per treatment and 7 or 8 pigs per pen. A positive control (corn-soybean meal–based) diet containing no DDGS or midds (9.3% NDF) and a negative control diet with 30% DDGS and 19% midds (19% NDF) were fed throughout the entire trial (d 0 to 90). The other 4 treatments were arranged in a 2 × 2 factorial with the main effects of length of fiber reduction (23 or 47 d before marketing) and fiber level fed during the reduction period (low or medium). Pigs on these treatments were fed the negative control before the reduction treatment. The medium-fiber diet contained 15% DDGS and 9.5% midds (14.2% NDF) with the low-fiber diet was the positive control diet. Increasing the feeding duration of the low-fiber diets lowered overall ADFI (linear, P= 0.03) and improved G:F (linear, P< 0.01). Lowering the fiber level for the last 23 d did not influence growth performance; however, lowering the fiber level improved carcass yield (P= 0.002), with a greater response (P< 0.001) when the low-fiber diet was fed for 23 d. Jowl fat iodine value (IV) decreased when the longer lower fiber diets were fed (linear, P< 0.01) and was lower (P< 0.001) for pigs fed the low-fiber diet during the fiber reduction period than pigs fed the medium-fiber diet during the same time period; however, increasing the time lower fiber diets were fed from 23 to 47 d further reduced (P< 0.01) jowl IV. Increasing the duration that the control diet was fed by increasing the reduction time from 23 to 47 d increased (P< 0.01) backfat depth. Reducing the fiber level decreased full large intestine weight (linear, P= 0.005) with a greater response (P= 0.04) when the low-fiber diet was fed during the reduction period instead of the medium-fiber diet. In summary, lowering the fiber level before marketing can improve G:F, carcass yield, carcass IV, and reduce large intestine weight; however, the optimal duration of the fiber reduction period depends on the targeted response criteria.

Research has demonstrated that swine feed can be a fomite for viral transmission and certain feed additives can effectively reduce viral contamination. However, additional information is needed to evaluate the efficacy of additives when feed is inoculated with more than one virus. The objective of this study was to evaluate the efficacy of two feed additives for mitigation of porcine epidemic diarrhea virus (PEDV) and porcine reproductive and respiratory syndrome virus (PRRSV) when inoculated individually or together. Feed additives included: 1) no treatment, 2) 0.33% commercial formaldehyde-based product (Sal Curb, Kemin Industries, Des Moines, IA), and 3) 0.50% medium chain fatty acids blend (MCFA; 1:1:1 ratio of C6:C8:C10, Sigma Aldrich, St. Louis, MO). Samples were inoculated with PEDV and PRRSV alone or together at an inoculation concentration of 106TCID50/g for all viruses. Once inoculated, feed was stored at ambient temperature for 24-h before analyzed via qRT-PCR. For samples inoculated with PEDV or PRRSV alone, a qRT-PCR assay was used which was designed to detect PEDV or PRRSV nucleic acid. For co-inoculated samples, an assay was designed to independently detect both PEDV and PRRSV within a single reaction. For PEDV alone, there was marginally significant evidence that feed additives resulted in differences in cycle threshold (Ct) value (P = 0.052), but no evidence was observed for pairwise differences. For PRRSV alone, formaldehyde increased Ct compared to the untreated control and MCFA treatment (P < 0.05). For co-infection of PRRSV and PEDV, MCFA and formaldehyde increased Ct (P < 0.05) in comparison to non-treated feed. In summary, formaldehyde increased Ct values in feed when contaminated with PRRSV while both mitigants increased Ct value in feed when co-inoculated with PRRSV and PEDV.

