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Two experiments were conducted to evaluate the possible interaction of nursery space allocations and grow-finish space allocations in swine. In Exp. 1, crowding was achieved by varying the number of pigs per pen. During the nursery phase, decreasing the space allocation (0.16 [m.sup.2]/pig vs 0.25 [m.sup.2]/pig; 8 and 12 pens per treatment, respectively) by increasing the number of pigs per pen (18 vs 12) resulted in a decrease in daily feed intake (0.609 vs 0.683 kg/d; P [is less than] 0.001) and daily gain (0.364 vs 0.408 kg/d; P [is less than] 0.001). Pigs were mixed within nursery treatment groups and reassigned to grow-finish pens (6 pens per treatment) at the end of the 35-d nursery period providing either 0.56 [m.sup.2]/pig (14 pigs/pen) or 0.78 [m.sup.2]/pig (10 pigs/pen). Crowding during the grow-finish phase decreased daily feed in-take (P [is less than] 0.003) and daily gain (P [is less than] 0.001). In Exp. 2, space allocations of 0.16 [m.sup.2]/pig vs 0.23 [m.sup.2]/pig during the nursery phase (24 pens per treatment) resulted in a decrease in daily feed intake (0.612 vs 0.654 kg/d; P [is less than] 0.005) and daily gain (0.403 vs 0.430 kg/d; P [is less than] 0.001). Pigs remained in the same (social) groups when moved to the grow-finish phase. Unlike Exp. 1, there was no effect of crowding during the grow-finish phase (0.60 [m.sup.2]/pig vs 0.74 [m.sup.2/pig) on daily feed intake or daily gain. The difference in results between experiments suggests that the response to crowding during the grow-finish phase may depend in part on whether pigs are mixed and sorted following movement from the nursery. Key Words: Mixing, Pigs, Spacing

This study was conducted to evaluate whether cooled floor pads combined with chilled drinking water could alleviate negative impacts of heat stress on lactating sows. Thirty sows (Landrace × Yorkshire, Parity = 1 to 6) were housed in individual farrowing stalls in two rooms with temperatures being controlled at 29.4°C (0700-1900 hours) and 23.9°C (1900-0700 hours). Sows in one room (Cool), but not in the other room (Control) were provided cooled floor pads (21-22°C) and chilled drinking water (13-15°C). Behavior of sows (15 sows/treatment) was video recorded during farrowing, and days 1, 3, 7, 14, and 21 after farrowing. Videos were viewed continuously to register the birth time of each piglet, from which total farrowing duration and birth intervals were calculated. The number of drinking bouts and the duration of each drinking bout were registered for each sow through viewing videos continuously for 2 h (1530-1730 hours) each video-recording day. Postures (lying laterally, lying ventrally, sitting, and standing) were recorded by scanning video recordings at 5-min intervals for 24 h each video-recording day, and time budget for each posture was calculated. Rectal temperature and respiration rate were measured for all sows the day before and after farrowing, and then once weekly. Sow and litter performance was recorded. Data were analyzed using the Glimmix procedure of SAS. The cooling treatment did not affect sow behavior or litter performance. Sows in the Cool room had lower rectal temperature (P = 0.03) and lower respiration rate (P < 0.001), consumed more feed (P = 0.03), tended to have reduced weight loss (P = 0.07), and backfat loss (P = 0.07) during lactation than sows in the Control room. As lactation progressed, sows increased drinking frequency (P < 0.001) and time spent lying ventrally (P < 0.0001), standing (P < 0.001), and sitting (P < 0.0001), and decreased time spent lying laterally (P < 0.0001) in both Cool and Control rooms. While cooled floor pads combined with chilled drinking water did not affect sow behavior, they did alleviate heat stress partially, as indicated by decreased rectal temperature, respiration rate, weight, and backfat loss, and increased feed intake in lactating sows., (© The Author(s) 2021. Published by Oxford University Press on behalf of the American Society of Animal Science. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Current floor space allowances were determined in research studies conducted 10 to 20 yr ago using pigs that were marketed at a BW of about 113 kg or less. Currently, pork producers are regularly marketing pigs that weigh over 128 kg. Given this precipitous increase in market weight, we conducted 2 experiments to determine if floor space allowances previously determined apply to pigs marketed at greater than 128 kg. Experiment 1 was conducted at 5 university research stations throughout the Upper Midwest region. In this experiment, we evaluated the growth performance, salivary cortisol concentrations, and lesion scores of pigs weighing between 27 and 138 kg provided 0.71, 0.80, 0.89, 0.98, or 1.07 m/pig of floor space. Within each station, group size (range = 6 to 19 pigs) remained constant across floor space treatments but pen size was altered to achieve the desired space allocations. There were 14 replicate pens for each treatment. Overall, increasing floor space allowance increased final BW (linear, = 0.04) and tended (linear, < 0.06) to increase ADG and ADFI. There were no improvements in final BW or ADG beyond 0.89 m/pig. The G:F was not influenced by increasing floor space allocation. Salivary cortisol concentrations and lesion scores were not affected by floor space allowances. Experiment 2 focused on floor space needs of pigs nearing market weight and was conducted at 4 research stations. Pigs weighing about 130 kg were assigned to pens that provided 0.71, 0.80, 0.89, 0.98, or 1.07 m/pig of floor space. Group size ranged from 4 to 11 pigs per pen but was constant across floor space treatments within station. The study lasted 2 wk and there were 8 replicate pens per treatment. As floor space allowance increased, ADG (0.86, 0.95, 0.95, 1.10, and 1.06 kg; linear, < 0.01), ADFI (3.03, 3.26, 3.22, 3.49, and 3.25 kg; quadratic, < 0.05), and final BW (145.6, 145.7, 146.4, 148.3, and 147.9 kg; linear, < 0.01) increased. Based on the results of these 2 experiments, pigs marketed at about 138 kg require at least 0.89 m/pig to support optimal growth performance. However, heavier pigs (about 148 kg) at the end of the finishing period require 0.98 m/pig.

A study was conducted to evaluate the effect of tail docking on the welfare and performance of victimized pigs by tail biting and tail biters. Pigs ( = 240; 25.7 ± 2.9 kg average weight), including 120 pigs that were tail docked at birth and 120 pigs that remained with intact tails, were used. Pigs were housed in 8 pens of 30 pigs in a confinement barn for 16 wk, with 4 pens each housing pigs of both sexes with docked or intact tails. Tail biters and victimized pigs with damaged tails were identified during outbreaks of tail biting. Growth performance was monitored, and skin lesions on the tail, ears, and body were assessed. Blood samples were collected from focal tail biters, victimized pigs, and nonvictimized pigs for analysis of total serum protein, IgG, and substance P concentrations. When pigs were marketed, carcass weights and the number of pigs with carcass trim loss were recorded. During the growing-finishing period, 48% of pigs with docked tails and 89% of pigs with intact tails experienced lesions on their tails, including 5% of docked pigs and 30% of intact pigs identified as victimized pigs that experienced puncture wounds with signs of infection on their tails or loss of tails ( < 0.001). Victimized pigs tended to gain less weight ( = 0.07) between 17 and 21 wk of age than other pigs when tail biting prevailed in this study. Victimized pigs were more frequently ( = 0.04) sold for less than full value and had a lower dressing percentage ( < 0.001) compared with nonvictimized pigs. For victimized pigs, total serum protein and IgG concentrations were elevated 5 d after tails were injured, suggesting that tail damage can cause inflammation, which may lead to carcass abscesses and trim loss. Compared with victimized pigs and nonvictimized pigs, tail biters had lower total serum protein ( = 0.01) and IgG ( = 0.01) concentrations, indicating that tail biters may experience poor immune functions. Results of this study demonstrated that tail docking reduced tail damage in pigs kept in a confinement system. Tail damage can cause inflammation and reduce the value of market pigs. More research is needed to test whether compromised immune functions predispose pigs to tail biting.

Diets containing more than 20% distiller's dried grains with solubles (DDGS) reduce fat firmness in pork, but supplementation of cottonseed oil or crude glycerol may improve fat firmness. The objective of this study was to assess the effect of feeding minimally refined cottonseed oil or crude glycerol on growth performance, carcass composition, and fat quality of growing-finishing pigs. Mixed sex pigs ( = 216; 24 ± 4 kg initial BW) were blocked by BW and allotted to 1 of 3 dietary treatments: 1) a basal corn-soybean meal diet with 40% DDGS (CON), 2) CON diet plus 5% minimally refined cottonseed oil added throughout the experiment (COT), or 3) CON fed during the first 8 wk and CON + 8% crude glycerol fed during the last 6 wk of the experiment (GLY). Although diets were not isocaloric, total AA-to-ME ratios were calculated to be equal among diets. Carcass composition was estimated using real-time ultrasound 2 d before harvest. Gilts (16/treatment) closest to the mean BW of each pen were harvested (115 ± 8 kg BW), and bellies were retrieved for in-depth analysis of fat quality. Belly fat was sampled and analyzed for fatty acid composition. Overall, ADFI of pigs fed COT (2.30 kg/d) was less ( < 0.01) than that of pigs fed CON or GLY (2.47 and 2.49 kg/d, respectively). Pigs fed COT (0.93 kg/d) had greater ( < 0.01) ADG compared with pigs fed CON or GLY (0.88 and 0.87 kg/d, respectively). Greater ( < 0.01) G:F was observed for pigs fed COT (0.41) than for pigs fed CON or GLY diets (0.36 and 0.35, respectively). Final BW of pigs fed COT (124.3 kg) was greater ( < 0.01) than that of pigs fed CON or GLY (118.9 and 118.6 kg, respectively). Pigs fed COT had greater ( < 0.01) HCW (94.9 kg) compared with pigs fed CON or GLY (89.9 and 89.2 kg, respectively). No differences were observed for dressing percentage (75.7, 76.3, and 75.3%), fat-free carcass lean percentage (50.5, 49.7, and 50.0%), and belly flop angle (6.21, 8.57, and 6.06°) for CON, COT, and GLY, respectively. Pigs assigned to COT had higher ( < 0.01) melting point of belly fat compared with pigs assigned to CON or GLY (30.4 vs. 26.3 and 25.3°C, respectively). Pigs fed COT had increased ( < 0.05) SFA, PUFA, and iodine value (IV) compared with CON-fed pigs. Glycerol supplementation had no influence on SFA, MUFA, and PUFA concentrations or IV of belly, jowl, and back fat compared with CON. In conclusion, COT diets improved growth performance due to greater energy density, but carcass composition was not affected by treatments. In this experiment, feeding neither COT nor GLY improved fat firmness of pigs fed diets containing 40% DDGS.

Ultraviolet light irradiation of spray-dried porcine plasma (SDPP) decreases the risk of disease transmission, but it may decrease the activity of bioactive components in SDPP. Therefore, the objectives of this study were to determine growth performance, morbidity, and mortality responses of nursery pigs fed UV-irradiated SDPP (UV-SDPP) compared with nonirradiated spray-dried bovine plasma (SDBP). Pigs ( = 480; 6.09 ± 2.4 kg initial BW) were blocked by initial BW, and blocks were assigned to pens. the sex ratio was equalized within blocks and pens. Pens were randomly assigned to 1 of 5 dietary treatments (8 pigs/pen and 12 replicates/treatment) in a 3-phase feeding program (phase 1 = d 0 to 13, phase 2 = d 14 to 27, and phase 3 = d 28 to 55). Dietary treatments included a control diet without UV-SDPP or SDBP and diets containing 3% UV-SDPP, 3% SDBP, 6% UV-SDPP, or 6% SDBP during phase 1. Diets were formulated to meet or exceed nutrient requirements and contained the same concentrations of standardized ileal digestible Lys and Lys:ME ratio within phases. Pigs were provided ad libitum access to diets throughout the 55-d experiment. Dietary inclusion rates during phase 2 were reduced to 1.5% UV-SDPP, 1.5% SDBP, 3% UV-SDPP, and 3% SDBP, and all pigs were fed a common diet without UV-SDPP or SDBP during phase 3. Growth performance data were analyzed as a 2 × 2 factorial arrangement of treatments with a control within a completely randomized block design to evaluate the main effects of plasma processing (UV irradiated vs. nonirradiated) and dietary inclusion level, and block, room, and pen were random effects. In phase 1, there were no differences in G:F among treatments, but pigs fed 6% UV-SDPP and 6% SDBP had greater ( < 0.01) ADG (0.11 vs. 0.08 kg/d) and ADFI (0.17 vs. 0.15 kg/d) than pigs fed the control, 3% SDBP, and 3% UV-SDPP diets. After phase 1 (d13), feeding UV-SDPP or SDBP increased ( = 0.02) the BW of pigs. In phases 2 and 3 and the overall feeding period (d 0 to 55), there were no differences in ADG, ADFI, and G:F among dietary treatments. There was a linear decrease ( < 0.01) in mortality of nursery pigs as dietary inclusion rate of SDBP and UV-SDPP increased. In conclusion, feeding SDBP or UV-SDPP diets improved ADG and ADFI during the first 2 wk after weaning due to improved feed consumption, and UV irradiation appeared to have no detrimental effects on the feeding value of SDPP.

