Pork preference for consumers in china, Japan and South Korea.

Competition in global pork markets has increased as trade barriers have opened as a result of free trade agreements. Japanese prefer both loin and Boston butt, while Chinese prefer pork offal. Frozen pork has increased in terms of imports into China. Japanese consumers consider pork meat origin along with pork price when making purchase decisions. While the Chinese prefer a strong tasting pork product, South Korean consumers show very strong preferences to pork that is higher in fat. Therefore, South Korean consumers have a higher demand for pork belly and Boston butt. Consequently, the supply and demand of pork in Korea is hardly met, which means that importation of high fat parts is inevitable. In Korea there is lower preference toward low fat parts such as loin, picnic shoulder, and ham. During the economic depression in South Korea there have been observable changes in consumer preferences. There remains steep competition among the pork exporting countries in terms of gaining share in the international pork market. If specific consumer preferences would be considered carefully, there is the possibility to increase the amount of pork exported to these countries.

Comparison of Growth Performance of Antibiotic-free Yorkshire Crossbreds Sired by Berkshire, Large Black, and Tamworth Breeds Raised in Hoop Structures.

The objective of this study was to compare body weight, ADG, and feed:gain ratio of antibiotic-free pigs from Yorkshire dams and sired by Yorkshire (YY), Berkshire (BY), Large Black (LBY) or Tamworth (TY) boars. All the crossbred pigs in each of three trials were raised as one group from weaning to finishing in the same deep-bedded hoop, providing a comfortable environment for the animals which allowed rooting and other natural behaviors. Birth, weaning and litter weights were measured and recorded. From approximately 50 kg to market weight (125 kg), feed intake and body weights were recorded manually (body weight) or using a FIRE (Feed Intake Recording Equipment, Osborne Industries Inc. Osborne, Kansas) system with eight individual feeding stations. Feed intake data for 106 finishing pigs between 140 and 210 d of age and the resulting weights and feed conversion ratios were analyzed by breed type. Least square means for body weights (birth, weaning and to 240 d) were estimated with Proc Mixed in SAS 9.2 for fixed effects such as crossbreed and days of age within the sire breed. The differences within fixed effects were compared using least significant differences with DIFF option. Individual birth weights and weaning weights were influenced by sire breed (p<0.05). For birth weight, BY pigs were the lightest, TY and YY pigs were the heaviest but similar to each other and LBY pigs were intermediate. For weaning weights, BY and LBY pigs were heavier than TY and YY pigs. However, litter birth and weaning weights were not influenced by sire breed, and average daily gain was also not significantly different among breed types. Tamworth sired pigs had lower overall body weight gain, and feed conversion was lower in TY and YY groups than BY and LBY groups (p<0.05), however, number of observations was somewhat limited for feed conversion and for Tamworth pigs. Overall, no convincing differences among breed types were noted for this study, but growth performance in the outdoor environment was satisfactory.

Comparison of pork quality and sensory characteristics for antibiotic free yorkshire crossbreds raised in hoop houses.

The objective of this study was to compare pork characteristics and to determine consumer acceptability of pork chops from antibiotic free Yorkshire crossbreds sired by Berkshire (BY), Large Black (LBY), Tamworth (TY) or Yorkshire (YY) boars and reared in hoop houses. The experiments were conducted at the North Carolina Agricultural and Technical State University (NCA&TSU) Farm in Greensboro, NC and the Cherry Research Station Center for Environmental Farming Systems (CEFS) Alternative Swine Unit in Goldsboro, NC (source of antibiotic free Yorkshire sows used at both places). Twenty-four sows were artificially inseminated at each location in each of three trials. Litters were weaned at 4 wks old, and reared within deep-bedded outdoor hoop houses. To compare pork characteristics, 104 randomly selected animals were harvested at a USDA-inspected abattoir at approximately 200 d of age. Variables measured included pH, color score, L*, a*, b*, marbling score, drip loss, hot carcass weight, backfat thickness (BF), loin muscle area (LMA), and slice shear force. Sensory panel tests were also conducted at two time periods. The data was analyzed with GLM in SAS 9.01 including location, trial, and sire breed as fixed effects. Backfat thickness, LMA, color score and a* were different among breeding groups (p<0.05). The LBY pigs had thicker backfat and smaller LMA than the other breed types. The TY and YY had less backfat than all other breed groups. Color score was lower for YY than BY and LBY but intermediate for TY. The a* was lower for TY than other breeds except LBY which was intermediate. For one sensory panel test, YY pork was more preferred overall as well as for juiciness and texture compared to BY and LBY (p<0.05), but no impact of breed type was noted for the other test, with values similar for BY, LBY, TY and YY pork. This information may help small farmers make decisions about breed types to use for outdoor production.

Phenotypic and genetic correlations between gilt estrus, puberty, growth, composition, and structural conformation traits with first-litter reproductive measures.

