Market Weight Pigs Research Articles

Effects of space allowance on behaviour during lairage, stress physiology, skin lesion scores and meat quality of market-weight pigs transported in an actively-ventilated vehicle in the summer

This study aimed at assessing the effects of space allowance on microclimate and pig stress during transportation in a mechanically-ventilated vehicle. On each journey (6), 114 pigs were randomly assigned to different space allowances (0.46, 0.49 or 0.59 m2/pig) tested in the near-front, middle and near-rear compartments and on the top, middle and bottom decks. In each compartment, ambient conditions (e.g., T°C and RH%) were monitored. Behaviour was recorded during lairage. A total of 162 pigs were selected for the analysis of blood hematocrit proportion and lactate, and creatine kinase (CK) concentrations, and the evaluation of meat quality in the loin and ham muscles. The bottom deck was more humid before and during transport (P ≤ 0.05) and pigs from this location stood and drank more in lairage (P < 0.001). Pigs transported on the top deck had greater blood lactate and CK concentrations (P < 0.05) than those transported on the bottom deck, and when transported at 0.49 m2/pig produced paler loins (P < 0.05) than those transported at 0.46 m2/pig. The within-trailer location had a greater impact on the microclimate, collected animal welfare measures, and meat quality of pigs transported in an actively ventilated trailer than space allowance.

49 Leveraging Big Data Analytics to Improve Disease Surveillance and Welfare in Pig Production

Abstract Large amounts of data are routinely collected in pig production, including operational farm data and, more recently, data from digital tools such as remote and on-site sensing technologies. Furthermore, additional sources of information, such as demographic, economic, and weather variables, can be combined with farm data. Integrating and analyzing such data can generate valuable insights and data-driven decision-making tools for disease surveillance, animal welfare, and production system optimization. This presentation discusses two examples of big data integration and analysis in the context of optimizing management practices in pig production. The first example pertains to a data analytics project related to total transportation losses (TTL) of market-weight pigs, an important animal welfare concern that economically impacts producers and abattoirs. After merging and checking data for errors, the final dataset included 4.5M+ pigs from 420 farms loaded in 26,819 shipments delivered to two abattoirs. Results from a generalized additive mixed model (GAMM) technique showed that the risk of loss per shipment was constant for temperature-humidity index (THI) values between −10 and 10. Additionally, a strong interaction between wind speed and precipitation was associated with TTL. TTL were strongly associated with the type of driver and the distance traveled, in addition to weather variables. The second example pertains to swine disease surveillance, in which data from a multi-site system, where pigs are transported between farms after each particular production phase, were investigated. Reports of 76,566 shipments across sites were obtained and used to characterize pig movement flow, conduct percolation analysis to investigate network robustness to interventions for diseases with different transmissibility, and assess the potential impact of each farm type on disease dissemination across the system. Topological properties of networks were investigated, such as the number of nodes and edges, degree assortativity, density, average path length, diameter, clustering coefficients, giant strongly connected component, giant weakly connected component, giant in component, and giant out component. Overall, the results indicated that gilt development units, nursery, and sow farms have a more central role in the pig production hierarchical structure. As such, they are potential major factors in the introduction and spread of diseases in the system. Wean-to-finishing and finishing sites displayed high in-degree values, indicating that they are more susceptible to infection. Additionally, the characteristics of a disease should have strong implications for biosecurity practices across production sites.

Evaluating the efficacy and safety of differing gun caliber and ammunition combinations for the euthanasia or depopulation of market-weight pigs

Objective: Evaluate the effectiveness and safety of firearm caliber and ammunition combinations that could be used on farm for euthanasia of market-weight pigs. Materials and methods: Heads from 64 market-age pigs (32 barrows and 32 gilts) were collected from a federally inspected slaughter facility. Heads were randomly assigned to one of 4 caliber and ammunition combinations: .22 long rifle (LR), .22 Magnum (Mag), .38 Special, and 9 mm. The fully jacketed ammunition was discharged from each of the 4 unique firearms (each with a 16-in barrel length) while ensuring a consistent muzzle to forehead distance of 12.7 cm. Results: The 9 mm bullets traveled further through the head and into the ballistic gel (P < .001) and the furthest total distance (P < .001). Bullets from the .38 Special traveled further into the ballistic gel and a further total distance than both the .22 LR and .22 Mag (P < .001). The trauma area of the brain was greater for the 9 mm and the .38 Special bullets when compared to .22 LR or .22 Mag, respectively (P < .001). There was no difference in the trauma area of the brain for the .22 LR bullets compared to .22 Mag bullets (P = .12). Implications: This proof-of-concept study generated data to define efficacy and safety considerations when using a firearm to euthanize market-weight pigs and demonstrated that the .22 LR full metal jacket bullet could provide predictable euthanasia in market-weight pigs with minimal risk of contralateral emergence.