Growth performance of immunologically castrated (IC) pigs (863 total) was determined at increasing time intervals between the second Improvest (gonadotropin releasing factor analog-diphtheria toxoid conjugate; Zoetis Inc., Florham Park, NJ) dose and slaughter (TD) and with 4 different dried distillers grains with solubles (DDGS) feeding strategies (FS) in a 4 × 3 factorial arrangement of treatments. The feeding period was divided into 4 separate diet phases. Dietary treatments included 1) corn-soybean meal control diets (PCon), 2) a gradual decrease of dietary DDGS inclusion rate from 40%, 30%, 20%, and 10% in phases 1 to 4 (GD), respectively, 3) feeding 40% DDGS diets in phases 1 to 3 and removal of DDGS from the phase 4 diet (WD), and 4) feeding 40% DDGS diets in all 4 phases (NCon). Pigs received the second Improvest dose at 9 (TD9), 7 (TD7), or 5 (TD5) wk before slaughter. In each group, all pigs were slaughtered on the same day. There were no 3-way interactions among FS, TD, and week of feeding period for any measure of growth performance. Pigs fed PCon and WD had greater ( < 0.05) overall ADFI than pigs fed NCon, especially when slaughtered 9 wk after the second Improvest dose (2.45 and 2.44 vs. 2.31 ± 0.08 kg/d, respectively). This response was partly due to withdrawing DDGS from the diet at 19 wk of age (WD), which led to a tendency ( < 0.10) for increased ADFI from the wk 19 to 21 interval to the wk 21 to 24 interval (3.26 vs. 3.51 ± 0.09 kg/d, respectively). During the same time period, ADFI was unchanged ( > 0.05) in pigs fed PCon, GD, and NCon. Overall G:F was improved ( < 0.05) in TD5 pigs compared with TD9 pigs and tended ( < 0.10) to be improved compared with TD7 pigs. Final BW was similar among pigs fed GD, WD, and PCon (123.1, 122.3, and 125.3 kg, respectively), but pigs fed PCon and GD had greater ( < 0.05) BW than pigs fed NCon (120.0 kg). Throughout the growing-finishing period, BW was similar among TD treatments. The GD FS was more effective than the WD FS in maintaining overall G:F (0.424 and 0.414 ± 0.005, respectively) and ADG (0.94 and 0.93 ± 0.03 kg/d, respectively), which were similar ( > 0.05) to those of pigs fed PCon (0.427 ± 0.005 and 0.96 ± 0.03 kg/d, respectively). Growth performance of pigs fed GD more closely reflected that of pigs fed PCon than that of pigs fed WD. Delaying the second dose of Improvest from 9 to 5 wk before slaughter resulted in improved growth performance.

Back, belly, and jowl fat samples of pigs fed control corn-soybean meal-based diets and diets containing 4 sources of distillers dried grains with solubles (DDGS) were used to determine the impact of feeding DDGS with variable oil content on pork fat quality and to evaluate the precision and accuracy of published iodine value (IV) prediction equations. Dietary treatments consisted of 4 corn-soybean meal diets containing 40% DDGS from different sources with 10.7, 5.6, 14.2, or 16.0% ether extract (EE; as-fed) content. Diets did not contain any other supplemental lipid sources. Regardless of fat depot, SFA content (g/100 g fat) of pigs fed 5.6% EE DDGS (35.4) was greater ( < 0.05) than that of pigs fed 14.2 or 16.0% EE DDGS sources (34.4 and 30.2, respectively) and tended to be greater ( < 0.10) than that of pigs fed 10.7% EE DDGS (34.6). Pigs fed 10.7 and 14.2% EE DDGS had greater ( < 0.01) SFA concentration than pigs fed 16.0% EE DDGS. Regardless of fat depot, MUFA content (g/100 g fat) of pigs fed 10.7, 5.6, and 14.2% DDGS sources were similar (43.7, 43.1, and 43.0, respectively) but were greater ( < 0.01) than that of pigs fed 16.0% EE DDGS (40.0). A dietary treatment × fat depot interaction was observed for PUFA ( < 0.05) and IV ( = 0.079). Pigs fed 10.7, 5.6, and 14.2% DDGS sources had reduced ( < 0.01) PUFA concentration and IV compared with pigs fed 16.0% EE DDGS, but the magnitude of responses in PUFA and IV to the variable oil content of DDGS was greater in backfat than in belly and jowl fat. Carcass fat IV data were used to evaluate prediction error (PE) and bias of published carcass fat IV prediction equations. Equations using dietary C18:2 content or IV product as a single predictor resulted in highly variable PE (g/100 g) ranging from 3.43 to 8.36 and bias (g/100 g) ranging from -5.05 to 5.66. Using equations that included additional diet composition information and pig growth performance factors decreased PE (3.27 to 4.73) and bias (-3.37 to 1.73) of prediction for backfat compared with equations only based on the characteristics of dietary lipid, but this improvement was limited in the prediction for belly and jowl fat. Predictions based on percentage of DDGS in diets had the greatest PE (6.66 to 9.19) and bias (5.53 to 8.00).

This experiment evaluated the effects of feeding distillers' dried grains with solubles (DDGS) and wheat middlings (WM) in diets with similar estimated NE content on growth performance and carcass characteristics of growing-finishing pigs. Pigs ( = 384; 29.1 ± 3.6 kg initial BW) were blocked by initial BW, and within blocks, pens were randomly allotted to 1 of 4 dietary treatments (8 pigs/pen and 12 replicates/treatment) in a 4-phase feeding program (29 to 50, 50 to 75, 75 to 100, and 100 to 120 kg BW). Dietary treatments were arranged in a 2 × 2 factorial design and formulated to consist of: 1) corn and soybean meal (CON), 2) CON with 30% DDGS, 3) CON with 15% WM, and 4) CON with 30% DDGS and 15% WM. Diets met or exceeded nutrient requirements published by the and were formulated to contain the same concentrations of standardized ileal digestible (SID) Lys and meet or exceed minimum SID AA to Lys ratios within phases. No significant interactions for DDGS × WM × phase or DDGS × WM were observed for all growth performance criteria. Pigs fed diets containing 30% DDGS had reduced ( < 0.05) ADFI (1.76 vs. 1.86 kg/d) and ADG (0.85 vs. 0.91 kg/d) compared with pigs fed diets with no DDGS in phase 1 but not in other phases. The G:F of pigs fed diets containing DDGS was not different during phase 1 to 3 but was greater ( < 0.01) in phase 4 (0.313 vs. 0.291) compared with that of pigs fed diets with no DDGS. Pigs fed diets containing 15% WM had similar ADFI and G:F but reduced ( < 0.05) ADG (0.86 vs. 0.90 kg/d) compared with pigs fed diets without WM in phase 1, but no difference in ADG was observed in phases 2 to 4. No DDGS × WM interaction was observed for carcass traits. Pigs fed diets containing 30% DDGS had reduced ( < 0.01) HCW (86.5 vs. 89.9 kg), carcass yield (72.3 vs. 73.6%), LM area (45.0 vs. 47.9 cm), and percentage of carcass fat-free lean (52.1 vs. 53.4%), but backfat depth was not affected compared with pigs fed diets with no DDGS. Pigs fed diets containing 15% WM had lower carcass yield (72.7 vs. 73.1%; < 0.05) and HCW (87.7 vs. 88.7 kg; < 0.10) than pigs fed diets with no addition of WM, but other carcass traits were not affected. In conclusion, overall ADG and G:F were not affected by feeding 30% DDGS or 15% WM when diets were formulated on the NE basis, but more accurate and dynamic estimation of NE content for DDGS sources is needed to optimize caloric efficiency at different physiological ages of pigs.

This experiment evaluated the effect of antioxidants, oil content in distiller's dried grains with solubles (DDGS), quality of distiller's corn oil, and storage time on lipid peroxidation. A source of low-oil DDGS (LO-DDGS; 5.0% ether extract [EE], as-fed basis), high-oil DDGS (HO-DDGS; 13.0% EE, as-fed basis), and 2 sources of distiller's corn oil (DCO; 1.20, 0.08, and 0.48% moisture, insoluble impurities, and unsaponifiables [MIU], respectively [DCO-1], and 1.20, 0.01, and 0.10% MIU, respectively [DCO-2]) were obtained. Each of the 4 ingredients was divided into 18 representative subsamples (approximately 908 g for DDGS or 2 kg of DCO). Six subsamples of each ingredient were mixed with either no supplemental antioxidants (CON), Rendox-CQ (REN; 1,000 mg/kg EE; Kemin, Industries, Des Moines, IA), or Santoquin-Q4T (SAN; 1,500 mg/kg EE; Novus International, St. Louis, MO). Each mixture ( = 72) was split into thirds, and 1 portion was immediately frozen at -20°C (d 0). Two portions were stored under hot (38.6 ± 0.1°C) and humid conditions (94.0 ± 0.3% relative humidity) for 14 or 28 d. The MIXED procedure of SAS was used to evaluate the effects of ingredient, antioxidant, storage time, and interactions, with d-0 values used as a covariate. From d 14 to 28, peroxide value (PV), -anisidine value (AnV), and thiobarbituric acid reactive substances (TBARS) of DCO and DDGS increased by 3- to 4-fold ( < 0.05). Over the entire storage period, PV of DCO-1 and HO-DDGS (12.3 ± 0.3 and 12.6 ± 0.3 mEq O/kg oil, respectively) exceeded ( < 0.05) that of DCO-2 and LO-DDGS (9.6 ± 0.3 and 9.3 ± 0.3 mEq O/kg oil, respectively). Adding REN or SAN ( < 0.05) reduced TBARS and AnV relative to CON (TBARS = 11.0 ± 0.2 mg malondialdehyde Eq/kg oil and AnV = 6.5 ± 0.2) over the entire period (mean of d 14 and 28), but TBARS and AnV did not differ ( > 0.05) between antioxidants (TBARS = 6.1 ± 0.2 and 5.9 ± 0.2 mg malondialdehyde Eq/kg oil, respectively, and AnV = 1.9 ± 0.2 and 1.8 ± 0.2 for REN and SAN, respectively). The PV on d 14 and 28 and overall was less ( < 0.05) when either antioxidant was added relative to CON (16.0 mEq O/kg) and was greater for ingredients treated with SAN ( < 0.05) compared with REN (8.8 ± 0.2 and 8.0 ± 0.2 mEq O/kg oil for SAN and REN, respectively). In summary, antioxidants reduced peroxidation of DDGS and DCO by approximately 50% during 28 d of storage at 38.6°C and 94.0% relative humidity, but neither antioxidant completely stabilized the ingredients.

This experiment evaluated the effects of including peroxidized corn dried distillers grains with solubles (DDGS) in diets for sows and nursery pigs on growth performance, vitamin E (VE), and Se status, and the incidence of mulberry heart disease (MHD) of nursery pigs. Sows (n = 12) were fed corn-soybean meal diets (C-SBM) or C-SBM diets with DDGS (40% and 20% in gestation and lactation, respectively) for 3 parities. In the third parity, 108 weaned pigs (BW = 6.6 ± 0.36 kg) were blocked by BW within litter, assigned to pens (2 pigs/pen; 5 and 4 pens per litter for groups 1 and 2, respectively), and pens were assigned 1 of 3 nursery diets: 1) corn-soybean meal (CON), 2) 30% peroxidized DDGS (Ox-D), and 3) 30% Ox-D with 5 × NRC (1998) level of VE (Ox-D+5VE) for 7 wk, in a 2 × 3 factorial arrangement of sow and nursery diets (n = 9 pens/treatment). The peroxidized DDGS source in nursery diets contained concentrations of thiobarbituric acid reactive substances (TBARS) and peroxide values that were 25 and 27 times greater than a reference corn sample. Sow colostrum, milk, and serum, as well as pig serum and liver samples, were analyzed for α-tocopherol and Se concentrations. Pig serum was analyzed for glutathione peroxidase activity (GPx), TBARS, and sulfur-containing AA (SAA). Pig hearts were evaluated for gross and histopathological lesions indicative of MHD, but none were detected. Pigs from sows fed DDGS tended to have reduced (P = 0.07) VE in serum during lactation and reduced VE at weaning (P < 0.01; 5.6 vs. 6.7 ± 0.1 µg/mL) compared with pigs from sows fed C-SBM. Inclusion of DDGS in sow diets reduced the VE status of pigs during lactation, but not in the nursery when MHD can be a concern. Pigs fed Ox-D+5VE (P = 0.08) tended to have, and those fed Ox-D (P = 0.04) had greater ADFI than pigs fed CON, but ADG was not affected (P > 0.1) by nursery diet. Feeding Ox-D or Ox-D+5VE increased (P < 0.05) serum α-tocopherol compared with CON (2.5, 2.8, and 3.4 ± 0.09 µg/mL, respectively), but TBARS and GPx were not affected by nursery diet. Serum concentration of SAA was 40% to 50% greater (P < 0.01) for pigs fed Ox-D or Ox-D+5VE compared with those fed C-SBM, which was likely due to greater (P < 0.01) SAA intake for pigs fed Ox-D. The antioxidant properties of SAA may have spared VE and Se and masked any effect of Ox-D on metabolic oxidation status. Therefore, increasing the dietary VE concentration was unnecessary in nursery diets containing Ox-D.

Crossbred pigs (n = 315) were blocked by initial BW (6.8 ± 1.1 kg) and randomly assigned to 1 of 4 dietary treatments to evaluate the effects of dietary inclusion of tallow and corn distillers dried grains with solubles (DDGS) on pig growth, carcass traits, and pork fat quality. Diets consisted of a corn-soybean meal control diet (CON) and another 3 corn-soybean meal diets containing 5% tallow (T), 30% DDGS (D), or 5% tallow plus 30% DDGS (TD) in a 2 × 2 factorial arrangement of treatments. Diets were formulated to contain similar levels of available P and standardized ileal digestible Lys:ME among treatments. Pigs were housed in 40 pens, with 7 to 8 pigs per pen, to provide 10 replicates per treatment. Overall ADG did not differ among treatments. Compared with CON (2.76 kg/d) and T (2.59 kg/d), feeding 30% DDGS reduced the ADFI (interaction, P > 0.05) of pigs when fed with 5% tallow (2.45 kg/d for TD) but not when fed alone (2.76 kg/d for D). There was no effect of DDGS on overall G:F, but pigs fed diets with tallow had greater (P < 0.01) G:F (0.4) than pigs fed no tallow (0.37). Feeding tallow increased (P < 0.01) HCW, carcass yield, and backfat depth of pigs independent of DDGS. Feeding DDGS reduced (P < 0.01) belly firmness, as measured by belly flop angle, independent of tallow (D = 71.8° and TD = 57.7° vs. CON = 134.0° and T = 113.4°) and tallow also tended to reduce belly firmness (P < 0.10). Feeding DDGS and tallow reduced the concentration of SFA in belly fat, while the concentration of MUFA were increased (P < 0.01) by feeding tallow but not DDGS. Conversely, feeding DDGS increased (P < 0.01) the concentration of PUFA in belly fat but there was no effect of tallow. An interaction (P = 0.03) between DDGS and tallow for iodine value (IV) of belly fat was observed, in which addition of tallow or DDGS increased the IV of belly fat (64.22 for T and 71.22 for D vs. 59.01 for CON) but addition of both reduced IV (67.88 for TD). The IV of belly fat and backfat were correlated (P < 0.01) with the IV product of the diet fed in phase 3 (r = 0.49 and r = 0.81, respectively). In conclusion, adding 5% tallow to 30% DDGS diets improved G:F and carcass yield while reducing the IV of belly fat. However, pork fat firmness as measured by belly flop angle was not improved.