The objective was to estimate correlations of gilt estrus, puberty, growth, composition, and structural conformation traits with first-litter reproductive measures. Four groups of gilts (n = 1,225; Genetic Improvement Services of NC, Newton Grove, NC) entered the NC Swine Evaluation Station (Clayton, NC) averaging 162 d of age and were observed daily for symptoms of estrus. Once symptoms of first estrus were observed in 70% of gilts, recording of symptoms of estrus in all gilts occurred every 12 h for 30 d, utilizing fence-line boar contact. Subjective estrous traits were maximum and total strength of standing reflex, as observed with and without the presence of a boar, and strength of vulva reddening and swelling. Objective estrous traits consisted of vulva redness, vulva width, length of estrus, and age at puberty. Growth and composition traits included BW at puberty, days to 114 kg, and 10th rib backfat and LM area at 114 kg and at puberty. Subjective structural conformation traits were muscle mass, rib width, front leg side view, rear leg side view, front legs front view, rear legs rear view, and locomotion. First-litter sow traits included if gilt farrowed (Stay), age at first farrowing (AFF), total number of piglets born (TNB), and weaning to conception interval (WCI). Variance components were estimated using an animal model with AIREMLF90 for linear traits and THRGIBBS1F90 for categorical traits. Heritability estimates for Stay, AFF, and TNB were 0.14, 0.22, and 0.02, respectively. Genetic correlations between length of estrus, the standing reflex traits, and age at puberty with Stay were 0.34, 0.34 to 0.74, and -0.27, respectively, and with AFF were -0.11, -0.04 to -0.41, and 0.76, respectively. Days to 114 kg had genetic associations with Stay, AFF, and TNB of 0.52, -0.25, and -0.08, respectively. Backfat at 114 kg had genetic correlations with Stay, AFF, and TNB of -0.29, 0.14, and 0.47, respectively. Vulva redness and TNB were negatively correlated phenotypically (r = -0.14) and genetically (r = -0.53). Associations between structural conformation traits with Stay, AFF, TNB, and WCI were generally low to moderate and favorable. Selection for longer length of estrus, stronger standing reflex, or younger age at puberty would increase the proportion of gilts that farrow and reduce age at first farrowing.

Effects of chronic exposure of diets with reduced concentrations of aflatoxin and deoxynivalenol on growth and immune status of pigs.

This study investigated the growth and immune responses of pigs fed diets containing reduced concentrations of aflatoxin (AF) and deoxynivalenol (DON) from naturally contaminated corn. Sixty gilts (13.9 ± 0.2 kg of BW) were randomly assigned to 4 treatments (5 replicate pens per treatment and 3 pigs per pen): A (a control diet without detectable AF and DON); B (a diet with 60 µg of AF/kg and 300 µg of DON/kg); C (a diet with 120 µg of AF/kg and 600 µg of DON/kg); and D (a diet with 180 µg of AF/kg and 900 µg of DON/kg). Pigs were allowed ad libitum access to feed and water for 33 d. Feed intake and BW were measured weekly and pigs were bled (8 mL) on d 33 to measure the numbers of blood cells, to conduct liver function tests, and to measure immunological variables including IgG, IgM, interferon γ, IL4, IL6, and tumor necrosis factor α. One pig representing the average BW of each pen was killed to obtain the liver, kidneys, and spleen for weight, tissue color measurement, and histological evaluation of tissue damage. When compared with A, pigs in C and D tended to have reduced ADG (0.52 vs. 0.43 and 0.41 kg/d, respectively; P = 0.058) and ADFI (1.04 vs. 0.92 and 0.88 kg/d, respectively; P = 0.061). White blood cell count of pigs in D (23.4 × 10(3) cells/µL) was greater (P < 0.05) than those in A, B, and C (18.4, 18.5, and 16.8 × 10(3) cells/µL, respectively. Serum tumor necrosis factor α concentration of pigs in D (335 pg/mL) differed (P < 0.05) from those in A and C (299 and 290 pg/mL, respectively). Pigs in B and D had greater (P < 0.05) fibrosis in liver tissues than those in A. Collectively, this study shows that diets containing both AF and DON greater than 60 and 300 µg/kg, respectively, may reduce growth and decrease feed intake, whereas diets containing 120 µg of AF/kg and 600 µg of DON/kg may result in altered immune health, systemic inflammation, and partial liver damage, causing further reduction in growth of pigs.

Estimates of variance components for genetic correlations among swine estrus traits.

Variance components and genetic correlations were estimated among estrus, puberty, growth, and composition traits in Landrace-Large White gilts (n = 1,225; Genetic Improvement Services, Newton Grove, NC) from 59 sires and 330 dams. Four groups of gilts entered the North Carolina Swine Evaluation Station in Clayton at an average age of 162 d and were checked daily for estrus. Once 70% of gilts had reached puberty, recording of estrus symptoms occurred every 12 h for 30 d, using fence-line boar contact. Subjective estrus traits were maximum strength of standing reflex with or without a boar present, total strength of standing reflex with or without a boar present, and strength of vulva reddening and swelling. Objective estrus traits consisted of vulva redness, vulva width, length of estrus in consecutive days based on 12-h observations, and age at puberty (AGEPUB). Growth and composition traits included puberty weight, days to 114 kg (DYS), 10th-rib backfat, and 10th-rib LM area at 114 kg (BF, LMA) and puberty. Variance components were estimated using AIREMLF90 with an animal model. All models included gilt development diet class and breed composition as fixed effects, entry age as a covariate (except DYS, BF, and LMA), a random common litter effect, and a random animal genetic effect. Heritability estimates for length of estrus, maximum strength of the standing reflex with a boar, total strength of the standing reflex with a boar, maximum strength of the standing reflex without a boar, total strength of the standing reflex without a boar, vulva redness, strength of vulva reddening and swelling, and vulva width were 0.21, 0.13, 0.26, 0.42, 0.42, 0.26, 0.45, and 0.58, respectively. Heritability estimates for AGEPUB, puberty weight, 10th-rib backfat at puberty, 10th-rib LM area at puberty, DYS, BF, and LMA were 0.29, 0.39, 0.41, 0.38, 0.24, 0.47, and 0.39, respectfully. Common litter effect estimates ranged from 0.01 to 0.09. The estimated genetic correlation between length of estrus and maximum strength of standing reflex with a boar was 0.99. Genetic correlations between AGEPUB and length of estrus, maximum strength of standing reflex with a boar, and vulva redness were -0.23, -0.32, and 0.20, respectively. Length of estrus had positive genetic associations with DYS and BF (0.30 and 0.29, respectively). It was concluded that past selection for lean BW gain may have weakened the strength of the standing reflex and that sufficient genetic variation exists to make selection for improved swine estrus traits effective.