A Pork Industry in the Backyard: An Analysis of Toxoplasma gondii Infection in Serbia's Pigs.

As pork is an important source for Toxoplasma gondii infection, we have analyzed T. gondii genotypes and toxoplasmosis prevalence in pigs in Serbia in the context of production statistics and economics to assess the specific risk to public health. Genotyping was performed using MnPCR-RFLP; T. gondii-specific IgG antibodies were detected using a modified agglutination test (MAT); and statistical data were extracted from official records and provided by government authorities. The results indicate that, from 2006 to 2021, the median number of annually slaughtered pigs was 5.6 million, yet only 36.1% were processed by abattoirs. The remainder were "backyard pigs" slaughtered on family farms and homesteads. Toxoplasmosis seroprevalence in market-weight (MW) pigs prior to 2006 was 15.2%, and was 15.1% in 2019. The seroprevalence in owned city cats, likely infected by livestock meat, was 33.2%. ToxoDB#1 was identified in pig tissues. The results indicate that backyard pigs are the backbone of the industry and provide as much as 60% of the pork in Serbia. The seroprevalence in pigs and city cats shows that farms are reservoirs for the parasite. Thus, innovative means of reducing T. gondii infection designed with backyard farmers in mind are needed to reduce the risk to public health.

Prevalence of carcass lesions and their effects on welfare, carcass composition and meat quality in slaughtered pigs

Abstract The aims of this study were to determine the prevalence of carcass lesions in slaughtered pigs and to quantify their relationships with different animal characteristics, pre-slaughter factors, blood measurements, performance indices, carcass composition and meat quality traits. Data was recorded for 30 journeys referring to 1080 market-weight pigs that originated from 15 commercial small-scale finishing farms. Carcass lesions were visually assessed on the slaughterline in different parts of the carcass, i.e., anterior, middle and posterior, using a three-point scale. Complete blood count was investigated. The following performance indices and carcass composition traits were measured: average lifetime daily weight gain, live, hot and cold carcass weights, cooler shrinkage, dressing percentage, backfat thickness and meatiness. Meat pH and temperature were measured 45 minutes postmortem. Of the 1080 pigs slaughtered in 30 batches, 70.28% displayed some degree of lesions on the carcass (moderate – 30.00%; severe – 40.28%). The carcass lesions were the most prevalent (50.20%) in the posterior part of the pig carcass. RYR 1 genotype, live weight, loading density, lairage time, lairage density and slaughter season affected the carcass lesion prevalence. The presence of carcass lesions, irrespective of severity, was associated with alterations in blood measurements in slaughtered pigs, indicating compromised animal welfare. The presence of severe carcass lesions in slaughtered pigs was significantly associated with increased meat pH45min, which led to the highest occurrence of dark, firm and dry pork. In contrast, there was strong evidence of association between the presence of moderate carcass lesions in slaughtered pigs and both decreased meat pH45min and increased meat T45min, which led to the highest occurrence of pale, soft and exudative pork among the carcass lesion groups. In conclusion, this study showed a high prevalence of carcass lesions in slaughtered pigs, whereby the risk of their occurrence was affected by both animal characteristics and pre-slaughter conditions. Also, the presence of carcass lesions in slaughtered pigs, irrespective of severity, was significantly associated with alterations in the blood measurements and pork quality.

Cartilage-Sparing Properties of Equine Omega Complete in an Organ Culture Model of Cartilage Inflammation.

The purpose of this study was to determine anti-inflammatory and/or chondroprotective effects of Equine Omega Complete (EOC) on cartilage explants stimulated with lipopolysaccharide (LPS). Explants were aseptically prepared from the intercarpal joints of 17 market-weight pigs and placed in culture at 37°C for a total of 120 hours. For the final 96 hours, explants were conditioned with a simulated digestion extract of EOC (0, 36 or 180 μL/mL), and for the final 48 hours explants were stimulated with LPS (0 or 15µg/mL). Media was removed and replaced every 24 hours. Samples from the final 48 hours were analyzed for biomarkers of cartilage inflammation (prostaglandin E2 [PGE2] and nitric oxide [NO]) and cartilage structure (glycosaminoglycan [GAG]). At the end of the culture period cartilage explants were stained for an estimate of cell viability. Stimulation of unconditioned explants with LPS significantly increased media concentrations of PGE2, GAG and NO compared with that from unstimulated explants. LPS stimulation did not significantly affect cell viability. Both concentrations of EOC prevented significant LPS-stimulated cartilage release of GAG without impairing chondrocyte viability. No other effects of treatment were observed. These data provide evidence for a non-cytotoxic, chondroprotective effect of EOC in cartilage. This in vitro experiment supports the use of EOC in protecting against the detrimental effects of inflammation on cartilage structure.