An experiment was conducted to measure the apparent ileal digestibility (AID) and apparent total tract digestibility (ATTD) of fatty acids in diets containing 0 or 30% corn distillers dried grains with solubles (DDGS) and 0, 5, or 10% tallow. Barrows (n = 24; initial BW = 25 kg) were surgically fitted with a T-cannula at the distal ileum. Pigs (n = 4/diet) were randomly assigned to diets: corn-soybean meal control (CON), CON plus 5% tallow (5T0D), CON plus 10% tallow (10T0D), CON plus 30% DDGS (0T30D), CON plus 5% tallow and 30% DDGS (5T30D), and CON plus 10% tallow and 30% DDGS (10T30D). Eight replicates per treatment were achieved by randomizing diets among pigs for a second collection period. Each pig was fed their respective diet for a 5-d adaptation period followed by 3-d fecal collection and 2-d ileal digesta collection periods. The AID and ATTD of fatty acids was calculated using the index method and acid-insoluble ash as an indigestible marker. When tallow was added to diets with 0% DDGS, there was no effect on AID of palmitic acid (C16:0) or SFA, while AID of stearic acid (C18:0) was increased (66.87% for CON, 72.06% for 5T0D, and 76.81% for 10T0D; P < 0.01). However, when diets contained 30% DDGS, the AID of all SFA was reduced as levels of tallow increased C16:0 (77.62% for 0T30D, 69.66% for 5T30D, and 68.43% for 10T30D), C18:0 (85.87% for 0T30D, 64.08% for 5T30D, and 61.25% for 10T30D), and SFA (79.88% for 0T30D, 68.23% for 5T30D, and 66.29% for 10T30D). The AID of MUFA was not affected when tallow was added to diets with 30% DDGS but actually increased in 5T0D and 10T0D. The amount of apparent ileal digested fatty acids increased with the addition of DDGS and tallow regardless of their digestibility. Amounts of ileal digested MUFA and PUFA increased when both DDGS (P < 0.01) and tallow (P < 0.01) were included in the diet compared to when either ingredient was excluded. For ileal digestible SFA, an interaction (P < 0.01) between DDGS and tallow was observed. Interactions between DDGS and tallow were observed for ATTD of all fatty acids (P < 0.01), except for linoleic acid and PUFA, which were not affected by dietary treatment. The amount of ileal digestible PUFA increased with tallow addition independent from the inclusion level of DDGS and it was a function the dietary concentration of the fatty acid. Adding tallow to corn-soybean based diets increased the amount of digested SFA, but in diets with DDGS, the increment in amount of ileal digestible SFA was less prominent due to lesser digestibility of SFA.

A total of 108 barrows (6.67 ± 0.03 kg BW) were assigned to 12 dietary treatments in a 4 × 3 factorial design plus a corn-soybean meal control diet to evaluate the effect of lipid source and peroxidation level on DE, ME, and apparent total tract digestibility (ATTD) of DM, GE, ether extract (EE), N, and C in young pigs. Main effects were lipid source (corn oil [CN], canola oil [CA], poultry fat [PF], and tallow [TL]) and peroxidation level (original lipids [OL], slow oxidation [SO] of lipids heated for 72 h at 95°C, or rapid oxidation [RO] of lipids heated for 7 h at 185°C). Pigs were provided ad libitum access to diets for 28 d followed by an 8-d period of controlled feed intake equivalent to 4% BW daily. Diets were formulated based on the ME content of CA with the standardized ileal digestible Lys, Met, Thr, Trp, total Ca, and available P:ME balanced relative to NRC (1998) recommendations. Lipid peroxidation analysis indicated that compared with the OL, SO and RO had a markedly increased concentrations of lipid peroxidation products, and the increase of peroxidation products in CN and CA were greater than those in PF and TL. Addition of lipids to diets increased (P < 0.05) ATTD of EE and tended to improve (P = 0.06) ATTD of GE compared with pigs fed the control diet. Feeding CN or CA increased (P < 0.05) ATTD of DM, GE, EE, N, and C compared with feeding TL, while feeding PF improved (P < 0.05) ATTD of GE and EE and tended to increase (P = 0.06) ATTD of C compared with TL. Pigs fed CN had increased (P = 0.05) percentage N retention than pigs fed TL. No peroxidation level effect or interaction between lipid source and peroxidation level on DE and ME was observed. Lipid source tended (P = 0.08) to affect DE but not ME values of experimental lipids (P > 0.12). Digestible energy values for CA (8,846, 8,682, and 8,668 kcal/kg) and CN (8,867, 8,648, and 8,725 kcal/kg) were about 450 kcal/kg greater than that of TL (8,316, 8,168, and 8,296 kcal/kg), with PF being intermediate (8,519, 8,274, and 8,511 kcal/kg), for OL, SO, and RO lipids, respectively, respectively. In conclusion, lipid source affected ATTD of dietary DM, GE, EE, N, and C, and N retention and tended to influence the DE value of the lipid but did not significantly affect their ME value. Rapid and slow heating of lipids used in this study increased lipid peroxidation products but had no detectable effects on nutrient and energy digestibility as well as DE and ME values of the various lipids.

To evaluate the effect of feeding thermally oxidized vegetable oils and animal fats on growth performance, liver gene expression, and liver and serum fatty acid and cholesterol concentration in young pigs, 102 barrows (6.67 ± 0.03 kg BW) were divided into 3 groups and randomly assigned to dietary treatments in a 4 × 3 factorial arrangement. The main factors were lipid source (n = 4; corn oil [CN], canola oil [CA], poultry fat [PF], and tallow [TL]) and lipid peroxidation level (n = 3; original lipids [OL], slow oxidation [SO] through heating at 95°C for 72 h, or rapid oxidation [RO] through heating at 185°C for 7 h). Pigs were provided ad libitum access to diets in group pens for 28 d followed by controlled feed intake in metabolism crates for 10 d. On d 39, all pigs were euthanized for liver samples to determine liver weight, lipid profile, and gene expression patterns. Lipid oxidation analysis indicated that compared with the OL, SO and RO of lipids had a markedly increased concentrations of primary and secondary peroxidation products, and the increased lipid peroxidation products in CN and CA were greater than those in PF and TL. After a 28-d ad libitum feeding period, pigs fed RO lipids tended to have reduced ADFI (P = 0.09) and ADG (P < 0.05) compared with pigs fed OL, and pigs fed CA had reduced G:F (P < 0.05) compared with pigs fed all other lipids. Pigs fed RO lipids tended to have increased relative liver weight (P = 0.09) compared with pigs fed OL. Liver triglyceride concentration (LTG) in pigs fed OL was greater (P < 0.05) than in pigs fed SO lipids and tended to be greater (P < 0.07) than in pigs fed SO. The reduced LTG were consistent with increased (P < 0.05) mRNA expression of PPARα factor target genes (acyl-CoA oxidase, carnitine palmitoyltransferase 1, and mitochondrial 3-hydroxy-3-methylglutary-CoA synthase) in pigs fed SO and RO lipids compared with pigs fed OL. Pigs fed CN or CA tended to have increased LTG (P = 0.09) compared with pigs fed TL. Liver cholesterol concentration in pigs fed CN was less (P < 0.05) than in pigs fed PF and tended to be less (P = 0.06) than in pigs fed TL, whereas pigs fed CA had a reduced (P < 0.05) liver cholesterol compared with pigs fed PF or TL. In conclusion, feeding thermally oxidized lipids negatively affected growth performance and LTG of young pigs, which was associated with an upregulation of fatty acid catabolism pathways.

The objective of this experiment was to evaluate peroxidation in 4 lipids, each with 3 levels of peroxidation. Lipid sources were corn oil (CN), canola oil (CA), poultry fat, and tallow. Peroxidation levels were original lipids (OL), slow-oxidized lipids (SO), and rapid-oxidized lipids (RO). To produce peroxidized lipids, OL were either heated at 95°C for 72 h to produce SO or heated at 185°C for 7 h to produce RO. Five indicative measurements (peroxide value [PV], p-anisidine value [AnV], thiobarbituric acid reactive substances [TBARS] concentration, hexanal concentration, 4-hydroxynonenal [HNE] concentration, and 2,4-decadienal [DDE]) and 2 predictive tests (active oxygen method [AOM] stability and oxidative stability index [OSI]) were performed to quantify the level of oxidation of the subsequent 12 lipids with varying levels of peroxidation. Analysis showed that a high PV accurately indicated the high level of lipid peroxidation, but a moderate or low PV may be misleading due to the unstable characteristics of hydroperoxides as indicated by the unchanged PV of rapidly oxidized CN and CA compared to their original state (OL). However, additional tests, which measure secondary peroxidation products such as AnV, TBARS, hexanal, HNE, and DDE, may provide a better indication of lipid peroxidation than PV for lipids subjected to a high level of peroxidation. Similar to PV analysis, these tests may also not provide irrefutable information regarding the extent of peroxidation because of the volatile characteristics of secondary peroxidation products and the changing stage of lipid peroxidation. For the predictive tests, AOM accurately reflected the increased lipid peroxidation caused by SO and RO as indicated by the increased AOM value in CN and CA but not in poultry fat and tallow, which indicated a potential disadvantage of the AOM test. Oxidative stability index successfully showed the increased lipid peroxidation caused by SO and RO in all lipids, but it too may have disadvantages similar to AnV, TBARS, hexanal, DDE, and HNE because OSI directly depends on quantification of the volatile secondary peroxidation products. To accurately analyze the peroxidation damage in lipids, measurements should be determined at appropriate time intervals by more than 1 test and include different levels of peroxidation products simultaneously.

To evaluate the effect of feeding thermally oxidized lipids on metabolic oxidative status, gut barrier function, and immune response of young pigs, 108 barrows (6.67 ± 0.03 kg BW) were assigned to 12 dietary treatments in a 4 × 3 factorial arrangement in addition to a corn-soybean meal control diet. Main effects were 4 lipid sources (corn oil [CN], canola oil [CA], poultry fat [PF], and tallow [TL]) and 3 oxidation levels (original lipids [OL], slow oxidation [SO] of lipids heated for 72 h at 95°C, or rapid oxidation [RO] of lipids heated for 7 h at 185°C). Pigs were provided ad libitum access to diets for 28 d followed by controlled feed intake for 10 d. After a 24-h fast on d 38, serum was collected and analyzed for α-tocopherol (α-T), thiobarbituric acid reactive substances (TBARS), endotoxin, haptoglobin, IgA, and IgG. On the same day following serum collection, lactulose and mannitol were fed and subsequently measured in the urine to evaluate gut permeability. There was a source × peroxidation interaction for serum α-T concentration where pigs fed SO or RO had decreased (P < 0.05) serum α-T concentration compared with pigs fed OL in CA and CN diets but not in pigs fed PF and TL diets. There was no source × peroxidation interaction for serum TBARS, but among all lipid sources, pigs fed SO or RO lipids had increased (P < 0.05) serum TBARS compared with pigs fed OL. In addition, pigs fed CN or CA had greater (P < 0.05) serum TBARS compared with pigs fed PF or TL diets. There were no lipid source × peroxidation level interaction or lipid source or peroxidation level effects on serum endotoxin, haptoglobin, IgA, or IgG. Pigs fed lipid supplemented diets tended to have increased serum endotoxin (P = 0.06), IgA (P = 0.10), and IgG (P = 0.09) compared with pigs fed the control diet. There were no lipid source × peroxidation level interaction or lipid source or peroxidation level effects on urinary TBARS and lactulose to mannitol ratio. Compared with pigs fed the control diet, pigs fed diets containing lipids had a lower lactulose to mannitol ratio (P < 0.01). In conclusion, feeding weaning pigs diets containing 10% thermally oxidized lipids for 38 d, especially vegetable oils containing greater concentrations of PUFA, appeared to impair oxidative status but had little influence on gut barrier function or serum immunity parameters.

This study used an endocrinological approach to explain the differences between sows that have higher vs. lower preweaning mortality in a group-farrowing system. The association between sows that had 2 or more piglets die within the first 72 h postfarrowing (high risk) or sows that had 1 or no piglets die within the first 72 h postfarrowing (low risk) with changes in serum hormone concentrations was investigated. Multiparous sows (n = 63; parity 2 to 7) from 4 contemporary breeding groups, each mated within a week, were used. Sows were housed in a group-farrowing system where 8 sows farrowed in individual pens and shared a communal feeding and dunging area in each room. Reproductive performance, including total born, born alive, and stillborn per litter, individual weight of piglets at birth and weaning (at 5 wk postfarrowing), litter size at weaning, preweaning mortality of piglets, and sow BW before farrowing and after weaning, were recorded for all sows. Of these sows, 14 sows from 2 breeding groups were selected randomly for blood sampling through an indwelling ear vein catheter. A blood sample was collected daily from each sow 2 d prefarrowing through 2 d postfarrowing. Serum samples were analyzed for prolactin, oxytocin, cortisol, and urocortin concentrations using RIA. Among the 14 sows, 7 sows lost 2 or more piglets during the first 72 h after farrowing and were classified as high risk sows, and the other 7 sows lost 0 or 1 piglet during the same period and were classified as low risk sows. Catheters in 11 sows (5 high risk sows and 6 low risk sows) remained functional for the entire sampling period. Results indicate that high risk sows farrowed larger litters (live born = 13.8 ± 0.50 vs. 11.3 ± 0.48 piglets; P = 0.03) with lighter piglets (1.4 ± 0.04 vs. 1.7 ± 0.05 kg; P < 0.001) compared with low risk sows. In addition, high risk sows had greater oxytocin concentrations (0.09 vs. 0.07 ng/mL; SE = 0.02, P = 0.01), which might be associated with larger litters farrowed, compared with low risk sows. There were no differences between high risk and low risk sows (P > 0.30) in terms of serum prolactin, cortisol, or urocortin concentrations. These results suggest that litter size and birth weight of piglets played an important role in preweaning mortality of piglets and hormone concentrations in sows were not associated with piglet mortality in the group-farrowing system used.