Descriptive flavor analysis of bacon and pork loin from lean-genotype gilts fed conjugated linoleic acid and supplemental fat.

This study evaluated the combined effects of dietary CLA and supplemental fat (SF) source on organoleptic characteristics of bacon and pork loin samples in lean-genotype gilts (n = 144). Gilts (49.3 kg of BW) were randomly assigned to a 3 x 2 factorial design, consisting of SF [0% SF, 4% yellow grease (YG), or 4% tallow] and linoleic acid (LA; 1% corn oil or 1% CLA). Animals were slaughtered (113 kg) after a feeding period of 47 d. A trained sensory panel (n = 6 members) developed a flavor profile on commercially cured bacon samples (12 descriptors) and center-cut, boneless, pork loin chops (18 descriptors, using a 14-point, universal intensity scale). Bacon samples from pigs fed 4% SF were considered to have a sweeter flavor (4.07 +/- 0.07) than those fed 0% SF (3.89 +/- 0.07; P < 0.04). The intensity of salty flavor was greater in bacon samples from pigs fed LA (6.18 +/- 0.09) compared with those fed CLA (5.86 +/- 0.10; P < 0.04). The intensity of salty aftertaste of bacon was greater when LA was combined with YG (5.21 +/- 0.14; P < 0.07) or tallow (5.44 +/- 0.14; P < 0.01) than for LA alone (4.85 +/- 0.14, but SF combined with CLA was not different from CLA alone (fat x LA; P < 0.02). Sour flavor intensity tended to be lower in loin samples from pigs fed CLA than for those fed LA (1.60 vs. 1.73 +/- 0.06; P < 0.09). Samples from animals fed 4% tallow tended to have lower (P < 0.09) notes of astringent aftertaste (1.42 +/- 0.08) compared with those fed 0% SF (1.62 +/- 0.09) or 4% YG (1.66 +/- 0.09). Overall, the flavor differences for bacon and loin samples were minimal, with most means differing by 1 point or less on the 14-point intensity scale. The sensory panel results indicate consumer acceptance of bacon and pork products from pigs fed CLA will not likely differ from commodity pork products.

Effects of pig age at market weight and magnesium supplementation through drinking water on pork quality.

Thirty-two halothane-negative pigs (109 +/- 0.6 kg of BW) were used to determine the effect of pig age at marketing (and thus growth rate), and magnesium supplementation through drinking water, on pork quality. Two initial groups of 50 pigs that differed by 30 +/- 2 d of age were fed diets to meet or exceed nutrient requirements beginning at 28 kg of BW. Sixteen average, representative pigs were selected from each group to represent older, slow-growing pigs and younger, fast-growing pigs. For the duration of the study, pigs were individually penned, provided 2.7 kg of feed (0.12% Mg) daily, and allowed free access to water. After 7 d of adjustment, pigs were blocked by sex and BW and allotted to 0 or 900 mg of supplemental Mg/L as MgSO4 in drinking water for 2 d before slaughter. All 32 pigs were then transported (110 km) to a commercial abattoir on the same day and slaughtered 2.5 h after arrival. Longissimus and semimembranosus (SM) chops were packaged and stored to simulate display storage for fluid loss and Minolta color determinations at 0, 2, 4, 6, and 8 d. Two remaining sections of the LM were vacuum-packaged and stored at 4 degrees C for 25 or 50 d. Fast- (younger) and slow- (older) growing pigs differed by 27 +/- 0.3 d of age (153 and 180 +/- 0.3 d; P < 0.001) at similar BW (108 and 110 +/- 0.6 kg of BW; P = 0.13). Supplementation of Mg tended to increase plasma Mg concentration (24.1 vs. 21.8 +/- 0.8 ppm; P = 0.06) but did not affect Mg concentration in LM or SM. Fluid loss of displayed LM or SM, and purge loss, color, and oxidation of vacuum-packaged LM or SM were not affected by age or Mg (P > 0.10). Surface exudate of the SM from older pigs was lower than that of younger pigs (61 vs. 74 +/- 6 mg; P = 0.05) but was not different for the LM (P = 0.22). The LM from older pigs displayed for 4 and 8 d; P < 0.05) were less yellow (lower b*) than younger pigs. The SM from older pigs had lower lightness (L*) initially (47.9 vs. 49.5 +/- 0.4) and after 2 d (49.7 vs. 51.1 +/- 0.4), 6 d (52.1 vs. 53.7 +/- 0.4) and 8 d (54.5 vs. 55.9 +/- 0.4) of display storage. Younger pigs had greater oxidation of the LM than older pigs on d 8 of display (P < 0.01), and Mg decreased oxidation on d 8 within younger pigs (P < 0.05). Pork quality was improved in older pigs as indicated by less exudate, reduced yellowness of the LM, reduced paleness of the SM, and reduced oxidation of the LM. However, Mg supplementation through the water for 2 d did not affect pork quality of either older, slower growing pigs or younger, faster growing pigs.

