Juliana Bonin Ferreira

Surgical castration is a routine management procedure in swine production that raises welfare concerns due to pain, inflammation, and risk of post-procedure complications. Topical products are commonly applied to castration wounds, but their efficacy in promoting healing and reducing inflammation has not been systematically evaluated. This study investigated and compared the efficacy of five commercially available antiseptic and barrier topical products on wound healing, inflammatory responses, and growth performance in piglets undergoing surgical castration. One hundred and ninety piglets, 3–5 days-old of age, were evaluated under the following treatments: Iodine, Oinkment ^® , PhytoCare ^® , Vetericyn ^® , Zinc Oxide, or intact controls (NoCast). Treatments were applied immediately after castration (D1). Body weights were recorded at baseline (D0; day before castration) and at weaning. Blood samples were collected on days 0 (baseline), 7, and 14 for analysis of prostaglandin E₂ (PGE₂) and haptoglobin. Infrared thermography (IRT) was used to assess surface temperature. Histological evaluation of wound healing was performed on subsets of piglets on days 7 and 14. No treatment effects were observed on body weight or pre-weaning survival; castrated piglets grew similarly to intact controls. Concentrations of PGE₂ declined over time ( P < 0.001) but did not differ between treatments, suggesting it may have limited utility as an inflammatory biomarker in neonatal pigs. Haptoglobin concentrations increased across all groups by days 7 and 14, including intact controls, indicating minimal specificity for castration-related inflammation. In contrast, IRT consistently distinguished castrated from intact piglets, supporting its potential as a non-invasive indicator of inflammatory responses. Histological evaluations showed expected time-dependent healing progression, with epidermal thickness correlating with wound severity, but no treatment effects were found. None of the tested topical products were superior to others in regard to wound healing or reduced systemic inflammation under a single-application protocol. While safe and without adverse effects on growth, benefits are unclear when compared to a traditional iodine treatment. The current standard operational procedure for castration requires piglets to receive Iodine after castration to reduce infection risk. Future research should explore no treatment option, repeated applications, microbial wound presence, and behavioral indicators to better evaluate post-castration wound-care strategies.

Biosecurity measures enforced by the swine industry are in place not only to protect a single farm, but also the vast community of interconnected swine farms. Vehicles play a role in disease movement and given that most pigs move throughout the system multiple times during their lives, vehicle cleanliness is key to preventing disease spread. The objective of this study was to determine the infectivity of PEDV on various swine industry vehicles and evaluate the associated cleaning and disinfection (C&D) methods. Viral swabs were collected from various locations on swine industry vehicles and were used to make the bioassay inoculums which were given to a total of 54 piglets enrolled across two bioassays: a pilot bioassay to ensure the samples were collected and stored in a way that preserved the virus, and a full bioassay testing samples collected from vehicles post C&D. The piglets enrolled in the pilot bioassay tested positive for PEDV within 48 hours, confirming the methods were appropriate and capable of infecting piglets with PEDV. From the full bioassay, the piglets inoculated with samples collected from inside the pigs-to-market vehicle cabins experienced severe diarrhea and tested positive for PEDV. No other experimental treatment group experienced persistent clinical symptoms of PEDV in the full bioassay, suggesting the concentration of infectious PEDV remaining after C&D was not enough to cause severe PED in healthy piglets. However, the cleaning efficacy varied greatly across vehicle types, suggesting that producers should continue to uphold and improve vehicle C&D.

Background/Objectives: Porcine reproductive and respiratory syndrome virus (PRRSV) remains one of the most economically significant pathogens in the global swine industry. Despite the availability of commercial vaccines for over three decades, they fail to induce sterile immunity and often provide inconsistent protection against heterologous PRRSV strains. This study aimed to predict vaccine immunogenicity by detecting strain-specific immune responses that related to an immune correlate of protection (CoP) against different PRRSV-2 strains. Methods: Post-weaning pigs were vaccinated with five commercially available PRRSV-2 vaccines or received sterile PBS injection as a control. At 28 days post-vaccination (dpv), all pigs were humanely euthanized for large-volume blood collection to isolate peripheral blood mononuclear cells (PBMCs) and plasma, establishing the immune bank. PBMCs and plasma from each group were then tested against six PRRSV-2 strains to evaluate immune responses. In addition, T cell epitope coverage between vaccine and field PRRSV-2 strains was assessed using the EpiCC (in silico) tool to enhance predictive capacity. Results: While neutralizing antibodies were undetectable in all vaccinated pigs at 28 dpv, PRRSV-specific IFNγ–producing cells were detected at various levels in each vaccinated group following restimulation with different PRRSV-2 strains. Additionally, a positive correlation was observed for the EpiCC coverage of the N gene and mean IFNγ responses to VR2332 (SLA class I and II) and NC24-6 (SLA class II). Conclusions: The PRRSV immune bank demonstrated potential as a tool for predicting vaccine immunogenicity against different PRRSV-2 strains and EpiCC provides additional information on T cell epitope cross conservation. The combined approach may provide a valuable framework for selecting PRRSV vaccines for more effective prevention and control in endemic areas.

