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Eighty-eight gilts [initial body weight (BW) 49.8 ± 0.8 kg] were recruited to determine the effects of moderate energy and protein restriction during the development period on changes in BW and backfat depth (BF) and subsequent lactation performance. Gilts were randomly assigned to one of four feeding programs: 1) standard commercial diet fed ad libitum (CON), 2) standard commercial diet fed 10% or 3) 20% below ad libitum, or 4) a high–fiber diet fed ad libitum [2.5 times more fiber (neutral detergent fiber) than the commercial diet to dilute net energy and crude protein by approximately 20% and 13%, respectively; FIB]. The gilts were housed individually and received the feeding programs between 90 and 190 (breeding) d of age and standard gestation and lactation diets thereafter. Litters were standardized to 12 ± 1 pigs within 48 h of farrowing; weaning occurred at 20.0 ± 0.4 d of age. Gilts that received the 20% restricted program had lower overall average daily feed intake (ADFI) during the development period (2.64 ± 0.04 kg; P < 0.05) versus all other feeding programs and gilts that received the 10% restricted program had lower ADFI than FIB and CON, which were not different (2.96 vs. 3.44 and 3.47 ± 0.04 kg for 10%, FIB and CON, respectively; P < 0.05). Plasma free fatty acid (FFA) concentrations on day 180 of age were lower for gilts that received the 10% and 20% restricted programs compared to gilts that received the FIB and CON programs, which were not different (97 and 86 vs. 220 and 149 ± 29 µEq/L, respectively; P < 0.05). Plasma concentrations of glucose, urea, prolactin, and IGF-1 were not different among feeding programs on day 180 of age. At breeding, gilts that received the FIB and 10% programs had lower BW and BF versus CON (145.7 and 144.8 vs. 155.2 ± 0.9 kg and 14.4 and 14.8 vs. 16.5 ± 0.2 mm for BW and BF, respectively; P < 0.05) but greater BW than gilts that received the 20% restricted program (137.9 kg; P < 0.05). The BW and BF of gilts did not differ at the end of gestation or at weaning. The ADFI of sows during lactation and offspring birth weight and growth rate during lactation and the 5-wk nursery period were not influenced by gilt development feeding program. Therefore, a high-fiber feeding program could be used in group-housing gilt-development scenarios, where feed is offered ad libitum, to control BW and BF prior to breeding without influencing milk production in the subsequent lactation period.

Influenza A viruses (IAVs) are common causes of respiratory infection in pigs. The objective of this study was to characterize the circulation of IAVs between weaning and market age on the basis of development of antibody response and molecular epidemiology of detected viruses. Two batches of weaned pigs were followed in the nursery and finisher barns with a sample of 81 and 75 pigs. Nasal swabs and blood samples were collected from individual pigs for virological and serological analyses. A H3N2 subtype virus, of cluster IV, was detected in Study 1, with a maximum of 97.9% identity to HA gene of viruses previously isolated in Ontario. In Study 2, a H1N1 subtype virus, of 2009 H1N1 pandemic lineage, was detected, with a maximum of 97.8% identity to HA gene of viruses previously isolated in Ontario. On the basis of HA gene, it was observed that pigs were being detected with the same virus over time. The existence of antibody titers for IAV other than the isolated one confirmed that more than one subtype can circulate in the same population. In Study 1, pigs with higher numbers of IAV detection had lower serological titers for the same virus that was confirmed to circulate in the nursery (P

Background Salmonella enterica serovars are a major cause of foodborne illness and have a substantial impact on global human health. In Canada, Salmonella is commonly found on swine farms and the increasing concern about drug use and antimicrobial resistance associated with Salmonella has promoted research into alternative control methods, including selecting for pig genotypes associated with resistance to Salmonella. The objective of this study was to identify single-nucleotide variants in the pig genome associated with Salmonella susceptibility using a genome-wide association approach. Repeated blood and fecal samples were collected from 809 pigs in 14 groups on farms and tonsils and lymph nodes were collected at slaughter. Sera were analyzed for Salmonella IgG antibodies by ELISA and feces and tissues were cultured for Salmonella. Pig DNA was genotyped using a custom 54 K single-nucleotide variant oligo array and logistic mixed-models used to identify SNVs associated with IgG seropositivity, shedding, and tissue colonization. Results Variants in/near PTPRJ (p = 0.0000066), ST6GALNAC3 (p = 0.0000099), and DCDC2C (n = 3, p Salmonella, while variants near AKAP12 (n = 3, p RALGAPA2 (p = 0.0000760) may be associated with susceptibility. Conclusions Further study of the variants and genes identified may improve our understanding of neutrophil recruitment, intracellular killing of bacteria, and/or susceptibility to Salmonella and may help future efforts to reduce Salmonella on-farm through genetic approaches.

Background The heightened prevalence of Salmonella Typhimurium remains a public health and food safety concern. Studies have reported antibiotic, flavophospholipol, may have the ability to reduce Salmonella in swine, as well as alter the gut microbiota in favour of beneficial bacteria by inhibiting pathogenic bacteria. Thus, the objective of this study was to investigate the fecal microbiota of weaned pigs receiving in-feed flavophospholipol and challenged with Salmonella Typhimurium. Results Twenty-one weaned pigs were fed either a diet containing 4 ppm of flavophospholipol (treatment group) or a non-medicated feed (control group) for 36 days post-weaning (Day 1 to Day 36). The pigs were orally challenged with a 2 mL dose of 108 CFU/mL of S. Typhimurium at Day 7 and Day 8. Community bacterial DNA extracted from fecal samples collected at Day 6 (before challenge) and Day 36 (28 days after challenge) were used to assess the fecal microbiota using the V4 region of the 16S rRNA gene with Illumina MiSeq next-generation sequencing. Sequencing data were visualized using mothur and analyzed in JMP and R software. The fecal microbiota of pigs in the treatment group had differences in abundance of phyla (Firmicutes, Proteobacteria) and genera (Lactobacillus, Roseburia, Treponema, unclassified Ruminococcaceae, Blautia, Streptococcus, Megasphaera, Dorea, Sporobacter, Peptococcus, unclassified Firmicutes, Clostridium IV and Campylobacter) when compared to pigs that were controls, 28 days after challenge with Salmonella (P P = 0.001) and decrease in Firmicutes (P = 0.012) and genus Roseburia (P = 0.003) in the treated pigs suggestive of possible microbial dysbiosis. An increased abundance of genera Lactobacillus (P = 0.012) was also noted in the treated group in comparison to the control. Conclusion Based on these findings, it is difficult to conclude whether treatment with 4 ppm of flavophospholipol is promoting favorable indigenous bacteria in the pig microbiota as previous literature has suggested.