Correlated responses in growth, carcass, and meat quality traits to divergent selection for testosterone production in pigs.

The objective of this project was to characterize changes in growth, carcass yield, and meat quality traits in castrates and gilts in response to divergent selection for testosterone production. In generation 21, endogenous testosterone concentrations in Duroc boars of the high (HTL) and low (LTL) testosterone lines averaged 49.0 and 27.8 ng/mL (P < 0.01), respectively. Eight LTL and 10 HTL boars were used to sire 29 LTL and 33 HTL litters. To remove the effects of inbreeding, these same boars were mated to females of a Large White x Landrace composite (WC) to generate 11 WC by LTL litters (WLT) and 23 WC by HTL litters (WHT). Castrates and gilts were then allotted to LTL (n = 53), HTL (n = 61), WLT (n = 102), and WHT (n = 101) for testing. Growth and carcass traits analyzed included days to 114 kg (D114), ADG, backfat adjusted to 114 kg (ABF), LM area adjusted to 114 kg and predicted percent lean (PPL). Fat-O-Meater data collected were adjusted fat depth (AFD), adjusted loin depth, and percent lean. Meat quality traits characterized at 24 h postmortem included marbling score, percent lipid, pH, drip loss, color score, and Minolta L*, a*, and b*. Data were analyzed with a mixed model including fixed effects of line, mating type (purebred or crossbred), sex, and the random effect of sire nested within line. All possible interactions among fixed effects were tested. The HTL had fewer D114 (P < 0.05), greater ADG (P < 0.01), greater ABF (P < 0.01), and lower PPL (P < 0.01) than LTL. The WHT and WLT did not differ for D114, ADG, or ABF. The WHT had smaller LM area adjusted to 114 kg (P < 0.05) and greater drip loss (P < 0.05) than WLT. The WLT had lower adjusted loin depth (P < 0.05) than LTL and HTL. The LTL and HTL had greater subjective scores for marbling (P < 0.05) compared with WLT and WHT. The least squares mean for percent lipid for HTL and LTL was 4.00. The WHT had greater means for L*, a*, and b* (P < 0.05) than WLT. Pigs selected for increased testosterone production grew faster and produced fatter carcasses than pigs selected for decreased testosterone. Changes in growth, carcass yield, and meat quality traits were detected in castrates and gilts in response to divergent selection for testosterone production.

Genetic parameters for various random regression models to describe total sperm cells per ejaculate over the reproductive lifetime of boars.

The objective of this study was to model the variances and covariances of total sperm cells per ejaculate (TSC) over the reproductive lifetime of AI boars. Data from boars (n = 834) selected for AI were provided by Smithfield Premium Genetics. The total numbers of records and animals were 19,629 and 1,736, respectively. Parameters were estimated for TSC by age of boar classification with a random regression model using the Simplex method and DxMRR procedures. The model included breed, collector, and year-season as fixed effects. Random effects were additive genetic, permanent environmental effect of boar, and residual. Observations were removed when the number of data at a given age of boar classification was < 10 records. Preliminary evaluations showed the best fit with fifth-order polynomials, indicating that the best model would have fifth-order fixed regression and fifth-order random regressions for animal and permanent environmental effects. Random regression models were fitted to evaluate all combinations of first- through seventh-order polynomial covariance functions. Goodness of fit for the models was tested using Akaike's Information Criterion and the Schwarz Criterion. The maximum log likelihood value was observed for sixth-, fifth-, and seventh-order polynomials for fixed, additive genetic, and permanent environmental effects, respectively. However, the best fit as determined by Akaike's Information Criterion and the Schwarz Criterion was by fitting sixth-, fourth-, and seventh-order polynomials; and fourth-, second-, and seventh-order polynomials for fixed, additive genetic, and permanent environmental effects, respectively. Heritability estimates for TSC ranged from 0.27 to 0.48 across age of boar classifications. In addition, heritability for TSC tended to increase with age of boar classification.

Effects of supplemental magnesium concentration of drinking water on pork quality.