An experiment was conducted to evaluate the interactive effects of dietary distillers dried grains with solubles (DDGS) in sow diets and housing systems on reproductive performance and longevity. Sows (311 for parity 0 and 90 for parity 1) were assigned randomly within parity to 1 of 4 treatments and maintained on these treatments for up to 3 reproductive cycles. Sows were fed either fortified corn-soybean meal control diets (CON) during gestation and lactation or diets containing 40% DDGS in gestation and 20% DDGS in lactation and were housed either in individual stalls or group pens with electronic sow feeders during gestation. Sows fed DDGS had smaller (P < 0.05) litter size (born alive, 11.0 vs. 11.6; weaning, 9.8 vs. 10.2) and had more (P < 0.05) stillborns (0.9 vs. 0.7) than sows fed CON. Litters nursing sows fed DDGS gained less weight (P < 0.01) than litters nursing sows fed CON (47.8 vs. 49.8 kg, respectively). Group-housed sows tended to farrow smaller litters (born alive, 11.0 vs. 11.5; P < 0.10) and had fewer pigs at weaning (9.9 vs. 10.2; P < 0.05) compared with stall-housed sows. Litters from group-housed sows tended (P < 0.10) to gain less weight while suckling than those from stall-housed sows (48.3 vs. 49.4 kg, respectively). Diet did not affect the percentage of sows that completed each successive reproductive cycle. Stall housing tended to increase (P = 0.06) the completion rate of sows at the second reproductive cycle (80.0 vs. 68.2%) and increased (P < 0.05) the completion rate of sows in the third reproductive cycle (68.9 vs. 55.8%) compared with group housing. Sows fed DDGS produced fewer (P < 0.05) live-born pigs (26.2 vs. 27.4) and tended (P < 0.10) to have fewer pigs weaned (23.7 vs. 24.5) over 3 reproductive cycles compared with sows fed CON. Stall-housed sows farrowed more (P < 0.05) total pigs (30.1 vs. 26.7) and live pigs (28.4 vs. 25.2) and had more weaned pigs (25.2 vs. 23.1) compared with group-housed sows over 3 reproductive cycles. In conclusion, long-term feeding of DDGS decreased litter size and sow productivity but did not affect sow longevity. Long-term housing of sows in group pens decreased litter size, sow longevity, and sow productivity. The detrimental effects of housing pregnant sows in pens were most notable when sows were fed corn-soybean meal-based diets compared with DDGS diets.

Lipid peroxidation in animal feed can negatively affect growth performance and meat quality. Weanling pigs (n = 432; BW = 6.6 ± 0.4 kg) were used to evaluate the effects of feeding peroxidized distillers dried grains with solubles (DDGS) with 3 levels of vitamin E (α-tocopheryl acetate) on growth performance, carcass composition, fatty acid composition of pork fat, and lipid peroxidation in LM. The DDGS source used in this study contained the highest thiobarbituric acid reactive substances (TBARS) value, peroxide value, and total S content (5.2 ng malondialdehyde/mg oil, 84.1 mEq/kg oil, and 0.95%, respectively) among 30 DDGS sources sampled. Pens within blocks were assigned randomly to 1 of 6 diets in a 2 × 3 factorial arrangement of treatments with 8 pens per treatment and 9 pigs per pen. Pigs were fed a corn-soybean meal (CON) or 30% peroxidized DDGS (Ox-DDGS) diets with 3 levels of vitamin E: none supplemented (No-E), NRC (1X-E), or 10X NRC (10X-E). Compared to CON, inclusion of 30% Ox-DDGS in diets reduced (P < 0.001) final BW (110 vs. 107 kg), overall ADG (0.76 vs. 0.74 kg/d), and G:F (0.39 vs. 0.37). Increasing dietary vitamin E concentrations improved G:F (P = 0.03) of pigs fed 10X-E and 1X-E vs. No-E diets (0.39 and 0.39 vs. 0.38, respectively). Hot carcass weight, dressing percentage, backfat depth, and LM area were reduced (P < 0.01) in pigs fed Ox-DDGS compared to CON, but percentage of fat-free carcass lean was not affected. Feeding Ox-DDGS increased (P < 0.001) PUFA concentration, particularly linoleic acid (P < 0.001), and iodine value (P < 0.001) in belly fat and backfat compared to pigs fed CON. Dietary vitamin E levels did not affect fatty acid profiles in belly or back fat. Loin muscle TBARS were measured to determine the lipid peroxidation level in pork loins. Although pigs were fed a Ox-DDGS source in this study, TBARS in LM were similar between Ox-DDGS and CON treatments. There was no interaction between Ox-DDGS and dietary vitamin E concentration in LM TBARS. Alpha-tocopherol concentration in LM was greater (P < 0.001) in 10X-E than No-E or 1X-E dietary treatments. Compared to CON, feeding Ox-DDGS increased α-tocopherol concentration in LM of pigs fed No-E (1.0 vs. 3.1 mg/kg; P = 0.005) but not in those fed 1X-E or 10X-E. These results indicate that feeding diets containing 30% Ox-DDGS to wean-finish pigs may negatively affect growth performance, but supplementation of additional vitamin E in the diet did not counteract these effects.

Pressures from consumers concerned with sow well-being in gestation stalls have encouraged producers to consider how to transition from individual gestation stalls to pens in existing buildings. The aim of this study was to evaluate the performance and well-being of sows in pens that were retrofitted from stalls (2.1 by 0.55 m). Large pens (5.5 by 7.3 m) housed 26 sows and small pens (5.5 by 1.7 m) housed 6 sows, with equal floor space allowance (1.5 m(2)/sow) in both pens. Floor space allowance in pens was set to ensure that pens and stalls occupied the same building space per sow. Data were collected from 815 sows (parity 1 to 8) in 13 large pens, 26 small pens, and 326 stalls that served as control. All sows were mated in stalls and moved to pens or stalls after pregnancy confirmation at 5 wk after mating. Daily feed allowance for sows was dropped on a solid floor in pens and was equal in all 3 housing systems. Sows stayed in their assigned gestation housing treatment for 1 pregnancy. Data were analyzed using the Proc FREQ and the Proc Mixed procedures of SAS. Sows in large pens gained less weight during gestation than sows in small pens and stalls (33.4 vs. 39.5 and 41.5 kg, SE = 1.64; P = 0.01). In addition, the proportion of sows assigned to the study that farrowed was the lowest in large pens (92%, χ(2) = 9.52; P < 0.01) and the highest in stalls (98%), with sows in small pens being intermediate (95%). Consequently, the highest percent of sows were removed from large pens (15.8%, χ(2) = 6.75; P < 0.05) and lowest percent of sows were removed from stalls (9.2%), with sows in small pens being intermediate (11.7%) during the study period. Causes for sow removal were different among the housing treatments. Poor reproductive performance was the top reason for culling sows in large pens and in stalls. In small pens, mortality was the top reason for sow removal. Housing treatment did not affect live litter size at birth (12.5, 12.2 and 12.3 piglets, SE = 0.21) or weaning (10.2, 10.1 and 10.3 piglets, SE = 0.20) for large pens, small pens, or stalls, respectively. Results suggest that the performance and well-being of sows were compromised in pens, as indicated by decreased farrowing rates and increased sow removal rates. The limited floor space allowance and the competitive floor feeding system could be major contributors to the compromised performance and well-being of group-housed sows in this study.

Values for the concentration of standardized ileal digestible (SID) CP, Lys, Met, Thr, and Trp from 34 sources of distillers dried grains with solubles (DDGS) were obtained from a series of 5 experiments with the objective of predicting the concentration of SID AA from physical and chemical assays. The concentration of NDF, ADF, hemicellulose, acid detergent insoluble CP (ADICP), and KOH soluble protein (SolCP) were measured and calculated in all DDGS sources. Likewise, particle size was measured and color of each source of DDGS was determined with a Minolta colorimeter and HunterLab spectrometer and was expressed as lightness (L*), redness (a*), and yellowness (b*). The HunterLab spectrometer also provided optical density that was recorded between 400 and 700 nm. Front face fluorescence was measured at 360 nm excitation and recorded from 380 to 600 nm. Multiple linear regression and principal components analyses were performed to predict the concentration of SID AA among DDGS sources, and predicted means as well as predicted residual sums of squares (PRESS) were calculated to estimate accuracy and precision of the model. Some correlations (P < 0.05) were observed between ADF, hemicellulose, ADICP, and SolCP with SID CP and AA but were generally low (r < 0.51). There was a greater association (R(2) = 0.40; P < 0.05) between L* and SID Lys among DDGS sources when L* was less than 50 than when samples had L* values greater than 50. In addition, a* was negatively correlated (P < 0.05) with SID CP (r = -0.41), Lys (r = -0.59), and Met (r = -0.50) whereas b* tended to be positively correlated (P < 0.10) with SID Lys (r = 0.31) and Trp (r = 0.30) and was correlated (P = 0.05) with SID Met (r = 0.43) and Thr (r = 0.36). There were no correlations between NDF or particle size with SID CP and AA. Optical density, along with CP, was highly predictive of SID Lys (R(2) = 0.97; PRESS = 0.05), Thr (R(2) = 0.94; PRESS = 0.06), and Trp (R(2) = 0.93; PRESS = 0.004) but not SID Met (R(2) = 0.39; PRESS = 0.12). Front face fluorescence was also highly predictive of SID Lys (R(2) = 0.99; PRESS = 0.07), Met (R(2) = 0.95; PRESS = 0.05), Thr (R(2) = 0.99; PRESS = 0.008), and Trp (R(2) = 0.99; PRESS = 0.006). In conclusion, correlations between ADICP, SolCP, NDF, particle size, and color measurements with SID AA concentrations were poor, but optical density and front face fluorescence methods appear to provide good predictions of SID AA concentrations in DDGS. However, these prediction equations need to be validated using samples of DDGS from a separate data set.

The objective of this investigation was to determine the effect of a reduced nocturnal temperature (RNT) regimen on performance of weaned pigs and energy consumption during the nursery phase of production. The age of weaned pigs assigned to experiments ranged from 16 to 22 d. In Exp. 1, 3 stations conducted 2 trials under a common protocol that provided data from 6 control rooms (CON; 820 pigs) and 6 RNT rooms (818 pigs). Two mirror-image nursery rooms were used at each station. Temperature in the CON room was set to 30°C for the first 7 d, then reduced by 2°C per week through the remainder of the experiment. Room temperature settings were held constant throughout the day and night. The temperature setting in the RNT room was the same as CON during the first 7 d, but beginning on the night of d 7, the room temperature setting was reduced 6°C from the daytime temperature from 1900 to 0700 h. The use of heating fuel and electricity were measured weekly in each room. Overall, ADG (0.43 kg), ADFI (0.62 kg), and G:F (0.69) were identical for CON and RNT rooms. Consumption of heating fuel [9,658 vs. 7,958 British thermal units (Btu)·pig(-1)·d(-1)] and electricity (0.138 vs. 0.125 kilowatt-hour (kWh)·pig(-1)·d(-1)] were not statistically different for CON and RNT rooms, respectively. In Exp. 2, 4 stations conducted at least 2 trials that provided data from 9 CON rooms (2,122 pigs) and 10 RNT rooms (2,176 pigs). Experimental treatments and protocols were the same as Exp. 1, except that the RNT regimen was imposed on the night of d 5 and the targeted nighttime temperature reduction was 8.3°C. Neither final pig BW (21.8 vs. 21.5 kg; SE = 0.64), ADG (0.45 vs. 0.44 kg; SE = 0.016), ADFI (0.61 vs. 0.60 kg; SE = 0.019), nor G:F (0.75 vs. 0.75; SE = 0.012) were different for pigs housed in CON or RNT rooms, respectively. Consumption of heating fuel and electricity was consistently reduced in RNT rooms for all 4 stations. Consumption of heating fuel (10,019 vs. 7,061 Btu·pig(-1)·d(-1); SE = 1,467) and electricity (0.026 vs. 0.021 kWh·pig-1·d-1; SE = 0.004) were lower (P < 0.05) in the RNT rooms compared with CON rooms. This represents a 30% reduction in heating fuel use and a 20% reduction in electrical use with no differences in pig growth performance or health. From these experiments, we conclude that imposing a RNT regimen from 1900 to 0700 h is effective in reducing energy costs in the nursery without compromising pig performance, which will reduce production costs and decrease emissions of greenhouse gases.

Some sources of corn dried distillers grains with solubles (DDGS) contain relatively high amounts of oxidized lipids produced from PUFA peroxidation during the production process. These oxidized lipids may impair metabolic oxidation status of pigs. The objective of this study was to understand the effects of feeding corn-soybean meal diets (CON) or diets containing 30% highly oxidized DDGS with 1 of 3 levels of supplemental vitamin E (dl-α-tocopheryl acetate), none, the 1998 NRC level (11 IU/kg), and 10x the 1998 NRC level (110 IU/kg), on oxidative status of nursery pigs. The DDGS source used in this study contained the greatest thiobarbituric acid reactive substances (TBARS) value, peroxide value, and total S content (5.2 ng/mg oil, 84.1 mEq/kg oil, and 0.95%, respectively) relative to 30 other DDGS sources sampled (mean values = 1.8 ng/mg oil, 11.5 mEq/kg oil, and 0.50%, respectively). Barrows (n = 54) were housed in pens and fed the experimental diets for 8 wk after weaning and transferred to individual metabolism cages for collection of feces, urine, blood, and liver samples. Total S content was greater in DDGS diets than in CON (0.39 vs. 0.19%). Dietary inclusion of 30% DDGS improved apparent total tract digestibility of S (86.8 vs. 84.6%; P < 0.001) and S retained (2.94 vs. 2.07 g/d; P < 0.01) compared with CON. Although pigs were fed highly oxidized DDGS in this study, serum TBARS were similar between DDGS and CON treatments. There was an interaction between DDGS and dietary vitamin E level for serum concentrations of α-tocopherol. Serum α-tocopherol concentrations were greater (P < 0.001) in pigs fed DDGS diets than those fed CON when dl-α-tocopheryl acetate was not provided or provided at the NRC level but were similar when dl-α-tocopheryl acetate was supplemented at the 10x NRC level. Pigs fed DDGS diets had greater serum concentrations of S-containing AA, particularly Met (P < 0.001) and taurine (P = 0.002), compared with those fed CON. Liver glutathione concentration was greater in pigs fed DDGS diets than CON (56.3 vs. 41.8 nmol/g). Dietary inclusion of DDGS (P < 0.001) and vitamin E (P = 0.03) increased enzyme activity of glutathione peroxidase. The elevated concentrations of S-containing antioxidants (Met, taurine, and glutathione) in vivo may protect pigs against oxidative stress when feeding highly oxidized DDGS. Therefore, the increased S content in DDGS may be beneficial, and increasing concentrations of vitamin E in diets may not be necessary to protect pigs against metabolic oxidative stress when feeding high S and highly peroxidized DDGS.

