Prevalence and risk factors for medical events following exercise at Australian Greyhound race meetings

Aim

A prospective, observational study to determine the prevalence of post‐exercise conditions at Australian Greyhound race meetings and to assess association with race performance and other environmental, race‐ and dog‐related factors was undertaken.

Methods

A total of 4020 starters were observed (2813 Greyhounds, 1009 trainers, 536 races, 52 race meets, 48 race dates and 11 race tracks) following a race. The presence of diaphragmatic flutter (DF), ataxia, seizure, collapse or sudden death was recorded. Risk factors were screened by univariable logistic regression prior to multivariable backward stepwise model building.

Results

In this study, 962 starters (n = 768 dogs) had DF (23.9%), 16 starters were ataxic (0.4%) and there were no observed cases of collapse, seizure or sudden death. Race track location, increasing race distance, race grade based on increasing 1st place prize value, lower (earlier) race number at the meeting, age, a previous observation of DF at the last start, females, colour (white) and better finishing position were all associated with an increased risk of a Greyhound being observed with DF. However, when logistic regression assessing the random effect of dog was performed, the presence of previous DF was not significant. In this cohort, DF was common following strenuous exercise in Greyhounds and on its own does not appear to result in reduced performance or distress to the animal.

Conclusion

The incidence of ataxia was low and collapse, seizure and sudden death were not observed. However, even though uncommon, ataxia has welfare concerns for racing Greyhounds that warrants further investigation.     

Local immunity in the respiratory tract of the chicken. II. The secretory immune response to newcastle disease virus and the role of IgA

The nature, specificity and characteristics of the secretory immune response in the respiratory tract of the chicken were investigated in young specific-pathogen-free chickens after vaccination with live lentogenic and inactivated Newcastle disease virus (NDV). Virus-neutralizing (VN) activity considerably exceeding transudation levels from serum were detected in lachrymal fluid, saliva and tracheal washes following infection by both ocular and oral routes. Heat inactivated virus inoculated into the trachea evoked neither serum nor secretory VN activity, whereas a commercial inactivated virus vaccine in mineral oil adjuvant stimulated high titres of serum antibody and some VN activity in tracheal fluids.Antibody in secretions limited, but did not prevent, reinfection of the trachea when birds were challenged 2 weeks later. In contrast to an elevation of circulating antibody titre, challenge induced only a repeated primary response of secreted antibody.All secretions contained IgA which, at least in saliva, accounted for 85% of its activity, the remainder being due to IgG. Fluorescent localization of immunoglobulin producing cells (IPC) demonstrated large numbers containing IgA in association with the upper respiratory tract, particularly in the Harderian gland which contained dense aggregations of plasma cells, many of which were producing IgA.It is concluded that the respiratory tract of the chicken possesses an antibody mediated secretory immune system analogous to that of mammalian species.     

Influence of acepromazine maleate on the equine haematocrit

The effect of acepromazine maleate (ACP) on the equine venous haematocrit and total plasma protein concentration was studied in six clinically normal horses. Total plasma protein concentration was not appreciably influenced by ACP. However, the haematocrit decreased with the duration, but not the degree, of the decrease being dose-related. Mean haematocrit values returned to control levels by 12 h after 0.05 mg ACP/kg body weight and 21 h after 0.15 mg ACP/kg body weight.     

Pleural effusion secondary to thoracic metastatic mammary adenocarcinoma in a mare

A 17-year-old Quarter Horse mare was examined nearly 3 years after excision and cryotherapy of a papillary mammary gland adenocarcinoma. The mare had been used for pleasure riding since surgery, but had recently developed progressive dyspnea. The mare had clinical evidence of pleural effusion, but died before further clinical examination and treatment were instituted. Necropsy revealed deep mammary masses with similar nodules in the deep inguinal, renal, and mediastinal lymph nodes and in the lungs, pericardium, visceral and parietal pleurae, and left ovary. The masses were identified as papillary mammary gland adenocarcinoma. Large volumes of free pleural and peritoneal fluid were detected. The pleural fluid contained similar neoplastic cells that could have been readily detected by exfoliative cytologic examination had the mare survived.     

Association of Fusarium Species in the Wheat Stem Rot Complex

Data from a national survey were analysed to investigate whether there was interdependence among the Fusarium species, which cause the stem rot complex of wheat. About 25 wheat stems were sampled from each of 260 sites over the main wheat growing areas in the UK. Occurrence of each Fusarium species on individual stems was determined. Fusarium culmorum, F. avenaceum and Microdochium nivale were the three dominant species, detected in 248, 185 and 239 out of the 260 sites. There were no interactions among species in the distribution of the three species over the 260 sites. Several statistical tests were used to determine whether there was interdependence among the three species on the same stem within each site. Of the three species, there was only limited evidence of competition between F. culmorum and F. avenaceum.     