In Canada, piglets receive analgesia to control pain after surgical castration. There is interest in examining the potential to mix non-steroidal anti-inflammatory drugs with iron dextran prior to injection to minimize piglet handling and labor. The objective of this study was to compare pharmacokinetics and the relative bioavailability of ketoprofen given alone (3.0 mg/kg IM) versus the same dose of ketoprofen mixed with iron dextran (52.8 mg/kg IM) (ketoprofen + iron dextran) before injection in piglets. Piglets 8 to 11 d old were allocated into 2 treatment groups (n = 8/group). Plasma drug concentrations were measured using mass spectrometry at 13 time points after injection. No significant differences were detected between the 2 groups when examining pharmacokinetic parameters (e.g., C(max), T(max), AUC) or relative bioavailability for either S- or R-ketoprofen enantiomers (P > 0.05). However, pain control efficacy and food safety studies of these formulations are required to further examine this practice.

Background Respiratory diseases are among the most important factors affecting swine farm productivity in Canada. The objectives of this study were to investigate antibody responses to porcine reproductive and respiratory syndrome virus (PRRSV), influenza A virus (IAV), and Mycoplasma hyopneumoniae (M. hyopneumoniae) from weaning to the end of the finisher stage on a subset of commercial swine farms in Ontario, Canada, and to examine the association between nursery diet and antibody responses. Results Overall, older pigs were more likely to test seropositive for PRRSV and less likely to test seropositive for M. hyopneumoniae (p p M. hyopneumoniae (p M. hyopneumoniae, respectively, from the end of nursery to the end of finisher were classified as seropositive. Pigs fed a plant-based (low complexity) diet during nursery were more likely to be seropositive for PRRSV (p M. hyopneumoniae due to nursery diet complexity. Conclusions This study provides information regarding changes in serum antibody in pigs across different stages of production and highlights periods of vulnerability. Additionally, these findings may encourage further research into the effects of nursery diet complexity on disease susceptibility and immune response.

Sixty-three gilts were recruited at 90 days of age to evaluate the effects of a high-fiber gilt development feeding program on body weight and composition at breeding. Gilts (initial BW 50.9 ± 0.9 kg) were housed individually and randomly attributed to one of four feeding programs: [1] commercial diet fed ad libitum (CON), [2] commercial diet fed 10%, or [3] 20% below ad libitum, and [4] a high-fiber diet fed ad libitum (25% more fiber than the commercial diet and energy density reduced by 5%; FIB). Gilts received the feeding program between 90 days of age and breeding at ~190 days of age. Body weight and feed disappearance were determined weekly. Backfat depth was determined at 90, 145 (puberty), 160, and 190 (breeding) days of age. Over the entire experimental period, CON and FIB gilts had greater ADFI (mean of 3.50 ±0.07 kg) compared to 10% (2.95 ± 0.06 kg) and 20% gilts (2.70 ± 0.07kg; P < 0.05). The FIB feeding program reduced total energy and lysine intakes to amounts similar to 10%; both intakes were less than CON but greater than 20% gilts (P < 0.05). The ADG of FIB was less between days 145 (puberty) and 160 of age compared to CON gilts (0.86 vs. 1.09 ± 0.07 kg; P < 0.05). At breeding, FIB and 10% weighed less (146.5 ± 1.6 kg) than CON (152.7 ± 1.6 kg) and more than 20% gilts (138.7 ± 1.5 kg; P < 0.05). The FIB had less backfat than CON at breeding (14.9 vs. 16.7 ± 0.5 mm; P < 0.05), but did not differ from 10% or 20% gilts. In conclusion, the FIB feeding program limited energy intake, growth, and body fatness of gilts at breeding, even though gilts were offered feed ad libitum. Therefore, high-fiber feeding programs could be a practical means to control growth rates of developing gilts in commercial scenarios.

Simple Summary The presence of Salmonella on farms is a concern to the swine industry. Much of the focus of on-farm surveillance has been directed to the finishing stage because of food safety issues, but it is important to study Salmonella transmission during the nursery stage in order to develop control strategies. In this study, 50 cohorts of weaned pigs were monitored for Salmonella using blood samples taken at weaning and again near the end of the nursery stage and tested for antibodies. At the time of the second blood sampling, rectal swabs were obtained from the same pigs and cultured for Salmonella. A questionnaire regarding housing and management was also completed and used to evaluate risk factors for herds with active infection. If one pig out of the 20 tested in a cohort was found to be positive either based on the growth of Salmonella on culture or a rising antibody titre, then it was assumed that Salmonella was spreading among the pigs in that cohort. Active spread of Salmonella occurred in 80% of the nursery cohorts. Unfortunately, no risk factors were identified to explain the difference between positive and negative nurseries, including whether or not the farm used antibiotics. Abstract The objectives of this study were: to identify nursery cohorts with an active Salmonella infection using combined serological and bacteriological methods, and to try to identify risk factors associated with swine nurseries with active Salmonella spread. Twenty pigs from each of 50 cohorts of weaned pigs from 44 different nursery barns were sampled about the time of weaning and near the end of the nursery stage. Information regarding farm management and biosecurity practices were collected using a questionnaire. Blood samples were obtained at both visits, while rectal swabs were collected at the second visit. An enzyme-linked immunosorbent assay (ELISA) was used to test sera for Salmonella antibodies and rectal samples were cultured for Salmonella. A nursery cohort was identified as having an active Salmonella infection if Salmonella was cultured from one or more of the 20 pigs or if serological evidence suggested exposure to Salmonella. The association between farm-level management covariates and active Salmonella infection was assessed in 46 cohorts using a logistic regression model. Nine of 46 (20%) cohorts produced Salmonella-free pigs. The remaining 37 (80%) cohorts were classified as having an active infection. Examination of risk factors failed to identify how negative and positive nurseries differed.

Simple Summary Post-procedural castration pain control in piglets in Canada is managed with non-steroidal anti-inflammatory drugs (NSAIDs) such as meloxicam and ketoprofen. While combining NSAIDs with iron dextran (ID) reduces piglet injections and handling, it is unknown if this will affect NSAID pain control efficacy. This study evaluated the time it takes a pig to navigate an obstacle chute after surgical castration as an objective measure of pain control. The differences in navigation time of pigs given NSAIDs alone or mixed with ID prior to castration were compared. The results indicate that castrated piglets given either NSAIDs alone or mixed with ID navigated the chute as fast as non-castrated piglets, and faster than castrated piglets not given NSAIDs. This provides evidence that when NSAIDs are combined with iron and administered as a single injection, the NSAIDs remain effective at controlling castration pain. Abstract The efficacy of analgesics such as meloxicam and ketoprofen to control pain in piglets when mixed with iron dextran (ID) before injection is unknown. The purpose of this study was to compare perceived pain in castrated piglets treated 1 h before castration with either of these drugs alone, or when mixed with ID, by observing the time it takes for piglets to navigate a chute. Piglets were divided into seven treatment groups (n = 25 piglets per treatment group) including castration with analgesia (meloxicam or ketoprofen), castration with analgesic plus ID, castration without analgesic or ID, sham handled and given ID, and sham handled alone. Piglets were placed in a short chute and their time to navigate the chute was recorded at four timepoints following castration. Piglets given meloxicam or ketoprofen, with or without ID did not differ from each other in their chute navigation times. Additionally, these piglets did not differ from treatment groups that were not castrated. Piglets castrated without analgesia had significantly longer navigation times. These results indicate that meloxicam or ketoprofen, whether mixed with ID prior to injection or not, provide similar analgesic efficacy.