Thirty-two barrows were used to determine the effects of supplemental Mg in drinking water on pork quality. Pigs were determined to be free of the halothane and Napole mutations and were individually penned. After a 7-d adjustment period, barrows (111 +/- 1 kg BW) were blocked by BW and allotted randomly within block to 0, 300, 600, or 900 mg of supplemental Mg from Mg sulfate/L of drinking water for 2 d before slaughter. Pigs were not allowed access to feed (0.13% Mg) for 15 h before slaughter but continued to have access to experimental water treatments. Pigs were loaded and transported 110 km (1.75 h) to a commercial abattoir and remained in lairage for 5 h before slaughter. The LM was removed 24 h postmortem. Retail storage was simulated for 8 d, and the remaining LM was vacuum-packaged for 25 or 50 d at 4 degrees C. Plasma Mg concentration increased linearly (P = 0.001) with Mg supplementation; however, Mg concentration of the LM was not affected (P = 0.99) by Mg supplementation. Surface exudate, drip loss, and retail fluid loss of the LM were not affected (P > 0.10) by Mg. Lightness (L*) and redness (a*) of the LM were not affected (P > 0.10) by Mg, with the exception of initial redness (cubic; P = 0.05). Pigs supplemented with 300 or 900 mg of Mg/L had lower yellowness (b*) values of the LM displayed for 0 to 6 d than pigs supplemented with 0 or 600 mg of Mg/L (cubic; P < 0.05). Lightness of the LM after 25 (quadratic; P = 0.03) or 50 (quadratic; P = 0.04) d of vacuum-packed storage was greater at 300 and 600 mg of Mg/L than at 0 or 900 mg/L. Yellowness tended to be greater after 50 d, but not after 25 d, of vacuum-packaged storage for 300 or 600 mg of Mg/L compared with 0 or 900 mg/L (quadratic; P = 0.08). Oxidation of the LM, determined by thiobarbituric acid reactive substances after 4 d of retail storage, increased linearly (P = 0.05) as Mg increased in the drinking water. Furthermore, oxidation of the LM after 8 d of retail storage tended to increase linearly (P < 0.10), primarily because of the high oxidation of LM from pigs supplemented with 900 mg of Mg/L compared with controls (224 vs. 171 +/- 19 microg/kg, respectively). Oxidation of the LM was greater for pigs supplemented with 300 or 900 mg/L compared with 0 or 600 mg of Mg/L (cubic; P < 0.06) after 25 d of vacuum-packed storage. Magnesium did not improve pork quality characteristics of practical significance in pigs without the halothane and Rendement Napole mutations.

Effects of chemical hydrogenation of supplemental fat on relative apparent lipid digestibility in finishing swine.

Four experiments were conducted to evaluate lipid digestibility in finishing swine fed chemically hydrogenated fats. Dietary chromic oxide was used as an inert marker to measure the apparent digestibility of supplemental fat (SF) that consisted of fully hydrogenated (FH), partially hydrogenated (PH), or PH products blended with other fat sources. In Exp. 1, diets containing 5% SF (as-fed basis) comprising 100, 66.7, 33.3, or 0% FH animal fat (iodine value = 2.5), with the balance contributed by soy oil, were fed to gilts (n = 24). Apparent digestibility increased linearly (-12.0, 26.0, 61.2, and 72.6%; P < 0.001) as the amount of FH fat in the diet decreased, suggesting the digestibility of FH to be near zero. Experiment 2 (2 x 4 factorial; n = 48) evaluated diets containing 5% (as-fed basis) blended fat (FH tallow and yellow grease) to achieve iodine values of 20, 30, 40, or 50 compared with PH tallow with identical iodine values. Digestibility of diets formulated with PH tallow was greater than those containing blended fat (73.4 vs. 67.2%; P < 0.01), especially at lower iodine values (interaction; P < 0.10). In Exp. 3, digestibility was measured in pigs (n = 96) fed 5% (as-fed basis) PH choice white grease with iodine values of 20, 40, 60, or 80. Increasing iodine value did not alter digestibility (66.2, 69.2, 68.2, and 69.7%). Experiment 4 investigated digestibility (n = 32) of diets formulated with 8% (as-fed basis) PH fat (iodine value 20 or 50) with 0.10% lysolecithin as an emulsifier. Lipid digestibility was 14.5% greater in the 8% SF diet with an iodine value of 50 compared with the diet with an iodine value of 20 (79.15 vs. 69.12%; P < 0.001), but lysolecithin was without effect. These experiments indicate that partial hydrogenation is superior to blending unsaturated fat with saturated fat sources and that digestibility is not greatly affected by decreasing the iodine value via partial hydrogenation.

Urinary excretion of collagen degradation markers by sows during postpartum uterine involution.

Incomplete uterine involution is the putative cause of the increased embryo mortality and reproductive failure often exhibited by sows that lactate for less than 21 days. Since such short lactation lengths are common in American swine production, an effective technique to monitor the postpartum involution process and test this hypothesis might be valuable. Rapid and extensive catabolism of uterine collagen is essential for normal postpartum involution. The objective of this study was to characterize postpartum excretion of two biochemical markers of collagen degradation. In experiment I, urine samples were collected from five sows every other day from the day before parturition (day -1), through a 21-day lactation, to day 8 postweaning. The collagen crosslinks hydroxylysyl pyridinoline (HP), which is present in many tissues, and lysyl pyridinoline (LP), which is primarily concentrated in bone, were assayed by both ELISA and HPLC. Urinary levels of both free (ELISA) and total (HPLC) HP and LP increased (P < 0.001) approximately two-fold during lactation. The mean molar ratio of total HP:LP increased (P < 0.001) from 6.6 +/- 1.6 at day 1 to a maximum of 10.2 +/- 1.5 at day 7 postpartum and averaged 9.1 +/- 0.3 for the entire sampling period. These data are consistent with a postpartum increase of soft tissue collagen catabolism since bone has a low HP:LP ratio of 4 and soft tissues like the uterus have a high HP:LP ratio of >/=20 because they contain only trace amounts of LP. Since HPLC (total) and ELISA (free) crosslinks estimates were highly correlated (r = 0.85-0.91, P < 0.001) in experiment I, only the less technical ELISA technique was used in experiment II. Urine samples were collected from 21 sows every third day from day 1 to 19 of lactation. Sows from this second group exhibited one of four distinct crosslinks excretion patterns: peak on day 1 (n = 3), peak on day 7 (n = 4), peak on day 10, 13 or 16 (n = 7), or no peak (n = 7). This variation of postpartum crosslinks excretion among sows was not related to parity, body weight, lactation body weight change, litter size, or litter birth weight. Overall, data from experiments I and II indicate that urinary HP does increase postpartum in a pattern temporally consistent with uterine involution. However, significant variation among sows in the magnitude and timing of peak HP excretion was evident.

