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Two experiments were conducted to investigate increasing unground and finely ground soybean hulls fed in meal or pelleted form on nursery and finishing pig performance. In experiment 1, 1,100 nursery pigs (initially 6.8 ± 0.1 kg and 28 d of age) were used in a 42-d study with 11 replicates per treatment. Treatments were arranged in a 2 × 2 × 2 factorial with main effects of soybean hulls (10% vs. 20%), grind type (unground, 617 µ vs. ground, 398 µ), and diet type (pelleted vs. meal form). No three-way or soybean hull level × grind type interactions were observed. Overall, average daily gain (ADG) was increased (P < 0.05) by pelleting, decreased (P < 0.05) by grinding, but unaffected by soybean hull levels. Grind type × diet form interactions were observed (P < 0.05) for gain:feed ratio (G:F) and a tendency for average daily feed intake (ADFI; P < 0.10). This was because grinding soybean hulls decreased (P < 0.05) ADFI and increased (P < 0.05) G:F when fed in meal form; however, grinding did not affect ADFI and decreased (P < 0.05) G:F when diets were pelleted. Increasing soybean hulls increased (P < 0.05) ADFI and decreased (P < 0.05) G:F when diets were fed in meal form, but these effects were not observed when diets were pelleted (diet form × soybean hull level interaction, P < 0.06). In experiment 2, 1,215 pigs (initially 21.1 ± 0.1 kg) were used in a 118-d study with nine replications per treatment. Treatments were a corn–soybean meal–based control diet and four diets arranged in a 2 × 2 factorial with the main effects of soybean hulls (7.5% vs. 15%) and grind type (unground, 787 µ vs. ground, 370 µ). All diets were fed in meal form. No soybean hull level × grind type interactions were observed for any growth or carcass responses. Increasing dietary soybean hulls from 0% to 15%, regardless of particle size, did not affect ADG or ADFI, but decreased (linear, P < 0.02) G:F. Carcass yield, hot carcass weight, and backfat depth decreased (linear, P < 0.03) whereas percentage lean increased (linear, P < 0.01) with increasing soybean hulls. Pigs fed ground soybean hulls had increased backfat depth (P < 0.01) and decreased (P < 0.01) percentage lean and fat-free lean index. In summary, increasing soybean hulls up to 20% decreased G:F in nursery and finishing pigs, whereas pelleting nursery diets improved ADG and eliminated the negative effect of increasing soybean hulls on G:F. Grinding soybean hulls reduced growth performance in nursery and finishing pigs.

Four experiments were conducted to investigate the effects of increasing dietary soybean hulls without or with distillers dried grains with solubles (DDGS) and net energy (NE) formulation on nursery pig performance. In experiment 1, a total of 210 nursery pigs (initially 6.6 ± 0.1 kg) were used in a 34-d study. Pigs were fed one of five diets that contained increasing soybean hulls (0%, 5%, 10%, 15%, and 20%). Diets were not balanced for NE. Increasing soybean hulls decreased (linear, P < 0.01) average daily gain (ADG) and gain:feed ratio(G:F), and tended to decrease average daily feed intake (ADFI; quadratic, P < 0.10). In experiment 2, 210 nursery pigs (initially 13.6 ± 0.1 kg) were used in a 20-d study to determine the effect of equal NE formulation in diets with soybean hulls. Pigs were fed one of five diets containing 0% (control), 10%, or 20% soybean hulls either balanced to contain equal NE to the control diet or not balanced for energy. Diets containing 10% and 20% soybean hulls with balanced NE contained 3.60% and 7.15% added soybean oil, respectively. Increasing soybean hulls decreased (linear, P < 0.01) ADG regardless of formulation method. Pigs fed increasing soybean hulls without added fat had decreased (linear, P < 0.01) G:F. Increasing soybean hulls in diets with balanced NE decreased (linear, P < 0.02) ADFI, but did not affect G:F. In experiment 3, 600 pigs (initially 6.8 ± 0.1 kg) were used in a 42-d study. Pigs were fed 1 of 10 diets containing 0%, 3%, 6%, 9%, or 12% soybean hulls without or with DDGS (15% from d 0 to 14, 30% from d 15 to 42). Feeding DDGS reduced (P < 0.04) ADG and ADFI, and tended to increase (P < 0.06) G:F. Increasing soybean hulls decreased G:F quadratically (P < 0.03) in diets without DDGS, but decreased G:F linearly (P < 0.01) in diets with DDGS (soybean hulls × DDGS interaction, P < 0.05). In experiment 4, 304 barrows (initially 11.7 ± 0.2 kg) were used in a 21-d study. Pigs were fed one of eight diets containing 0%, 5%, 10%, or 15% soybean hulls with or without 20% DDGS. No soybean hull × DDGS interactions were observed. Increasing soybean hulls tended to decrease (linear, P < 0.08) G:F. In conclusion, feeding low levels of soybean hulls did not affect nursery pig performance but more than 5% soybean hulls, with or without DDGS, decreased G:F. Formulating diets containing soybean hulls on an equal NE basis eliminated the negative effects on G:F, but the NE (1,003 kcal/kg) of soybean hulls used in this study was underestimated.

Research has shown that carcass yield in swine is reduced when ingredients with high neutral detergent fiber (NDF) content. Carcass yield reduction from feeding high-fiber ingredients results from an increase in the weight of intestinal contents. NDF has been shown to result in the digestive contents to swell in the large intestine by absorbing water thus increasing the fecal volume in the large intestine. Considering the financial implications of changing carcass yield, the objective of this project was to develop a regression equation to estimate carcass yield from dietary NDF and strategies where high-NDF ingredients are taken out of the diet in the last dietary phases before slaughter (withdrawal period; WP). Data from 8 experiments (43 observations) originated from 6 journal articles and 1 technical memo were used to develop the regression equation. The WP of high NDF ingredients was either none or ranged from 5 to 63 d in the experiments. Treatment diets of each trial were reformulated to obtain dietary nutrient content using the NRC ingredient library (NRC, Nutrient requirements of swine. 11th ed, 2012). Composition of experimental diets was used to calculate dietary net energy, crude protein, crude fiber, NDF, and acid detergent fiber in the last two dietary phases. These dietary compositions along with the number of days of WP were used to develop regression equations. The model was determined using a step-wise selection procedure starting with guided forward selection through individual predictor variables, with a statistical significance at P < 0.05 used to determine inclusion of terms in the final model. The regression analysis showed that WP, NDF level in the dietary phase prior to the final phase (NDF1), NDF level in the last dietary phase before marketing (NDF2), and the interaction between NDF2 and WP were the most important variables in the dataset to predict carcass yield. The resulting regression equation was as follows: carcass yield, % = 0.03492 ± 0.02633 × WP (d) – 0.05092 ± 0.02862 × NDF1 (%) – 0.06897 ± 0.02931 × NDF2 (%) – 0.00289 ± 0.00216 × (NDF2 [%] × WP [d]) + 76.0769 ± 1.33730. In conclusion, high levels of NDF up to slaughter had a negative impact on carcass yield. Increasing the length of the WP improved carcass yield; however, the effect of WP was dependent on the level of NDF2. The equation herein provides a tool to estimate of the impact of dietary NDF on carcass yield.