The authors wish to make the following corrections to their paper [...]

Background Porcine reproductive and respiratory syndrome, swine influenza, and mycoplasmal pneumonia are some of the most prevalent respiratory diseases affecting swine farm productivity in Canada. Monitoring for the prevalence of the infectious agents associated with these diseases on farm may help to improve herd-specific control strategies and to minimize the impact of disease on commercial swine farms. The objectives of this study were to investigate antibody responses to porcine reproductive and respiratory syndrome virus (PRRSV), influenza A virus (IAV), and Mycoplasma hyopneumoniae ( M. hyopneumoniae ) from weaning to the end of the finisher stage on a subset of commercial swine farms in Ontario and to examine the effects of nursery diet on antibody responses. Results Serology found 8, 61, and 31% of pigs at weaning, 1, 31, and 22% at the end of nursery, 8, 38, and 18% at the end of grower, and 11, 48, and 25% at the end of the finisher stage tested seropositive for PRRSV, IAV, and M. hyopneumoniae, respectively. Of the groups tested for PRRSV, IAV, and M. hyopneumoniae, 3, 14, and 5 groups had > 20% of pigs that tested seropositive at least once over the course of production (“high seropositivity”). In general, seropositivity was more likely to be lower at the end of nursery compared to the other production stages for all three pathogens, and more likely to be higher for PRRSV and IAV at weaning, end of grower, and end of finisher. Pigs that were seropositive for PRRSV were more likely to be seropositive forM. hyopneumoniae (p < 0.001). Overall, pigs fed a low complexity diet during nursery were more likely to be seropositive for PRRSV (p < 0.001) and IAV (p = 0.04). Conclusions This study provides information regarding changes in serum antibody in pigs across different stages of production and highlights periods of vulnerability. Additionally, these findings may encourage further research into the effects of nursery diet complexity on disease susceptibility and immune response.

In order to efficiently have a consistent supply of service-ready gilts available to incorporate into each batch of breeding sows, it is necessary to manipulate the timing of estrus and possibly the timing of ovulation of gilts. Estrus can be synchronized by the withdrawal of altrenogest after at least 14 days of treatment. It is possible that protocols developed to induce ovulation, and therefore allow fixed-time artificial insemination (FTAI), can improve the predictability of gilt breeding. This study investigated the effect of two FTAI protocols in gilts on reproductive performance and timing of farrowing and piglet weaning weight compared to gilts bred based on signs of estrus after cessation of altrenogest. Puberty was induced in gilts, followed by treatment with altrenogest. Following altrenogest withdrawal, 180 gilts were assigned to one of three treatment groups. Group 1 gilts (LUT, n = 62) were treated with 600 IU equine chorionic gonadotropin 24 h after altrenogest withdrawal and 5 mg porcine luteinizing hormone (pLH) 80 h later, followed by a single FTAI 36 h after pLH. Group 2 gilts (TRI, n= 61) received 2 mL of a gonadotropin-releasing hormone agonist, triptorelin acetate, intravaginally 6 d after altrenogest withdrawal and were bred by a single FTAI 24 h later. Group 3 gilts (CON, n = 57) were observed for estrus and bred twice by AI, 24 h apart. LUT and TRI gilts farrowed closer together (2.4 &plusmn, 1.6 and 2.9 &plusmn, 1.2 d(days), respectively) compared to CON gilts (4.5 &plusmn, 3.3 d). Piglets in LUT were 80 g (p &lt, 0.001) heavier and piglets in TRI were 64 g (p &lt, 0.05) heavier at weaning than CON piglets, when controlling for birth weight. Results indicate that FTAI might be useful as a means of minimizing the time from the first to the last gilt farrowing in a breeding batch of gilts. However, modifications of the protocols may be required to ensure optimum farrowing rates and litter size.

Streptococcus suis naturally inhabits the tonsils and nasal cavities of pigs. Some strains can cause systemic infection, leading to a wide range of diseases. A case-control study was conducted to (i) examine serotypes isolated from systemic sites (blood/meninges/spleen) in cases, (ii) determine whether serotypes in systemic sites were found in upper respiratory sites (tonsil/nasal cavity) of the same cases, and (iii) determine the serotypes in upper respiratory sites of case and farm and pen- matched controls. In total, 606 samples from 128 pigs were cultured for S. suis. The isolates were examined for presence of gdh and recN genes by polymerase chain reaction (PCR) and were identified as S. suis if both genes were present. The S. suis isolates were then serotyped using a two step-multiplex PCR. Serotypes 9 (n = 9), (2,1/2) (n = 7) and untypable isolates (n = 7) were most commonly found in systemic sites. Detection of serotypes 9 (p = 0.03) in upper respiratory sites were positively associated with their detection in systemic sites of cases, while a trend was seen with serotype (2,1/2) (p = 0.07). Last, no association between serotypes recovered from upper respiratory sites of cases and controls could be detected. Untypable isolates were detected in high frequency, which warrants further investigation. This study confirms that a variety of serotypes can be found in commercial swine production and shows a difference in serotypes recovered from systemic sites in pigs with clinical signs of S. suis infections.

In-transit losses of market hogs represent a small proportion of all market-weight pigs shipped in a year. This suggests that individual pig factors may be a significant cause of in-transit losses along with more traditionally considered environmental and transport factors. An investigation was performed to determine whether cardiac pathology and heart weights were associated with pigs that did or did not die during transport to an abattoir. The hearts from 70 pigs that died in-transit to one Ontario abattoir and 388 pigs that arrived alive were collected and examined. Hearts from pigs that died during transport demonstrated greater frequencies of cardiac lesions (P < 0.05). These included hypertrophy of ventricle walls (Left: 97% vs. 64%; Right: 86% vs. 57%), dilation of ventricle chambers (Left: 79% vs. 0.5%; Right: 100% vs. 5%), and dilation of the pulmonary artery and aorta (59% vs. 1.5%). Total heart weight to body weight ratios were increased (3.6 vs. 3.3 g/kg) and left ventricle plus septum weight over right ventricle weight ratio was decreased in pigs that died during transport over non–in-transit loss pigs (2.5 vs. 2.8; P < 0.05). This may indicate reduced cardiac function in hogs that died during transport. Pigs with reduced cardiac function would have exercise intolerance and be more susceptible to death during transport due to the increased cardiac workload required during sorting, loading, and transport of the pigs to the abattoir. Further research to quantify cardiac function in pigs with cardiac lesions or abnormal heart weight ratios is warranted.