Factors affecting temporal relationships between estrus and ovulation in commercial sow farms.

The main objective was to examine effects of season, parity, genotype, lactation length, and weaning-to-estrus interval on duration of estrus (DE) and onset of estrus-to-ovulation interval (EOI) in three sow farms. Detection of estrus and ovulation by the back-pressure test and transabdominal ultrasonography, respectively, were performed every 6 h from day 2-10 postweaning in 535 sows (approximately 89 per farm per season). The average weaning-to-estrus interval, DE, and EOI of the 501 sows that returned to estrus by day 10 postweaning were 4.6+/-0.1 days, 55.2+/-0.5 h, and 41.8+/-0.5 h, respectively. Farm x season (P<0.01), parity x season (P <0.05), and farm x weaning-to-estrus interval (P<0.05) interactions for DE and EOI were detected. Sows weaned in the summer had an 8 h longer (P<0.001) DE and EOI than those weaned in the spring on farms 1 and 3. On farm 2 however, DE and EOI did not differ (P=0.09) in sows weaned in summer versus spring. On each farm, parity 3 and > or =4 sows had a 4.5 h longer (P<0.05) DE and EOI than parity 1 and 2 sows in the summer, but there were no differences (P>0.11) in DE or EOI among parity classes in the spring. There was a linear decrease of DE (P<0.001) and EOI (P<0.05) as weaning-to-estrus interval increased from the 3 to the > or =7 day class on each farm. However, the range of weaning-to-estrus interval that exhibited a stepwise decrease of DE and EOI was narrower on farm 1 (3-5 days) than farms 2 and 3 (3-6 days). Only farms 1 and 3 had multiple genotypes. Genotype did not affect (P>0.14) DE on either farm, but the EOI of genotype B was 4 h shorter (P<0.05) than genotype C on farm 1. On each farm, DE decreased linearly (P<0.01) as lactation length increased from < or =13 to > or =20 days. In general, factors that affected EOI also affected (P<0.05) the percentage of inseminations that occurred within 24 h pre- to 3h post-ovulation. These data indicate that factors other than weaning-to-estrus interval, such as season and parity, can significantly alter DE and EOI. However, the effects of season and weaning-to-estrus interval on DE and EOI can be inconsistent among different farms.

Effects of vitamin C supplementation on plasma ascorbic acid and oxalate concentrations and meat quality in swine.

Two experiments were conducted to determine the effects of vitamin C supplementation 48 h before slaughter on plasma ascorbic acid and oxalate concentrations and its effect on pork quality. In Exp. 1, 16 pigs (87.8+/-2.13 kg BW) were blocked by sex and weight and assigned randomly within block to one of three vitamin C treatments: 1) control; 2) 1,000 mg/L; or 3) 2,000 mg/L supplemented in the drinking water for a 48-h period. This was then followed by an additional 48-h period without supplemental vitamin C. Vitamin C increased plasma ascorbic acid concentrations (11.6, 19.5, and 23.4 microg/mL for 0, 1,000, and 2,000 mg/L of vitamin C; P < 0.05) within 6 h of supplementation. Plasma ascorbic acid concentrations from treated pigs decreased and did not differ from those of control pigs (13.7, 18.2, and 18.6 microg/mL for 0, 1,000, and 2,000 mg/L of vitamin C; P = 0.30) within 2 h of ending supplementation. No differences in plasma ascorbic acid concentrations were found between the two levels of supplementation. Vitamin C did not affect plasma oxalate or cortisol; however, cortisol tended to increase quadratically (P = 0.077) with vitamin C after 96 h. In Exp. 2, 30 pigs (107.5+/-0.54 kg BW) were blocked by sex and weight and assigned randomly within block to one of three vitamin C treatments: 1) control; 2) 500 mg/L; or 3) 1,000 mg/L supplemented in the drinking water 48 h before slaughter. Pigs were slaughtered 4 to 5 h after vitamin C supplementation ended, and loin samples were collected for meat quality measurements. At the time of slaughter, no differences in plasma ascorbic acid or cortisol were observed, but oxalate tended (P = 0.074) to increase quadratically with increasing vitamin C. Muscle ascorbic acid at slaughter and lactic acid in muscle at 0 and 1.5 h after slaughter were not different; however, lactic acid increased (P = 0.048) quadratically at 24 h after slaughter. Vitamin C did not affect initial or ultimate pH. Initial fluid loss (P = 0.041), and fluid loss on d 4 (P = 0.014) and 8 (P = 0.076) of simulated retail display; L* on d 0 (P = 0.038), 4 (P = 0.010), and 8 (P = 0.051); a* on d 0 (P = 0.021); and b* on d 0 (P = 0.006), 4 (P = 0.035), and 8 (P = 0.017) were negatively affected in a quadratic manner when vitamin C was supplemented. Vitamin C tended (P = 0.086) to increase oxidation in chops on d 0, but not d 4 or 8. Results indicate that on-farm supplementation of vitamin C was generally not effective in improving pork quality, which may be related to timing relative to slaughter.