Dietary phosphorus concentration greatly affects pig’s growth performance, environmental impact and diet cost. A total of 1080 pigs (initially 5.9 ± 1.08 kg) from three commercial research rooms were used to determine the effects of increasing standardized total tract digestible (STTD) P concentrations in diets without and with phytase on growth performance and percentage bone ash. Pens (10 pigs/pen, 9 pens/treatment) were balanced for equal weights and randomly allotted to 12 treatments. Treatments were arranged in two dose titrations (without or with 2000 units of phytase) with six levels of STTD P each. The STTD P levels were expressed as a percentage of NRC (2012) requirement estimates (% of NRC; 0.45 and 0.40% for phases 1 and 2, respectively) and were: 80%, 90%, 100%, 110%, 125% and 140% of NRC in diets without phytase and 100%, 110%, 125%, 140%, 155% and 170% of NRC in diets with phytase. Diets were provided in three phases, with experimental diets fed during phases 1 (days 0 to 11) and 2 (days 11 to 25), followed by a common diet from days 25 to 46. On day 25, radius samples from one median-weight gilt per pen were collected for analysis of bone ash. During the treatment period, increasing STTD P from 80% to 140% of NRC in diets without phytase improved average daily gain (ADG; quadratic, P < 0.01), average daily feed intake (ADFI; quadratic, P < 0.05) and gain–feed ratio (G : F; linear, P < 0.01). Estimated STTD P requirement in diets without phytase was 117% and 91% of NRC for maximum ADG according to quadratic polynomial (QP) and broken-line linear (BLL) models, respectively, and was 102%, 119% and >140% of NRC for maximum G : F using BLL, broken-line quadratic and linear models, respectively. When diets contained phytase, increasing STTD P from 100% to 170% of NRC improved ADG (quadratic, P < 0.05) and G : F (linear, P < 0.01). Estimated STTD P requirement in diets containing phytase was 138% for maximum ADG (QP), and 147% (QP) and 116% (BLL) of NRC for maximum G : F. Increasing STTD P increased (linear, P < 0.01) the percentage bone ash regardless of phytase addition. When comparing diets containing the same STTD P levels, phytase increased (P < 0.01) ADG, ADFI and G : F. In summary, estimated STTD P requirements varied depending on the response criteria and statistical models and ranged from 91% to >140% of NRC (0.41% to >0.63% of phase 1 diet and 0.36% to >0.56% of phase 2 diet) in diets without phytase, and from 116% to >170% of NRC (0.52% to >0.77% of phase 1 diet and 0.46% to >0.68% of phase 2 diet) for diets containing phytase. Phytase exerted an extra-phosphoric effect on promoting pig’s growth and improved the P dose-responses for ADG and G : F.

In wean-to-finish pig production, leftover finisher feed from the previous group is commonly blended with nursery diets as weanling pigs enter the facility. Two experiments were conducted to evaluate feeding the last finisher diet to nursery pigs. The timing (phase) and dose were evaluated. Each experiment used 1,260 pigs from two commercial research rooms with 21 pigs per pen and 30 pens per room (15 pens per treatment). Pigs were fed commercial nursery diets in a five-phase feeding program, and phase changes were based on a feed budget. In experiment 1, pens of pigs (initially 5.83 kg) were blocked by body weight, gender, and room and allotted to one of four treatments. Treatments included standard nursery diets throughout (control) or standard diets with 2.5 kg/pig of the last finisher feed blended at the beginning of phase 2, 3, or 4. Growth responses during the intermediate periods were promptly decreased (P < 0.05) once the finisher feed was introduced regardless of phase in which it was blended. However, during the overall nursery period, blending the finisher diet into phase 2 decreased (P < 0.05) average daily gain (ADG) and average daily feed intake (ADFI), but did not affect gain:feed ratio (G:F), compared with control pigs or those that had blended diet in phase 4 with blending of phase 3 diet intermediate. In experiment 2, weaned pigs were fed common phase 1 and 2 diets before the start of the experiment. At the beginning of phase 3, pens of pigs (initially 10.6 kg) were blocked by body weight and room and allotted to one of four treatments. Treatments consisted of a dose-titration of blending increasing amounts of finisher feed (0, 1.25, 2.50, and 3.75 kg/pig) into the phase 3 nursery diet. Overall, blending increasing amounts of the last finisher feed with phase 3 nursery diet decreased ADG (linear, P = 0.050) and tended to decrease (linear, P < 0.07) ADFI and final body weight. However, there was no evidence for difference in overall G:F. In conclusion, blending finisher feed into the early nursery diets decreased overall ADG and ADFI; however, pigs greater than 11 kg had improved ability to compensate for the negative effects of blending the last finisher feed on overall growth performance. Nevertheless, increasing the amounts of finisher feed fed to 11-kg pigs from 0 to 3.75 kg/pig resulted in a linear decrease in overall ADG and ADFI. Economic analysis indicated no change in income-over-feed-cost due to the timing and dose of blending finisher feed into nursery diets.

Three studies were conducted to determine the effects of source and concentration of Na and Cl on pig growth performance from 7 to 12 kg. In all three experiments, pigs were fed a common diet (0.33% Na and 0.77% Cl) for 7 or 8 d after weaning then randomly assigned to dietary treatments. In Exp. 1, 360 mixed-sex pigs were used in a 14-d study with 15 replications per treatment and six pigs per pen. Treatments included a 10% dried whey diet with 0.60% added salt (0.37% Na and 0.75% Cl); or three diets with 7.2% crystalline lactose with either: 0.35% added salt (0.18% Na and 0.47% Cl); 0.78% added salt (0.35% Na and 0.72% Cl); or 1.15% NaHCO3 and 0.40% KCl (0.35% Na and 0.45% Cl). Pigs fed the 0.78% added salt-lactose diet had greater (P < 0.05) ADG than pigs fed the 0.35% added salt-lactose diet, with others intermediate. In Exp. 2, 360 barrows were used in a 14-d study with 12 replications per treatment and five pigs per pen. Treatments included two added salt diets (providing 0.13% Na and 0.35% Cl or 0.35% Na and 0.68% Cl), three diets with Na and Cl provided by KCl and NaHCO3 (0.13%, 0.35%, or 0.57% Na and 0.50% Cl), or a diet with NaHCO3 and CaCl2 (0.35% Na and 0.50% Cl). Regardless of Na source, ADG and ADFI increased (quadratic, P < 0.05) as dietary Na increased from 0.13% to 0.35%, with no further benefits observed thereafter. There was no evidence for differences among pigs fed NaCl or NaHCO3 nor evidence for differences among pigs fed the different Na and Cl sources at similar concentrations. In Exp. 3, 300 pigs were used in a 21-d trial with 10 replications per treatment and five pigs per pen. Treatments included a control diet with added salt to provide 0.33% Na and 0.55% Cl or five diets with 0.33 % Na and added KCl to provide 0.09, 0.21, 0.32, 0.45, or 0.55% Cl. ADG and G:F increased (quadratic, P < 0.035) as Cl increased from 0.09% to 0.32%. Pigs fed the control diet (added salt) and the 0.55% Cl diet had similar ADG. For ADG and ADFI, the broken line linear model indicated a breakpoint of 0.23% Cl. For G:F, the quadratic polynomial model suggested the maximum at 0.38% Cl. In conclusion, 7 to 12 kg pigs fed diets that contained at least 0.35% Na and 0.38% Cl had greater ADG and G:F compared to pigs fed diets with lower concentrations and minimal effects were observed among the sources of Na or Cl used in these studies.

