Prevalence and geographic distribution of canine and feline blastomycosis in the Canadian prairies

This retrospective study reports patient signalment, method of diagnosis and geographic distribution, and examines trends in prevalence and seasonal distribution of blastomycosis cases submitted to a veterinary diagnostic laboratory in Saskatchewan over a 21-year period. Of the 143 cases that originated from Saskatchewan and Manitoba 137 were from canine and 6 from feline patients. Signalment was similar to that previously reported. All cases originated in southern Saskatchewan and Manitoba, primarily from Regina, Moose Jaw, Swift Current, and Winnipeg. Case numbers showed a significant increase in the period 2001 to 2010 compared to 1990 to 2000. Seasonally, there was an increasing trend in the number of diagnoses from February to November. There was no correlation between average seasonal temperature or average seasonal total precipitation and the number of cases of blastomycosis. The persistence of blastomycosis in southern Saskatchewan indicates that Blastomyces dermatitidis is now endemic in this region.     

Influence of exercise on thermographically determined surface temperatures of thoracic and pelvic limbs in horses

OBJECTIVE: To determine the amount of time required for surface temperatures of thoracic and pelvic limbs in horses to return to pre-exercise temperatures after high-speed treadmill exercise, as detected via infrared thermographic imaging. DESIGN: Prospective study. ANIMALS: 6 Thoroughbreds. PROCEDURES: All horses had been trained on and conditioned to use of a high-speed treadmill. Baseline thermographic images were obtained 3 days prior to exercise (baseline). Horses were exercised on a treadmill at a walk for 5 minutes, a slow trot (3 m/s) for 5 minutes, a trot (5 to 6 m/s) for 5 minutes, and a slow gallop (6 to 8 m/s) for 5 minutes, then back to a trot for 3 minutes, a slow trot for 3 minutes, and a walk for 3 minutes prior to stopping. Thermal images were obtained immediately after stopping exercise (0 minutes) and 5, 15, 45, and 60 minutes and 6 hours after stopping exercise. Ambient temperature surrounding each horse was recorded. RESULTS: In all regions, significant differences in surface temperatures were detected between thermograms obtained before exercise and those obtained immediately after, 5 minutes after, and 15 minutes after exercise was stopped. There were no significant differences in surface temperatures between thermograms obtained before exercise and those obtained > or = 45 minutes after exercise was stopped. CONCLUSIONS AND CLINICAL RELEVANCE: In horses, images generated via infrared thermography are not influenced by exercise-generated heat > or = 45 minutes after exercise is stopped.     

Spatial analysis of an anthrax outbreak in Saskatchewan, 2006

An outbreak of anthrax in Saskatchewan in 2006 affected more than 800 animals at 150 locations. The purpose of this study was to assess the spatial and temporal patterns among the cases to determine if there were any significant trends associated with this outbreak. Case and population data were first analyzed for each individual farm location and then again as aggregate data per rural municipality using spatial and spatiotemporal statistical methods such as Oden's Ipop, Cuzick-Edwards' test, spatial scan test, and other mapping techniques. East central Saskatchewan was identified as a primary high risk area, particularly during July 2006. The results of the study led to the conclusion that within this high-risk region, flooding in spring followed by hot and dry conditions could have been a factor in the development of the outbreak.     

Old manor parks as potential habitats for forest flora in agricultural landscapes of Estonia

Forest biodiversity conservation in intensively managed agricultural landscapes is a constant concern. The dispersal ability of forest plants is, hypothetically, the major limiting factor in fragmented forest landscapes and, therefore, we tested the validity of the theoretical dispersal scheme for plants in fragmented landscapes: ancient forest > woody corridor > emerging forest patch. To this end, we examined the distribution pattern of forest-dwelling plant species in rural landscapes, specifically the occurrence of common forest plant species in old historical forests and in closed-canopy stands of rural ornamental parks, planted on an agricultural land one–two centuries ago.We found that (i) the shade tolerant plant flora in parks’ stands more resemble forests than woody linear habitats (corridors), (ii) nearly 50% of the local forest species pool was present in parks, (iii) the abundance of seed source habitats and the ecological quality of the target habitat determine success rate of colonization. Models predicted that optimal stand characteristics for forest herbs are a minimum area 2.5 ha, canopy closure 0.7–0.8, basal area of trees 10–20 m² ha^?1 and the presence of moderate understory management.We conclude that only patch-type habitats provide suitable environmental conditions for forest-specific plant species. Many common forest plant species are capable of long-distance dispersal between habitat patches across hostile agricultural land, and accordingly, their dispersal follows a modified scheme of the island biogeography, without intermediary role of corridor habitats. Old rural manor parks provide an ecosystem service for nature conservation by harbouring forest biodiversity, and should be considered as potential refugium habitats.     