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

Two experiments (384 pigs; C22 × L326; PIC) were conducted to determine the interactive effect of dietary L-carnitine and ractopamine HCl (RAC) on the metabolic response of pigs to handling. Experiments were arranged as split-split plots with handling as the main plot and diets as subplots (4 pens per treatment). Dietary L-carnitine (0 or 50 mg/kg) was fed from 36.0 kg to the end of the experiments (118 kg), and RAC (0 or 20 mg/kg) was fed the last 4 wk of each experiment. At the end of each experiment, 4 pigs per pen were assigned to 1 of 2 handling treatments. Gently handled pigs were moved at a moderate walking pace 3 times through a 50-m course and up and down a 15° loading ramp. Aggressively handled pigs were moved as fast as possible 3 times through the same course, but up and down a 30° ramp, and shocked 3 times with an electrical prod. Blood was collected immediately before and after handling in Exp. 1 and immediately after and 1 h after handling in Exp. 2. Feeding RAC increased (P < 0.01) ADG and G:F, but there was no effect (P > 0.10) of L-carnitine on growth performance. In Exp. 1 and 2, aggressive handling increased (P < 0.01) blood lactate dehydrogenase (LDH), lactate, cortisol, and rectal temperature and decreased blood pH. In Exp. 1, there was a RAC × handling interaction (P < 0.06) for the difference in pre- and posthandling blood pH and rectal temperature. Aggressively handled pigs fed RAC had decreased blood pH and increased rectal temperature compared with gently handled pigs, demonstrating the validity of the handling model. Pigs fed RAC had increased (P < 0.01) LDH compared with pigs not fed RAC. Pigs fed L-carnitine had increased (P < 0.03) lactate compared with pigs not fed L-carnitine. In Exp. 2, pigs fed RAC had lower (P < 0.02) blood pH immediately after handling, but pH returned to control levels by 1 h posthandling. Lactate, LDH, cortisol, and rectal temperature changes from immediately posthandling to 1 h posthandling were not different (P > 0.10) between pigs fed L-carnitine and those fed RAC, indicating that L-carnitine did not decrease recovery time of pigs subjected to aggressive handling. These results suggest that pigs fed 20 mg/kg of RAC are more susceptible to stress when handled aggressively compared with pigs not fed RAC. Dietary L-carnitine fed in combination with RAC did not alleviate the effects of stress. This research emphasizes the importance of using proper animal handling techniques when marketing finishing pigs fed RAC.

Three experiments using 1,356 pigs (C22 × 336 PIC) were conducted to determine the interactive effects of dietary L-carnitine and ractopamine hydrochloride (RAC) on carcass characteristics and meat quality of finishing pigs. Experiments were arranged as factorials with main effects of L-carnitine and RAC; L-carnitine levels were 0, 25, or 50 mg/kg in Exp. 1 and 2 and 0 or 50 mg/kg in Exp. 3, and RAC levels of 0, 5, or 10 mg/kg in Exp. 1 and 0 or 10 mg/kg in Exp. 2 and 3. Dietary L-carnitine was fed from 38 kg to slaughter (109 and 118 kg in Exp. 1 and 3, respectively) or for 4 wk before slaughter (109 kg in Exp. 2). Ractopamine HCl was fed for 4 wk in all experiments. Exp. 1 and 2 were conducted at university research facilities (2 pigs per pen), and Exp. 3 was conducted in a commercial research barn (23 pigs per pen). In Exp. 1, an L-carnitine × RAC interaction (P < 0.02) was observed for LM visual color, L*, and a*/b*. In pigs fed RAC, increasing L-carnitine decreased L* and increased visual color scores and a*/b* compared with pigs not fed RAC. Ultimate pH tended to increase (linear, P < 0.07) with increasing L-carnitine. Drip loss decreased (linear, P < 0.04) in pigs fed increasing L-carnitine. In Exp. 2, firmness scores decreased in pigs fed increasing L-carnitine when not fed RAC, but firmness scores increased and drip losses decreased with increasing L-carnitine when RAC was added to the diet (L-carnitine × RAC interaction, P < 0.04). Percentage lean was greater (P < 0.01) for pigs fed RAC in Exp. 2. In Exp. 3, fat thickness decreased and lean percentage increased in pigs fed L-carnitine or RAC, but the responses were not additive (L-carnitine × RAC interaction, P < 0.03). Furthermore, pigs fed L-carnitine tended (P < 0.06) to have decreased LM drip loss percentage whereas pigs fed RAC had decreased (P < 0.05) 10th rib and average backfat and decreased drip loss than pigs fed diets without RAC. These results suggest that dietary RAC increased carcass leanness and supplemental L-carnitine reduced LM drip loss when fed in combination with RAC.