Wheatgrass extract has chondroprotective and anti-inflammatory effects on porcine cartilage

Lameness is a commonly observed disorder in sows and negatively impacts both animal welfare and the profitability of the pig sector. The purpose of this study was to determine anti-inflammatory and/or chondroprotective effects of wheatgrass (WG) on porcine cartilage explants stimulated with lipopolysaccharide (LPS). Explants were aseptically prepared from the intercarpal joints of nine market-weight pigs and placed in culture at 37°C for a total of 120 hours. For the final 96 hours, explants were conditioned with an aqueous extract of WG (0, 5 or 15 μg/mL), and for the final 48 hours explants were stimulated with LPS (0 or 10 µg/mL). Media was removed and replaced every 24 hours. Samples from the final 48 hours were analyzed for biomarkers of cartilage inflammation [prostaglandin E2 (PGE2) and nitric oxide (NO)] and cartilage structure [glycosaminoglycan (GAG)], and cartilage explants were stained for an estimate of cell viability. Stimulation of explants with LPS significantly increased media concentrations of PGE2, GAG and NO compared with that from unstimulated explants. LPS stimulation did not significantly affect cell viability. Conditioning of explants with WG (5 μg/mL) significantly reduced LPS-stimulated cartilage release of PGE2, NO, and GAG (5 and 15 μg/mL), without impairing chondrocyte viability. These data provide evidence for a non-cytotoxic chondroprotective and anti-inflammatory effect of WG extract in cartilage and suggest a role of WG in protection against cartilage breakdown, inflammation, and pain associated with osteoarthritis.

Commercial straight-deck trailer vibration and microclimate conditions during market-weight pig transport during summer

The objective of this study was to collect and quantify three-axis acceleration data from six locations within commercial pig transport trailers during summer. Two trucks with straight-deck trailers transporting two loads per day were observed for 5 consecutive days (N= 20). Accelerometers were placed under the floor of each trailer’s top and bottom decks (DECs) in the center of three sections (SECs): fore, middle, and aft. Data from each trailer section were processed to calculate z- and x,y-axis root mean square (RMS) values and vibration dose values (VDVs) during loading, transport, and unloading. There were no DEC × SEC interactions or SEC main effects for z-axis RMS or VDV during any transportation stage (P> 0.06). The bottom deck had a greater x,y-axis RMS than the top deck during all transportation stages (P< 0.01). The bottom deck had a greater x,y-axis VDV than the top deck during loading and transport (P< 0.03), but there was no difference (P= 0.52) during unloading. The bottom deck had a greater z-axis RMS and VDV than the top deck during loading and transport (P< 0.01), but there were no differences during unloading (P> 0.07). There were no SEC effects for x,y- and z-axis RMSs and VDVs during all transportation stages (P> 0.06). Acceleration values were compared with exposure action values (EAV; injury possible) and exposure limit values (ELV; injury likely) vibrations thresholds. Over the 5 observation days during all transport stages, a greater percentage of compartments violated both RMS and VDV thresholds in the x,y orientation (average 90%) than in the z orientation (average 76%). Overall, these data indicate that bottom decks experience greater three-axis vibrations than top decks in straight-deck trailers and that pigs on bottom decks may experience greater discomfort during transportation that could contribute to fatigue or the non-ambulatory condition.