Based on results of a recent meta-analysis, we hypothesized that increased dietary Val, Ile, or Trp could correct possible amino acid interactions because of excess Leu in diets containing high levels of corn protein, namely dried distiller’s grains with solubles (DDGS). A total of 1,200 pigs (PIC TR4 × (Fast LW × PIC L02); initially 33.6 ± 0.6 kg) were used in a 103-d study. The 6 dietary treatments were corn–soybean meal (SBM)-DDGS-based as follows: (1) high SBM and low level of l-Lys HCl (HSBM), (2) high l-Lys HCl and moderate Ile, Val, Trp (AA above NRC 2012 estimates; NC), (3) moderate l-Lys HCl and high Ile, Val, and Trp (PC), and PC with either increased (4) L-Val (PC+Val), (5) L-Ile (PC+Ile), or (6) L-Trp (PC+Trp). Pigs fed the NC diet were predicted to have the poorest average daily gain (ADG), the PC diet to be intermediate, and pigs fed the HSBM, PC+Val, PC+Ile, and PC+Trp have the same and highest predicted ADG. In the grower period (34 to 90 kg), ADG was greater (Ρ < 0.05) for the pigs fed HSBM and PC+Val diets than the NC with pigs fed other diets intermediate. Pigs fed HSBM were more (Ρ < 0.05) efficient (G:F) than the NC and PC with pigs fed other diets intermediate. In the finisher period (90 to 136 kg), ADG was greater (Ρ < 0.05) for pigs fed PC+Ile than that of the NC with pigs fed other diets intermediate. Pigs fed PC+Val had greater (Ρ < 0.05) average daily feed intake (ADFI) than the NC with pigs fed other diets intermediate. However, PC+Ile pigs were more (Ρ < 0.05) efficient than PC+Val with pigs fed other diets intermediate. Overall, ADG was greater (Ρ < 0.05) for pigs fed HSBM, PC+Val, and PC+Ile diets than the NC with pigs fed other diets intermediate. Pigs fed the PC+Val diet had greater (Ρ < 0.05) ADFI than the NC with pigs fed other diets intermediate. No differences were detected between treatments for overall G:F or other carcass characteristics. In conclusion, increasing Val or Ile in high l-Lys-HCl-DDGS-based diets improved growth performance compared with pigs fed diets containing high levels of l-Lys HCl without added Val and Ile. These results present evidence that the recently developed meta-analysis can predict the relative differences in overall ADG for pigs fed the NC, PC, PC+Val, and PC+Ile diets; however, the predicted G:F was less accurate. The data demonstrate that the negative effects of high Leu concentrations in corn-DDGS-based diets can be reversed by increasing the ratios of Val and Ile relative to Lys.

ObjectivesThe objective of this study was to evaluate the effects of pork hot carcass weight on loin quality and palatability of top loin chops.Materials and MethodsThe pigs in this study were raised to exceed standard market weights. Pork loins (N = 200) were collected from 4 different hot carcass weight groups: light (LT; less than 111.8 kg), medium-light (MLT; 111.8- 119.1 kg), medium-heavy (MHVY; 119.1- 124.4), and a heavy (HVY; 124.4 and greater). Prior to fabrication, purge loss percentage, instrumental color, subjective color and marbling, and pH were taken for each loin. Following fabrication, chops were assigned to fat and moisture analysis, Warner-Bratzler shear force (WBSF), consumer sensory analysis, or trained sensory analysis. For WBSF, consumer, and trained panels, chops were thawed for 24 h prior to analysis. Chops were cooked on clam-shell style grills and removed from the heat with the internal temperature rising to a peak internal temperature of 71°C. Consumers (N = 197) evaluated each sample for tenderness, juiciness, flavor like, and overall liking on 0 to 100 continuous line scales. Consumers were also able to indicate “yes” or “no” if the chop was acceptable for all palatability traits and overall. Trained panelists evaluated each sample for initial juiciness, sustained juiciness, myofibrillar tenderness, connective tissue amount, overall tenderness, pork flavor, and off flavor on similar 0 to 100 continuous line scales.ResultsLoins from all weight groups differed (P < 0.05) in weight (LT < MLT < MHVY < HVY). No carcass weight effects (P > 0.05) were found for loin instrumental color, subjective color, subjective marbling, purge loss percentage, pH, WBSF, moisture percentage, fat percentage, and drip loss. Carcass weight did not affect (P > 0.05) juiciness or flavor like ratings but did affect (P < 0.05) tenderness ratings and overall liking ratings. Chops from the HVY group were rated as more tender (P < 0.05) compared to chops from the LT weight group. Additionally, chops from the HVY weight group had greater (P < 0.05) consumer overall liking rating compared to chops from both the LT and MLT weight treatments. Hot carcass weight treatment did not contribute (P > 0.05) to the percentage of chops rated acceptable for flavor and overall liking. Chops from the HVY weight carcasses had the greatest (P < 0.05) percentage of chops rated acceptable for juiciness. Chops from LT carcasses had the lowest percentage of chops rated acceptable for tenderness. Trained sensory results also reflected tenderness and juiciness differences among carcass weight treatments. For both initial and sustained juiciness, chops from MHVY carcasses were rated as juicier (P < 0.05) compared to chops from both MLT and LT carcasses. Additionally, chops from the LT hot carcass weight treatment had the lowest (P < 0.05) myofibrillar tenderness ratings. Chops from MHVY and HVY carcasses were similar (P > 0.05) with greater (P < 0.05) overall tenderness ratings compared to chops from LT carcasses.ConclusionThese results indicate that as hot carcass weight increased, there were no negative effects on loin quality, and top loin chops from heavier weight carcasses had improved tenderness and juiciness compared to chops from lighter carcasses. This provides evidence that as the hot carcass weights of pigs in the United States continue to increase there will be no negative effects on quality and palatability.