Simple Summary Tail-biting in commercial pig-rearing facilities is a welfare concern. Serious outbreaks may occur sporadically, particularly in the grower-finisher stage of production. A scoping review was undertaken to determine if there is general agreement on the common risk factors and appropriate intervention strategies of tail-biting. Online databases were explored for relevant articles and information was extracted from the articles based on predetermined questions. Important risk factors varied between studies, as did successful interventions. The provision of rooting material to alleviate a pig’s innate exploratory behavior was determined to be a common prevention/intervention strategy. Deciphering between risk factors and interventions in the literature was not always possible. Overall, the cause of tail-biting was determined to be multifactorial. Abstract Tail-biting is globally recognized as a welfare concern for commercial swine production. Substantial research has been undertaken to identify risk factors and intervention methods to decrease and understand this vice. Tail-biting appears to be multifactorial and has proven difficult to predict and control. The primary objective of the scoping review was to identify and chart all available literature on the risk factors and interventions associated with tail-biting in pigs. A secondary objective was to identify gaps in the literature and identify the relevance for a systematic review. An online literature search of four databases, encompassing English, peer-reviewed and grey literature published from 1 January 1970 to 31 May 2019, was conducted. Relevance screening and charting of included articles were performed by two independent reviewers. A total of 465 citations were returned from the search strategy. Full-text screening was conducted on 118 articles, with 18 being excluded in the final stage. Interventions, possible risk factors, as well as successful and unsuccessful outcomes were important components of the scoping review. The risk factors and interventions pertaining to tail-biting were inconsistent, demonstrating the difficulty of inducing tail-biting in an experimental environment and the need for standardizing terms related to the behavior.

In-transit losses (ITL) of market-weight pigs are defined as pigs that die or pigs that become nonambulatory during loading and shipping from the farm to the abattoir. The low proportion of ITL in market pigs implies that individual pig factors may influence ITL, in addition to commonly considered environmental or transport factors. Postmortem examinations of in-transit-loss pigs ( = 85) from 1 Ontario, Canada, abattoir indicated the cause of death to be acute heart failure as a result of cardiac lesions that developed prior to transport. The presence of preexisting cardiac lesions may explain why no or only a few pigs die in a trailer even when the entire load is exposed to extreme temperatures and other common transport risk factors.

It was recently shown that a teat that is not used in the first lactation will have a reduced development and milk yield in the second lactation. In the current study, the impact of imposing a suckling period of 2, 7, or 21 d during the first lactation on piglet performance, milk composition, endocrine status, and mammary gene expression of sows in their second lactation was studied. Pregnant Yorkshire gilts were divided into 3 groups according to lactation length: 1) 2-d lactation (2D; = 20), 2) 7-d lactation (7D; = 20), and 3) 21-d lactation (21D; = 21). After weaning, sows were bred and kept for a second parity. In both lactations, litters were standardized to 12 piglets with 12 functional teats and surplus teats were sealed. In the second lactation, piglets were weighed on d 2, 7, 14, 21 (weaning), 31, and 56 postpartum, and sow feed intake was recorded. On d 110 of gestation and on d 21 of lactation, mammary biopsies were performed on 10 sows per treatment to obtain parenchymal tissue samples for determination of mRNA abundance for , , , , , and genes. Milk samples and jugular blood samples were also obtained from sows on d 21 of lactation. Standard composition analyses (DM, fat, protein, and lactose) were done in milk. Concentrations of prolactin, IGF-1, glucose, and urea were measured in blood. There was a tendency for 21D sows to consume more feed than 2D or 7D sows during the first week of lactation ( 0.10). Concentrations of prolactin, IGF-1, urea, and glucose in sows on d 21 of lactation were not affected by treatment ( > 0.10). Dry matter, fat, protein, and lactose contents in milk were not altered by treatment ( > 0.10). On d 110 of gestation, gene expression was greater ( = 0.05) in 21D sows than in 7D sows. On d 21 of lactation, gene expression of was greater ( = 0.05) and that of tended to be lower ( < 0.10) in 7D sows than in 2D sows. The mRNA abundance of also tended to be lower ( < 0.10) in 2D sows than in 7D sows. Results indicate that increasing the duration of lactation from 2 d to 7 d or to 21 d in first-parity sows did not improve growth rate of their piglets in the subsequent lactation. This suggests that suckling of a teat for 2 d during the first lactation is sufficient to ensure optimal mammary development.

Background Food animal veterinarians face commodity specific and urgent global challenges yet conditions preventing use of best available knowledge have been sparsely studied. The American Association of Swine Veterinarians (AASV) membership (N = 1289) was surveyed online to benchmark their information priorities and their motivations and sources for keeping current with infectious disease research, and to describe their reported time, skill, access, and process as barriers to knowledge translation (KT). Results Respondents (n = 80) were mostly from Canada (n = 40) and the U.S.A (n = 31) and demographics approximated the AASV’s. Colleagues are the first choice for information on difficult cases (49%, 95%CI: 38–61). Half of respondents (53%, 95%CI: 41–64) spend an hour or less per week keeping up with infectious disease research. The majority reported moderate or less than moderate efficiency (62%, 95%CI: 51–72), and moderate or greater stress (59%, 95%CI: 48–70) with their process for keeping up. Journal article methods sections are commonly not read, almost a third (32%, 95% CI: 22–43) reported either they do not evaluate statistical methods or that they had poor confidence to do so, and half (52, 95%CI: 41–63) could not explain ‘confounding bias’. Approximately half (55%, 95%CI: 41-69) with direct oversight of swine herds had full access to 2 or fewer academic journals. Approximately a third of respondents (34%, 95%CI: 24–46) selected only formats involving single research studies (either full text or summaries) as preferred reading materials for keeping current over expert summaries of the body of evidence. Conclusion KT barriers are considerable and a source of stress for many swine veterinarians. Sub-optimal efficiency with keeping up and low confidence to appraise aspects of research are concerns. Results are consistent with previous literature and illustrate need for improved KT infrastructure and for additional training in statistical methods and interpretation of primary research. Further evaluation is warranted of why approximately a third of veterinarians in this study, for the purpose of keeping up, preferentially choose to review individual research studies over choices that would include an expert summary of the body of evidence. Consideration of reasons for this preference will be important in the planning of KT infrastructure improvements.