2 Vibration Profiles of Commercial Straight-Deck Trailers Transporting Market-Weight Pigs During Summer

Abstract The objective was to collect and quantify three-axis acceleration data from locations within commercial transport trailers shipping market weight pigs during summer. Two trucks and straight-deck trailers, owned and operated by a single producer, were observed during two loads per day for five consecutive days. Three-axis accelerometers were placed under top and bottom deck floors in the center of the fore, center, and aft compartments. Z-axis and combined x- and y-axis data were processed to generate root-mean-square (RMS) values and vibration dose values (VDV) during loading, trailer movement, and unloading. At all periods of the trip and both sets of axis data, there were no Deck × Area interactions (P > 0.11) for RMS and VDV values. During loading and movement, the bottom deck had greater z-axis RMS and VDV values than the top deck (P < 0.01), but there was no difference (P = 0.07) during unloading. There were no Area effects for z-axis RMS and VDV values during all time periods (P > 0.06). During all periods, the top deck had greater x,y-axis RMS values than the bottom deck (P < 0.02). During loading and movement, the bottom deck had greater x,y-axis VDV values than the top deck (P < 0.03), but there was no difference (P = 0.52) during unloading. There were no Area effects for x,y-axis RMS and VDV values during all time periods (P > 0.07). Individual trip RMS and VDV values were compared with exposure action values (EAV; injury possible) and exposure limit values (ELV; injury likely). At all parts of the trip, trailer RMS and VDV violated between 51% and 99% EAV and ELV thresholds. These data indicate top and bottom decks vibrate differently and pigs experience vibrations that may contribute to fatigued pig syndrome or the non-ambulatory condition.

Infectious dose of Senecavirus A in market weight and neonatal pigs.

Foot-and-mouth disease virus (FMDV) is a picornavirus that produces a highly transmissible vesicular disease that can devastate meat and dairy production to such an extent that FMDV-free countries commit significant economic resources to maintain their FMDV-free status. Senecavirus A (SVA), also a picornavirus, causes vesicular disease in swine that is indistinguishable from FMDV. Since 2015, SVA outbreaks have been reported around the world requiring FMDV-free countries to investigate these cases to rule out FMDV. Understanding the pathogenesis of the SVA and its ability to transmit to naïve populations is critical to formulating control and prevention measures, which could reduce FMDV investigations. The primary objective of this study was to determine the infectious dose of SVA in market weight and neonatal pigs. A 2011 SVA isolate was serially hundred-fold diluted to create four challenge inoculums ranging from 106.5 to 100.5 TCID50/ml. Four market weight pigs individually housed were intranasally inoculated with 5 mL of each dose (n = 16). Serial ten-fold dilutions were used to create 6 challenge inoculums ranging from 105.5 to 100.5 TCID50/ml for neonatal pigs. Again, four animals in individual housing were challenged orally with 2 mL of each dose (n = 24). Detection of SVA by PCR in collected samples and/or neutralizing antibody response was utilized to classify an animal as infected. The minimum infectious dose for this study in market weight animals was 1,260 TCID50/ml (103.1 TCID50/ml) and for neonates it was 316 TCID50/ml (102.5 TCID50/ml). Knowledge of the infectious dose of SVA can guide biosecurity and disinfection measures to control the spread of SVA.

Swine behavioral and physiological response to increasing sodium nitrite oral drench administration and resulting tissue residues

Objectives: This study aimed to evaluate the physiological and behavioral responses of pigs administered sodium nitrite, determine an ideal dosing rate by oral drenching of sodium nitrite for depopulation events, and evaluate the nitrite residue present in the ocular fluid and skeletal muscle after sodium nitrite administration. Materials and methods: Four groups of 10 market weight pigs (40 market weight pigs total) and 1 group of 10 sows were used. Each group of market weight animals received a different oral drench dose of sodium nitrite solution (1× [400-441 mg/kg], 2× [800-882 mg/kg], 2.5× [1000-1102 mg/kg], and 3× [1200-1323 mg/kg]) and was observed for distress behaviors. Two market weight animals in each treatment group were implanted with a monitor to measure body temperature, heart rate, and activity levels. The dosing rate with apparent best behavioral and physiological response was applied to the 10 sows and the same behaviors monitored. After death was confirmed, ocular fluid and skeletal muscle samples were collected from the sows. Results: An increased dosage of sodium nitrite greatly reduced the time to distress with a significant linear relationship. A higher frequency of vocalizations and the most frequent spikes in activity levels were observed in the lowest dosing group. No correlation was found between ocular fluid nitrite and skeletal muscle sodium nitrite concentrations. Implications: Oral drenching of sodium nitrite is a viable method for swine depopulation events. Higher doses of sodium nitrite have better welfare associations. Ocular fluid nitrite anion concentrations do not correlate with sodium nitrite skeletal muscle concentrations.

Combined effects of weather conditions, transportation time and loading density on carcass damages and meat quality of market-weight pigs.

