Development and validation of a farm- and province-level swine flow simulation model using discrete events and Ontario swine farm and provincial input data.

Infectious disease events can cause disruptions in service-based and agricultural industries. The list of possible events is long and varies from the incursion or emergence of a reportable animal pathogen to the recently documented interruptions caused by the COVID-19 pandemic. There is a need to develop models that can determine the impact of pathogens and mitigation measures on populations that are not directly affected by the pathogen in the case of a reportable disease, particularly when the health and welfare of these populations could be affected due to resulting disruptions in trade and supply chains. The primary objective of this study was to develop a discrete-event simulation (DES) model of swine production, including pork processing, for scenarios without major disruptions, which could be scaled from the level of an individual farm to the entire province of Ontario, Canada. The secondary objective was to validate the developed simulation against observed farm- and province-level statistics. A weekly discrete-event simulation consisting of 3 connected areas (a sow farm, a pig farm, and abattoirs) was developed using AnyLogic modelling software. Using Mann-Whitney tests, model outputs representative of the standard industry statistics were compared to data from 6 individual farms separately, as well as to provincial data from Ontario. A scalable discrete-event simulation of the swine production system for typical scenarios was accomplished. The model outputs were consistent with individual farm and industry statistics. As such, the model can be used to simulate swine production at distinct levels and could be further modified to represent swine marketing in other provinces or internationally.

Les maladies infectieuses peuvent provoquer des perturbations dans les industries de services et agricoles. La liste des événements possibles est longue et varie de l'arrivée ou de l'émergence d'un agent pathogène animal à déclaration obligatoire aux interruptions récemment documentées causées par la pandémie de COVID-19. Il est nécessaire d'élaborer des modèles permettant de déterminer l'impact des agents pathogènes et des mesures d'atténuation sur les populations qui ne sont pas directement affectées par l'agent pathogène dans le cas d'une maladie à déclaration obligatoire, en particulier lorsque la santé et le bien-être de ces populations pourraient être affectés en raison des conséquences dues aux perturbations du commerce et des chaînes d'approvisionnement. L'objectif principal de cette étude était de développer un modèle de simulation à événements discrets (DES) de la production porcine, y compris la transformation du porc, pour des scénarios sans perturbations majeures, qui pourraient être étendus du niveau d'une ferme individuelle à l'ensemble de la province de l'Ontario, Canada. L'objectif secondaire était de valider la simulation développée par rapport aux statistiques observées au niveau de la ferme et de la province. Une simulation à événements discrets hebdomadaire composée de 3 zones connectées (un élevage de truies, un élevage de porcs et des abattoirs) a été développée à l'aide du logiciel de modélisation AnyLogic. À l'aide des tests de Mann-Whitney, les résultats du modèle représentatifs des statistiques standards de l'industrie ont été comparés aux données de 6 fermes individuelles séparément, ainsi qu'aux données provinciales de l'Ontario. Une simulation à événements discrets évolutive du système de production porcine pour des scénarios typiques a été réalisée. Les résultats du modèle étaient cohérents avec les statistiques individuelles des exploitations et des industries. Ainsi, le modèle peut être utilisé pour simuler la production porcine à des niveaux distincts et pourrait être modifié davantage pour représenter la commercialisation du porc dans d'autres provinces ou à l'échelle internationale.(Traduit par Docteur Serge Messier).

A case of tail-biting on a multi-site swine operation in Ontario.

This case study describes a severe tail-biting event on a multi-site swine operation in Ontario and outlines the management strategies implemented in an attempt to control the problem. An established social order was clearly present before the tail-biting event occurred. Over 40% of tail-docked pigs in 3 of 8 grower-finisher barns were severely affected, leading to higher mortality and increased numbers of pigs re-housed in hospital pens. Environmental factors, management practices, and animal health in the barns experiencing the tail-biting event are described, including detection of the mycotoxin deoxynivalenol in corn at > 2 ppm. Changes implemented in response to tail-biting included altering the phase-feeding schedule, adding enrichment devices, and increasing surveillance. The subsequent cohort of pigs was followed through the finisher barns and did not engage in the same severity or prevalence of tail-biting as the previous cohort of pigs which experienced the tail-biting event. Key clinical message: No single factor was identified as the initiating cause for the severe tail-biting event. The subsequent cohort of pigs in 4 barns of the same operation were monitored for tail-biting from entry until market, and the incidence of tail-biting was very low.