Conventional practice is to breed sows by artificial insemination (AI) at least twice using approximately three billion sperm per insemination upon estrus at standing heat. This research explored the use of combined technologies, including fixed-time insemination (FTAI) and an alternative catheter design that reportedly reduces semen backflow, in order to reduce the number of inseminations and the semen dosage and maintain reproductive efficiency. The FTAI technique used in this study was to inject I.M. 600 IU equine chorionic gonadotropin (eCG) at weaning and 5 mg porcine luteinizing hormone (pLH) to stimulate ovulation 80 h later, followed by a single insemination 36 h after the pLH injection. The two catheters used in this study were a conventional foam-tipped insemination catheter and a Gedis catheter. The Gedis catheter is designed to be completely inserted into the vagina. The semen is enclosed along the length of the rod and held in place by a gel cap that melts when inserted into the cervix. Sows were assigned to the following treatments: Group 1 (n = 135), bred twice with a conventional catheter and a standard semen dose of approximately three billion sperm in 80 mL, Group 2 (n = 123), FTAI with conventional catheter and a standard semen dose, Group 3 (n = 127), FTAI with Gedis catheter and a standard semen dose, Group 4 (n = 126), FTAI with Gedis catheter and a reduced semen dose with one billion sperm. The farrowing rates were 81.6%, 77.7%, 74.0%, and 62.7% for Groups 1 to 4, respectively. The likelihood of farrowing was lower for Group 3 and Group 4 compared to Group 1 (odds ratio (OR) = 0.57, p = 0.08 and OR = 0.35, p = 0.001, respectively). Likewise, litter size of Group 3 and Group 4 was smaller than Group 1 (p = 0.006 and p = 0.04, respectively). Overall, the combination of Gedis catheter and FTAI resulted in decreased reproductive performance that outweighed the value of using less semen.

Streptococcus suis naturally colonizes the upper respiratory tract of pigs and can lead to severe disease conditions. Although there are several serotypes associated with disease, untypable isolates have also been observed. The objective of this study was to investigate the relatedness of untypable S. suis isolates detected in clinical cases and healthy pigs in Ontario, Canada, and their relation to typing serotypes. One hundred fifty-six isolates obtained from 33 cases and 26 farm-and-pen-matched control pigs were sequenced using Illumina HiSeq sequencing. Protein sequences of the capsular polysaccharide genes (cps) were identified and analyzed using a maximum likelihood tree. Among the 27 untypable isolates, 3 were from systemic sites of cases and 13 and 11 were from upper respiratory sites of cases and controls, respectively. One hundred fifty-six isolates were grouped into 17 distinct groups based on the cps gene tree. Isolates from these 17 distinct individual cps groups were distributed among a minimum of one farm and maximum of eight farms. Untypable isolates were detected in 12 of those groups and each cps group had untypable isolates present amongst multiple farms. Interestingly, the three systemic untypable isolates not only coexisted with other serotypes found in the same location of the same pigs but were also found among different cps groups. These isolates are of interest and warrant further investigation. Overall, a wide diversity of S. suis among untypable isolates was observed in this study.

The porcine reproductive and respiratory syndrome virus (PRRSV) is an enveloped RNA virus, with high mutation rates and genetic variability ; which is evident by the large number of discrete strains that co-circulate in swine populations. Veterinary practitioners frequently identify certain discrete PRRSV strains as having a higher clinical impact on production. However, with exception of a few strains, production impact is not well characterized for the majority of PRRSV variants. Predictive analytics, coupled with routine diagnostic sequencing of PRRSV, provide opportunities to study the clinical impact of discrete PRRSV strains on production. Thus, the primary objective of this research was to evaluate clinical impact of discrete PRRSV clades observed in Ontario sow farms. PRRS viruses were classified into discrete clades using Bayesian analysis of the nucleotide sequences of the ORF-5 region of the genome. Production data were gathered through veterinary clinics from herds participating in the ongoing PRRSV surveillance system. Data about pre-weaning mortality, sow mortality, and abortion rates were measured up to 8 weeks post initial PRRSV outbreak. Through conventional regression analysis, results support that clinical impact of the viruses varied among clades over time for abortion rate (p = 0.05) and pre-weaning mortality (p < 0.01). Using predictive modelling approaches based on grouped K-fold cross-validation, it was identified that PRRSV clade designations and other measured factors showed low predictive performance for abortion (R2 = 0.07), pre-weaning mortality (R2 = 0.09), and sow mortality (R2 = 0.04). Clade designation consistently showed moderate importance for abortion and pre-weaning mortality, with clade 2 viruses being identified, on average, as having higher impact. These results demonstrate that the prediction of clinical impact, through production parameters, based on phylogenetic classification of PRRS viruses is possible. However, very high impact outbreaks were difficult to predict across production parameters. More surveillance- derived data are required to continue to improve predictive performance of the models.

The excessive use of antibiotics in food animal production has contributed to resistance in pathogenic bacteria, thereby triggering regulations and consumer demands to limit their use. Alternatives for disease control are therefore required that are cost-effective and compatible with intensive production. While vaccines are widely used and effective, they are available against a minority of animal diseases, and development of novel vaccines and other immunotherapeutics is therefore needed. Production of such proteins recombinantly in plants can provide products that are effective and safe, can be orally administered with minimal processing, and are easily scalable with a relatively low capital investment. The present report thus advocates the use of plants for producing vaccines and antibodies to protect farm animals from diseases that have thus far been managed with antibiotics; and highlights recent advances in product efficacy, competitiveness, and regulatory approval.

Summary Salmonella is an important human pathogen, and production animals as well as water are known potential sources. This study helped provide insight into the epidemiology of Salmonella by comparing Salmonella strains found in humans to those detected in production animals and water in the same geographic area and time frame. Salmonella was found in 55% of broiler, 30% of swine, 13% of dairy, and 10% of beef manure samples and 23% of water samples. At the farm level, Salmonella was found on 93% of broiler, 81% of swine, 32% of beef and 30% of dairy farms. Salmonella strains of importance to public health were found in all sources tested; however, they appeared to be more common in the broilers. A number of the farms in this study were mixed farms, in that they had more than one production animal species on the farm. At both the sample and farm levels, beef-only farms had a significantly lower Salmonella prevalence (5% and 7%, respectively) than beef farms with additional production animal species (e.g. poultry) (12% and 42%, respectively) (P ≤ 0.05). Additionally, a number of mixed farms had more than one commodity sampled for this study and similar Salmonella strains by phage type and PFGE were found in the poultry and the other sampled commodity on the farm. This information can help inform the evidence base needed to help target interventions and modify best practices in production agriculture.

The objectives of this study were to describe networks of Ontario swine sites and their service providers (including trucking, feed, semen, gilt and boar companies); to categorize swine sites into clusters based on site-level centrality measures, and to investigate risk factors for porcine reproductive and respiratory syndrome (PRRS) using information gathered from the above-mentioned analyses. All 816 sites included in the current study were enrolled in the PRRS area regional control and elimination projects in Ontario. Demographics, biosecurity and network data were collected using a standardized questionnaire and PRRS status was determined on the basis of available diagnostic tests and assessment by site veterinarians. Two-mode networks were transformed into one-mode dichotomized networks. Cluster and risk factor analyses were conducted separately for breeding and growing pig sites. In addition to the clusters obtained from cluster analyses, other explanatory variables of interest included: production type, type of animal flow, use of a shower facility, and number of neighboring swine sites within 3km. Unadjusted univariable analyses were followed by two types of adjusted models (adjusted for production systems): a generalizing estimation equation model (GEE) and a generalized linear mixed model (GLMM). Results showed that the gilt network was the most fragmented network, followed by the boar and truck networks. Considering all networks simultaneously, approximately 94% of all swine sites were indirectly connected. Unadjusted risk factor analyses showed significant associations between almost all predictors of interest and PRRS positivity, but these disappeared once production system was taken into consideration. Finally, the vast majority of the variation on PRRS status was explained by production system according to GLMM, which shows the highly correlated nature of the data, and raises the point that interventions at this level could potentially have high impact in PRRS status change and/or maintenance.