This study investigated the interactive effects of weather conditions, transportation time and loading density on carcass damages and meat quality traits of market-weight pigs under commercial conditions. The following pork quality parameters were measured: pH and temperature; colour; drip, thawing and cooking loss; and textural traits. Pigs were assigned to one of eight groups arranged in a 2 2 2 factorial design according to the weather conditions (hot and cold), transportation time (short and long) and loading density (high and low). A three-way ANOVA and Tukey's post-test (multiple comparisons) were performed to assess the differences between groups in examined pork quality traits. Pigs exposed to short transportation ( 20 ) at high loading density (0.29 ) during hot weather conditions produced meat with the lowest initial and ultimate meat pH value and sensory colour scores, and the highest initial temperature and the occurrence of pale, soft and exudative pork. The occurrence of pale, soft and exudative pork was reduced 5-fold during hot weather conditions when pigs were exposed to longer transportation ( 210 ) and low loading density (0.53 ). Pigs exposed to short transportation ( 20 ) at high loading density (0.41 ) during cold weather conditions produced the highest quality pork (the highest percentage of red, firm and non-exudative pork) characterised by lowest drip loss and value and the highest sensory colour scores. The highest percentages of carcass damages were recorded in pigs exposed to both low (0.50 ) and high (0.33 ) loading density during long transportation ( 210 ) in cold weather conditions. In conclusion, weather conditions and loading density are of greater importance for the occurrence of carcass damages and pork quality variation than transportation time.

Effects of handling procedure during unloading on welfare and meat quality of market-weight pigs

This study aimed to examine the effects of handling procedure during unloading on blood glucose level, carcass lesions and meat quality of market-weight pigs. Rough handling during unloading was related to higher blood glucose level and frequency of slipping and falling. In contrast, gentle handling during unloading was related to the lower blood glucose level and frequency of slipping and falling, but the higher frequency of reluctance to move and turning back. Rough handling during unloading resulted in a higher carcass lesion score, and the higher tendency towards lesions on the middle part of the carcass and handling-type carcass lesions. Pigs subjected to rough handling during unloading had a higher meat temperature 45 minutes after slaughter, lower meat pH value 45 minutes and 24 hours postmortem, higher drip and cooking loss, higher L* and b* values and lower sensory colour score, and consequently, produced a higher prevalence of pale, soft and exudative meat. In contrast, pigs exposed to gentle handling during unloading produced a lower percentage of pale, soft and exudative meat, but a higher percentage of pale, firm, and nonexudative. In conclusion, gentle handling during unloading resulted in improved animal welfare, decreased stress intensity, and increased pork quality.

Cartilage explant model reflects resolvin D1 increase during recovery from LPS stimulation

Purpose: Osteoarthritis (OA) is a low-grade chronic inflammatory condition wherein the homeostatic balance of catabolic and anabolic processes favour the former, leading to a net decline in structural integrity of cartilage. The dissimilating pathways contributing to this decline have attracted much scientific scrutiny, with a host of pro-inflammatory cytokines and catabolic enzymes now known to orchestrate the protracted but eventual loss in joint function. Yet, amid the homeostatic badinage between repair and decline, there lies a wealth of reparative physiology which delays the tissue failure which characterizes clinical OA. An improved understanding of the interplay between pro-inflammatory and pro-resolving mediators can inform better management of early-stage OA, which can thus prolong healthy tissue function. Resolvin D1 (RvD1) is a pro-resolving mediator, which has been found to be dysregulated in rheumatoid arthritis and assists with resolving acute inflammation. The role of RvD1 in cartilage recovery from pro-inflammatory stimulation with lipopolysaccharide (LPS) is not known. We hypothesized that after an acute bout of inflammation in the articulating joint, cartilage-derived RvD1 is increased during the recovery phase, and thus participates in initiating inflammation resolution. The aim of this pilot study was to quantify production of RvD1 by cartilage explants following in vitro exposure to LPS. Methods: A single front limb from seven market weight pigs were collected and aseptically dissected extracting 0.4mm articular cartilage explants from the intercarpal joint. Explants were cultured in media (DMEM, antibiotics, amino acids) and incubated at 37°C and 7%CO2 for 168h. Media was removed and refreshed every 24h, following the first 48h of acclimatization explants were stimulated with LPS (0 or 10μg/mL) for 48h (collection time: 0h-S, 24h-S, 48h-S), followed by 48h of recovery (72h-R, 96h-R) in which media was refreshed without LPS stimulation. Media samples from the final 96h (0h-S to 96h-R) were collected every 24h during media changes and analyzed for nitric oxide (NO) (Greiss Reaction) and RvD1 (ELISA). Data were analyzed using a PROC GLIMMIX model (SAS Studio) looking at time-treatment interactions and visualized with two scatter plot graphs. Data are shown as mean±SEM and significance was accepted at p<0.05. Results: LPS stimulated explants elicited an increase in NO compared to controls from 0h-S to 48h-S and continued to increase until 72h-R (p=0.0006), as shown in Figure 1. RvD1 did not elicit a significant response to LPS stimulation but when graphed over time (0h-S to 96h-R) as seen in Figure 2, did visually show a change in response to stimulation and in comparison to its unstimulated controls. RvD1 response in unstimulated explants was elevated at 24h-R, (2109.40±188.56pg/mL) before continuously decreasing until 96h-R (1514.63±203.50pg/mL). RvD1 release in LPS stimulated explants decreased from 0h-S to 48h-S (0h: 1790.83±188.56pg/mL;48h:1489.11±203.50pg/mL) then increased until 96h-R (72h: 1743.28±177.16pg/mL; 96h:1814.47±177,17pg/mL).View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Efficacy of phage therapy in pigs: systematic review and meta-analysis.