Two experiments were conducted to determine the effects of standardized ileal digestible (SID) Trp:Lys in grow-finish swine diets containing 30% dried distillers grains with solubles (DDGS). Within each experiment, crystalline Lys and Trp replaced soybean meal to alter the dietary SID Trp:Lys concentration but maintain minimum ratios of other AA to Lys. In Exp. 1, 638 pigs (36.3 kg initial BW) were used in a 105-d trial (6 pens per treatment). Pens of pigs were randomly allotted to 1 of 4 dietary treatments with SID Trp:Lys of 14.0, 15.0, 16.5, and 18.0%. From d 0 to 42, as Trp:Lys increased, ADG increased (quadratic; P = 0.05) and ADFI tended to increase (quadratic; P = 0.07) with no changes in G:F. Both ADG and ADFI were maximized at Trp:Lys of 16.5%. From d 42 to 105, increasing SID Trp:Lys increased (linear; P < 0.001) ADG and ADFI. Unlike data from d 0 to 42, the response was linear through the greatest SID Trp:Lys of 18.0%. Overall (d 0 to 105), increasing SID Trp:Lys increased (linear; P < 0.001) final BW, ADG, ADFI, and HCW. In Exp. 2, 1,214 pigs (66.3 kg initial BW) were used in a 73-d finishing trial (9 pens per treatment). Pens of pigs were randomly allotted to 1 of 5 dietary treatments with SID Trp:Lys of 15.0, 16.5, 18.0, and 19.5 and the 15.0% Trp:Lys diet with l-Trp added to achieve 18.0% SID Trp:Lys. Overall (d 0 to 73), ADG, ADFI, G:F, and final BW improved (linear; P < 0.03) as dietary SID Trp:Lys increased through 19.5%. No differences were found in growth performance between the 2 diets containing 18.0% SID Trp:Lys. For carcass traits, increasing SID Trp:Lys resulted in increased HCW (linear; P = 0.01) and a tendency toward a decreased (quadratic; P = 0.09) backfat depth and fat-free lean index (FFLI), with pigs fed diets containing 16.5 and 18.0% SID Trp:Lys having increased FFLI and lower backfat depth compared with pigs fed 15.0 and 19.5% SID Trp:Lys. Pigs fed the diet with added crystalline Trp tended to have increased (P = 0.08) backfat depth and decreased FFLI (P = 0.10) compared with pigs fed the same SID Trp:Lys without crystalline Trp. The results indicated that the optimal SID Trp:Lys was 16.5% from 36.3 to 72.6 kg but at least 19.5% from 72.6 to 120.2 kg in corn-soybean meal diets containing 30% DDGS.

A total of 2,152 pigs (C22 × 336 PIC) were used in 4 experiments to determine the interactive effects of dietary l-carnitine and ractopamine HCl (RAC) on finishing pig growth performance. All trials were arranged as factorial arrangements with main effects of l-carnitine (0, 25, or 50 mg/kg in Exp. 1 and 2 and 0 or 50 mg/kg in Exp. 3 and 4) and RAC (0, 5, or 10 mg/kg in Exp. 1 and 0 or 10 mg/kg in Exp. 2, 3, and 4). Dietary carnitine was fed from 38 to 109 kg (Exp. 1 and 3) or for the last 4 or 3 wk before slaughter (118 kg; Exp. 2 and 4, respectively). Ractopamine HCl was fed for 4 wk (Exp. 1, 2, and 3) or 3 wk (Exp. 4) before slaughter. Experiments 1 and 2 were conducted in university research facilities, and Exp. 3 and 4 were conducted in a commercial research facility. All diets were formulated to contain 1.00% total Lys during the last phase of each experiment. In all experiments, pigs fed RAC had increased (P < 0.05) ADG and G:F compared with pigs fed no RAC. Feeding l-carnitine before the RAC feeding period did not affect pig growth performance. In Exp. 1 and 2, l-carnitine did not affect ADG during the last 4 wk; however, in Exp. 2, G:F tended (quadratic; P = 0.07) to improve with increasing l-carnitine. In Exp. 3, l-carnitine × RAC interactions were observed (P < 0.04) for ADG and G:F. Both added l-carnitine and RAC improved performance, but the response was not additive. In Exp. 4, pigs fed l-carnitine had increased (P < 0.04) ADG (0.88 vs. 0.84 kg) and G:F (0.36 vs. 0.35) compared with pigs fed no l-carnitine, and the response was additive to that of RAC. Analysis of treatments common to all experiments showed that pigs fed RAC had increased (P < 0.01) ADG (1.03 vs. 0.93 kg) and G:F (0.40 vs. 0.35) compared with pigs fed no RAC. Pigs fed l-carnitine tended to have increased (P = 0.07) ADG (1.00 vs. 0.96 kg) and improved (P < 0.01) G:F (0.38 vs. 0.37) compared with pigs not fed l-carnitine. These results confirm that RAC improves growth performance of finishing pigs. Added l-carnitine improved growth performance of finishing pigs, and the greatest response was observed in Exp. 3 and 4, which were conducted in commercial research environments. These experiments imply that adding l-carnitine to a finishing diet does not enhance the growth effects of RAC and that effects of RAC and l-carnitine on ADG and G:F are independent.

