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Wagner A.E.,University of Guelph | Wu P.F.,Ontario Ministry of Agriculture and Food
American Society of Agricultural and Biological Engineers Annual International Meeting 2014, ASABE 2014 | Year: 2014

Bovine spongiform encephalopathy (BSE) is a neurodegenerative disease that can transmit from cattle to humans. Humans can contract a variant version of the disease, named variant Creutzfeldt-Jakob disease (vCJD), from the consumption of beef infected with BSE. The infective agent is a misfolded protein called prion, which concentrates in tissues including the skull, brain, trigeminal ganglia, eyes, tonsils, spinal cord and dorsal root ganglia of cattle aged 30 months or older, and distal ileum of cattle of all ages. These tissues are collectively known as specified risk material (SRM). SRM are required to be removed from all cattle slaughtered for human consumption, and are also banned from all animal feeds, pet foods and fertilizers. In Ontario, Canada, acceptable disposal methods include destruction by incineration, alkaline hydrolysis and thermal hydrolysis. Alternatively, SRM can be disposed of by permanent containment. Methods of containment include burial and use of sanitary landfills operating under provincial jurisdiction as waste disposal site. Composting and rendering are acceptable intermediate steps used to reduce the SRM volume and to convert the SRM into a fuel source for final destruction.

Alton G.D.,University of Guelph | Pearl D.L.,University of Guelph | Bateman K.G.,University of Guelph | McNab B.,Ontario Ministry of Agriculture and Food | Berke O.,University of Guelph
BMC Veterinary Research | Year: 2013

Background: Abattoir condemnation data show promise as a rich source of data for syndromic surveillance of both animal and zoonotic diseases. However, inherent characteristics of abattoir condemnation data can bias results from space-time cluster detection methods for disease surveillance, and may need to be accounted for using various adjustment methods. The objective of this study was to compare the space-time scan statistics with different abilities to control for covariates and to assess their suitability for food animal syndromic surveillance. Four space-time scan statistic models were used including: animal class adjusted Poisson, space-time permutation, multi-level model adjusted Poisson, and a weighted normal scan statistic using model residuals. The scan statistics were applied to monthly bovine pneumonic lung and " parasitic liver" condemnation data from Ontario provincial abattoirs from 2001-2007.Results: The number and space-time characteristics of identified clusters often varied between space-time scan tests for both " parasitic liver" and pneumonic lung condemnation data. While there were some similarities between isolated clusters in space, time and/or space-time, overall the results from space-time scan statistics differed substantially depending on the covariate adjustment approach used.Conclusions: Variability in results among methods suggests that caution should be used in selecting space-time scan methods for abattoir surveillance. Furthermore, validation of different approaches with simulated or real outbreaks is required before conclusive decisions can be made concerning the best approach for conducting surveillance with these data. © 2013 Alton et al.; licensee BioMed Central Ltd.

Congreves K.A.,University of Guelph | Smith J.M.,Agriculture and Agri Food Canada | Nemeth D.D.,Ontario Ministry of Agriculture and Food | Hooker D.C.,University of Guelph | Van Eerd L.L.,University of Guelph
Canadian Journal of Soil Science | Year: 2014

Soil organic carbon (SOC) is crucial for maintaining a productive agro-ecosystem. Long-term research must be synthesized to understand the effects of land management on SOC storage and to develop best practices to prevent soil degradation. Therefore, this review compiled an inventory of long-term Ontario studies and assessed SOC storage under common Ontario land management regimes via a meta-analysis and literature review. In general, greater SOC storage occurred in no-till (NT) vs. tillage systems, in crop rotation vs. continuous corn, and in N fertilizer vs. no N fertilizer systems; however, soil texture and perhaps drainage class may determine the effects of tillage. The effect on SOC storage was variable when deeper soil depth ranges (0-45 cm) were considered for NT and rotational cropping, which suggests an unpredictable effect of land management on SOC at depths below the plough layer. Therefore, researchers are encouraged to use the presented inventory of nine long-term research sites and 18 active experiments in Ontario to pursue coordinated studies of long-term land management on SOC at depths extending below the plough layer.

Chiu G.Z.,University of Guelph | Shelp B.J.,University of Guelph | Bowley S.R.,University of Guelph | Deell J.R.,Ontario Ministry of Agriculture and Food
Canadian Journal of Plant Science | Year: 2015

‘Honeycrisp’ apples (Malus × domestica Borkh.), including fruit treated with the ethylene antagonist 1-methylcyclopropene (1-MCP), can be susceptible to controlled atmosphere (CA)-related injury of the flesh tissue during storage. To better understand the biomarkers associated with this physiological disorder, we compared the temporal responses of the universal stress signature, γ-aminobutyrate (GABA), and visual symptoms of CA-related injury in apples subjected to elevated CO2. Fruit were treated with or without 1-MCP prior to CA [2.5 kPa O2, 5 (elevated) or 0.03 (ambient) kPa CO2] storage at either 3 or 20°C for up to 24 wk. At 208C, 1-MCP-treated apples displayed symptoms of CA-related injury by 3 wk of elevated CO2 storage; a similar 15% disorder incidence was apparent by 6 wk in non 1-MCP-treated fruit. A maximal incidence of 30% for this disorder occurred after 24 wk at 3°C in fruit held at elevated CO2, regardless of 1-MCP treatment. At 20°C, GABA levels were 48% higher within 6 wk of the transfer of 1-MCP-treated fruit to elevated CO2. At 3°C, a 2.6-fold increase in GABA level occurred by week 6 of elevated CO2 storage, and was maintained for an additional 18 wk thereafter; a similar change in GABA level was apparent in non 1-MCP-treated fruit, albeit delayed until week 18 of storage. These findings indicate that shifts in GABA are associated with the onset of visual symptoms of CA-related injury in ‘Honeycrisp’ fruit in response to elevated CO2, regardless of 1-MCP. © 2015, Agricultural Institute of Canada. All rights reserved.

Lum G.B.,University of Guelph | Shelp B.J.,University of Guelph | DeEll J.R.,Ontario Ministry of Agriculture and Food | Bozzo G.G.,University of Guelph
Plant Science | Year: 2016

In combination with low temperature, controlled atmosphere storage and 1-methylcyclopropene (ethylene antagonist) application are used to delay senescence of many fruits and vegetables. Controlled atmosphere consists of low O2 and elevated CO2. When sub-optimal partial pressures are used, these practices represent multiple abiotic stresses that can promote the development of physiological disorders in pome fruit, including flesh browning and cavities, although there is some evidence for genetic differences in susceptibility. In the absence of surface disorders, fruit with flesh injuries are not easily distinguished from asymptomatic fruit until these are consumed. Oxidative stress metabolites tend to accumulate (e.g., γ-aminobutyrate) or rapidly decline (e.g., ascorbate and glutathione) in vegetative tissues exposed to hypoxic and/or elevated CO2 environments. Moreover, these phenomena can be associated with altered energy and redox status. Biochemical investigations of Arabidopsis and tomato plants with genetically-altered levels of enzymes associated with the γ-aminobutyrate shunt and the ascorbate-glutathione pathway indicate that these metabolic processes are functionally related and critical for dampening the oxidative burst in vegetative and fruit tissues, respectively. Here, we hypothesize that γ-aminobutyrate accumulation, as well energy and antioxidant depletion are associated with the development of physiological injury in pome fruit under multiple environmental stresses. An improved understanding of this relationship could assist in maintaining the quality of stored fruit. © 2016 Elsevier Ireland Ltd.

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