Limits on the use and efficacy of various antibiotics coupled with negative consumer perception of the practice have together spurred substantial research into compounds that could reduce the use antibiotics to control bacterial diseases in pigs. Bacteriophages are often among such potential compounds, and various groups have examined the efficacy of bacteriophages or bacteriophage products in limiting transmission or colonization of targeted bacteria. The study presented here provides a systematic review of such studies followed by a meta-analysis of aggregated data produced by each study. The data set was limited to inputs (n = 19; 576 total observations) from studies where: 1) live pigs were inoculated with a known quantity of challenge bacteria; 2) challenged animals were treated with a known quantity of phages; 3) concentrations of the challenge bacteria were measured in different tissues/fluids following phage treatment; and 4) SD (or SE to allow calculation of SD) was reported. Concentrations of challenge bacteria were significantly lower in phage-treated pigs versus challenged but untreated pigs (P < 0.0001; effect size = −1.06 1log10 colony-forming units [CFU]/g). The effect size of phage treatment was significantly greater (P < 0.05) in samples collected 48 to 96 h following phage treatment versus those collected ≤ 24 h following phage treatment. Likewise, effect size of phage treatment was significantly greater in piglets versus market-weight pigs. Across observations, phage treatment effect sizes were greatest (P < 0.01) in fecal samples versus ileal or cecal samples. Taken together, these data indicate that phage treatment can significantly reduce the concentrations of targeted bacteria in pigs; scenarios exist, however, where phage treatment could predictably be more or less effective.

PSIII-4 Determining the Efficacy and Safety of Differing Caliber/Ammunition Combinations for the Humane Euthanization and Subsequent Mass Depopulation of Market Weight Pigs

Abstract The objective of this proof of concept exercise was to validate a field applicable methodology designed to objectively assess the multiple caliber/ammunition combinations available for the safe and humane euthanization of market weight pigs during mass depopulation events. Heads of an equal number of barrows and gilts (n = 64) were randomly assigned to one of four caliber/ammunition combinations consisting of the .22 LR, .22 Mag, 0.38 Special, and 9mm. Fully jacketed (FMJ) ammunition was discharged from each of four unique firearms while ensuring that the distance from the muzzle to the forehead was consistent. The MIXED procedure of SAS was used to test the fixed effects of sex and caliber. No differences in skull thickness existed between sex (P = 0.32) or caliber/ammunition combination (P = 0.34). There was no difference in entrance wound diameter between the .38 Special and the 9mm (P = 0.15) yet the entrance wound diameter of the .38 Special and 9mm was larger than both the .22 LR and .22 Mag, respectfully (P &amp;lt; 0.0001). The 9mm bullets traveled further into the ballistic gel (P &amp;lt; 0.0001) and the furthest total distance (P &amp;lt; 0.0001). Bullets from the .38 Special traveled further into the ballistic gel and a further total distance than both the .22 LR and .22 Mag (P &amp;lt; 0.0001). There was no difference in the measurable trauma area of the brain for the 9mm bullets compared to .38 Special bullets (P = 0.83). The measurable trauma area of the brain was greater for the 9mm and .38 Special bullets when compared to both the .22 LR and .22 Mag (P &amp;lt; 0.0001). In conclusion, the efficacy and safety of the multiple caliber/ammunition combinations available for use in the euthanization of market weight pigs can be objectively quantified, replicated, and reported.