A total of 1104 barrows and gilts (PIC 337 × 1050, Pig Improvement Company, Hendersonville, TN), weighing 36 ± 1 kg were used in a 109-d study to evaluate effects of dietary L-carnitine and dried distillers grains with solubles (DDGS) on growth, carcass traits, and loin and fat quality. Pigs were blocked by BW and randomly assigned to 1 of 6 treatments, with 7 pens per treatment. Treatments were arranged as a 2 × 3 factorial, with main effects of DDGS (30% in Phases 1, 2, and 3, and 20% in Phase 4) and L-carnitine (0, 50, or 100 mg/kg). Overall (d 0 to 109), dietary L-carnitine tended to improve ADG (linear, P = 0.07). Pigs fed 50 mg/kg L-carnitine but no DDGS had greater G:F than pigs fed 0 or 100 mg/kg, whereas when diets containing DDGS were fed, 50 mg/kg of L-carnitine reduced G:F compared with pigs fed 0 or 100 mg/kg (quadratic DDGS × L-carnitine, P < 0.01). There was no effect of DDGS × L-carnitine for any carcass traits, but pigs fed increasing dietary inclusion levels of L-carnitine produced heavier HCW (quadratic, P = 0.03), greater carcass yields (quadratic, P = 0.07), and greater fat depths (quadratic, P = 0.04), with the greatest response observed in pigs fed 50 mg/kg dietary L-carnitine. Feeding L-carnitine increased purge loss (linear, P = 0.03), whereas feeding DDGS tended to decrease (P = 0.06) LM marbling scores. The LM from pigs fed 50 mg/kg L-carnitine and DDGS had lower shear force values compared with LM chops from pigs fed either 0 or 100 mg/kg; however, shear force values were similar across dietary L-carnitine levels in diets devoid of DDGS (quadratic DDGS × L-carnitine, P < 0.01). Furthermore, increasing L-carnitine in DDGS diets increased fresh LM color scores, but pigs fed DDGS-free diets produced LM chops with similar subjective color scores (linear DDGS × L-carnitine, P = 0.03). As expected, feeding DDGS increased (P < 0.001) iodine value (IV) in jowl fat samples, but dietary L-carnitine did not alter IV. The concentrations of C18:2n-6 and C20:2 were decreased with increasing L-carnitine in DDGS-containing diets, but not in diets without DDGS (linear DDGS × L-carnitine, P ≤ 0.04). Results of this study indicate that dietary DDGS did not affect growth, but led to more unsaturation of jowl fat, whereas feeding 50 mg/kg of L-carnitine improved HCW and reduced C18:2n-6 in jowl fat when fed in combination with DDGS.