Effect of a ractopamine feeding program on growth performance and carcass composition in finishing pigs.

Barrows and gilts (n = 100 per gender) were used to determine the effects of an increasing, decreasing, or constant ractopamine (RAC) dietary concentration on growth performance and carcass characteristics. Pigs, within a gender, were assigned randomly to pens (five pigs per pen and 10 pens per treatment). Pens were assigned randomly to one of four dietary treatments at a starting weight of 71.2 kg, to target an average ending weight of 109 kg. The four dietary treatments (as-fed basis) were 1) control = 0 ppm RAC, wk 0 to 6; 2) RAC step-up = 5.0 ppm, wk 1 to 2; 10.0 ppm, wk 3 to 4; and 20.0 ppm, wk 5 to 6; 3) RAC step-down = 20.0 ppm, wk 1 to 2; 10.0 ppm, wk 3 to 4; and 5.0 ppm, wk 5 to 6; and 4) RAC constant = 11.7 ppm, wk 0 to 6. Feed allocation was recorded daily, and pigs were weighed and feed was weighed back every 2 wk. Jugular blood samples were obtained from two randomly selected pigs per pen on d -3, 7, 21, 35, and 41 for determination of plasma urea nitrogen (PUN) concentrations. Two pigs were selected randomly per pen and sent to a commercial slaughter facility at the end of the 6-wk experimental period. Carcass data were evaluated on an equal time basis and on an equal weight basis by using hot carcass weight (HCW) as a covariate. Overall, ADG and G:F were improved (P < 0.05) for pigs fed RAC compared with control, with no differences among RAC feeding programs. In wk 3 and 4, improvements (P < 0.05) in ADG and G:F were realized with the implementation of a RAC step-up program compared with control pigs. The concentrations of PUN were decreased (P < 0.05) at d 7 and 21 with RAC feeding, and a RAC step-up program maintained the decrease (P < 0.05) in PUN through d 35 and 41. A RAC step-up and constant program increased (P < 0.05) HCW and percent yield. Loin muscle area and percentage of fat-free lean increased (P < 0.05) and backfat thickness decreased (P < 0.05) in pigs fed RAC. If pigs were considered to be on feed for an equal time period, advantages (P < 0.05) were observed for weight of boneless trimmed ham, shoulder and loin for the step-up and constant RAC treatments compared with the controls. Feeding a RAC step-up or constant feeding program resulted in favorable responses in growth performance and yielded more lean pork.

Timing of magnesium supplementation administered through drinking water to improve fresh and stored pork quality.

Thirty-two pigs were used to determine the timing effect of magnesium (Mg) supplementation given through drinking water on pork quality. Pigs (16 barrows and 16 gilts) were individually penned, provided 2.7 kg of feed (0.12% Mg) daily (as-fed basis), and allowed free access to water via a nipple waterer for the duration of the study. After 5 d of adjustment, pigs (120 +/- 0.8 kg BW) were allotted randomly by weight and sex to 900 mg/L of supplemental Mg from magnesium sulfate heptahydrate in drinking water for -6, -4, -2, or 0 d relative to slaughter. The LM and semimembranosus (SM) muscles were removed 24 h postmortem. Retail display storage was simulated for 8 d, and the LM was vacuum-packaged for 25 or 50 d at 4 degrees C. Magnesium did not affect the pH of the LM at either 45 min (P = 0.15) or 24 h postmortem (P = 0.23). However, the pH of the SM at 24 h postmortem tended to be greater (P = 0.08) for pigs consuming Mg for 2 d than for those not supplemented. Fluid loss after 8 d of storage was less (P < 0.05) in the LM of pigs supplemented with Mg for 6 d than in those without supplementation. Furthermore, fluid loss from the SM of pigs provided supplemental Mg for 2 d, but not for 4 or 6 d, was lower (P < 0.05) on each day of retail display than the SM of unsupplemented pigs. Minolta L*, a*, and b* color measurements of the LM during display storage were not (P > 0.10) affected by Mg supplementation. However, Mg supplementation for 2 or 4 d decreased paleness (lower L* value) after 25 d (P < 0.05), but not 50 d (P > 0.10) of vacuum-packaged storage. Magnesium addition for 2 d decreased the extent of oxidation (thiobarbituric acid-reactive substances) of the LM after 4 d of display storage compared with 0 d of Mg (P < 0.05). Oxidation of the SM during 8 d of display storage increased linearly (P < 0.05) as duration of supplementation increased from 2 to 6 d but did not differ (P = 0.22) from 0 d of Mg supplementation. Although the response to Mg supplementation was variable, supplementation for 2 d before slaughter was considered most efficacious because of the following: decreased fluid loss from the SM, and lower lipid oxidation formation in the LM during retail storage; a darker, more desirable LM color after 25 d of vacuum-packaged storage; and cost reductions compared with longer durations.

Diet and evaluators affect perception of swine waste odor: an educational demonstration.