60 Chondroprotective effect of an omega-3 fat supplement in a cartilage explant model of inflammation

Omega-3 fatty acid-enriched supplements (n3FAs) are commonly fed to horses for prevention of cartilage breakdown, though few have objective evidence for efficacy. Dietary n3FAs are metabolized to less inflammatory eicosanoids than their n6FA counterparts, and facilitate acceleration of inflammation resolution. The effect of n3FAs on cartilage inflammation has not been described. Equine Omega Complete (EOC) (Southern Equine Distributing; Erin ON) is an equine n3FAs made up of stabilized fish oil, soya oil and vitamin E (n3FA content: DHA-8.53mg/mL, EPA-12.93mg/mL). The objective of the current study was to evaluate the effect of a simulated digestion extract of EOC on response of cartilage explants to an inflammatory stimulus [lipopolysaccharide (LPS)] with respect to biomarkers of inflammation [prostaglandin E 2 (PGE 2 ) and nitric oxide (NO)], cartilage turnover [glycosaminoglycan (GAG)], and cell viability. We predicted that EOC would blunt inflammatory and catabolic effects of LPS without adversely affecting cell viability. Cartilage explants were aseptically prepared from the intercarpal joint of 18 market weight pigs and cultured at 37°C and 7% CO 2 for 120h. Explants were conditioned with Blank Digest fluid (B), or digest fluid containing EOC [T1 (36 µL/mL) or T3 (108 µL/mL); approximately equivalent to 60 or 180 mL/day for a 500 kg horse], and explants were stimulated with LPS (0 or 10 µg/mL) for the final 48 h. After 120 h of culture, explants were weighed and stained for live (calcein-AM) and dead (Ethidium homodimer-1) cells. Media from the final 48 h was analyzed for GAG (DMMB assay), NO (Griess Reaction), and PGE 2 (ELISA). Data were analyzed using a 2-way RM-ANOVA (SigmaPlot, Version 12), and significance was accepted at P < 0.05. LPS stimulation of B explants produced a significant increase in PGE 2 , GAG and NO. Conditioning of explants with T1 and T3 prevented significant increase in LPS-induced GAG release ( P = 0.15, P = 0.20, respectively). Neither T1 nor T3 significantly affected LPS-induced NO. There was no effect of LPS or EOC on cell viability. The data demonstrate that conditioning of cartilage explants with a simulated digestion extract of EOC prevents LPS-mediated breakdown of cartilage matrix, providing evidence for a chondroprotective effect of the supplement in horses at risk for development of degenerative articular disorders. Future studies should explore the effects of EOC on inflammation resolution via induction of n3FA-derived compounds such as resolvin D1.

Measurement of the three-axis vibration, temperature, and relative humidity profiles of commercial transport trailers for pigs.

The objective of this study was to collect and interpret three-axis acceleration, temperature, and relative humidity data from six locations within commercial transport trailers shipping market-weight pigs. Transport was observed in Kansas (n = 15) and North Carolina (n = 20). Prior to loading, three-axis accelerometers were affixed to six locations on the trailers: top fore (TF), top center (TC), top aft (TA), bottom fore (BF), bottom center (BC), and bottom aft (BA) compartments. Data were post-processed to calculate root-mean-square (RMS) accelerations and vibration dose values (VDV) in the vertical direction and the horizontal plane. These values were compared with exposure action values (EAV) and exposure limit values (ELV), vibration levels deemed uncomfortable and potentially dangerous to humans. Additionally, RMS and VDV were compared among the trailer compartments. The vertical RMS accelerations for all compartments exceeded the EAV for loads measured in Kansas, and for the majority of the compartments measured in North Carolina. Many compartments, specifically the BA compartment from all trips, exceeded the vertical ELV. Regardless of where the data were collected, fewer compartments exceeded the EAV in the horizontal orientation. Only BA compartments exceeded the ELV in the horizontal orientation. There were Area × Level interactions for vertical and horizontal RMS and VDV (P < 0.01). The BF compartment had a greater vertical RMS value than the TF, TC, and BC (P < 0.02) compartments, but did not differ (P = 0.06) from the TA compartment. The vertical RMS of the TA compartment did not differ from the TF, TC, and BC compartments (P > 0.13). The BF compartment had a greater (P = 0.02) vertical VDV value than the TC location, but did not differ from the other locations (P > 0.16). All other locations did not differ in vertical VDV (P > 0.12). The BF compartment had greater horizontal RMS than the TC and TA compartments (P < 0.01), but did not differ from TF and BC compartments (P > 0.12). All other compartments did not differ in horizontal RMS (P > 0.34). All compartments, aside from the BA compartment, did not differ in horizontal VDV (P > 0.19). Vibration analyses indicated the BA compartment had the greatest vertical and horizontal vibrations and a large percentage of the compartments exceed the EAV and ELV, which indicated pigs may have experienced uncomfortable trips that could cause discomfort or fatigue.