Two studies were conducted to determine the effects of diet form (meal vs. pellet) and feeder design (conventional dry vs. wet/dry) on finisher pig performance. Experiments were arranged as 2 × 2 factorials with 11 replications per treatment and 26 to 29 pigs per pen. In Exp. 1, pigs (n = 1,290; initial BW 46.8 kg) were used in a 91-d study. Pelleted diets averaged approximately 35% fines throughout the study. Overall, pigs fed pelleted diets or via wet/dry feeders had greater (P < 0.07 and 0.001, respectively) ADG than pigs fed meal diets or fed with a dry feeder. Diet form × feeder interactions (P < 0.02) were observed for G:F. Pigs fed either meal or pelleted diets via a wet/dry feeder had similar G:F, but pigs fed pelleted diets in dry feeders had poorer G:F than pigs with meal diets in dry feeders. In Exp. 2, pigs (n = 1,146; initial BW 38.2 kg) were used in a 104-d study. From d 0 to 28, a diet form × feeder design interaction (P < 0.01) was observed for ADG, which was due to decreased ADG in pigs fed pelleted diets from a conventional dry feeder compared with pigs fed meal diets from the same feeder type whereas there was no difference in wet/dry feeders based on diet form. Pigs fed pelleted diets had poorer (P < 0.01) G:F than pigs fed meal diets. This result appeared to be due to poor pellet quality (39.6% fines). From d 42 to 86, pellet quality improved (4.4% fines) and a diet form × feeder interaction was observed for ADG in which pigs fed meal diets in a dry feeder had decreased (P < 0.05) ADG than pigs fed pelleted diets in dry feeders or pigs presented either diet in wet/dry feeders. Pigs fed pelleted diets had improved (P < 0.001) G:F. Pigs fed via wet/dry feeders had increased (P < 0.03) ADFI and G:F compared with pigs fed via dry feeders. Overall, pigs fed with wet/dry feeders had increased (P < 0.02) ADG and ADFI and poorer G:F than pigs with dry feeders whereas pigs given pelleted diets had improved (P = 0.05) G:F compared with pigs presented meal diets. These studies found that pigs fed from wet/dry feeders had increased ADG and ADFI compared with pigs fed via dry feeders regardless of diet form. Additionally, pellet quality appeared to influence responses because pigs fed high-quality pellets via dry feeders had better growth performance than pigs fed meal diets. Conversely, if pellet quality was poor, the feed efficiency benefits associated with pelleting were lost.

Two studies were conducted to determine the effects of feeder adjustment and trough space on growth performance of finishing pigs. In Exp. 1, 234 pigs (initial BW 41.5 kg) were used in an 89-d trial. Pigs were randomly allotted to 1 of 3 treatments with 9 replications of 8 pigs/pen and 1 replicate with 6 pigs/pen. Treatments consisted of a minimum feeder gap setting of 1.27, 1.91, or 2.54 cm. Feeders were adjusted to a minimum gap setting, but the agitation plate could be moved upward to a maximum opening of 1.91, 2.54, or 3.18 cm, respectively. Feeder adjustments of 1.27, 1.91, and 2.54 cm averaged 28, 58, and 75% pan coverage, respectively. From d 0 to 58, increasing feeder gap improved (linear; P≤ 0.04) ADG and ADFI, but decreased (linear; P <0.05) G:F. Although the response was linear for ADG, no increase occurred (quadratic; P= 0.15) beyond the 1.91-cm feeder gap setting. From d 58 to 89, increasing feeder gap setting tended (linear; P= 0.08) to worsen G:F. Overall (d 0 to 89), pigs fed with increasing feeder gap had decreased (linear; P <0.03) G:F due to increased (linear; P <0.02) ADFI. In Exp. 2, 288 pigs (initial BW 41.3 kg) were used in a 91-d study to evaluate the effects of feeder trough space (4.45 vs. 8.9 cm/pig) and minimum feeder gap opening of 1.27 cm (narrow) vs. 2.54 cm (wide). The treatments were arranged in a 2 × 2 factorial with 6 replications per treatment. Feeder trough space was altered by having pens of either 8 to 16 pigs per pen with all pigs provided 0.74 m2floor space per pig. From d 0 to 56 and 56 to 91, no adjustment × space interactions or effects of trough space were observed. From d 0 to 56, pigs with the wide feeder gap setting had decreased (P< 0.02) G:F compared with those that had the narrow feeder gap setting. From d 56 to 91, pigs with the wider feeder gap setting had increased (P< 0.001) ADFI, but consequently had decreased (P< 0.01) G:F. Overall (d 0 to 91), no trough space × feeder adjustment interactions were observed. However, ADG tended to increase (P= 0.08) as feeder trough space increased from 4.45 to 8.9 cm/pig. Pigs fed with the wide feeder gap setting had increased (P< 0.01) feed disappearance and decreased (P< 0.01) G:F compared with pigs with the narrow feeder gap setting. These data indicate that pigs from 41 to 68 kg need approximately 58% pan coverage, whereas pigs greater than 68 kg should have approximately 28% pan coverage to optimize growth and reduce feed wastage.