Background/Objectives: Porcine reproductive and respiratory syndrome virus (PRRSV) remains one of the most economically significant pathogens in the global swine industry. Despite the availability of commercial vaccines for over three decades, they fail to induce sterile immunity and often provide inconsistent protection against heterologous PRRSV strains. This study aimed to predict vaccine immunogenicity by detecting strain-specific immune responses that related to an immune correlates of protection (COPs) against different PRRSV-2 strains. Methods: Post-weaning pigs were vaccinated with five commercially available PRRSV-2 vaccines or received sterile PBS injection as a control. At 28 days post-vaccination (dpv), all pigs were humanely euthanized for large-volume blood collection to isolate peripheral blood mononuclear cells (PBMCs) and plasma, establishing the immune bank. PBMCs and plasma from each group were then tested against six PRRSV-2 strains to evaluate immune responses. In addition, T cell epitope coverage between vaccine and field PRRSV-2 strains was assessed using the EpiCC (in silico) tool to enhance predictive capacity. Results: While neutralizing antibodies were undetectable in all vaccinated pigs at 28 dpv, PRRSV-specific IFN g –producing cells were detected at various levels in each vaccinated group following restimulation with different PRRSV-2 strains. Additionally, a positive correlation was observed for the EpiCC coverage of the N gene and mean IFN g responses to VR2332 (SLA class I and II) and NC24-6 (SLA class II). Conclusions: The PRRSV immune bank demonstrated potential as a tool for predicting vaccine immunogenicity against different PRRSV-2 strains and EpiCC provide additional information on T cell epitope cross conservation. The combined approach may provide a valuable framework for selecting PRRSV vaccines for more effective prevention and control in endemic areas.

Porcine epidemic diarrhea virus (PEDV) is one of the most devastating pathogens of global swine health and welfare. It is well known that contaminated fomites and vehicle movements play an important role in farm-to-farm PEDV spread, but the efficacy of cleaning and disinfection (C&D) protocols on the reduction in dissemination risk via vehicles and trailers remains unclear. This study used swine industry data to determine how frequently vehicles and trailers were contaminated with PEDV RNA before and after C&D. Environmental RNA samples were collected at three eastern North Carolina C&D sites from four different vehicle types: crew trucks, feed trucks, pigs-to-farm trucks and trailers, and pigs-to-market trucks and trailers. A total of 2,004 samples were collected from truck cabins, trailers, and tires before and after C&D with two commercial disinfectants at two different concentrations. An in-house RT-qPCR assay was used to detect the presence of PEDV RNA only (not infectivity status). Results suggest that pigs-to-market trucks hauling live pigs were the most likely to be contaminated with PEDV (82.06% of trucks tested positive before C&D and 89.55% tested positive after C&D), while feed trucks were the least likely contaminated (11.73% of trucks testing positive before C&D and 11.25% testing positive after C&D). Based on PEDV RNA detection, we demonstrated that quaternary ammonium and glutaraldehyde is a more effective disinfectant compared to advanced hydrogen peroxide in eliminating detectable PEDV RNA. Results also show that truck cabins are just as contaminated as the exterior of their vehicles. Based on these results, vehicle biosecurity measures should be evaluated and modified to prevent the spread of PEDV.

Progesterone plays an important role in initial conceptus development and in a successful pregnancy, but results related to progesterone or its analogues (altrenogest) supplementation in early pregnancy of pigs are conflicting. The present study evaluated the effects of altrenogest supplementation in sows during days 6 and 12 of pregnancy on reproductive performance. On day 6 of pregnancy, 301 females were allocated at random to one of the following treatments: CON (Control: non-supplemented females, n = 163) or ALT (females daily supplemented with 20 mg of altrenogest, orally, from day 6 to 12 of pregnancy, n = 138). Ovulation was considered as occurred at 48 h after the first estrus detection to standardize the first day of pregnancy. The supplementation increased the number of total piglets born (ALT: 17.3 ± 0.4; CON: 16.6 ± 0.4), piglets born alive (ALT: 15.6 ± 0.4; CON: 14.8 ± 0.3), and placenta weight (ALT: 4.2 ± 0.1; CON: 3.8 ± 0.1) and decreased the stillbirth rate (ALT: 5.9 ± 0.6; CON: 7.6 ± 0.6) and the number of piglets born weighing less than 800 g (ALT: 6.6 ± 0.6; CON: 8.0 ± 0.6), without impairment on farrowing rate. These results demonstrated that altrenogest supplementation on swine females between days 6 and 12 of pregnancy may be used to improve reproductive performance.

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 < 0.01). Thorough knowledge of all endemic viral strains is fundamental for development of infection and disease control, particularly in complex production systems. This may include consideration of sampling and testing strategies which could detect circulation of all IAV variants, even if they have low prevalence.

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 < 0.05). High within-pen intracluster correlation coefficients (> 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.

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 < .05). These results suggest that microclimate conditions can influence transmission patterns of influenza viruses in swine barns, and that even a herd with relatively simple demographics could have persistent and cocirculation of two different influenza A viruses IAV strains.