140 Relaxin Regulates Porcine Adipose Tissue Development by Inhibiting Preadipocyte Number, Stimulating Lipolysis, and Upregulating mRNA Expression of Adipokine, Fatty Acid Metabolism and Extracellular Matrix Genes

Abstract Relaxin (RLN) is best known as a reproductive hormone that remodels cervical connective tissue. However, porcine adipose tissue can secrete and respond to RLN, suggesting locally derived RLN could modulate adipose tissue development and function. To test this hypothesis, primary cultures of porcine subcutaneous adipose tissue stromal-vascular (AT-SV) cells and visceral adipose tissue explants were utilized as model systems to determine the effect of 100 ng/ml exogenous RLN on 1) preadipocyte proliferation and differentiation, 2) the mRNA expression of adipokine, extracellular matrix protein and fatty acid metabolism genes, and 3) lipolytic rate in porcine adipose tissue. AT-SV cells were harvested from 3-day-old neonatal pigs (n=6) and plated in vitro in growth medium containing either vehicle or RLN for cell number assays or were induced to differentiate by treatment with insulin, hydrocortisone, and rosiglitazone for 8 days in the presence or absence of RLN for adipogenesis assays. Total RNA was extracted from differentiating cultures on days 0 and 8 post-induction. Real-time PCR was then utilized to determine changes in mRNA expression for target genes. For lipolysis and cell signaling experiments, visceral adipose tissue was obtained from market weight pigs at harvest, minced into explants, and cultured in serum-free medium in the presence or absence of RLN and cAMP pathway modulators with differences in glycerol release determined following 2-hour treatment. Overall, RLN decreased preadipocyte number 1.27-fold under serum-free conditions (P &amp;lt; 0.05), enhanced adipogenesis based upon 2.4-fold increase in GAPDH activity (P &amp;lt; 0.05) and a 2.2-fold increase in ORO accumulation (P &amp;lt; 0.05) while significantly increasing the mRNA expression of multiple metabolic, adipokine, and extracellular matrix component genes. RLN treatment stimulated glycerol release by 3-fold via the cAMP pathway (P &amp;lt; 0.01). Collectively, these data support the hypothesis that RLN regulates adipose tissue development through stimulating adipogenesis and modulating adipocyte metabolism.

Culturing Articular Cartilage Explants in the Presence of Autologous Adipose Tissue Modifies Their Inflammatory Response to Lipopolysaccharide.

The purpose of the current study was to explore the effect of autologous adipose tissue on cartilage responses to lipopolysaccharide (LPS). We hypothesized that LPS elicits an inflammatory response in cartilage, and that response is augmented in the presence of adipose tissue. Furthermore, we hypothesized that this augmented inflammatory response is due, at least in part, to increased exposure of cartilage to adipose tissue-derived c3a. Porcine cartilage explants from market-weight pigs were cultured in the presence or absence of autologous adipose tissue for 96 hours, the final 48 hours of which they were stimulated with LPS (0 or 10 μg/mL). Adipose tissue explants were also cultured alone, in the presence or absence of LPS. Media from all cartilage treatments was assayed for c3a/c3a des Arg, PGE2, GAG, and NO, and the viability of cartilage tissue was determined by differential fluorescent staining. Media from adipose tissue explants was assayed for c3a/c3a des Arg and PGE2. LPS produced a significant increase in PGE2, GAG, and NO production when cartilage was cultured in the absence of adipose tissue. Coculture of adipose tissue prevented a significant increase in PGE2 in cartilage explants. There was no effect of adipose tissue on LPS-induced GAG or NO, but the presence of adipose tissue significantly reduced cell viability in LPS-stimulated cartilage explants. Adipose tissue explants from lean animals reduced inflammatory responses of cartilage to LPS via a c3a/c3a des Arg-independent mechanism and were associated with a significant decline in cell viability. Thus, contrary to our hypothesis, adipose tissue from lean animals does not augment the inflammatory response of cartilage to stimulation by LPS. The mechanism of modulatory effects of adipose tissue on LPS-induced increase in PGE2 and decline in chondrocyte viability requires further research but appears to have occurred via a mechanism that is independent of adipocentric c3a/c3a des Arg.