Our objectives were to compare a conventional dry (5-space, 152.4-cm-wide) and a wet-dry (double-sided, each side = 38.1-cm-wide single space) feeder and to determine if changing the source of water to a location separate from a wet-dry feeder would result in improved G:F and carcass characteristics. Water supply to the wet-dry feeder was shut off and the cup waterer was turned on in 8 pens at 8 (d 69) or 4 (d 97) wk prior to harvest. For the remaining 8 wet-dry feeder pens, the feeder provided the sole water source for the entire experiment. A total of 1,296 pigs (PIC, 337 × 1050; initially 19.4 kg BW) were used, with 27 pigs/pen (14 barrows and 13 gilts) and 24 pens/feeder design. From d 0 to 69, pigs fed with the wet-dry feeder had increased (P< 0.05) ADG, ADFI, G:F, and d 69 BW compared with those using the conventional dry feeder. Overall (d 0 to 124), pigs using fed with the water source in the wet-dry feeder the entire time had greater (P< 0.05) ADG, ADFI, final BW, and HCW the other treatments. The overall G:F was not different (P> 0.05) among pigs fed with the different feeder treatments. Pigs fed with the wet-dry feeder where water source was changed at 4 wk before harvest had greater (P< 0.05) ADG than pigs that used a conventional dry feeder. Pigs where the water source was changed at 4 wk had greater (P< 0.05) ADFI than those were the water source was changed 8 wk prior to harvest, and for pigs fed with the conventional dry feeder ADFI was intermediate. Back fat depth of pigs where the water source was changed at 8 wk before harvest was reduced (P< 0.05) compared with all other treatments and LM depth was greater (P< 0.05) than that of pigs using a conventional dry feeder and where the water source was changed at 4 week before harvest. Pigs fed using the wet-dry feeder visited the feeder less frequently (P< 0.05) and spent less total time at the feeder (P< 0.05) than those fed with the conventional dry feeder. The differences in feeding patterns remained even after the access to water was removed from the wet-dry feeder, with no change in the amount of aggressive behavior observed at the feeder. Pigs fed with a wet-dry feeder had an increased growth rate compared with those fed with a conventional dry feeder. Although measures of carcass leanness were improved by changing the location of the water, removing the water from the feeder also eliminated any net improvement in BW from using a wet-dry feeder.

Our objective was to compare effects of a conventional dry (CD, 152.4-cm-wide, 5-space, Staco Inc., Schaefferstown, PA) and a wet–dry (WD, double-sided, each side = 38.1-cm-space, Crystal Springs, GroMaster Inc., Omaha, NE) feeder using various feeder adjustment openings on the growth performance and carcass characteristics of growing–finishing pigs (Sus scrofa). In Exp. 1, 1,296 pigs (BW 19 kg) were used in a 27-d study to evaluate 3 feeder openings nested within each feeder design. From d 0 to 27, pigs fed with a WD feeder had similar ADG, but lower (P< 0.02) ADFI and greater G:F than pigs fed with a CD feeder. Increased adjustment opening increased (linear, P< 0.01) ADG and ADFI by pigs fed with a WD feeder, and increased (linear, P< 0.01) ADFI by pigs fed with a CD feeder. In Exp. 2, 1,248 pigs (BW 33 kg) were used to evaluate 3 feeder openings nested within each feeder design in a 93-d study. Pigs fed with a WD feeder had greater (P< 0.05) ADG, ADFI, final BW, HCW, and backfat, but decreased fat-free lean index (FFLI) than those fed with a CD feeder. Increased opening of the WD feeder resulted in greater (linear, P< 0.05) ADG, ADFI, HCW, and backfat, but lower FFLI. No differences among CD feeder openings were observed, and G:F did not differ among all feeder treatments. In Exp. 3, 1,287 pigs (BW 38 kg) were used in a 92-d factorial experiment with 4 feeder treatments and 2 diet types (low and high byproduct diets). Feeder treatments were CD at approximately a 2.4-cm opening, WD at a 3.2-cm opening, WD changed to a 2.5-cm opening on d 56, and WD changed to a 2.5-cm opening on d 28 and a 1.9-cm opening on d 56. Pigs fed with a WD feeder had greater (P< 0.01) ADG, ADFI, HCW, and backfat, but decreased FFLI than pigs fed with a CD feeder. Decreasing the WD feeder opening during the study decreased (P< 0.05) ADG. Pigs with the WD feeder opening decreased to 1.9 cm had reduced (P< 0.05) ADFI and backfat, but increased FFLI compared with pigs with a WD feeder opening of 3.2 cm. Feed efficiency did not differ among treatments. In conclusion, ADG, ADFI, HCW, and backfat were increased with the WD feeder evaluated in this experiment, but the growth of pigs fed with a WD feeder was more sensitive to differences in feeder adjustment than that of pigs fed with a CD feeder.