ObjectivesThe objective of this study was to evaluate the effect of increased pork hot carcass weights on consumer visual acceptability and purchase intent ratings of top loin chops cut to various thicknesses in a price labeled versus unlabeled retail display scenario.Materials and MethodsPigs in this study were intentionally raised to reach heavier hot carcass weights when compared to industry standards. Pork loins (N = 200) were collected from 4 different hot carcass weight groups: a light weight (LT; less than 111.8 kg), medium-light weight (MLT; 111.8 to 119.0 kg), medium-heavy weight (MHVY; 119.1 to 124.4), and a heavy weight (HVY; 124.4 and greater). Loins were fabricated into 4 pairs of chops of specified thicknesses (1.27, 1.91, 2.54, and 3.18 cm) at Day 7, 8, or 9 postmortem. For each chop loineye area, length and width were measured. One chop from each specified thickness was then randomly assigned to be packaged with a label containing package price and weight information. The other paired chop was packaged without a label. Consumers (N = 393; 8 per panel) from the Manhattan, KS, area assessed chops from each weight group × thickness combination in both labeled and unlabeled scenarios. Chops were assessed on a 0 to 100 continuous line scale for desirability and purchase intent. Consumers were also able to indicate “yes” or “no” if the chop was either desirable and if they would purchase the chop.ResultsAs hot carcass weight increased, there was an increase in loineye area and chop length, with chops from HVY carcasses having greater (P < 0.05) loineye areas and lengths compared to all other weight treatments. For both appearance and purchase intent ratings, chops from HVY carcasses were given higher (P < 0.05) ratings compared to LT chops. Additionally, consumers gave greater (P < 0.05) appearance ratings to thicker cut chops. There was a hot carcass weight × chop thickness interaction (P < 0.05) for the percentage of consumers that indicated the chop was desirable overall. Regardless of hot carcass weight treatment, chops with a thickness of 1.27 cm had the lowest (P < 0.05) percentage of consumers indicate they were desirable overall. Within the LT and MLT weight treatments, chops with a thickness of 1.91 and 2.54 cm were similar (P > 0.05) with the greatest (P < 0.05) percentage of consumers who indicated they were desirable. Within the HVY weight treatment, chops with a thickness of 2.54 cm had the greatest (P < 0.05) percentage of consumers who indicated they were desirable. A greater (P < 0.05) percentage of consumers indicated “yes” they would purchase chops cut to a thickness of 2.54 cm compared to all other thicknesses. Additionally, there was a greater (P < 0.05) percentage of consumers who indicated they would purchase chops that were unlabeled compared to chops labeled with weight and pricing information.ConclusionThese results indicate that carcass weight and chop thickness can affect consumer preference and purchasing decisions. Thus, both should be considered by retailers when marketing fresh pork top loin chops.

A total of 2,117 pigs were used in two 35-d growth experiments to determine the effects of increasing added Cu from tri-basic copper chloride (TBCC) or a Cu-methionine chelate (Cu-chelate) on nursery pig growth performance. In experiment 1, 1,452 pigs (350 barrows [DNA 200 × 400; initially 5.9 ± 0.17 kg] in group 1 and 1,102 pigs [PIC 1050 × 280; initially 6.0 ± 0.26 kg] in group 2) were weaned at approximately 21 d of age. In experiment 2, 665 pigs (350 barrows, DNA 200 × 400; initially 6.4 ± 0.19 kg, in group 3 and 315 pigs, DNA 241 × 600; initially 5.2 ± 0.49 kg, in group 4) were weaned at approximately 21 d of age. Pigs in groups 1, 2, and 3 were fed a common starter diet for 7 d and pigs in group 4 were fed a common diet for 5 d after weaning before starting experiments. On d 0 of each experiment, pens of pigs were blocked by body weight (BW) and assigned to 1 of 7 dietary treatments. Treatments were arranged as a 2 × 3 factorial plus one control diet, with main effects of Cu source (TBCC vs. Cu-chelate) and level. Copper levels were 50, 100, or 150 mg/kg in experiment 1 and 75, 150, or 225 mg/kg in experiment 2. Diets were corn-soybean meal-based and fed in meal form in two phases (d 0 to 14 and 14 to 35). In experiment 1 from d 0 to 35, there was a Cu source × level interaction (linear, P < 0.05) for average daily gain (ADG) and d 35 BW where the magnitude of improvement with increasing Cu was greater in pigs fed Cu-chelate compared to those fed TBCC. Increasing added Cu increased (linear, P < 0.01) average daily feed intake (ADFI) and gain:feed (G:F). Although Cu source did not influence G:F, pigs fed Cu from Cu-chelate had greater (P ≤ 0.01) ADG and ADFI than those fed Cu from TBCC. In experiment 2, from d 0 to 35, there were no evidence for Cu source × level interactions. Increasing Cu increased (linear, P < 0.05) ADG and final BW. The increase in ADG combined with unaffected ADFI resulted in marginally increased G:F (linear, P = 0.052). In summary, these results suggest that increasing dietary Cu from TBCC or a Cu-chelate improved overall ADG, and d 35 BW in nursery pigs and Cu source has potential to influence nursery pig performance.

Two, 120-d, experiments were conducted to determine the effects of standardized ileal digestible (SID) lysine (Lys), added Cu (tribasic copper chloride, Intellibond C; Micronutrients, Inc., Indianapolis, IN), and duration of Cu supplementation on growth performance, carcass characteristics, and fat quality in finishing pigs. In Exp. 1, 1,248 pigs (PIC 337 × 1050; initially 29.0 kg) were allotted to one of six dietary treatments, balanced on average pen weight in a randomized complete-block design with 26 pigs per pen and eight replications per treatment. Treatments were arranged in a 3 × 2 factorial with main effects of SID Lys (85, 92.5, and 100% of the estimated requirement) and added Cu (0 or 150 mg/kg). There were no Cu × SID Lys interactions observed for growth performance or liver Cu concentrations. Increasing SID Lys increased (linear, P < 0.05) ADG, feed efficiency (G:F), final weight, and HCW. Pigs fed 150 mg/kg added Cu had marginally increased (P < 0.10) ADG, G:F, and final weight. Liver Cu concentrations were greater (P = 0.001) in pigs fed added Cu. A marginal Cu × Lys interaction (P = 0.052) was observed for jowl fat iodine value (IV) as increasing SID Lys in pigs fed added Cu increased IV, but decreased IV in pigs not fed added Cu. For Exp. 2, 1,267 pigs (PIC 337 × 1,050; initially 26.4 kg) were allotted to one of eight dietary treatments arranged in a split-plot design. Whole-plot treatments included SID Lys (92.5 or 100% of the estimated requirement) and within each Lys level, there was a 2 × 2 factorial arrangement of treatments with either 0 or 150 mg/kg added Cu and two feeding durations (60 or 120 d). Added Cu did not affect growth performance. Pigs fed 100% of the SID Lys requirement had increased (P < 0.05) ADG, G:F, and final weight compared with those fed 92.5%. A Cu × SID Lys interaction (P < 0.05) was observed for carcass yield and backfat depth. Pigs fed 92.5% SID Lys had increased carcass yield and decreased backfat depth with added Cu; however, pigs fed 100% SID Lys had decreased carcass yield and increased backfat depth with added Cu. Hot carcass weight was increased (P < 0.05) by feeding 100% SID Lys and was marginally (P < 0.10) increased by adding Cu to the diets. In summary, the growth response to added Cu was inconsistent between experiments; however, increasing SID Lys improved growth performance and carcass characteristics.