Two experiments were conducted to evaluate the effects of feeding continuously a diet containing 40% dried distillers grains with solubles (DDGS) or intermittently diets containing 20 or 40% DDGS on growth performance and carcass quality of pigs. Responses of the pigs to abrupt introduction and removal of dietary DDGS with differing concentrations of standardized ileal digestible (SID) AA were also evaluated. In Exp. 1, crossbred pigs (n=216; initial BW=51.3±3.1 kg) were assigned randomly to 1 of 4 treatments, which included a corn-soybean meal control (CON), a 20% DDGS diet (D20), a switch between D20 and CON (D20-CON), and a switch between a 40% DDGS diet and CON (D40-CON) with 6 pens per treatment. Pigs abruptly introduced and removed from a 20% DDGS diet (D20-CON) exhibited no differences in growth performance or carcass quality compared with CON pigs. However, intermittently feeding a 40% DDGS diet (D40-CON) resulted in lighter HCW (P<0.05) compared with all other treatments. In Exp. 2, crossbred pigs (n=324; initial BW=33.2±3.0 kg) were assigned randomly to 1 of 6 treatments, including a corn-soybean meal control (CON), a 40% low SID AA DDGS diet (LD), a 40% high SID AA DDGS diet (HD), LD and CON diets alternated (LD-CON), HD and CON diets alternated (HD-CON), or HD and LD diets alternated (HD-LD) with 6 pens per treatment. Final BW and ADG were less (P<0.05) for LD and HD-LD pigs compared with CON pigs, but HD pigs tended to have reduced (P<0.10) final BW and ADG. Loin muscle area was smaller for LD and HD-LD pigs compared with CON pigs (P<0.05). Percentage carcass lean was not affected by dietary treatment. Backfat of DDGS-fed pigs was more unsaturated than CON pigs, but AA digestibility of DDGS did not affect this response. Digestibility of AA in DDGS can influence pig performance and carcass quality when fed at high concentrations (40% or more). The use of a high SID AA DDGS source may diminish some of the negative responses observed for growth performance and carcass characteristics when feeding high concentrations of DDGS if accurate values of SID AA are used in diet formulation. Periodic inclusion and removal of 40% DDGS from diets did not adversely affect growth performance or carcass quality regardless of the SID AA digestibility of the DDGS used. These results indicate that it is possible to abruptly incorporate and remove DDGS from grower-finisher swine diets without meaningful detrimental effects on growth performance or carcass quality.

Young sows are subordinate and vulnerable in group-housing systems because they usually lose most fights and suffer more injuries than mature sows at mixing. This study was conducted to evaluate effects of sorting by parity on reducing aggression and associated stress with the aim to improve welfare and performance of first-parity sows in a group-housed system. Sows and gilts (n = 180) from 6 breeding groups were used. Within each group, 2 groups of 15 females were mixed in each of 2 treatment pens after weaning and remained there throughout the entire gestation period. The control pen consisted of 11 multiparous and 4 first-parity sows, and the treatment pen consisted of 11 gilts and 4 first-parity sows. Before mixing and at the end of the gestation period, sows and gilts were weighed individually, assessed for BCS, and measured for backfat thickness. Injury scores were assessed before and 48 h after mixing and wean-to-mating intervals, farrowing rate, and litter performance at the subsequent farrowing were recorded for all females. Aggressive interactions involving first-parity sows were video recorded for 72 h immediately after mixing in each pen. Data were analyzed using the Glimmix procedure of SAS with a Poisson regression model for count data and a Gaussian model for continuous data. All females in treatment pens sustained fewer scratches (P = 0.01) after mixing than females in control pens. First-parity sows in treatment pens fought more frequently (P = 0.01), tended to fight for longer periods (P = 0.08), and won more fights (P = 0.04) of parallel pressing but had fewer injures (P = 0.03) after mixing, gained more BW (P = 0.01) during gestation, and had greater farrowing rates (P = 0.03) compared with first-parity sows in control pens. The results suggest that sorting by parity shielded first-parity sows from severe injuries caused by mixing-induced aggression so that their welfare and performance can be improved in group housing systems.

A study was conducted to compare growth performance and behaviors of group-farrowed pigs with those of confinement-farrowed pigs. A total of 216 pigs (8 wk of age) were used, with an equal number of group-farrowed or confinement-farrowed pigs from 1 farrowing batch. Group-farrowed pigs were farrowed in bedded, individual pens and mingled into a group of 8 litters at 12 (±1.3) d of age. Pigs were weaned at 33 (±1.3) d and remained in the farrowing room until 8 wk of age. Confinement-farrowed pigs were farrowed in farrowing crates. At weaning (32 ± 2.0 d of age), confinement-farrowed pigs were mixed and moved to pens of 9 pigs in a confinement nursery and remained there until 8 wk of age. At 8 wk of age, pigs from the 2 housing systems were allocated to 24 pens of 9 pigs in a confinement growing-finishing barn, with 12 pens from each of the housing systems. Within farrowing system, pigs from different groups or pens were mixed upon entering the growing-finishing barn. Individual BW was recorded at allotment (wk 0) to the growing-finishing barn and every 2 wk thereafter for 14 wk. Feed intake and G:F were monitored on a pen basis every 2 wk between wk 0 and 14 of the study period. Behaviors of pigs were video recorded in 6 pens of each housing treatment for 24 h on the day of mixing (d 0), d 7, and d 14 after mixing in the finisher barn. The video recordings were scanned at 5-min intervals to calculate behavioral time budgets for lying, standing, eating, drinking, and belly nosing. Data were analyzed using the Proc Mixed model of SAS with repeated measures. Compared with confinement-farrowed pigs, group-farrowed pigs spent more time lying (85.7 vs. 82.7%; SE = 0.75; P < 0.001) and belly nosing (0.05 vs. 0.02%; P < 0.05) and less time standing (5.8 vs. 7.5%; SE = 0.49; P < 0.01) and eating (7.3 vs. 9.3%; SE = 0.40; P < 0.001). The difference in behavioral time budgets was associated with differences in performance of pigs from the 2 housing systems. Group-farrowed pigs exhibited greater ADG (866 vs. 814 g; SE = 10.3; P < 0.01) for the initial 2 wk after mixing, less ADFI (2,004 vs. 2,188 g; SE = 42.5; P < 0.05), and improved G:F (0.431 vs. 0.393; SE = 0.0078; P < 0.01) for the entire 14-wk study period compared with confinement-farrowed pigs. These results suggest that group-farrowed pigs were more efficient than confinement-farrowed pigs in utilizing dietary energy for BW gain by lying more and standing and eating less during the growing and finishing period.

No methods have been published for repeated blood sampling via an ear vein in group-housed sows. Therefore, the objective of this study was to develop a minimally invasive technique for the insertion of an ear vein catheter for repeated blood sampling in group-housed peripartum sows while minimizing any impact on production performance. Thirty-three multiparous pregnant sows were used including 18 catheterized sows and 15 control sows. In a group-farrowing barn, sows (8/room) shared a communal area and farrowed in individual, free-access pens. Treatment sows were anesthetized, and 1 ear was prepared aseptically 2 to 4 d before their expected farrowing date. A sterile needle was inserted into the largest and straightest portion of the vein, and the catheter, which was medical-grade microbore tubing, was inserted through the needle at least 24 cm. The needle was withdrawn, and the catheter was fixed into position and sutured to the ear. A blunt-end probe point cannula was glued onto the distal end of the catheter, and an adaptor injection cap with male Luer lock was placed on the end. The catheter was coiled and placed in a protective purse, which was cemented directly to the skin on the back of the shoulders. The catheter was flushed with heparinized saline to ensure patency. Once sows were able to stand, an elastic bandage was wrapped around the neck and upper body of the sow to hold the protective purse and exposed catheter in position. Blood samples were collected every 24 h, and catheters were flushed with heparinized saline after each collection. Fourteen of the 18 insertions were successful, and 11 of those remained functional for 4 d or more. Differences were not observed in reproductive performance between catheterized and noncatheterized sows.

Two studies were conducted to assess the energy content of low-solubles distillers dried grains (LS-DDG) and their effects on growth performance, carcass characteristics, and pork fat quality in grow-finish pigs. In Exp. 1, 24 barrows (Yorkshire-Landrace × Duroc; 80 to 90 d of age) in 2 successive periods were assigned to 1 of 6 dietary treatments. In individual metabolism stalls, pigs were fed a corn-soybean meal diet (control); control replaced by 30, 40, or 50% LS-DDG; or control replaced by 30 or 40% distillers dried grains with solubles (DDGS) at 3% of their initial BW for 12 d. All diets contained 0.25% CrO(2). During the 5-d collection period, feces and urine were collected from each pig. Feed, feces, and urine were analyzed for DM, GE, and N concentrations, and feed and feces were analyzed for Cr content. The ME content of LS-DDG (2,959 ± 100 kcal/kg of DM) was similar to that determined for DDGS (2,964 ± 81 kcal/kg of DM). In Exp. 2, 216 Yorkshire-Landrace × Duroc pigs were blocked by initial BW (18.8 ± 0.76 kg) and assigned to 1 of 24 pens (9 pigs/pen). Pens within block were allotted to 1 of 3 dietary treatments (8 pens/treatment) in a 4-phase feeding program: a corn-soybean meal control (control), control containing 20% LS-DDG, or control containing 20% DDGS. Treatment had no effect on final BW, ADG, ADFI, or HCW. Pigs fed LS-DDG had similar G:F (0.367) compared with pigs fed DDGS (0.370), but tended (P = 0.09) to have decreased G:F compared with pigs fed the control (0.380; pooled SEM = 0.004). Dressing percent was less (P < 0.01) for pigs fed LS-DDG (72.8%) and DDGS (72.8%) compared with the control (73.8%; pooled SEM = 0.22). Pigs fed LS-DDG (54.8%) had greater (P = 0.02) carcass lean compared with pigs fed DDGS (53.4%), but were similar to pigs fed control (54.1%; pooled SEM = 0.33). Bellies from pigs fed DDGS (12.9°) were softer (P < 0.01) than those from pigs fed control (17.7°; pooled SEM = 1.07) as determined by the belly flop angle test. Feeding LS-DDG (14.1°) tended (P < 0.10) to create softer bellies compared with control-fed pigs. The PUFA content of belly fat was reduced (P < 0.01) by LS-DDG (14.0%) compared with DDGS (15.4%), but was increased (P < 0.05) compared with pigs fed the control (9.4%; pooled SEM = 0.34). In conclusion, LS-DDG and DDGS had similar ME values and inclusion of 20% LS-DDG in diets for growing-finishing pigs supports ADG and ADFI similar to that of diets containing 20% DDGS, and may reduce negative effects on pork fat compared with DDGS.

The objective of this study was to determine the effects of dietary Trp supplementation on mixing-induced aggression and the associated stress, and on reproductive performance in gestating sows. After weaning, sows were mixed in pens with electronic sow feeders on concrete-slatted floors. Each pen housed 21 ± 2.8 sows, with approximately 2.7 ± 0.43 m(2)/sow of floor space allowance. Multiparous sows (n = 168) from 8 breeding groups were used, with 4 groups assigned to a control diet and 4 groups assigned to a high-Trp diet. Control sows received corn- and soybean meal-based diets throughout gestation (0.15% Trp) and lactation (0.21% Trp). Three days before and after mixing, sows assigned to the high-Trp treatment received approximately 2.3 times the dietary Trp (0.35% in the gestation diet and 0.48% in the lactation diet) fed to control sows. Six focal sows (2 sows from each of parity 1, 2, and 3 or greater) in each pen were designated and videotaped for 72 h after mixing to determine the type and number of aggressive interactions among sows. Before and 48 h after mixing, saliva samples were collected from focal sows, and scratches were assessed on all sows. Data were analyzed using the FREQ and GLIMMIX procedures (SAS Inst. Inc., Cary, NC). Aggression among sows was intense during the initial 6 h and decreased between 6 and 72 h after mixing. The initial aggression caused scratches and increased cortisol concentrations (P < 0.05). Mature sows tended to fight for longer periods (112 vs. 52 s/h per sow, SE = 23.8; P < 0.10) but had fewer scratches caused by aggression (injury score = 4.3 vs. 6.5, SE = 1.13; P < 0.01) than parity-1 sows. Supplementation of dietary Trp reduced the total duration of head-to-head knocking (P < 0.05) but did not affect other aggressive behaviors. There was no difference between dietary treatments in injury scores or saliva cortisol concentrations. Sows in the high-Trp treatment had more total piglets born (12.5 vs. 10.5 pigs/litter, SE = 0.55; P < 0.05) and more stillborn piglets (1.5 vs. 0.8 pigs/litter, SE = 0.20; P < 0.05), but had no significant change (P = 0.12) in piglets born alive (10.8 vs. 9.7 pigs/litter, SE = 0.42) compared with control sows. The results indicate that the initial aggression after mixing caused more injuries in young sows than in mature sows. Supplementation of dietary Trp at 2.3 times the control amount for a short period did not effectively reduce aggression and the associated stress in sows at mixing.