Four experiments were conducted to determine the standardized ileal digestible (SID) Lys requirement of pigs (Sus scrofa) from 7 to 14 kg. In Exp. 1, 294 pigs (6.8 kg BW) were used in a 28-d growth trial with 7 pigs per pen and 7 pens per treatment. Treatment diets were fed from d 0 to 14, and a common diet was fed from d 14 to 28. The 6 SID Lys levels tested were 1.15, 1.23, 1.30, 1.38, 1.45, and 1.53%. The diets were corn- and soybean-meal [Zea maysL. and Glycine max(L.) Merr.] based, with 10% spray-dried whey, 4.5% fish meal, and contained 3.37 Mcal of ME/kg. From d 0 to 14, ADG increased (quadratic, P< 0.001) as SID Lys increased from 1.15 to 1.30% with no further increase at greater levels. Gain:feed increased (linear, P< 0.001) with increasing SID Lys. Experiments 2 to 4 were 14-d growth trials with diets containing 1.22, 1.32, 1.42, 1.52, or 1.62% SID Lys. Diets were corn- and soybean-meal based with 3.45 Mcal of ME/kg. Soybean meal and lactose were constant in all diets at 30 and 7% of the diet, respectively. In Exp. 2, 840 pigs (7.6 kg BW) were used, with 24 pigs per pen and 7 pens per treatment. Increasing SID Lys from 1.22 to 1.42% increased (quadratic, P< 0.01) ADG and G:F with no further improvement observed in pigs fed the 1.52 or 1.62% SID Lys diets during d 0 to 14. In Exp. 3, 1,260 pigs (8.5 kg BW) were used with 42 pigs per feeder (2 pens per feeder) and 6 feeders per treatment. Increasing dietary Lys increased (quadratic, P< 0.02) ADG and G:F with the greatest response observed as SID Lys increased from 1.22 to 1.32% and, then, slight improvements with 1.42 and 1.52% during d 0 to 14. In Exp. 4, 770 pigs (7.4 kg BW) were used with 22 pigs per pen and 7 pens per treatment. Increasing SID Lys increased (quadratic, P= 0.05) ADG with pigs fed 1.32 and 1.42% SID Lys diets having the greatest BW gains during d 0 to 14. Increased SID Lys decreased (linear, P< 0.001) ADFI and increased (linear, P< 0.001; quadratic, P= 0.02) G:F. In conclusion, results of these experiments indicate that the 1998 NRC Lys recommendations (e.g., 1.19% SID Lys for 5 to 10 kg pigs) are less than required for optimal growth for 7 to 14 kg pigs. One-slope straight broken-line analysis indicated that the SID Lys requirement for optimal growth was at least 1.30% for ADG and 1.37% for G:F, or at least 3.86 and 4.18 g SID Lys/Mcal ME, respectively. Quadratic broken-line analysis indicated that the SID Lys requirement for optimal growth was at least 1.37% for ADG and 1.54% for G:F, or at least 4.19 and 4.92 g SID Lys/Mcal ME, respectively.