A total of 320 weanling pigs (all barrows, initially 5.71 kg BW; Line 1050, PIC Hendersonville, TN) were used to determine whether the Lys level fed during one phase of the nursery influences the response to Lys during subsequent phases. Our hypothesis was that feeding decreasing dietary Lys concentration in early phases, but feeding adequate concentrations in later phases might result in similar pig growth as those fed a more conventional approach with step-wise decreases in dietary Lys as pigs become heavier. Eight dietary regimens were used in a split-plot design. There were three dietary phases, and within phase, a high or low standardized ileal digestible (SID) Lys diet was fed. Pigs were fed either 1.35% or 1.55% SID Lys during phase 1 (days 0 to 7), 1.15% or 1.35% SID Lys in phase 2 (days 7 to 21), and 1.05 or 1.25% SID Lys during phase 3 (days 21 to 35). The low dietary Lys concentrations were achieved by reducing both crystalline Lys and intact protein sources from the high Lys diets. From days 0 to 7, feeding high SID Lys improved (P < 0.01) G:F, but no evidence for differences in ADG or ADFI were observed. Similarly, from days 7 to 21, there were no evidence for differences in ADG or ADFI among pigs fed the two Lys levels, but those fed high SID Lys had improved (P < 0.03) G:F. From days 21 to 35, pigs fed the high Lys diet had increased (P < 0.01) ADG and G:F compared with those fed low SID Lys, but there were no effects on ADFI. For the overall trial (days 0 to 35), there were no dietary interactions among phases, indicating that the Lys level fed in each phase did not influence the response to Lys in subsequent phases. Thus, pigs fed the high Lys level during phase 3, regardless of previous Lys levels in phases 1 and 2, had greater (P < 0.05) overall ADG and G:F compared with other treatment groups. In conclusion, relatively low dietary Lys concentrations can be fed in the early nursery phases (approximately 6 to 12 kg) without any negative impact on overall growth performance provided that adequate Lys levels are fed thereafter (12 to 20 kg).

Three experiments were conducted to determine the effects of fish meal source on nursery pig growth performance. In experiment 1, 250 pigs (PIC 327 × 1,050, initially 7.1 ± 1.00 kg) were fed either a corn-soybean meal-based diet, a diet containing 8.3% enzymatically treated soybean meal (HP 300, Hamlet Protein, Findlay, OH), or diets containing 6% fish meal from one of three sources (IPC 790, The Scoular Company, Minneapolis, MN; Special Select Menhaden, Omega Proteins, Houston, TX; LT Prime Menhaden, Daybrook Fisheries Inc., New Orleans, LA; source 1, 2, and 3, respectively). In a completely randomized design, there were five pigs per pen and 10 pens per treatment with diets fed for 13 d. There was no evidence for differences in ADG or ADFI among pigs fed the three fish meal sources; however, pigs fed source 1 had marginally decreased (P = 0.068) G:F compared with pigs fed diets with other protein sources. In experiment 2, 350 barrows (DNA Line 200 × 400; initially 6.5 ± 0.90 kg) were assigned to one of seven dietary treatments including the same control diet and diets containing the three fish meal sources used in experiment 1, but fed at 3% or 6%. There were five pigs per pen and 10 pens per treatment with diets fed for 14 d. A source × level interaction (linear, P < 0.05) for ADG and G:F was observed. Increasing fish meal source 1 increased ADG and G:F; however, pigs fed source 2 had improved ADG and G:F at 3%, but decreased performance at 6% compared with control pigs. Pigs fed source 3 had no further improvements in ADG or G:F beyond the 3% inclusion. Fishmeal analysis for total volatile N, and modified Torry digestibility did not appear to correspond with any growth performance differences measured in experiments 1 or 2. In experiment 3, 700 barrows (DNA Line 200 × 400, initially 6.5 ± 0.84 kg) were fed a control diet or four diets with 6% fish meal (source 3) containing either 0.87%, 8.70%, 16.52%, or 24.35% fish solubles. There were five pigs per pen and 28 pens per treatment with diets fed for 21 d. Overall, pigs fed diets with fish meal had increased (P < 0.05) ADG and ADFI compared with pigs fed the control diet. There was no evidence for differences in growth performance as fish solubles increased. In conclusion, inconsistencies were observed in growth responses to different fish meal sources, but the amount of fish solubles, total volatile N, or modified Torry digestibility of fishmeal does not appear to explain these differences.

Two studies were conducted to evaluate the growth performance and percentage bone ash of nursery pigs fed various combinations of Ca and P provided by inorganic sources or phytase. In Exp. 1, pens of pigs (n = 720, initially 6.1 ± 0.98 kg) were blocked by initial BW. Within blocks, pens were randomly assigned to one of six treatments (12 pens per treatment) in a three-phase diet regimen. Treatments were arranged in a 2 × 3 factorial with main effects of Ca (0.58% vs. 1.03%) and standardized total tract digestible (STTD) P (0.33% and 0.45% without phytase, and 0.45% with 0.12% of the P released by phytase). During treatment period, Ca × P interactions were observed for all growth criteria (P < 0.05). When diets had low Ca, pigs fed 0.45% STTD P with phytase had greater (P < 0.01) ADG and ADFI than those fed 0.33% or 0.45% STTD P without phytase. When high Ca was fed, ADG and ADFI were similar among pigs fed 0.45% STTD P with or without phytase and were greater than those fed 0.33% STTD P. Gain:feed was reduced (P < 0.01) when high Ca and low STTD P were fed relative to other treatments. On d 21, radiuses were collected from 1 pig per pen for bone ash analysis. Pigs fed 0.33% STTD P had decreased (P < 0.05) percentage bone ash than those fed 0.45% STTD P with or without phytase when high Ca was fed, but this P effect was not observed for low Ca diets (Ca × P interaction, P = 0.007). In Exp. 2, 36 pens (10 pigs per pen, initially 6.0 ± 1.08 kg) were used in a completely randomized design. Treatments were arranged in a 2 × 3 factorial with the main effects of STTD P (at or above NRC [NRC. 2012. Nutrient Requirements of Swine. 11(th) rev. ed. Washington (DC): National Academic Press.] requirement estimates) and total Ca (0.65, 0.90, and 1.20%). Experimental diets were fed during phases 1 and 2, followed by a common phase 3 diet. Diets at NRC (2012) P level contained 0.45% and 0.40% STTD P, compared with 0.56% and 0.52% for diets greater than the NRC (2012) estimates, in phase 1 and 2, respectively. During treatment period, increasing Ca decreased (linear, P = 0.006) ADG, but increasing STTD P marginally increased (P = 0.084) ADG, with no Ca × P interaction. When diets contained NRC (2012) P levels, pigs fed 1.20% Ca had decreased (P < 0.05) G:F than those fed 0.65% or 0.90% Ca; however, when high STTD P were fed, G:F was not affected by Ca (Ca × P interaction, P = 0.018). In conclusion, excess Ca decreased pig growth and percentage bone ash when diets were at or below NRC (2012) requirement for STTD P, but these negative effects were alleviated by adding monocalcium P or phytase to the diet.