Aberrant behaviours in grower pigs (e.g. tail-biting) have been shown to involve the serotonergic system and along with aggressive behaviours, to result in both significant economic losses and reduce animal welfare. Tryptophan (TRP) acts as a direct precursor to serotonin and so the objective of this study was to determine whether varying inclusion rates of dietary L-tryptophan (TRP) effect aggression, behaviour and growth in grower pigs (n=90). Three feed treatments were examined in a completely randomized block design 1) Control diet (TRP at 100% standard ileal digestible (SID) requirement), 2) TRP at 175% SID requirement and 3) TRP at 250% SID requirement. Each trial (n=2) lasted a total of 29 days, with feed and water being provided ad libitum. Sex, weight and litter origin were balanced across pens in each trial (n = 3 pens/treatment [5 pigs/pen]). All feed was weighed and feed intake measured. Pig weights were recorded weekly. Behaviour was recorded continuously 12 h/d (06:00-18:00), 3 d/wk. An ethogram of 13 mutually exclusive behaviours was used to assess behaviour and all instances of aggression were evaluated for severity and duration of fighting. Body scratch scores, tail lesions and ear lesions were also recorded (d 8, 15, 22 and 29). Plasma and serum samples were taken from 3 pigs/pen (n=27/trial) at four different time points (d 8, 15, 22 and 29) for analysis of TRP and serotonin respectively, using ELISA. Preliminary data analyses indicate no effect of diet on growth (P>0.05) and no differences in behaviour, aggression, or ear- or tail-lesions (P>0.05). ELISA results are forthcoming. Overall, data suggest L-tryptophan does not positively influence growth, behaviour or aggression in grower pigs.

Administration of iron (200 mg per piglet) on day 2 or 3 after birth to prevent anemia is a common practice in modern pig husbandry. However, it has been shown that despite supplementation, iron deficiency is common among fast-growing pigs at weaning, which is a time of stress and disease-challenge. Two trials were conducted to determine whether pigs with iron deficiency at weaning are more susceptible to enteric disease than pigs with adequate iron stores. In each trial all piglets at 3 days of age from 11 litters were assigned to a low (100 mg injectable iron dextran), medium (200 mg of iron dextran) or high (200 mg iron dextran at 3 and 14 days of age) iron treatment. Pigs were tested for susceptibility to F4+ ETEC using RFLP-PCR. For each trial 36 susceptible pigs were transported to the University of Guelph level 2 biosafety facility. Pigs were housed in 6 rooms with 2 pigs from each iron treatment per room. Blood samples were taken at weaning (21 days of age) to determine the hemoglobin status. One day after arrival, pigs in 5 rooms were challenged with 2 mL of 10(9) CFU of F4 ETEC. Clinical observations were recorded, and rectal swabs were collected and examined for presence of ETEC. At 2 days post-challenge, pigs were euthanized, and intestinal tissue samples were collected for histological examination. Overall, the iron status of the pigs could be categorized based on hemoglobin (hgb) as: anemic (hgb 90110g/L (n=29). Diarrhea was seen in 53% of anemic pigs, 57% of iron deficient pigs and 55% of the pigs with adequate iron levels. There was no significant difference in response to ETEC challenge in pigs with different iron supplementation or with different levels of hgb (P>0.05).

Salmonella is estimated to be one of the leading causes of enteric illness worldwide. Human salmonellosis is most frequently related to contaminated food products, particularly those of animal origin, such as pork. Pigs are often asymptomatic carriers of Salmonella, highlighting the importance of identifying high-prevalence farms and effective detection methods. The objectives of this study were to investigate Salmonella antibody responses and their association with on-farm shedding and Salmonella isolation at slaughter. Fourteen groups of pigs from eight farrowing sources were followed from birth to slaughter (totaling 796 pigs). Information about farm management was collected through a questionnaire. Blood and fecal samples were collected four times at different stages of production, and palatine tonsils/submandibular lymph nodes were obtained at slaughter. Sera were tested for Salmonella antibodies by enzyme-linked immunosorbent assay, and fecal/tissue samples were cultured for Salmonella. Data were analyzed using a mixed-effect multivariable modeling method with farm, litter, and pig as random effects. Salmonella seropositivity rates were 20.3%, 5.8%, 15.9%, and 37.3% at weaning, at the end of nursery, at end of grower, and at end of finisher, respectively. Salmonella seropositivity and shedding increased with age (p

Commercial production of swine often involves raising animals in large groups through the use of multi-stage production systems. In such systems, pigs can experience different degrees of contact with animals of the same or different ages. Population size and degree of contact can greatly influence transmission of endemic pathogens, including influenza A virus (IAV). IAV can display high genetic variability, which can further complicate population-level patterns. Yet, the IAV transmission in large multi-site swine production systems has not been well studied. The objectives of this study were to describe the IAV circulation in a multi-source nursery facility and identify factors associated with infection in nursery pigs. Pigs from five sow herds were mixed in one all-in/all-out nursery barn, with 81 and 75 pigs included in two longitudinal studies. Virus isolation was performed in Madin-Darby canine kidney cells and serology was performed using hemagglutination inhibition assays. Risk factor analysis for virological positivity was conducted using logistic regression and stratified Cox’s regression for recurrent events. In Study 1, at ≈30 days post-weaning, 100% of pigs were positive, with 43.2% of pigs being positive recurrently over the entire study period. In study 2, 48% of pigs were positive at the peak of the outbreak, and 10.7% were positive recurrently over the entire study period. The results suggest that IAV can circulate during the nursery phase in an endemic pattern and that the likelihood of recurrent infections was associated in a non-linear way with the level of heterologous (within-subtype) maternal immunity (p 0.75) were also observed for the majority of sampling times suggesting that pen-level factors played a role in infection dynamics in this study. Electronic supplementary material The online version of this article (doi:10.1186/s13567-017-0466-x) contains supplementary material, which is available to authorized users.

A longitudinal trial was conducted to determine the course of Salmonella shedding and antibody response in naturally infected grower-finisher pigs. Ten-week-old pigs (n = 45) were transferred from a farm with history of salmonellosis and housed at a research facility. Weekly fecal samples (weeks 1 to 11) as well as tissue samples at slaughter were cultured for Salmonella. Serum samples were tested for presence of Salmonella antibody by enzyme-linked immunosorbent assay (ELISA). Data were analyzed using a multilevel mixed-effects logistic regression model. Over 10 wk, 91% and 9% of pigs shed Salmonella ≤ 4 and > 5 times, respectively. The estimated median of Salmonella shedding duration was 3 to 4 wk but some pigs shed Salmonella for up to 8 wk. Salmonella shedding increased 1 wk post-arrival but followed a decreasing pattern afterwards up to week 11 (P < 0.05). Salmonella isolates (n = 29), which were recovered from 18 pigs at different occasions, were S. Typhimurium (28%), S. Livingstone (21%), S. Infantis (14%), S. Montevideo (7%), S. Benfica (3%), S. Amsterdam (3%), S. Senftenberg (17%), and S. I:Rough-O (7%). Of 11 pigs from which the first and last isolates were serotyped, 10 pigs were reinfected with a different serotype. At slaughter, Salmonella was isolated from 7 pigs, of which 5 (71%) had not tested positive for at least 7 wk prior to slaughter. Antibody response peaked 4 wk after the peak of Salmonella infection; Salmonella shedding reduced as antibody response elevated (P < 0.05). These findings indicate that pigs may shed Salmonella into the mid-point of the grower-finisher stage and may be reinfected with different serotypes.