Crossbred pigs (n = 216; BW = 31.3 ± 1.8 kg) were used to determine the effects of long- and short-term feeding of crude glycerol on growth performance, carcass traits, and pork quality of grow-finish pigs. Pigs were blocked by initial BW, and pens within blocks were assigned randomly to 1 of 3 dietary treatments (24 pens; 9 pigs/pen). Dietary treatments were control, a corn-soybean meal-based diet (CON); long-term, CON + 8% glycerol fed throughout the experiment (LT); and short-term, pigs fed CON for the first 6 wk followed by CON + 8% glycerol fed during the last 8 wk of the experiment (ShT). Pigs fed LT had greater (P < 0.05) ADG, whereas pigs fed ShT tended (P < 0.10) to grow faster than CON (CON = 0.962 kg/d, LT = 0.996 kg/d, and ShT = 0.992 kg/d; SE = 0.01). Pigs assigned to LT had greater (P < 0.05) ADFI compared with CON, whereas ShT-fed pigs had similar ADFI to CON (CON = 2.78 kg/d, LT = 2.93 kg/d, and ShT = 2.86 kg/d; SE = 0.03). Gain:feed tended (P < 0.10) to be greater for CON- and ShT-fed pigs compared with LT-fed pigs (CON = 0.346, LT = 0.339, and ShT = 0.346; SE = 0.002). Hot carcass weight was greater (P < 0.05) for LT-fed pigs compared with CON, whereas ShT-fed pigs had HCW similar to both LT- and CON-fed pigs (CON = 94.8 kg, LT = 97.5 kg, and ShT = 96.3 kg; SE = 0.90). Dressing percentage of CON-fed pigs was similar to both LT- and ShT-fed pigs, but LT-fed pigs tended to have greater (P = 0.06) dressing percentage than ShT-fed pigs (CON = 74.5%, LT = 74.9%, and ShT = 74.3%; SE = 0.16). Tenth-rib backfat (P = 0.26) and LM area (P = 0.17) were not affected by dietary treatment. There was a trend (P < 0.10) for LT-fed pigs to have a smaller fat-free lean percentage than CON-fed pigs (CON = 53.1%, LT = 52.26%, and ShT = 52.67%; SE = 0.25). Short-term glycerol feeding increased (P < 0.05) belly firmness compared with CON and had similar belly firmness compared with LT-fed pigs (CON = 29.46°, LT = 35.16°, and ST = 42.08°; SE = 3.07). Dietary treatment had no effect (P > 0.60) on pork quality of loins based on taste panel assessments. Feeding pigs 8% crude glycerol throughout the grow-finish period resulted in a 3% improvement in growth rate and a 2% depression in BW gain efficiency compared with CON diets. Grow-finish pigs fed diets containing 8% crude glycerol during the last 8 wk before slaughter achieved growth performance similar to pigs fed CON diets. Effects of crude glycerol on carcass traits seem to be limited to improvements in belly firmness with short-term feeding of glycerol.

A study was conducted to evaluate the dietary effect of adding increasing concentrations of distillers dried grains with solubles (DDGS) to corn- and soybean meal-based sow lactation diets on sow and litter performance, energy and N digestibility, plasma urea N (PUN), and milk fat and protein concentrations. Mixed-parity sows [n = 307; 221 ± 15 kg of BW, 4.54 parities, litter size of 10.6, and litter weight at birth (alive) of 15.14 kg] were assigned randomly to 1 of 5 dietary treatments: control (CON; corn-soybean meal); 10, 20, and 30% DDGS; and 30% DDGS high-protein (HP) diets. Sows were moved to farrowing rooms on d 109 of gestation and were fed the dietary treatments until weaning. Within each treatment group, feces and urine for energy and N digestibility analysis (from d 10 to 12 of lactation) and blood for PUN analysis and milk fat and protein concentrations (on d 0 and 19 of lactation) were collected from 6 randomly chosen parity 3 to 5 sows. There were no dietary effects (P = 0.10) of DDGS on ADFI of sows and sow backfat change. However, sows fed 30% DDGS HP lost more BW compared with sows fed CON (P < 0.05). There were no dietary effects (P = 0.71) of DDGS on preweaning mortality of piglets, litter weight gain, and piglet ADG. Dietary treatments did not affect (P > 0.05) DE, ME, N retention, or N digestibility of the diets. There were no differences in the concentrations of fat and protein in milk at weaning (d 19) among dietary treatments. Sows fed 20 and 30% DDGS had less (P < 0.05) PUN at weaning (d 19) than sows fed CON and 30% DDGS HP. Inclusion of up to 30% DDGS in a lactation diet did not affect (P > 0.05) sow and litter performance, DE and ME contents of the diets, N retention and digestibility, and milk composition compared with sows fed a corn-soybean meal CON diet. It was concluded that addition of up to 30% DDGS in a lactation diet will support satisfactory sow and litter performance.

An experiment was conducted to evaluate the effect of dietary crude glycerol in lactating sow diets on sow and litter performance under heat stress conditions. Mixed parity (range = 0 to 13) sows (n = 345; 253 +/- 24 kg of BW) were assigned randomly within gestation housing location and parity to 1 of 4 dietary treatments. Treatments consisted of a corn-soybean-based control diet (CON) and 3, 6, or 9% glycerol added at the expense of corn and soybean meal. Liquid crude glycerol was incorporated in the complete diet at the time of mixing. Dietary treatments were imposed on d 109 of gestation (2.25 kg/d) when sows were moved into farrowing rooms. Heat index during lactation in farrowing rooms exceeded 25 degrees C for all sows. At farrowing, sows were allowed ad libitum access to feed throughout lactation. Dietary treatment tended (P = 0.08) to influence ADFI of sows (CON = 6.04 kg/d; 3% = 6.21 kg/d; 6% = 5.69 kg/d; 9% = 6.00 kg/d; pooled SE = 0.18). Up to 9% crude glycerol in the diet had no effect on sow BW and backfat loss, weaning-to-estrus interval, preweaning mortality of piglets, and ADG of piglets. Increasing dietary glycerol linearly reduced (P = 0.10) litter size at weaning (CON = 9.50; 3% = 9.60; 6% = 9.36; 9% = 9.39; pooled SE = 0.08). Daily water consumption was not affected by dietary treatment. Crude glycerol did not affect respiration rates or rectal body temperatures, indicating no efficacy in reducing heat stress of sows. Plasma glycerol concentrations increased linearly (P < 0.05) as dietary crude glycerol increased (CON = 1.21 microM; 3% = 1.69 microM; 6% = 7.21 microM; 9% = 29.04 microM; pooled SE = 1.58), but plasma glucose concentrations were not affected. Crude protein content of the milk of sows was not affected (P = 0.16) by dietary treatment. Dry matter (P = 0.07) and crude fat (P = 0.09) content of the milk of the sows tended to increase linearly (DM basis: CON = 17.84%; 3% = 18.43%; 6% = 18.98%; 9% = 18.48%; pooled SE = 0.34; crude fat: CON = 4.78%; 3% = 4.91%; 6% = 5.50%; 9% = 5.24%; pooled SE = 0.30), whereas milk ash concentration tended (P = 0.09) to decrease linearly with increasing dietary glycerol (CON = 0.77%; 3% = 0.79%; 6% = 0.74%; 9% = 0.74%; pooled SE = 0.02). Increasing dietary crude glycerol linearly increased (P < 0.05) lactose concentration in the milk of sows (CON = 5.16%; 3% = 5.30%; 6% = 5.43%; 9% = 5.46%; pooled SE = 0.10). Results from this study indicate that lactating sows fed diets containing up to 9% crude glycerol perform similarly to sows fed a standard corn-soybean meal diet.

Crossbred pigs (n = 512) with an average initial BW of 22.1 +/- 0.54 kg were used to evaluate growth performance, carcass characteristics, and pork fat quality of grower-finisher pigs fed corn-soybean meal diets containing increasing content of distillers dried grains with solubles (DDGS). One of 4 dietary treatments was randomly assigned to each pen within sex. Dietary treatment and sex were the main factors in a 3-phase feeding program (BW = 22 to 53 kg, 53 to 85 kg, and 85 to 115 kg). Dietary treatments consisted of a corn-soybean meal control, or a corn-soybean meal diet containing 10, 20, or 30% DDGS. Overall, increasing the dietary DDGS content had no effect on ADG (P = 0.74), but ADFI was linearly reduced and G:F was linearly increased (P < 0.01). Dressing percentage, LM marbling and firmness, and belly firmness were linearly reduced (P < 0.01), but percentage of fat-free lean was linearly increased (P < 0.05) with increasing dietary DDGS. Subjective LM color score (P = 0.65), drip loss (P = 0.37), and ultimate pH of LM (P = 0.21) were not influenced by dietary DDGS. Japanese color scores for backfat (P = 0.41) and belly fat (P = 0.85) were similar among dietary treatments (P = 0.41). Feeding an increasing content of DDGS linearly increased (P < 0.05) PUFA concentration, particularly linoleic acid (C18:2), in belly fat, backfat, and LM intramuscular fat, but the increase in LM intramuscular fat was smaller in magnitude (P < 0.05) than in backfat and belly fat. Pigs fed an increasing content of DDGS had a linear increase (P < 0.05) in the iodine value of backfat, belly fat, and LM intramuscular fat of 58.4 to 72.4, 61.5 to 72.3, and 54.8 to 57.7, respectively. Oxidation of LM intramuscular fat measured on d 0, 14, 21, and 28 of storage was not affected by dietary treatment. Taste tests for LM showed no effects of diet on flavor, off-flavor (P = 0.36), tenderness (P = 0.66), juiciness (P = 0.58), and overall acceptability (P = 0.52) scores. Similarly, bacon flavor (P = 0.88), off-flavor, crispiness, and overall liking scores were not affected by increasing dietary DDGS, but bacon fattiness (P < 0.01) and tenderness (P < 0.05) scores were linearly reduced. These results showed no negative effects on growth performance or dressing percentage when growing-finishing pigs were fed diets containing up to 30% DDGS, but fat quality may not meet the standards of all pork processors when feeding diets containing more than 20% DDGS.

A study was conducted to determine the quantitative effects of feeding amount and withdrawal period of corn distillers dried grains with solubles (DDGS) from the diet on growth performance, carcass quality, and pork fat fatty acid profile. A total of 432 pigs (29.8 +/- 0.2 kg of BW) were randomly allotted to 1 of 9 dietary treatments in a completely randomized arrangement. The 9 treatments were the control (D0), D15-0 wk, D15-3 wk, D15-6 wk, D15-9 wk, D30-0 wk, D30-3 wk, D30-6 wk, and D30-9 wk, where D0, D15, and D30 indicate the dietary content of DDGS (0, 15, and 30%, respectively) and 0 wk, 3 wk, 6 wk, and 9 wk indicate the withdrawal period of DDGS from the diets before slaughter (0, 3, 6, and 9 wk, respectively). A dietary DDGS inclusion rate of 15 or 30%, without or with a withdrawal period, had no effect (P = 0.76) on ADG, ADFI, and G:F, except for a slight reduction (0.87 vs. 0.92 kg/d; P < 0.05) in ADG when pigs received the D30-0 wk treatment compared with the D0 treatment. Carcass quality, LM quality, and Japanese fat color scores for backfat and belly fat were not affected by dietary DDGS content (backfat, P = 0.47; belly fat, P = 0.17) or withdrawal period (backfat, P = 0.33; belly fat, P = 0.95). Compared with pigs fed the D0 diet, a smaller belly firmness score was observed (P = 0.04) in pigs that received the D30-0 wk treatment, but belly firmness in pigs fed the other treatments was not different (P = 0.26) from that of pigs fed the D0 diet. Linoleic acid content (C18:2; P < 0.001) and iodine value (IV; P < 0.001) of belly fat increased with increasing dietary DDGS content. Withdrawal of DDGS from the diet for 0 to 9 wk before slaughter resulted in a linear reduction in C18:2 content and the IV of belly fat in pigs fed the D15 diets (C18:2 content: 14.6, 13.3, 12.6, and 10.9%; P = 0.001; IV: 67.3, 64.4, 64.1, and 62.7; P = 0.02; for 0-, 3-, 6-, and 9-wk withdrawal, respectively) and the D30 diets (C18:2 content: 17.3, 16.1, 14.2, and 12.4%; P < 0.001; IV: 71.2, 68.2, 64.5, and 62.7; P < 0.001; for 0-, 3-, 6-, and 9-wk withdrawal, respectively). These results indicate that an inclusion rate of DDGS up to 30% in grower-finisher diets has minor effects on growth performance and that the desired effect of reducing the C18:2 content and IV of pork fat could be elicited in as little as 3 wk after withdrawing DDGS from the diet before slaughter.

A study was conducted to evaluate the effects of social familiarity and initial BW variation at mixing on performance and welfare of pigs born to group-housed lactating sows. A total of 180 pigs from 24 litters were used in a random design with 4 treatments in a 2 x 2 (social familiarity x initial BW uniformity) factorial arrangement. Pigs were born in group-farrowing rooms where they mingled in large groups of 66 to 80 pigs from 10 d of age. At 8 wk of age (BW=23+/-3.1 kg), pigs were allocated to 20 pens of 9 pigs (5 castrated males and 4 females) in a grow-finish room, with 5 pens assigned to each of 4 treatment combinations without consideration of relatedness. Familiar groups consisted of pigs from 1 farrowing room, and unfamiliar groups consisted of 3 pigs from each of 3 different farrowing rooms. Uniform BW groups were formed by using the middle 2 quartiles, and variable BW groups by using the heaviest and lightest quartiles of pigs. Aggression and activity behavior were directly observed by scan or continuous sampling during a period of 4 h on the first 3 d, d 7, and d 14 after grouping. Injury scores were assessed on all pigs immediately before and 48 h after grouping. Body weight gain and apparent feed intake were measured every 2 wk for 14 wk. Aggression in familiar groups was minimal throughout the observation periods. Compared with that in familiar groups, total duration of fighting was greater in unfamiliar groups on d 0 (upon grouping, 48.5 vs. 0.5+/-10.88 s/pig(-1).4 h(-1); P<0.001) and on d 1 (10.8 vs. 0.4+/-3.24 s/pig(-1).4 h(-1); P<0.05) after grouping. Unfamiliar pigs had greater injury scores (6.6 vs. 1.8+/-0.28; P<0.001) and spent less time eating on d 0 (5.1 vs. 8.8+/-0.92% of total observation time; P<0.01) after grouping compared with familiar pigs. The ADG and ADFI were decreased in unfamiliar groups during the initial 6 wk, but not for the entire 14-wk period in comparison with familiar groups. Body weight variation did not affect behavior and performance in familiar groups but increased aggression-induced injuries in unfamiliar groups. The results indicated that grouping unacquainted pigs derived from large groups induced overt aggression, associated injuries and initial reduction in performance, which causes welfare concerns on mixing pigs born to group-housed lactating sows.