A total of 1,080 pigs (initially 5.9 kg) were used to determine the standardized-total-tract-digestible (STTD) P requirements in diets without and with 2,000 units of phytase. Pens (10 pigs/pen, 9 pens/treatment) were balanced for weights and allotted to 12 treatments in two 6-level dose-titrations.The STTD P levels were expressed as percentage of the NRC (2012) requirement (0.45 and 0.40% for phases 1 [d 0–11] and 2 [d 11–25], respectively) and were: 80, 90, 100, 110, 125, and 140% of NRC in diets without phytase and 100, 110, 125, 140, 155, and 170% of NRC in diets with 2,000 units of phytase (assuming 0.158% STTD P released). On d 25, radius samples from 1 gilt/pen were collected for bone ash analysis. Linear and quadratic responses to increasing STTD P were tested using GLIMMIX procedure of SAS and modeled separately for each dose-titration. Increasing STTD P increased ADG (quadratic, P < 0.05), G:F (linear, P < 0.01), and percentage bone ash (linear, P < 0.01) regardless of phytase addition (Table 1). Estimated STTD P requirement in diets without phytase was 117 and 91% of NRC for maximum ADG according to quadratic polynomial (QP) and broken-line linear (BLL) models, respectively, and ranged from 102 to > 140% of NRC for G:F using BLL, broken-line quadratic, and linear models. Estimated P requirement in diets containing phytase was 138% for ADG (QP) and was 147% (QP) and 116% (BLL) of NRC for G:F. Comparing diets containing the same STTD P levels, phytase increased (P < 0.01) ADG and G:F. In conclusion, estimated P requirements varied depending on the response criteria and statistical models. Phytase promoted pig growth and improved the P dose responses for ADG and G:F.

In wean-to-finish systems, nursery diets are commonly blended with leftover finishing feed from the previous group. A total of 1,260 pigs (initially 10.6 kg) were used in a 28-d study to determine the effects of feeding increasing amounts of finishing feed to nursery pig on growth performance and economics. At weaning, pigs were placed into pens (21 pigs/pen) and fed commercial nursery diets in a 5-phase program with phases 1 and 2 fed before the start of the experiment. Phase changes were based on feed budgets of 2.5, 3.7, 3.7, 9.5, and 9.5 kg/pig in phases 1 to 5, respectively. At the beginning of phase 3, pens of pigs were blocked by weight and room and allotted randomly to 1 of 4 treatments (15 replications/treatment). Treatments consisted of a dose-titration of blending increasing amounts (0, 1.25, 2.50, and 3.75 kg/pig) of a late finisher feed (0.74% SID Lys) into phase 3 nursery diet. Data were analyzed using the GLIMMIX procedure of SAS with the fixed effect of dietary treatment and random effects of weight block and room. Contrasts were used to determine the linear and quadratic effects of increasing finisher feed amount. Overall, increasing the amount of late finisher feed blended into the phase 3 nursery diet decreased ADG (linear, P = 0.050) and tended to decrease (linear, P < 0.07) ADFI and final BW, but did not affect G:F (Table 1). Feed cost, gain value, and feed cost/kg gain decreased (linear, P < 0.05) as finishing feed budget increased from 0 to 3.75 kg/pig. However, income-over-feed-cost was not different among treatments. In conclusion, feeding increasing amounts of late finisher feed to 11-kg nursery pigs decreased overall ADG and ADFI, but did not affect income-over-feed-cost.

Antibiotics can be administered orally or parenterally in swine production, which may influence antimicrobial resistance (AMR) development in gut bacteria. A total of 40 barrows and 40 gilts were used to determine the effects of tylosin administration route on growth performance and fecal enterococcal AMR. The antibiotic treatments followed Food and Drug Administration label directions and were as follows: (1) no antibiotic (CON), (2) 110 mg tylosin per kg feed for 21 d (IN-FEED), (3) 8.82 mg tylosin per kg body weight through intramuscular injection twice daily for the first 3 d of each week for 3 weeks (IM), and (4) 66 mg tylosin per liter of drinking water (IN-WATER). Antibiotics were administered during d 0 to 21 and all pigs were then fed the CON diet from d 21 to 35. Fecal samples were collected on d 0, 21, and 35. Antimicrobial susceptibility was determined by microbroth dilution method. No evidence of route × sex interaction (p > 0.55) was observed for growth performance. From d 0 to 21, pigs receiving CON and IN-FEED had greater (p

Increasing dietary electrolyte balance (dEB) has been reported to linearly improve pig growth performance up to approximately 200 to 250 mEq/kg. However, recent data indicate that increasing dietary dEB reduced growth performance of nursery pigs. To attempt to solve this discrepancy, a total of 2,880 weanling pigs (327 × 1,050; PIC, Hendersonville, TN; 5.2 kg initial BW) were used to determine the effects of increasing dEB on nursery pig performance. Pens of pigs were blocked by BW and gender on arrival. Within block, pens were randomly assigned to one of four dietary treatments. There were 30 pigs per pen (60 pigs per double-sided feeder) and 12 replications (feeder) per treatment. Dietary treatments were fed in two phases. The phase 1 diet was based on corn–soybean meal, contained dried distillers grains with soblubles (DDGS), spray-dried whey, and specialty protein sources, and was fed from days 0 to 8. The phase 2 (days 8 to 21) diets contained corn, soybean meal, and DDGS with reduced amounts of specialty protein sources. Dietary electrolyte balance was determined using the following equation: dEB = [(Na × 434.98) + (K × 255.74) − (Cl × 282.06)] mEq/kg. The dEB of the four phase 1 diets were 84, 137, 190, and 243 mEq/kg, and dEB of the four phase 2 diets were 29, 86, 143, and 199 mEq/kg. After feeding experimental diets for 21 day, a common, commercial corn–soybean meal diet was fed to all pigs from days 21 to 35 and contained a dEB of 257 mEq/kg. During days 0 to 8, increasing dEB increased (quadratic, P < 0.05) ADG, ADFI, and G:F. From days 8 to 21, increasing dEB improved ADG (quadratic, P = 0.022) and ADFI (linear, P = 0.001), resulting in an improvement (quadratic, P = 0.001) in G:F. Overall (days 0 to 21), increasing dEB increased (linear, P < 0.05) ADG, ADFI, and improved (quadratic, P < 0.001) G:F. When a common diet was fed to all pigs from days 21 to 35, there was a linear reduction in ADG and G:F with increasing dietary dEB, but no effect of ADFI. For the overall nursery period (days 0 to 35), increasing dEB from days 0 to 21 increased (linear, P < 0.001) ADG and final BW, which was the result of increased (quadratic, P < 0.05) G:F and marginally greater (linear, P = 0.077) ADFI. In conclusion, increasing dietary dEB up to 243 and 199 mEq/kg (in phases 1 and 2, respectively) in nursery diets improved growth performance of weanling pigs.