An educational program was developed for extension agents, faculty, and graduate students to illustrate the effect of diet composition on odor from swine manure. Participants in this program first received a 2-h detailed review on odorous compounds in manure and the effect of diet on odor. For the second portion of the training, nine manure samples were used from pigs fed diets formulated with feed ingredients predicted to have different effects on odor emission or a nutritionally adequate corn-soybean meal diet. Participants were instructed to rate the odor from these samples for pleasantness, irritation, and intensity on a scale of 0 (best) to 8 (worst), using manure from the corn-soybean meal fed pig as the reference with a score defined as 4 for each variable. Results obtained were summarized and discussed before concluding the program. Participants were Cooperative Extension Agents (n = 13) with swine responsibilities and graduate students and faculty (n = 8). The manure from the diet with the worst odor scores (1% garlic) was rated at 70% more odorous across the three odor variables (P < 0.05) than the diet with the least odorous manure (purified diet). Even though a reference sample was used, individual participants differed in their perception of irritation across samples (P < 0.05), ranging in average score across diets from 2.4 (moderately better than reference) to 5.0 (slightly worse than reference). With extension agents, a 1 to 7 scale (very interesting to not at all interesting) was used for evaluation of the training session. Participants found the material to be interesting (mean = 1.7, SD = 0.7) and the training exercise to be well organized and coherent in its presentation (mean = 1.8, SD = 0.7). Participants enjoyed this training and learned that differences in odor are achievable through altering diet composition, and that the response to swine odor depends on individual odor perception.

Hydrogenated dietary fat improves pork quality of pigs from two lean genotypes.

Pork quality is influenced by nutrition, genetics, management, and pork-processing procedures. Pigs of lean genotype fed diets high in unsaturated fat may have thinner, lower-quality bellies with a soft fat composition. Therefore, we investigated the effects of supplementing 5% choice white grease that had been chemically hydrogenated to iodine values of 80, 60, 40, or 20 on pork quality. Diets were fed to barrows and gilts of two genotypes (NPD [Ham-line x Manor hybrid] and PIC [406, 419, or 420 x C22]; n = 240) in a 4 x 2 x 2 factorial design. Pigs (76.8 kg of mean initial weight) were placed on test at a common age and were fed dietary treatments for 52 d. Pigs of PIC genotype were heavier at trial initiation, had higher feed intake and feed conversion ratio (F/G; P < 0.05), and greater backfat (26.3 vs. 24.0 mm; P < 0.001) and loin depth (59.0 vs. 55.3 mm; P < 0.001) compared with the NPD genotype pigs. As the iodine value of dietary fat was reduced, belly thickness increased (P < 0.05) and length decreased linearly (P < 0.05). Congruently, belly fat iodine value decreased from 73.9 to 67.4 (linear effect; P < 0.001) and belly fat C18:2 concentration declined from 20.6 to 16.3% (linear and quadratic effect; P < 0.001). The belly mono- and polyunsaturated fat ratio increased 29% as diet iodine value declined from 80 to 20 (linear and quadratic effect; P < 0.001). Further, there was a linear increase (P < 0.001) in saturated fatty acid concentration of belly fat (C14:0, C16:0, and C18:0) as dietary fat iodine value declined. Quadratic (P < 0.005) effects were detected in the level of C18:1trans as iodine value decreased from 80 to 20, paralleling dietary content. Dietary fat iodine value did not affect fat digestibility, ADFI, or F/G. Pork belly quality was improved as defined by reduced iodine value, C18:2 content, increased saturated fatty acid content, increased thickness, and decreased length as dietary iodine value decreased. Results indicate that reduction of dietary fat iodine value by chemical hydrogenation has the desirable effect of improving pork quality and does not alter growth performance.

Conjugated linoleic acid in combination with supplemental dietary fat alters pork fat quality.

Interest in fortification of human foods, including pork, with conjugated linoleic acid (CLA) is growing and may provide benefits as a neutraceutical based on research evaluating CLA as an anticarcinogen, immune modulator, antiatherogenic agent and a body composition modulator. This study evaluated the combined effects of dietary CLA and supplemental fat source on growth, fatty acid composition and belly quality of lean genotype gilts (n = 144). Pigs (49.3 kg) were randomly assigned to six diets (3 x 2 factorial) varying in supplemental fat (none, 4 g/100 g yellow grease or 4 g/100 g tallow) and linoleic acid [1 g/100 g corn oil (CO) or 1 g/100 g CLA (CLA-60)] for 47 d. Both the cis-9, trans-11 and the trans-10, cis-12 isomers of CLA were increased in belly and longissimus fat depots from pigs fed CLA, and that increase was up to 92% greater when CLA was fed with 4 g/100 g supplemental fat (fat source x linoleic acid interaction, P < 0.05). Pigs fed CLA had a greater concentration of 18:0 and less 18:1 cis-9 (P < 0.01) in various fat depots, suggesting a reduction in Delta(9) desaturase activity. The iodine value of belly fat from pigs consuming tallow and CLA combined was reduced to 62.0 from an initial value of 70.4. CLA supplementation also increased belly weights (P < 0.05). CLA did not affect longissimus muscle area, backfat depth and the percentage of fat-free lean (P > 0.10), but it increased the subjective intramuscular fat score by 18.8% (P < 0.01). In conclusion, CLA enrichment of pork products may be enhanced when combined with additional supplemental dietary fat, and together with tallow can be used to increase the saturated fatty acid content of pork.