Two experiments were conducted to evaluate the effects of soluble (SF) and insoluble (ISF) dietary fiber during gestation on embryo survival and sow performance. In Exp. 1, 43 gilts were assigned randomly to 1 of 4 experimental diets: a corn-soybean meal control (C; 1.16% SF, 9.98% ISF); a 30% oat bran high in SF (HS; 3.02% SF, 10.06% ISF); a 12% wheat straw diet high in ISF (HIS; 1.08% SF, 18.09% ISF); and a 21% soybean hull diet (HS + HIS; 2.46% SF, 24.55% ISF). Gilts were fed the experimental diets based on their initial BW to meet their daily nutrient requirements. At estrus, gilts were inseminated artificially 3 times using pooled semen. Reproductive tracts were harvested 32 d postmating (range = 28 to 35 d). Statistical analysis of data included the effects of diet with days of gestation as a covariate. There were no differences in ovulation rate among gilts fed the experimental diets (avg. = 14.1). Number of live embryos was less for HIS and HS + HIS gilts compared with C and HS (9.9 and 9.1 vs. 11.9 and 10.6, respectively; P < 0.05). Total embryo survival rate (P < 0.05) was less for gilts fed HS + HIS compared with those fed the C and HS diets. These results suggest that high dietary ISF might decrease the total embryo survival rate without affecting ovulation rate. In Exp. 2, 716 sows were used in 3 concurrent trials. In trial 1, diets included a corn-soybean meal control (C; 0.43% SF, 10.50% ISF; n = 122) or a 31% oat bran diet (HS; 1.93% SF, 8.87% ISF; n = 124). In trial 2, diets included a C (n = 97) or a 13% wheat straw diet (HIS; 1.10% SF, 17.67% ISF; n = 119), and in trial 3 sows were fed a C (n = 123) or a 21% soybean hull diet (HS + HIS; 1.50% SF, 17.77% ISF; n = 131). All diets were offered to sows beginning 2 d postmating. All sows had ad libitum access to a standard lactation diet. Statistical analysis included the effects of diet, parity group, genetic line, and season as well as their interactions. The inclusion of SF and ISF in gestation diets did not affect litter size. Sows fed the HS + HIS diet had a greater ADFI and lost less BW during lactation (P < 0.01) than sows fed C. Under the conditions of this study, feeding gestating sows increased levels of SF and ISF from d 2 after breeding to d 109 of gestation did not increase litter size.

Twenty-four sows (12 nulliparous, 12 multiparous) were used to determine soluble fiber (SF) and insoluble fiber (ISF) effects on energy digestibility, N balance, and SF and ISF digestibility. Experimental diets included a corn-soybean meal control (C; 1.20% SF, 9.78% ISF), a 34% oat bran diet high in SF (HS; 3.02% SF, 10.11% ISF), a 12% wheat straw diet high in ISF (HIS; 1.11% SF, 17.86% ISF), and a 16% sugar beet pulp diet (HS + HIS; 2.32% SF, 16.08% ISF). Sows were assigned randomly to diets within parity group and individually fed to meet their energy requirements according to the NRC model assuming 10 pigs per litter and 40 kg of gestation gain. Total feces and urine were collected in 5-d periods at wk 5, 10, and 14 of gestation. There were no interactions between dietary treatments and parity group for any of the response criteria evaluated. Dietary energy digestibility was greatest (P < 0.01) for females fed C (87.9%) and HS (89.3%) diets compared with females fed diets high in ISF (HIS, 82.9; HS + HIS, 86.8%). Energy digestibility was not affected by stage of gestation. Dietary N digestibility was similar between C and HS (86.1 and 86.2%) but greater (P < 0.01) than HIS and HS + HIS (82.8 and 82.8%, respectively). Nitrogen digestibility declined (P < 0.05) as gestation progressed for sows fed HS only. Nitrogen retention as a percentage of N intake was not affected by diet (C, 51.8; HS, 44.0; HIS, 42.0; HS + HIS, 48.6). Soluble fiber digestibility was different (P < 0.01) among experimental diets (C, 85.8; HS, 89.5; HIS, 77.7; HS + HIS, 80.3%). Sows fed HS + HIS (61.8%) and HS (58.4%) had greater (P < 0.05) ISF digestibility than sows fed C (53.5%), whereas sows fed HIS (38.3%) had lower (P < 0.01) ISF digestibility than sows fed the other experimental diets. Greater digestibility of dietary energy (87.1 vs. 86.2%; P < 0.05), N (85.7 vs. 83.2%; P < 0.01), and ISF (54.5 vs. 51.2%; P < 0.06) was observed in multiparous vs. nulliparous sows. In conclusion, increased intake of ISF decreased energy digestibility, whereas increasing SF intake improved energy digestibility. Diet had no effect on N retention. Insoluble fiber digestibility improved when SF intake increased, suggesting that knowledge of specific dietary fiber components is necessary to accurately predict effects of dietary fiber on digestibility. Multiparous sows demonstrated a greater ability to digest fibrous diets than nulliparous sows.

A growth performance and carcass evaluation study was conducted to determine the maximal inclusion rate of corn distillers dried grain with solubles (DDGS) in grower-finisher pig diets when formulated on a total AA basis. A total of 240 (28.4 +/- 0.8 kg of BW) crossbred pigs [(Yorkshire x Landrace) x Duroc] were allotted randomly within sex and weight outcome groups to 1 of 24 pens. Pens were assigned randomly within the initial BW groups to 1 of 4 dietary treatment sequences in a 5-phase grower-finisher feeding program in a 4 x 3 factorial arrangement of treatments. The inclusion level of DDGS (0, 10, 20, or 30%) in the diet and the initial BW class [low (23.2 kg), medium (28.1 kg), or high (33.8 kg)] served as the main factors for the grower-finisher performance study. All diets were formulated to contain similar concentrations of total Lys, ME, calcium, and phosphorus within each phase. Pigs were slaughtered and carcass data were collected when the average BW of pigs in a pen reached 114 +/- 2.25 kg. Dietary treatment and initial weight groups did not interact for any response variables, and only the main effects of dietary treatment are presented. Pigs fed the 20 or 30% DDGS diets had reduced ADG (P < 0.05) compared with that of the 0 or 10% DDGS groups, but ADFI was unaffected by dietary treatment. Gain:feed decreased when pigs were fed 30% DDGS (P < 0.05) compared with the 0, 10, and 20% DDGS dietary inclusion levels. Loin depth was lower in pigs fed the 30% DDGS diets (P < 0.05), but backfat depth and percentage of carcass lean did not differ among treatments. Iodine number of carcass fat increased linearly (P < 0.01) with increasing dietary DDGS concentration, and belly firmness adjusted for belly thickness was reduced (P < 0.05) for pigs fed the 30% DDGS diets compared with pigs fed the 0 or 20% DDGS diets. Color measurements, ultimate pH, and visual evaluations (color, firmness, and marbling scores) of the LM did not differ among treatments. Cooking loss, 24-h drip loss, and total moisture loss were not affected by DDGS in the diets. However, differences were detected between 0 and 20% DDGS treatments for 11-d purge loss (P < 0.05). Dietary treatment did not affect Warner-Bratzler shear force of cooked loin chops. Results from this study indicate that when diets for grower-finisher pigs are formulated on a total AA basis, less than 20% DDGS should be included in the diet for optimal performance and carcass composition. Feeding DDGS in swine finishing diets did not have any detrimental effects on pork muscle quality.

A study was conducted to determine the effects of feeding a corn-soybean meal (control) diet vs. a corn-soybean meal-40% soybean hulls (high fiber) diet, as well as the frequency of feeding (once vs. twice daily), on the welfare and performance of gestating sows. Two hundred thirty-nine mixed-parity sows were assigned to a 2 x 2 factorial arrangement of treatments. Sows fed once daily received their entire meal at 0730, whereas sows fed twice daily received one-half of their feed allotment at 0730 and the other half at 1430. The behavior of 68 focal sows (> or = 16 sows per treatment combination) was observed on d 1 postweaning, and on d 40 and d 80 of gestation. The percentage of time standing, lying, sitting, feeding, inactive, and performing stereotypic behaviors was determined. Saliva samples were collected to determine cortisol concentrations. Sow BW and backfat depth were determined on d 0, 40, and 80 of gestation, within 24 h of farrowing, and at weaning. An energy and nitrogen digestibility study was conducted using 36 sows assigned to each of the 4 treatment combinations. Over a 24-h period, the sows fed the high-fiber diet spent less time lying (P < 0.05) than the sows fed the control diet. The frequency of feeding did not affect sow behavior measured over a 24-h period. During mealtimes, sows fed the high-fiber diet spent more time feeding (P < 0.05) than sows fed the control diet. Feeding the high-fiber diet did not affect stereotypic behavior measured over 24 h or during mealtimes. Neither diet nor feeding frequency affected salivary cortisol concentration. Sows fed the high-fiber diet gained less BW and lost backfat (P < 0.05) during gestation compared with sows fed the control diet, whereas sows fed once daily gained less BW and lost backfat (P < 0.05) compared with sows fed twice daily. Sows fed the high-fiber diet had fewer pigs born (P < 0.05) compared with sows fed the control diet. Feeding frequency had no effect on size or weight gain of litters. Sows fed the high-fiber diet exhibited lower digestibility of DM, energy, and N (P < 0.05) compared with sows fed the control diet. Feeding a high-fiber diet utilizing soybean hulls or increasing feeding frequency did not enhance the welfare of sows by reducing stereotypic behaviors nor did it improve reproductive performance.

Two experiments were conducted to determine the voluntary feed intake and performance of lactating sows fed diets containing a sucrose/milk chocolate product (MCP) blend (Exp. 1) or dried porcine solubles (DPS; Exp. 2). Dried porcine solubles is a coproduct of heparin extraction from porcine small intestines. In Exp. 1, mixed-parity sows (n = 108) at two research centers were assigned to a corn-soybean-meal-based diet formulated to contain 0.9% total lysine or a similar diet that contained 4% sucrose and 2% MCP on an as-fed basis. Sows were allowed ad libitum access to dietary treatments from the day of farrowing until pigs were weaned at approximately 21 d postpartum. Diet had no significant effect on voluntary feed intake of sows during lactation, backfat depth, or postweaning interval to estrus, but it had variable effects on body weight changes. Inclusion of the sucrose/MCP blend in diets elicited a 2% improvement in litter weaning weight at one research center and a 6% depression in litter weaning weight at the other center (diet x research center, P < 0.05). Litter size throughout lactation was unaffected by dietary treatment. In Exp. 2, mixed-parity sows (n = 119) at two research centers were assigned to corn-soybean meal-based diets formulated to contain 0.9% total lysine with 0, 1.5, or 3.0% added DPS. Sows were assigned to dietary treatments within research center, farrowing group, and parity at parturition. Dried porcine solubles tended to increase (P < 0.10) total feed consumed in the first 9 d of lactation and average daily feed intake over the entire lactation (6.03, 6.53, and 6.30 kg) for sows fed 0, 1.5, and 3.0% DPS, respectively. Litter size and weight on d 18 of lactation were not affected by concentration of DPS in the diet. Days from weaning to estrus and percentage of sows displaying estrus were not influenced by diet. We conclude that inclusion of the sucrose/MCP blend in the diet for lactating sows had no consistent effect on voluntary feed intake of sows and weight gain of nursing pigs. Inclusion of DPS at 1.5 or 3.0% tended to improve feed intake of lactating sows but had no significant influence on litter performance.

Two experiments were conducted to determine the effect of lightweight pig removal and remixing on performance to slaughter. Experiment 1 was a growing-finishing trial utilizing a total of 900 pigs (26.2+/-0.1 kg initial weight) that were sorted and remixed at a mean replicate BW of 72 kg. Experiment 2 was a wean-to-finish trial (17 d mean wean age; 4.8 kg +/- 0.1 BW) utilizing 225 barrows with sorting and remixing occurring 3 wk after weaning. Treatments were 15 pigs/ pen from initial weight to slaughter (15S), 20 pigs/pen from initial weight to time of sort and remix and then reduced to 15 pigs/pen (20/15), and 15 pigs/pen from time of sort and remix to slaughter comprised of the five lightest pigs from each of three 20/15 pens per replicate (15M). Space allocation was 0.56 m2/pig from 26 to 70 kg and 0.74 m2/pig thereafter in Exp. 1. In Exp. 2, pen size was fixed at 2.44 x 4.27 m. In Exp. 1, there was no effect (P > 0.20) of treatment on performance prior to 70 kg. Least squares means for ADG from time of sort and remix to first pig removal from a pen for slaughter at 113 kg were 0.93, 0.87, and 0.91 kg/d for the 20/15, 15M, and 15S treatments, respectively (P < 0.05). When comparing the population represented by the 20/15 + 15M treatments vs the 15S population, there was no difference (P > 0.20) in ADG, ADFI, feed conversion, or carcass lean content. In Exp. 2, pigs in the 20/15 treatment grew slower (P < 0.05) than 15S pigs for the first 21 d (0.20 vs 0.22 kg/d, respectively) with a lower ADFI (P = 0.06) and no difference in feed conversion. When comparing the population represented by the 20/15 + 15M treatments vs the 15S population after sorting and remixing, there was no effect (P > 0.15) of experimental treatments on ADG, ADFI, feed conversion efficiency, carcass lean content, or daily lean gain. These results suggest that removal of lightweight pigs and remixing of the removed pigs into pens of similar-weight pigs is ineffective in improving the overall performance of a population of pigs during the postweaning period.