A total of 256 pigs (initially 55.9 ± 4.88 kg) were used in a 71-d study to determine the effects of increasing space allowance and pig removal on pig growth performance. Pens of pigs were blocked by body weight (BW) and allotted to 1 of 4 space allowance treatments, initially with 8 pigs per pen and 8 pens per treatment. First 2 treatments included pens with 0.91 m2 per pig or 0.63 m2 per pig for the entire study; two additional treatments initially provided 0.63 m2 per pig, but either a gate was adjusted on days 28, 45, and 62 or the heaviest pig in the pen was removed from the pen on days 28 and 45 to provide more space and keep pigs in accordance with their predicted minimum space requirement [(m2) = 0.0336 × (BW, kg)0.67]. From days 0 to 14 (56 to 69 kg), there was no effect of stocking density observed for average daily gain (ADG), average daily feed intake (ADFI), and gain:feed (G:F). From days 14 to 28 (69 to 83 kg), pigs provided 0.91 m2 had increased (P < 0.05) ADG and G:F compared with those allowed 0.63 m2. Pigs provided 0.91 m2 were marginally heavier (P = 0.081) on day 28 and had greater ADFI (P = 0.025) during days 28 to 45 than those provided 0.63 m2 or those that had the heaviest pig removed. From days 45 to 62 (98 to 116 kg), pigs provided 0.91 m2 were heavier (P < 0.01) than all others, wheras pigs provided 0.63 m2 had reduced ADFI compared with other treatments. From days 62 to 71 (116 to 124 kg), pigs provided 0.91 m2 and those with space adjustment treatments had greater (P < 0.05) ADG and ADFI than those provided 0.63 m2. Overall (56 to 124 kg), pigs provided 0.91 m2 had increased (P = 0.001) ADG compared with those allowed 0.63 m2 with pigs provided space adjustments intermediate. In summary, pigs with 0.91 m2 grew faster and consumed more feed than pigs restricted in space. As pigs reached the critical k value, gate adjustments and pig removals affected growth similarly. As pigs grew to the predicted space requirement and were subsequently allowed more space, performance was greater than those provided 0.63 m2 but less than those allowed 0.91 m2. It appears that the industry accepted critical k value, 0.0336, may not be adequate for optimal pig performance across multiple BW ranges.

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 ( = 0.054), whereas this was significant for G:F ( = 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 (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.

Two experiments were conducted to evaluate potential detoxifying agents on growth of nursery pigs fed deoxynivalenol (DON)-contaminated diets. Naturally DON-contaminated wheat (6 mg/kg) was used to achieve desired DON levels. In a 21-d study, 238 pigs (13.4 ± 1.8 kg BW) were used in a completely randomized design with a 2 × 2 + 1 factorial arrangement. Diets were: 1) Positive control (PC;0.5 mg/kg DON), 2) PC + 1.0% Product V (Nutriquest LLC, Mason City, IA), 3) Negative control (NC; 4.0 mg/kg DON), 4) NC + 1.0% Product V, and 5) NC + 1.0% sodium metabisulfite (SMB; Samirian Chemicals, Campbell, CA). There were 6 or 7 replicate pens/treatment and 7 pigs/pen. Analyzed DON was decreased by 92% when pelleted with SMB, but otherwise matched formulated levels. Overall, a DON × Product V interaction was observed for ADG ( 0.05) with a tendency for an interaction for ADFI ( 0.10). As anticipated, DON reduced ( 0.001) ADG and ADFI, but the interaction was driven by even poorer growth when Product V was added to NC diets. Pigs fed NC diets had 10% poorer G:F ( 0.001) than PC-fed pigs. Reductions in ADG due to DON were most distinct (50%) during the initial period. Adding SMB to NC diets improved ( 0.01) ADG, ADFI, and G:F, and improved ( 0.02) ADG and G:F compared to the PC diet. A urinary balance study was conducted using diets 3 to 5 from Exp. 1 to evaluate Product V and SMB on DON urinary metabolism. A 10 d adaptation was followed by a 7 d collection using 24 barrows in a randomized complete block design. Pigs fed NC + SMB diet had greater urinary DON output ( 0.05) than pigs fed NC + Product V, with NC pigs intermediate. Daily DON excretion was lowest ( 0.05) in the NC + SMB pigs. However, degradation of DON-sulfonate back to the parent DON molecule was observed as pigs fed NC + SMB excreted more DON than they consumed (164% of daily DON intake), greater ( 0.001) than pigs fed the NC (59%) or NC + Product V (48%). Overall, Product V did not alleviate DON effects on growth nor did it reduce DON absorption and excretion. However, hydrothermally processing DON-contaminated diets with 1.0% SMB restored ADFI and improved G:F. Even so, the urinary balance experiment revealed that some of the converted DON-sulfonate can degrade back to DON under physiological conditions. While further research is needed to discern the stability of the DON-sulfonate, SMB appears promising to restore performance in pelleted DON-contaminated diets.

ObjectivesBetween 1995 and 2018, average hot carcass weight of U.S. pork carcasses increased from 82 kg to 96 kg, which is an increase of approximately 17%. At current rates, pork carcasses in the U.S. will weigh on average, 105 kg by the year 2030 and over 118 kg by 2050. Although this represents an increase in throughput efficiency due to increases in economy of scale, projecting continued increases in the future raises some concerns. Therefore, the objective was to characterize pork quality of carcasses ranging from 78 to 145 kg with a mean weight of 119 kg.Materials and MethodsCarcass composition, such as hot carcass weight (HCW), back fat depth and loin depth were measured on 666 carcasses. Additionally, loin quality measurements, such as pH, loin instrumental and visual color, and iodine value of clear plate fat were measured on approximately 90% of the total population. Ham quality, 14 d aged loin and chop quality measurements, and loin chop slice shear force (SSF) were evaluated on approximately 30% of the total population. Finally, myosin heavy chain fiber type determination was completed on approximately 50 carcasses selected from carcasses ranging from 97 to 133 kg. The slope of regression lines and coefficients of determination between hot carcass weights and quality traits were calculated using the REG procedure in SAS and considered significantly different from 0 at P ≤ 0.05.ResultsAs HCW increased loin depth (b1 = 0.2496, P < 0.0001), back fat depth (b1 = 0.1374, P < 0.0001), loin weight (b1 = 0.0345, P < 0.0001), chop weight (b1 = 1.6626, P < 0.0001), and ham weight (b1 = 0.1044, P < 0.0001) increased. There was a decrease in estimated lean (b1 = –0.0751, P < 0.0001) and iodine value (b1 = –0.0923, P < 0.0001) as carcass weight increased, however, HCW only accounted for ≤ 24% (R2 = 0.24) of the variation in estimated lean and iodine value. Additionally, there were no significant differences in gluteus medius pH (b1 = 0.0009, P = 0.30) or instrumental lightness (b1 = 0.0301, P = 0.15), redness (b1 = –0.0036, P = 0.73) or yellowness (b1 = 0.0058, P = 0.57) of the ham as carcass weight increased. As carcass weight increased, 1 d loin instrumental yellowness (b*) increased (b1 = 0.0092 P < 0.01), however HCW only explained 1% of the variation in b*. Heavier carcasses were more tender (decreased SSF of chops cooked to 71°C, (b1 = –0.0674, P < 0.0001), although HCW only explained 9% of the variation in SSF. Total cook loss of chops used for SSF determination decreased as HCW increased (b1 = –0.0512, P < 0.0001), and HCW explained 15% (R2 = 0.15) of the variation in total cook loss. There were no significant differences in fiber type percentage, type 1 (b1 = –0.0170, P = 0.81), 2a (b1 = –0.0786, P = 0.23), 2x (b1 = –0.0201, P = 0.80), or 2b (b1 = 0.1224, P = 0.37), or fiber type area, type 1 (b1 = –26.6331, P = 0.22), 2a (b1 = –40.7257, P = 0.07), 2x (b1 = –46.9459, P = 0.25), or 2b (b1 = –26.2537, P = 0.38) as HCW increased.ConclusionDue to the lack of variation explained by HCW (≤ 15%), pork quality traits are not expected to be compromised as HCW continues to increase. The results suggest that increasing HCW to 119 kg did not have detrimental effects on pork quality attributes.