The evaluation of pig hematology and biochemistry parameters is rarely done largely due to the costs associated with laboratory testing and labor, and the limited availability of reference intervals needed for interpretation. Within-herd and between-herd biological variation of these values also make it difficult to establish reference intervals. Regardless, baseline reference intervals are important to aid veterinarians in the interpretation of blood parameters for the diagnosis and treatment of diseased swine. The objective of this research was to provide reference intervals for hematology and biochemistry parameters of 3-week-old commercial nursing piglets in Ontario. A total of 1032 pigs lacking clinical signs of disease from 20 swine farms were sampled for hematology and iron panel evaluation, with biochemistry analysis performed on a subset of 189 randomly selected pigs. The 95% reference interval, mean, median, range, and 90% confidence intervals were calculated for each parameter.

The objective of this study was to investigate the association between environmental temperature and humidity and the presence of antibodies for two specific strains of swine influenza viruses: A/SW/ON/105-56/12/H3N2 (H3N2_D) and A/SW/ON/84/2012/H1N1 (H1N1_P). A cross-sectional study was performed in a commercial farm, and a total of 450 pigs at 10 weeks of age were blood sampled, by sampling 10 pigs per week for 45 weeks corresponding to 45 batches. Exposure of pigs to H3N2_D and H1N1_P virus was assessed by haemagglutination inhibition assay (HI), and a result of ≥1:40 was considered as indication of a positive exposure status for a specific strain. The selection of those two viruses was based on the fact that H1N1 was the dominant virus in Ontario herds, and H3N2 had been previously isolated in this particular farm. Environmental conditions were recorded through a portable device every 5 min and then summarized using descriptive statistics. The association between HI titres and environmental microconditions, in the nursery, was evaluated through random effect linear and logistic regression. The results showed that the prevalence for H1N1_P was high throughout the study (≥70%); however, for H3N2_D, the seroprevalence declined by the end of the study period. Results also showed an association between cumulative exposure to the viruses and temperature and relative humidity (p

In-transit losses (ITLs) of market weight pigs are defined as pigs that die and (or) pigs that become nonambulatory (NA) during the process of loading and shipping from the farm to the abattoir. An...

The aim of this study was to determine the effect of lactation length and treatment with gonadotrophins at weaning on reproductive performance of primiparous sows. After 3 wk of lactation, primiparous sows were either weaned (W3; n=273) or received a 7-d-old foster litter for a further 14 d of suckling (W5; n=199). At final weaning (3 wk or 5 wk lactation) sows were randomly assigned to receive an injection of 400 IU equine chorionic gonadotrophin plus 200 IU human chorionic gonadotrophin (PG600(®); W3 + P; n=108 and W5 + P; n=96) or no injection (W3; n=165 and W5; n=103). Sows were inseminated at first observed estrus after final weaning and 24h later. The proportion of sows showing estrus by 6 d post-weaning was greater (P

The aim of this study was to determine the association between the oestrous response of pre-pubertal gilts to gonadotrophin injection or boar exposure and their subsequent farrowing rate and litter size. At 154 days of age, randomly selected pre-pubertal gilts received an intramuscular injection of 400 IU equine chorionic gonadotrophin plus 200 IU human chorionic gonadotrophin (PG600(®) ; Merck Animal Health; n = 181). From the remaining pool of animals not treated with hormones, the first gilts showing signs of oestrus were selected to act as controls (n = 201). Boar exposure began at 155 days of age for both groups, and gilts were bred at a weight of approximately 130 kg. Comparisons were made between PG600(®) -treated gilts exhibiting oestrus or not within 7 days post-injection (early and late responders, respectively) and control gilts exhibiting oestrus or not within 30 days after beginning of boar exposure (select and non-select control gilts, respectively). By 162 days, oestrus was detected in 67.5% of PG600(®) -treated gilts compared with 5.7% of control gilts (p < 0.0001). The proportion of animals observed in oestrus at least three times before breeding was greater for select control gilts compared with early and late responder PG600(®) -treated gilts (p ≤ 0.001). There were no significant differences in farrowing rate and litter size between the four treatment groups. These data indicate that PG600(®) is an effective tool to induce an earlier oestrus in gilts, that subsequent farrowing rate and born alive litter size compare favourably to that of select gilts and that gilts failing to respond promptly to hormonal stimulation do not exhibit compromised fertility.

Salmonella Typhimurium is a foodborne pathogen and commonly present on pig farms. Probiotics have shown potential as a means of reducing Salmonella shedding in pigs. Three experimental challenge trials were conducted to investigate the potential application of newly isolated Lactobacillus isolates for controlling Salmonella infection in pigs. In each trial, 16 Yorkshire piglets (28-d old) were randomly allocated to 1 of 4 dietary treatments: (1) basal diet (BD), (2) naturally fermented (NF) feed, (3) Lactobacillus zeae-fermented (LZ-F) feed, and 4) Lactobacillus casei-fermented (LC-F) feed. All pigs consumed their assigned diets for 3 d prior to the challenge of Salmonella Typhimurium DT104 (approximately 6 log colony-forming units/pig) through gavage. Pediococcus pentosaceus, L. zeae, and L. casei were most abundant in NF, LZ-F, and LC-F feed, respectively. After the challenge, pigs on fermented feed had lower rectal temperature, diarrhea scores, serum haptoglobin concentrations, and intestinal Salmonella counts than the control group (BD) (p ≤ 0.01). Salmonella spp. were detected in both ileocecal lymph nodes (ICLN) and spleens from all pigs on BD, NF, and LC-F, but only 50% of spleens from pigs on LZ-F. Pigs had a dynamic spatial and temporal immune response to Salmonella infection and dietary treatments, as indicated by up- and downregulation in gene expression of inflammatory cytokines (interleukin (IL)-1β, IL-6, IL-10, interferon-γ, and tumor necrosis factor) in the ileum, ICLN, and spleen. The alternation in cytokine expression by fermented feed, particularly LZ-F, appeared to benefit pigs in combating Salmonella infection.

