RESUMEN
OBJECTIVE: Successful disease management requires effective surveillance. Slaughterhouse inspections provide opportunities to efficiently collect regular disease data from many animals across large areas. Toxoplasma is a cat-borne parasite that causes reproduction failure in sheep, although it is not visually detectable at slaughterhouses. Macroscopic sarcocystosis is a disease of sheep that is visually detectable at slaughter and is caused by parasites that share a similar biology with Toxoplasma. We investigated if sarcocystosis could act as a proximate measure for Toxoplasma exposure in sheep to facilitate its efficient surveillance at large scales. DESIGN/METHODS: We compared the presence of macroscopic sarcocystosis to Toxoplasma serostatus at the animal and farm levels. RESULTS: At the animal level, we found a weak association between Toxoplasma seropositivity and sarcocysts in the oesophagus (OR = 1.76 [95% CI: 1.17, 2.65; McFadden's R2 = 0.01]) but no association between Toxoplasma seropositivity and sarcocysts in skeletal muscles. At the farm level, the seroprevalence of Toxoplasma was strongly associated with oesophageal sarcocystosis prevalence (OR = 28.59 [95% CI: 13.07, 62.57; McFadden's R2 = 0.34]) but less strongly associated with sarcocystosis prevalence in skeletal muscles (OR = 7.91 [95% CI: 1.24, 50.39; McFadden's R2 = 0.02]). CONCLUSIONS: For Toxoplasma surveillance in sheep at the farm level, routine slaughter inspection and recording of macroscopic oesophageal sarcocystosis could be are liable and efficient proximate measure. The monitoring of oesophageal sarcocystosis may be a useful passive Toxoplasma surveillance tool for guiding the timing and location of other Toxoplasma detection methods to facilitate the management of Toxoplasma impacts within the sheep industry.
Asunto(s)
Enfermedades de los Gatos , Sarcocystis , Sarcocistosis/veterinaria , Enfermedades de las Ovejas , Toxoplasma , Animales , Gatos , Esófago , Estudios Seroepidemiológicos , OvinosRESUMEN
There is mounting evidence that bacteria originating from pigs degrade the environment of the pig shed and adversely affect the health of the animals and the pig-shed workers. α-haemolytic cocci (AHC) occur in pig-shed environments, but are regarded as commensals. Ammonia is also a component of the pig-shed environment, and is known to damage upper respiratory tract epithelia. The aim of this study was to determine whether polluted air in pig sheds adversely affected performance indicators in pigs. Modelling revealed a direct effect of AHC on voluntary feed intake and hence AHC are not commensal. No direct effect of ammonia on the pigs was detected, but the combination of AHC and ammonia stimulated the immune system in a progressive manner, and there were direct effects of immune stimulation on food intake and growth resulting in poorer feed-conversion efficiency, even though the effects remained subclinical. The authors conclude that exposure of the respiratory epithelia of pigs to viable AHC in the presence of ammonia redirects nutrients away from production and towards the immune system, explaining the impact of poor pig-shed hygiene on production parameters.
Asunto(s)
Microbiología del Aire , Amoníaco/análisis , Vivienda para Animales , Higiene , Porcinos/crecimiento & desarrollo , Aerococcus/aislamiento & purificación , Crianza de Animales Domésticos , Bienestar del Animal , Animales , Femenino , Humanos , Streptococcus/aislamiento & purificación , Porcinos/inmunología , Porcinos/metabolismo , Porcinos/microbiologíaRESUMEN
We undertook a literature search related to pig production facilities with two major aims: first, to review all the likely benefits that might be gained from air quality improvements; and second, to review previous research that had identified statistically significant factors affecting airborne pollutants and environmental parameters, so that these factors could be considered in a multifactorial analysis aimed at explaining variations in air pollutant concentrations. Ammonia, carbon dioxide, viable bacteria, endotoxins, and inhalable and respirable particles were identified as major airborne pollutants in the review. We found that high concentrations of airborne pollutants in livestock buildings could increase occupational health and safety risks, compromise the health, welfare, and production efficiency of animals, and affect the environment. Therefore, improving air quality could reduce environmental damage and improve animal and worker health. To achieve a reduction in pollutant concentrations, a better understanding of the factors influencing airborne pollutant concentrations in piggery buildings is required. Most of the work done previously has used simple correlation matrices to identify relationships between key factors and pollutant concentrations, without taking into consideration multifactorial effects simultaneously in a model. However, our review of this prior knowledge was the first important step toward developing a more inclusive statistical model. This review identified a number of candidate risk factors, which we then took into consideration during the development of multifactorial statistical models. We used a general linear model (GLM) to model measured internal concentrations, emissions, and environmental parameters in order to predict and potentially control the building environment.