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 (0.001) ADG and final BW regardless of AMMC addition. Feeding DON-contaminated diets elicited the most severe depression (0.001) in ADFI and G:F from d 0 to 3, remaining poorer overall (0.01) but lessening in severity as exposure time increased. Pigs fed DON diets had greater (0.05) within pen BW variation (CV) on d 28. Although the addition of 0.50% AMMC to diets restored (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,0.05), driven by decreased (quadratic,0.01) ADFI and poorer (quadratic;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.

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 D (800, 2,000, or 9,600 IU/kg) or as 25(OH)D (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 D/kg or 50 µg 25(OH)D/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)D suggested that maternal dietary vitamin D influenced (0.001 at weaning) serum concentrations early after weaning, but nursery vitamin D regimen had a larger impact (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 D had increased (quadratic,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)D had increased ( = 0.002) ADG compared with pigs weaned from sows fed 800 IU of vitamin D. Throughout finishing (d 35 postweaning until 135 kg), ADG was increased (quadratic, = 0.005) and G:F was improved (quadratic, = 0.049) with increasing maternal dietary vitamin D. Also, pigs from sows fed 50 µg/kg of 25(OH)D had increased ( = 0.002) ADG compared with pigs weaned from sows fed 800 IU of vitamin D. 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 (0.030) for pigs from sows previously fed 25(OH)D compared with pigs from sows fed 9,600 IU of vitamin D. Overall, pigs from sows fed 2,000 IU of vitamin D grew faster after weaning compared with pigs from sows fed 800 or 9,600 IU of vitamin D. Pigs from sows fed 25(OH)D hag greater ADG compared with pigs from sows fed 800 IU of vitamin D, and they had increased final BW and HCW compared with pigs from sows fed 9,600 IU of vitamin D.

In Exp. 1, 56 gestating sows (PIC 1050; 35 d postinsemination) were used in a 30-d trial to determine serum 25(OH)D response to increasing concentrations of dietary vitamin D. Sows were randomly allotted to 1 of 7 dietary D treatments (200, 800, 1,600, 3,200, 6,400, 12,800, or 25,600 IU of added D per kilogram of complete diet) with 8 sows per treatment. Increasing D increased (quadratic;0.001) serum 25(OH)D with the response depicted by the prediction equation: serum 25(OH)D, ng/mL = 35.1746 + (0.002353 × dietary D, IU/d) - (0.0000000156 × dietary D, IU/d). 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 D per kilogram of the diet or 50 µg of 25(OH)D (2,000 IU of D equivalent from Hy-D, DSM Nutritional Products, Parsippany, NJ) per kilogram of diet. There were 25 to 27 sows per treatment. Increasing dietary D increased (linear, = 0.001) serum 25(OH)D of sows on d 100 of gestation, at farrowing, and at weaning. Increasing D in sow diets increased piglet serum 25(OH)D at birth (linear, = 0.001) and weaning (quadratic, = 0.033). Sows fed 50 µg of 25(OH)D/kg had intermediate (0.004) serum 25(OH)D concentrations on d 100 of gestation, at farrowing, and at weaning compared with sows fed 2,000 IU of D/kg and sows fed 9,600 IU of D/kg. Pigs from sows fed 50 µg of 25(OH)D/kg had greater serum 25(OH)D compared with pigs from sows fed 2,000 IU of D/kg, but at weaning, serum 25(OH)D concentrations were similar. Also, pigs from sows fed 9,600 IU of D/kg had greater ( = 0.011) serum 25(OH)D at birth and weaning compared with pigs from sows fed 50 µg of 25(OH)D/kg. Maternal performance, litter characteristics, neonatal bone ash content, and neonatal muscle fiber characteristics were largely unaffected by the dietary vitamin D treatments. Overall, D and 25(OH)D are both useful at increasing serum 25(OH)D concentrations, but more D (on an equivalent IU basis) is needed to achieve similar serum 25(OH)D responses compared with feeding 25(OH)D. 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)D concentrations.

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 (CuSO; 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, = 0.057, = 0.068, and = 0.064 for G:F and caloric efficiency on a ME and NE basis, respectively). Ractopamine improved (0.001) overall ADG, G:F, and caloric efficiency, thereby increasing final BW by 3% with no change in ADFI. Ractopamine also increased (0.001) HCW, percentage carcass yield, G:F, loin depth, and percent fat-free lean and decreased ( = 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, = 0.011 and = 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. spp. and isolates displayed varying levels of resistance to certain antibiotics prior to initiation of treatments on d 0. Resistance to most antibiotics decreased (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.

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; = 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,0.033) ADFI but improved (quadratic,0.014) G:F. From d 40 to 83, decreasing wheat particle size increased (quadratic,0.018) ADG and improved (linear,0.002) G:F. Overall from d 0 to 83, reducing wheat particle size improved (linear,0.002) G:F. In Exp. 2, pigs (PIC 327 × 1050; = 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 (0.05) ADG and ADFI when compared with soft white winter wheat. There was a tendency (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 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 ( = 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 (0.05) ADG and G:F as well as heavier d-84 BW ( = 0.006) compared with pigs fed additional fat during only 1 period. Adding fat for the entire study increased ( = 0.032) backfat and tended to reduce ( = 0.079) the fat free lean index compared with pigs fed the control diet without added fat. Added fat also increased (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,0.05). Our study failed to show any feeding period × fat source interactions (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.

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.

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,0.001). Furthermore, the magnitude of BW gain response to increased energy intake was greater (0.001) for sows compared with gilts. Sows fed high energy intake had a reduced probability of piglets born alive (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 ( = 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 ( = 0.011) for females fed high, as opposed to low, energy intake. Furthermore, piglets born alive were approximately 97 ± 9.5 g heavier (0.001) for sows than for gilts. Preweaning mortality was decreased ( = 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.