Particulate organic matter as a source of variation in denitrification in clods of soil

Existing mechanistic models of denitrification in clods of soil describe the anaerobic activity in the centres of the clods, but they neglect the role of particulate organic materials. We therefore studied the effect of particulate organic matter on denitrification in soil both under pasture and in arable cultivation. Clods were separated into two compartments: (i) particulate organic matter and adhering soil exceeding 200 μm (coated POM), and (ii) the matrix (the rest of the soil). Potential denitrification and production of CO₂ were then estimated on coated POM, matrix and unfractionated soil. The quantity and the quality of coated POM were assessed individually in 100 clods from the pasture and 100 from the arable land. The rate of potential denitrification was similar in unfractionated soil from these treatments. However, it was 70 times greater in the coated POM than in the matrix from the arable soil. Production of CO₂ was nine times greater in the coated POM than in the matrix from the pasture soil and 33 times greater in the arable soils. These observations were the basis for a mechanistic model of denitrification, taking into account contributions from coated POM and the matrix. Denitrification rates in a computerized representation of clods from both pasture and arable soil had approximately the same distribution as experimental data both in the matrix and coated POM contributions in the cropped soil and in the matrix alone in the pasture soil. Coated particulate organic matter can explain more than half of the denitrification and most of the variation in denitrification when it increases microbial activity sufficiently and the soil structure limits the supply of O₂.     

The use of species-specific PCR-based assays to analyse Fusarium ear blight of wheat

Polymerase chain reaction (PCR) assays for the detection of various Fusarium species and Microdochium nivale subspecies were compared with conventional visual disease assessment using a field plot of wheat in which the central subplot was inoculated with F. culmorum . Visual disease assessment was performed on a range of samples taken from each of 15 subplots at growth stage 80. At harvest, each sample was divided into its component parts, i.e. grain, glume and rachis, and species-specific PCR analysis was used to detect the presence of F. culmorum , F. poae , F. avenaceum , F. graminearum , M. nivale var. majus and M. nivale var. nivale . Within the inoculated subplot there was good correlation between visual disease assessment and PCR analysis, both techniques indicating a high incidence of F. culmorum in this region. According to the visual disease assessment results, there was also a relatively high incidence of F. culmorum in most other regions of the field plot. However, according to PCR analysis the incidence of F. culmorum in many of the other subplots was relatively low and F. poae , M. nivale var. majus and var. nivale , and F. avenaceum were detected within the grain, glume and rachis tissues of many of the ear samples from these subplots. F. poae predominated in the glume component of ears and M. nivale var. majus and var. nivale in the rachis component. M. nivale PCR results revealed that 64% of infected samples involved var. majus , and 36% var. nivale . PCR analysis has highlighted some difficulties that may arise when using visual assessment for studying disease complexes.     

Reducing acrylamide precursors in raw materials derived from wheat and potato

A review of agronomic and genetic approaches as strategies for the mitigation of acrylamide risk in wheat and potato is presented. Acrylamide is formed through the Maillard reaction during high-temperature cooking, such as frying, roasting, or baking, and the main precursors are free asparagine and reducing sugars. In wheat flour, acrylamide formation is determined by asparagine levels and asparagine accumulation increases dramatically in response to sulfur deprivation and, to a much lesser extent, with nitrogen feeding. In potatoes, in which sugar concentrations are much lower, the relationships between acrylamide and its precursors are more complex. Much attention has been focused on reducing the levels of sugars in potatoes as a means of reducing acrylamide risk. However, the level of asparagine as a proportion of the total free amino acid pool has been shown to be a key parameter, indicating that when sugar levels are limiting, competition between asparagine and the other amino acids for participation in the Maillard reaction determines acrylamide formation. Genetic approaches to reducing acrylamide risk include the identification of cultivars and other germplasm in which free asparagine and/or sugar levels are low and the manipulation of genes involved in sugar and amino acid metabolism and signaling. These approaches are made more difficult by genotype/environment interactions that can result in a genotype being "good" in one environment but "poor" in another. Another important consideration is the effect that any change could have on flavor in the cooked product. Nevertheless, as both wheat and potato are regarded as of relatively high acrylamide risk compared with, for example, maize and rice, it is essential that changes are achieved that mitigate the problem.