Genetic improvement of pigs in tropical developing countries has focused on imported exotic populations which have been subjected to intensive selection with attendant high population-wide linkage disequilibrium (LD). Presently, indigenous pig population with limited selection and low LD are being considered for improvement. Given that the infrastructure for genetic improvement using the conventional BLUP selection methods are lacking, a genome-wide selection (GS) program was proposed for developing countries. A simulation study was conducted to evaluate the option of using 60 K SNP panel and observed amount of LD in the exotic and indigenous pig populations. Several scenarios were evaluated including different size and structure of training and validation populations, different selection methods and long-term accuracy of GS in different population/breeding structures and traits. The training set included previously selected exotic population, unselected indigenous population and their crossbreds. Traits studied included number born alive (NBA), average daily gain (ADG) and back fat thickness (BFT). The ridge regression method was used to train the prediction model. The results showed that accuracies of genomic breeding values (GBVs) in the range of 0.30 (NBA) to 0.86 (BFT) in the validation population are expected if high density marker panels are utilized. The GS method improved accuracy of breeding values better than pedigree-based approach for traits with low heritability and in young animals with no performance data. Crossbred training population performed better than purebreds when validation was in populations with similar or a different structure as in the training set. Genome-wide selection holds promise for genetic improvement of pigs in the tropics.

Genetic improvement of exotic and indigenous pigs in tropical developing countries is desired. Implementations of traditional selection methods on tropical pig populations are limited by lack of data recording and analysis infrastructure. Genome-wide selection (GS) provides an approach for achieving faster genetic progress without developing a pedigree recording system. The implications of GS on long-term gain and inbreeding should be studied before actual implementation, especially where low linkage disequilibrium (LD) is anticipated in the target population. A simulation case study of this option was performed on the basis of the available 60,000 SNP panel for porcine genome. Computer simulation was used to explore the effects of various selection methods, trait heritability, and different breeding programs when applying GS. Genomic predictions were based on the ridge regression method. Genome-wide selection performed better than BLUP and phenotypic selection methods by increasing genetic gain and maintaining genetic variation while lowering inbreeding, especially for traits with low heritability. Indigenous pig populations with low LD can be improved by using GS if high-density marker panels are available. The combination of GS with repeated backcrossing of crossbreds to exotic pigs in developing countries promises to rapidly improve the genetic merit of the commercial population. Application of this novel method on a real population will need to be performed to validate these results.

Community associated Clostridium difficile and MRSA are among the most common infection causing pathogens encountered in developed nations. It has been proposed that both pathogens may be foodborne with supporting evidence being based on the carriage in animals and recovery from meat at retail. The following reports on the incidence and dissemination routes of C. difficile and MRSA within a high capacity pork processing facility. Sampling of carcasses and processing environment was performed over two visits to the facility. C. difficile was isolated 80% (16/20) of manure samples taken within the holding area, with 45% (9/20) of holding area floor and wall samples testing positive for the pathogen. Three of the twenty carcasses (15%) sampled at post-bleed and a further 3 at post-evisceration also tested positive for C. difficile . No C. difficile were recovered from scald water samples, polisher/scraper units or on carcasses in the cold room at the end of the line. Ribotype 078 was the predominant C. difficile recovered with the remaining belonging to other ribotypes. MRSA was recovered from a single carcass at post-bleed and within the cold room, in addition to one sample taken from the holding area (overall prevalence of 2.7%). The MRSA isolates recovered from carcasses was spa t034 which is a commonly associated with pigs. The results of the study confirm that the holding area of slaughterhouse acts as a reservoir for C. difficile and MRSA although there was no evidence to suggest that the pathogens were disseminated into the processing lines. Consequently, it can be concluded that pork processing does not represent a significant risk of disseminating MRSA and C. difficile between carcasses.

External biosecurity protocols, aimed at preventing the introduction of new pathogens to the farm environment, are becoming increasingly important in the swine industry. Although assessments at the individual farm level occur regularly, efforts to cluster swine herds into meaningful biosecurity groups and to summarize this information at the regional level are relatively infrequent. The objectives of this study were: (i) to summarize external biosecurity practices on sow farms in southern Ontario; (ii) to cluster these farms into discrete biosecurity groups and to describe their characteristics, the variables of importance in differentiating between these groups, and their geographic distribution; and (iii) to identify significant predictors of biosecurity group membership. Data were collected using the Production Animal Disease Risk Assessment Program's Survey for the Breeding Herd. A subset of variables pertaining to external biosecurity practices was selected for two-step cluster analysis, which resulted in 3 discrete biosecurity groups. These groups were named by the authors as: (i) high biosecurity herds that were open with respect to replacement animals, (ii) high biosecurity herds that were closed with respect to replacement animals, and (iii) low biosecurity herds. Variables pertaining to trucking practices and the source of replacement animals were the most important in differentiating between these groups. Multinomial logistic regression provided insight into which demographic and neighborhood variables serve as significant predictors of biosecurity group membership (p

The process of weaning pigs alters intestinal structures and influences piglet behavior, which can result in anorexia. When housed in large groups, affected pigs can be difficult to identify at an early stage. The clinical signs of anorexia include loss in body condition (thinness) and repetitive oral behavior (chomping). The objective of this study was to determine if pigs identified at 4 to 7 days post-weaning on the basis of clinical signs were anorexic based on elevated serum beta-hydroxybutyrate (BHB) levels (ketosis). A total of 240 pigs from 8 farms (30 pigs per farm) were selected based on observation of their abnormal oral behavior (Chomp; n = 10), poor body condition, (Thin; n = 10), or healthy appearance (Control; n = 10). Standard laboratory testing and a ketone handheld meter were used to measure BHB levels and were compared using non-parametric receiver operating characteristic analyses. Most pigs selected based on clinical signs were not anorexic as confirmed by their normal BHB levels.

The objective of this study was to develop a discrete event agent-based stochastic model to explore the likelihood of the occurrence of porcine reproductive and respiratory syndrome (PRRS) outbreaks in swine herds with different PRRS control measures in place. The control measures evaluated included vaccination with a modified-live attenuated vaccine and live-virus inoculation of gilts, and both were compared to a baseline scenario where no control measures were in place. A typical North American 1,000-sow farrow-to-wean swine herd was used as a model, with production and disease parameters estimated from the literature and expert opinion. The model constructed herein was not only able to capture individual animal heterogeneity in immunity to and shedding of the PRRS virus, but also the dynamic animal flow and contact structure typical in such herds under field conditions. The model outcomes included maximum number of females infected per simulation, and time at which that happened and the incidence of infected weaned piglets during the first year of challenge-virus introduction. Results showed that the baseline scenario produced a larger percentage of simulations resulting in outbreaks compared to the control scenarios, and interestingly some of the outbreaks occurred over long periods after virus introduction. The live-virus inoculation scenario showed promising results, with fewer simulations resulting in outbreaks than the other scenarios, but the negative impacts of maintaining a PRRS-positive population should be considered. Finally, under the assumptions of the current model, neither of the control strategies prevented the infection from spreading to the piglet population, which highlights the importance of maintaining internal biosecurity practices at the farrowing room level.