Un cas de caudophagie dans une exploitation porcine à sites multiples en Ontario. Cette étude de cas décrit un cas grave de caudophagie dans une exploitation porcine à sites multiples en Ontario et décrit les stratégies de gestion mises en oeuvre pour tenter de limiter le problème. Un ordre social établi était clairement présent avant que l'événement de mordillage de queue ne se produise. Plus de 40 % des porcs à la queue coupée dans trois des huit élevages de type croissance-finition ont été gravement touchés, ce qui a entraîné une mortalité plus élevée et un nombre accru de porcs relogés dans des enclos hospitaliers. Les facteurs environnementaux, les pratiques de gestion et la santé animale dans les porcheries où sévissaient la caudophagie sont décrits, y compris la détection de la mycotoxine désoxynivalénol dans le maïs à > 2 ppm. Les changements mis en oeuvre en réponse à la caudophagie comprenaient la modification du calendrier d'alimentation par phases, l'ajout de dispositifs d'enrichissement et l'augmentation de la surveillance. La cohorte suivante de porcs a été suivie dans les porcheries de finition et n'a pas eu la même gravité ou prévalence de caudophagie que la cohorte précédente de porcs qui ont subi l'événement de caudophagie.Message clinique clé :Aucun facteur unique n'a été identifié comme la cause initiale de l'événement grave de caudophagie. La cohorte suivante de porcs dans quatre porcheries de la même exploitation a été surveillée pour la caudophagie depuis l'entrée jusqu'au marché, et l'incidence de la caudophagie était très faible.(Traduit par Dr Serge Messier).

Effect of Varying Levels of Dietary Tryptophan on Aggression and Abnormal Behavior in Growing Pigs.

Body lesions, resulting from tail-biting and ear-biting, can result in decreased health and welfare in pigs. Tryptophan, an indispensable amino acid, is needed to support protein deposition, and the synthesis of the neurotransmitter serotonin, which is important to mood, sleep-wake and eating patterns and might play a role in aggression and abnormal behavior. Two randomized block design studies were conducted to assess the influence of varying dietary tryptophan levels on aggression and abnormal behavior in 8-week-old pigs. Six diets were formulated which met or exceeded all nutrient requirements yet differed according to the dietary tryptophan content. The first study included control (100% standardized ileal digestible tryptophan), supplemented (175% standardized ileal digestible tryptophan), and supplement-plus (250% standardized ileal digestible tryptophan) experimental diets, while the second study included deficient (80% standardized ileal digestible tryptophan), adequate control (105% standardized ileal digestible tryptophan), and extra-tryptophan (130% standardized ileal digestible tryptophan) experimental diets. Concentrations of plasma tryptophan and large neutral amino acids (tyrosine, isoleucine, leucine, valine, and phenylalanine) were analyzed using ultra-performance liquid chromatography and the tryptophan to large neutral amino acid ratio was calculated. Analysis for time active, lying, and engaging in aggressive interactions was carried out using 10-min scan samples to determine behavioral time budgets of the pigs on different experimental diets. Pigs fed diets with supplemented tryptophan had higher concentrations of both plasma tryptophan and tryptophan to large neutral amino acid ratio compared to the pigs fed the control diet (P < 0.05) in the first study, while no significant differences were detected for plasma tryptophan or the tryptophan to large neutral amino acid ratio in the second study. Diet did not have an effect (P > 0.05) on weight, feed intake or behavior throughout the studies. The results suggest that an increase in dietary tryptophan relative to large neutral amino acids, fed for 29 days, impacts circulating plasma tryptophan and therefore, serotonin concentrations in the pig. Despite an increase in circulating plasma tryptophan in response to an increase in dietary tryptophan in the first study, we failed to see an impact of the dietary treatment on body, tail and ear-biting behavior under the conditions studied.

Tail-Biting in Pigs: A Scoping Review.

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.