A cooperative study involving six experiment stations and 236 crossbred litters was conducted to determine the effect of nominal nipple drinker water flows of 700 mL/min and 70 mL/min (actual = 701 and 76 mL/min, respectively) during winter (November through February; 124 litters) and summer (June through August; 112 litters) seasons on performance of lactating sows and their litters. Within a season, sows were paired according to expected farrowing date and assigned at random to crates. Water flow rate treatments were assigned at random to sows within pairs. Sows were housed in farrowing crates from d 109 of gestation until either d 21 (two stations) or d 28 of lactation (four stations). Within 24 h after farrowing, litters were adjusted to contain 8 to 12 piglets. Sow feed intake (SFI) and litter weight (LW) were recorded weekly. Sow weights were recorded at d 109 of gestation, d 0, and d 21 of lactation. Sows lactating beyond 21 d were also weighed on d 28. Analysis of covariance was applied to sow weight change, average daily SFI, and LW data where litter size after crossfostering was the covariate. Average ambient temperature 30 cm above the floor at 0830 and 1600 was 24.6 +/- 0.15 degrees C and 29.4 +/- 0.14 degrees C, respectively, during summer and 20.7 +/-0.13 degrees C and 21.8 +/- 0.11 degrees C during winter trials. Restricted drinker water flow rate decreased SFI (P < 0.01; 4.59 vs. 3.94 kg/d, respectively, for 700 and 70 mL/min) and increased BW loss (P < 0.01; 0.56 vs 0.89 kg/d, respectively for 700 and 70 mL/min) but did not affect litter size (P > 0.87) or LW (P > 0.89) during the first 21 d of lactation. During d 22 to 28, the 70 mL/min flow decreased SFI (P < 0.01; 5.02 vs. 4.47 kg/d respectively, for 700 and 70 mL/min). Over the 21-d lactation period, the 70 mL/min treatment depressed (P < 0.01) SFI more during the winter (5.12 vs. 4.24 kg/d for 700 and 70 mL/ min, respectively) than during the summer (4.05 vs 3.65 kg/d for 700 and 70 mL/min, respectively). Season affected SFI (P < 0.01; 4.68 vs. 3.85 kg/d, respectively, for winter and summer), sow weight loss (P < 0.001; 0.46 vs 0.83 kg/d, respectively, for winter and summer), and LW at 21 d (P < 0.05; 52.8 vs. 49.6 kg, respectively, for winter and summer) but not (P > 0.96) the number of pigs per litter. Results of this study suggest that ample access to drinking water and controlling ambient temperature during summer months are essential for sow and litter performance.

Effects of three dietary lysine (protein) concentrations during lactation on metabolic state, protein metabolism, reproductive hormones, and performance were investigated in 36 primiparous sows. Sows were assigned randomly to one of three diets containing .4% (low lysine, LL), 1.0% (medium lysine, ML), or 1.6% (high lysine, HL) total lysine from intact protein sources. All diets contained 2.1 Mcal NE/kg and exceeded the recommended requirements for all other nutrients. Actual lysine intakes over an 18-d lactation were 16, 36, and 56 g/d for sows fed LL, ML, and HL, respectively. Fractional breakdown rate of muscle was determined on d 4 and 15 of lactation by using a three-compartment kinetic model of 3-methylhistidine metabolism. Increasing lysine intake during lactation did not affect fractional breakdown rate of muscle on d 4 of lactation but decreased it on d 15 (P < .05). Sows fed LL had a reduced number of LH pulses on d 12 and 18 (P < .05) and reduced serum estradiol (E2) concentration on d 18 of lactation compared with sows fed ML and HL treatments. However, LH pulses and E2 concentrations were similar between ML and HL treatments (P > .35). Increasing lysine intake increased serum urea nitrogen (SUN) and postprandial insulin concentrations (P < .05) during lactation but had no effect on plasma glucose concentrations (P > .20). Sows fed HL had greater serum IGF-I on d 6 and 18 than sows fed ML (P < .05). Number of LH peaks was correlated with serum insulin concentration 25 min after feeding on d 6 and 18 (r = .31 to .41; P < .1) and pre- (r = .33 to .46) and postprandial (r = .30 to .58) SUN concentrations (P < .05) during different stages of lactation. Results indicate that, compared with medium lysine intake, low lysine intake increased muscle protein degradation and decreased concentrations of insulin, SUN, and estradiol and LH pulsatility. In contrast, high lysine (protein) intake increased SUN, insulin, and IGF-I, but did not increase secretion of estradiol and LH compared with medium lysine intake. Furthermore, nutritional impacts on reproduction may be mediated in part through associated effects on circulating insulin concentration.

Primiparous sows (n = 36) were used to evaluate the effects of dietary lysine intake in lactation on follicular development and oocyte maturation after weaning. Sows were assigned randomly to one of three diets containing .4% (low lysine, LL), 1.0% (medium lysine, ML), or 1.6% (high lysine, HL) total lysine. All diets contained 2.1 Mcal NE/kg and exceeded NRC (1988) requirements for all other nutrients. Actual lysine intakes over an 18-d lactation were 16, 36, and 56 g/d for sows consuming LL, ML, and HL, respectively. Ovarian data were analyzed for sows determined to have been slaughtered during the first proestrus period after weaning, using previously established criteria. Compared with sows fed ML and HL, sows fed LL tended to have lower uterine weight, follicular fluid volume, and follicular fluid (FF) estradiol (E2) content (P < .15), but similar ovarian weight and follicular fluid IGF-I concentration. Within the largest 15 preovulatory follicles, sows fed LL had a lower percentage of large (> or = 7.0 mm) follicles (33 vs 50 and 58%; P < .01) and a higher percentage of medium (5.5 to 7.0 mm) follicles (62 vs 44 and 39%; P < .01) but a similar percentage of small (< or = 5.5 mm) follicles (4.4 vs 5.9 and 3.7%; P > .15), respectively, compared with sows fed ML or HL. Standardized pools of oocytes aspirated from follicles of prepubertal gilts were incubated for 44 h with pooled FF recovered from the largest 15 follicles of each experimental sow. Fewer oocyte nuclei matured to metaphase II of meiosis when cultured with FF recovered from sows fed LL, than from sows fed ML or HL (47.1 vs 59.8 and 63.8%, respectively; P < .01). Our results suggest that low lysine (protein) intake in primiparous lactating sows impaired follicular development and reduced the ability of follicles to support oocyte maturation. However, high compared with medium lysine (protein) intake had no further positive effects on ovarian function.

Gilts (n = 208) were used to evaluate the effect of lysine (protein) intake over three parities on lactation and subsequent reproductive performance. Sows were assigned randomly to one of five experimental diets at each farrowing. The five corn-soybean mealbased lactation diets contained increasing concentrations of total lysine (.60, .85, 1.10, 1.35, and 1.60%) and CP (14.67, 18.15, 21.60, 25.26, and 28.82%). Other amino acids were provided at a minimum of 105% of the NRC (1988) ratio to the lysine requirement. Sows had ad libitum access to their assigned diets from parturition until weaning (19.5+/-.2 d postpartum). All sows were fed a common gestation diet (14% CP and .68% lysine) from weaning to next farrowing. Litter size was standardized by d 3 postpartum to 10 pigs in parity 1 and 11 pigs in parity 2 and 3. Increasing dietary lysine (protein) linearly decreased (P<.05) voluntary feed intake of parity 1 (from 5.4 to 4.6 kg/d), 2 (from 6.5 to 5.8 kg/d), and 3 sows (from 6.8 to 6.2 kg/d). With the increase of dietary lysine (protein) concentration during lactation, litter weight gain responded quadratically (P<.05) in all three parities. Maximal litter ADG was 2.06, 2.36, and 2.49 kg/d in parities 1, 2, and 3, respectively, which occurred at about 44, 55, and 56 g/d of lysine intake for parity 1, 2, and 3 sows, respectively. Increasing dietary lysine (protein) had no effect (P>.1) on sow weight change, weaning-to-estrus interval, and farrowing rate in all three parities and no effect on backfat change in parity 2 and 3, but tended to increase backfat loss linearly (P<.1) in parity 1. A linear decrease of second litter size (total born, from 11.7 to 10.1, P<.1; born alive, from 11.0 to 8.9, P<.01) was observed when dietary lysine (protein) increased during the first lactation. Lysine (protein) intake during the second lactation had a quadratic effect on third litter size (P<.05; total born: 13.3, 11.2, 11.6, 11.9, and 13.6; born alive: 11.8, 10.1, 10.3, 11.2, and 12.4). However, fourth litter size was not influenced by lysine (protein) intake during the third lactation. These results suggest that the lysine (protein) requirement for subsequent reproduction is not higher than that for milk production. Parity influences the lysine (protein) requirement for lactating sows and the response of subsequent litter size to previous lactation lysine (protein) intake.

Mixed-parity sows (n = 267) from five research stations were used to investigate whether a reduction of excess dietary amino acids would improve feed intake and performance of lactating sows experiencing heat stress. Experimental treatments included effects of room temperature (warm or hot) and diet (adequate protein [AP] or low protein [LP]). The corn-soybean meal AP diet was formulated to contain 16.5% CP, .8% lysine, and .67% digestible lysine. The LP diet was formulated to contain 13.7% CP, .76% lysine, and .66% digestible lysine using corn, soybean meal, and synthetic lysine. Feed intake during gestation was standardized at 1.8 kg x sow(-1) x d(-1). At parturition, litter size was adjusted to no fewer than nine pigs. Mean high temperature in the warm and hot rooms was 20.4 and 29.2 degrees C and mean low temperature was 17.7 and 27.1 degrees C, respectively. The hot environment reduced (P < .01) feed intake of sows (4.19 vs 6.38 kg/d) during lactation, weaning weight of sows (176.2 vs 193.6 kg), percentage of sows displaying estrus (79.2 vs 93.4%) by d 15 postweaning, and litter growth rate (1.74 vs 2.11 kg/d) and increased (P < .01) respiration rate of sows on d 10 postpartum (71.9 vs 36.5 breaths/min) compared with the warm environment. Litter size and backfat loss of sows were not affected by treatments. No significant diet x room temperature interactions were observed for voluntary feed intake, body weight loss, backfat loss, or respiration rate of sows. Litter growth rate was depressed by feeding the LP diet in the warm room but was improved by feeding the LP diet in the hot room (warm-AP, 2.17; warm-LP, 2.05; hot-AP, 1.71; hot-LP, 1.77 kg/d; P < .05). Reduction of dietary crude protein combined with supplementation of crystalline lysine to reduce concentrations of excess dietary amino acids did not significantly reduce heat stress of sows, but it did support slight improvements in weight gain of litters nursing heat-stressed sows.

Four experiments were conducted to study the effects of substituting milk chocolate product MCP) for dried whey (DW) on growth performance of starter pigs. In Exp. 1 (4 wk) and 2 (5 wk), 440 pigs (age, 25 d) were assigned to one of four diets: 1) 0% DW + 0% MCP, 2) 20% DW + 0% MCP, 3) 10% DW + 10% MCP, or 4) 0% DW + 20% MCP. Linear reductions (P < .06) in ADG, ADFI, and gain/feed (G/ F) were detected as MCP increased. Replacement of DW with 10% MCP had little effect on ADG or ADFI in Exp. 1, but it reduced them in Exp. 2. In Exp. 3(5 wk), 192 pigs (age, 20 d) were fed one of four complex diets: 1) 15% DW + 0% MCP, 2) 10% DW + 5% MCP, 3) 5% DW + 10% MCP, or 4) 0% DW + 15% MCP. As MCP increased, ADG and ADFI decreased linearly (P < .01), but growth performance was similar between pigs fed the 0 and 5% MCP diets. Experiment 4 was a 14-d preference trial in which the four diets from Exp. 3 and 270 pigs (age, 24 d) were used to make three comparisons: a) diet 1 vs diet 2, b) diet 1 vs diet 3, and c) diet 1 vs diet 4. Pigs consumed between 65 and 77% of their total feed intake as MCP-containing diets (P < .01). In summary, MCP could replace DW at a dietary level of 5% without reducing pig performance, but MCP at dietary levels of 10% or more reduced pig performance. Pigs strongly preferred MCP over DW.

Two experiments were conducted to evaluate the response of sows to high levels of dietary riboflavin. Responses evaluated were erythrocyte glutathione reductase activity coefficient (EGRAC, a biochemical indicator of riboflavin status) and reproductive performance. In Exp. 1, eight sows were fed diets either slightly deficient or superadequate in riboflavin throughout a reproductive cycle, beginning in midgestation. The EGRAC values confirmed the slight deficiency (P < .01) but did not clearly show a time when the sow is most likely to be deficient in riboflavin. In Exp. 2, 118 sows at two farms were fed diets providing 10 (control, 1.4 times the NRC [1988] requirement estimate), 60, 110, or 160 mg of riboflavin/d for 21 d beginning at breeding, and the control level through the remainder of the reproductive cycle. The percentage of sows farrowing tended to be lower (P < .10) for the control sows than for sows fed the other treatments (66.7, 85.7, 93.3, and 86.7% for 10, 60, 110, and 160 mg/d, respectively). This response is similar to other results reported previously. No other measure of reproductive performance nor EGRAC measured at any of five stages of the reproductive cycle, was affected by treatment. These results suggest that massive riboflavin supplementation of the sows' diet during early pregnancy may increase the percentage of farrowing but does no increase litter size.

Two hundred three (40 or 41/treatment, average parity 4.3) Large White x Landrace or Large White x Chester White x Landrace sows were used to determine the valine requirement of sows with a genetic capacity for high milk production. All diets were formulated to contain .90% total lysine, with all amino acids other than valine formulated to be at least 110% of their suggested estimates relative to lysine based on ratios derived from the National and Agricultural Research Councils. The control diet was formulated to .75% total valine, and crystalline valine replaced cornstarch to provide additional treatments containing .85, .95, 1.05, and 1.15% total dietary valine. Corresponding valine:lysine ratios were 83, 94, 106, 117, and 128%. Mean litter size after adjustment was 10.3 pigs across treatments, and average lactation length was 26 d. Number of pigs weaned was not affected by dietary valine (mean = 10.2 pigs), nor was daily sow feed (mean = 6.24 kg) or lysine (mean = 56 g) intake. Valine intake increased (linear, P < .001) as dietary valine increased. Litter weight at d 21 and at weaning (d 26) increased (linear, P < .02) with increasing dietary valine (62.4 to 65.5 kg and 76.1 to 79.9 kg, respectively). Litter weight gain increased from d 0 to 7 (linear, P < .06) and from d 0 to 21 and d 0 to weaning (linear, P < .02) as dietary valine increased. Dietary valine had no effect (P > .10) on sow weight change, 10th rib, or last lumbar backfat change from d 0 to 21 or d 0 to weaning or on days from weaning to estrus. These results demonstrate that increasing dietary valine for high-producing sows (21-d litter weights > 60 kg) results in improved litter weight gain. Based on the linear responses observed, the requirement is at least 1.15% of the diet (72 g/d of valine intake) to maximize litter weaning weight and litter weight gain, much greater than recommended currently by the National Research Council (100% of lysine, 36.5 g/d) or the Agricultural Research Council (70% of lysine, 25.5 g/d).