Asunto(s)
Contaminación del Aire Interior , Salud Ambiental , Arquitectura y Construcción de Instituciones de Salud/normas , Vivienda para Animales/normas , Salud Laboral , Microbiología del Aire , Contaminación del Aire Interior/análisis , Contaminación del Aire Interior/prevención & control , Amoníaco/análisis , Animales , Australia , Dióxido de Carbono/análisis , Interpretación Estadística de Datos , Monitoreo del Ambiente , Análisis Factorial , Humanos , Modelos Lineales , Modelos Teóricos , Factores de Riesgo , PorcinosRESUMEN
The concentrations of total airborne bacteria, respirable endotoxins, ammonia, and respirable and inhalable particles were monitored in 160 piggery buildings in Australia between autumn 1997 and autumn 1999. The overall mean airborne bacteria, respirable endotoxins, ammonia (NH3), and inhalable and respirable particle concentrations measured were 1.17 x 10(5) cfu m(-3), 33.1 EU m(-3), 3.7 ppm, 1.74 mg m(-3), and 0.26 mg m(-3), respectively. The characteristics of the buildings and management systems used were documented at the time of sampling. A multifactorial general linear model (GLM) statistical procedure was used to analyze the effects of housing and management factors on the concentrations of the airborne pollutants. Both airborne bacteria and respirable endotoxin concentrations were affected by building classification (type), and respirable endotoxin concentrations were positively correlated with increasing humidity. The concentrations of airborne bacteria increased as the level of pen hygiene (cleanliness) decreased. The NH3 concentrations were primarily affected by level of pen hygiene, building volume, pig flow management, and season. Building classification, pig flow management, season, building volume, ventilation rates, and temperature affected inhalable particle concentrations. Respirable particle concentrations were primarily affected by building classification, pen hygiene, pig flow management, season, ventilation rates, temperature, and humidity. These findings suggest that environmental improvement strategies (such as improved cleaning, ventilation, and temperature control) are likely to reduce airborne pollutant concentrations in pig buildings and in the environment, thus improving the health and welfare of both pigs and farm staff.
Asunto(s)
Microbiología del Aire , Contaminantes Ocupacionales del Aire/análisis , Contaminación del Aire Interior/análisis , Arquitectura y Construcción de Instituciones de Salud/normas , Vivienda para Animales/normas , Salud Laboral , Amoníaco/análisis , Crianza de Animales Domésticos/métodos , Animales , Australia , Dióxido de Carbono/análisis , Endotoxinas/análisis , Humanos , Humedad , Higiene , Modelos Lineales , Exposición Profesional/efectos adversos , Exposición Profesional/análisis , Factores de Riesgo , Estaciones del Año , Porcinos , TemperaturaRESUMEN
Between autumn 1997 and autumn 1999, we measured ventilation rates (using a CO2 balance method), air temperatures, and relative humidity (using self-contained dataloggers with built-in sensors) in 160 pig housing facilities in Queensland, South Australia, Victoria, and Western Australia, in each case over a 60 h period. In some buildings, the internal air velocities above the animals were also recorded. While the monitoring instruments were being set up, a detailed questionnaire was used to collect data on major housing features and management factors. This information was statistically analyzed to quantify the effects of housing and management factors on the resulting environment conditions using a multifactorial analysis. The overall mean air temperature, relative humidity, internal air velocity, and ventilation rate were 20.3 degrees C, 58.9%, 0.12 m s(-1), and 663.9 m3 h(-1) 500 kg(-1) live weight, respectively, across all buildings. Internal building temperature and humidity were affected statistically by the type of insulation material used, the classification of buildings, and external climatic conditions. Ventilation rates were primarily affected by the type of ventilation system used, height (size) of ventilation openings, stocking density (kg m(-3)), and length, width, and height of buildings. These findings should aid the development of strategies for the industry to improve environmental control in piggery buildings.
Asunto(s)
Contaminación del Aire Interior , Crianza de Animales Domésticos/métodos , Arquitectura y Construcción de Instituciones de Salud/normas , Vivienda para Animales/normas , Ventilación , Movimientos del Aire , Contaminantes Ocupacionales del Aire/análisis , Animales , Australia , Monitoreo del Ambiente/métodos , Humanos , Humedad , Factores de Riesgo , Encuestas y Cuestionarios , Porcinos , Temperatura , Ventilación/métodosRESUMEN
The internal concentrations and emission rates of ammonia (NH3), total bacteria, respirable endotoxins, and inhalable and respirable particles were monitored in 160 piggery buildings in four states of Australia (Queensland, Victoria, Western Australia, and South Australia) between autumn 1997 and autumn 1999. Emissions were calculated for individual buildings as a product of internal concentration and ventilation rate, which were estimated by a carbon dioxide balance method. Relative humidity and temperature were also measured. The overall mean emission rates of NH3, total bacteria, respirable endotoxins, inhalable particles, and respirable particles per 500 kg live weight from Australian piggery buildings were 1442.5 mg h(-1), 82.2 x 10(6) cfu h(-1), 20.1 x 10(3) EU h(-1), 1306.7 mg h(-1), and 254.7 mg h(-1), respectively. Internal concentrations of key airborne pollutants have been reported in companion articles. Building characteristics and management systems used in the piggeries were documented at the time of sampling and used in the subsequent statistical modeling of variations in pollutant emission rates. The emissions model used all statistically significant factors identified during prior modeling conducted for individual pollutant concentrations and ventilation airflow. The identification of highly significant factors affecting emission rates and internal concentrations should aid the development of strategies for the industry to reduce emission rates from individual buildings, thus improving the environmental performance of piggery operations. In the second part of the article, specific recommendations are made based on the overall study results.