The Effectiveness of Immunotherapy in Treating Exercise-Induced Pulmonary Hemorrhage

Inflammatory airway disease has been linked to exercise-induced pulmonary hemorrhage (EIPH), and consequently, we hypothesized that immunomodulation via concentrated equine serum (CES) treatment would reduce EIPH as evidenced by red blood cell (RBC) concentrations in bronchoalveolar lavage fluid (BALF). Separate trials were conducted on Thoroughbred horses treated with either CES (n = 6) or placebo (0.9% saline; n = 4). All horses completed pre-treatment and post-treatment (2 and 4 weeks after initiating treatment) maximal exercise tests on a 10% inclined treadmill (1 m/s/min increments to fatigue) over a 10-week period (2−3 weeks between tests), with bronchoalveolar lavage (BAL) performed 30 minutes after exercise. Treatment ensued 10 days after the pre-treatment exercise test, with horses receiving a series of five CES or placebo injections 24 hours apart (20 mL intratracheal and 10 mL intravenously), with subsequent weekly injections for 5 weeks thereafter. After CES treatment, both EIPH (RBC in BALF) and inflammation (white blood cell concentration [WBC] in BALF) were significantly diminished by the 4-week posttreatment run, demonstrating 46 ± 12% and 24 ± 11% decreases, respectively (P < 0.05). In contrast, EIPH was elevated significantly at the 4-week time point, and inflammation remained constant in the placebo trial. In conclusion, these preliminary data suggest that therapeutic intervention involving immunomodulation may represent a viable approach to reducing the severity of EIPH.     

Omega-3 Fatty Acid Supplementation Reduces Basal TNFα but Not Toll-Like Receptor-Stimulated TNFα in Full-Sized and Miniature Mares

It has been well documented that omega-3 long-chain polyunsaturated fatty acids (n-3 PUFA) confer a wide variety of health benefits to humans and animals. The current study was designed to evaluate the ability of n-3 PUFA to modulate the innate immune response in two diverse breeds of horses. Ten Quarter Horse and 10 American Miniature Horse mares were assigned to either an n-3-PUFA-supplemented or a control diet (five full-sized and five miniature mares/treatment) for 56 days. The treatment diet was designed to deliver 64.4 mg/kg body weight of combined eicosapentaenoic acid and docosahexaenoic acid daily. Blood was collected through jugular venipuncture into heparinized tubes on days 0, 28, and 56. Serum PUFA analysis was conducted by gas chromatography. Peripheral blood mononuclear cell production of tumor necrosis factor-α (TNFα) in response to toll-like receptor (TLR) ligands lipopolysaccharide, flagellin, and lipoteichoic acid was estimated using an equine-specific enyme-linked immunosorbent assay. Peripheral blood samples from day 56 were also analyzed for total and differential leukocyte counts and subjected to flow cytometric analysis. Body type did not affect basal or TLR-stimulated TNFα production. Serum PUFA analysis revealed a decrease in α-linolenic acid and substantial increases in arachidonic acid, eicosapentaenoic acid, docosahexaenoic acid, and docosapentaenoic acid at both day 28 and day 56 in horses fed n-3 PUFA (P < .0001 for all). Dietary n-3 PUFA supplementation reduced (P < .05) unstimulated basal, but not TLR-stimulated, TNFα production by peripheral blood mononuclear cells. Supplementation with n-3 PUFA neither affected total or differential leukocyte counts nor selected cell surface markers. These results suggest that n-3 PUFA supplementation in the horse can modify circulating PUFA and alter the inflammatory response by reducing basal TNFα production. Furthermore, under conditions of the current study and considering the end points evaluated, the American Miniature Horse could potentially be used as a model for full-sized horse breeds.     

Omega-3 Fatty Acid Supplementation Affects Selected Phospholipids in Peripheral White Blood Cells and in Plasma of Full-Sized and Miniature Mares

Dietary omega-3 fatty acids (n-3 PUFA), notably eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), impart health benefits in humans and animals. In horses, dietary n-3 PUFAs elevate EPA and DHA and may promote anti-inflammatory effects. No reports document effects of dietary n-3 PUFA on fatty acyl components of circulating and cellular phospholipids in horses nor whether responses to dietary n-3 PUFA are similar among horse breeds. Ten Quarter Horse and 10 American Miniature Horse mares were assigned to n-3 PUFA (64.4 mg· kg body weight [BW]⁻¹·d⁻¹) or control diet for 56 days. Blood was sampled at 0, 28, and 56 days. Apparent phospholipid molecular species from several classes (phosphatidylcholine [PC]; “ether-linked” phosphatidylcholine [i.e., alk(en)yl, acyl glycerophosphocholine] [ePC]; phosphatidylethanolamine [PE]; phosphatidylinositol [PI]; and phosphatidylserine [PS]) were determined in plasma and peripheral blood mononuclear cells (PBMC) by mass spectrometry. Statistical analysis showed that six phospholipid species had diet × day interactions (P < .05) for both plasma and PBMC. Further evaluation of these species demonstrated that the mole percentage of PC(38:6), PC(40:7), PC(42:10), PE(38:5), PE(40:6), and PE(40:7) (where x:y represents total acyl carbon:total carbon-carbon double bonds) in both plasma and PBMC phospholipids was elevated in horses fed n-3 PUFA (P < .001 for all). Analysis of the acyl product ions revealed that these contained an acyl chain of mass consistent with an n-3 PUFA. Thus, supplementation increased n-3 PUFA in selected plasma and PBMC phospholipids. The absence of breed effects suggests that miniature and full-size horses responded similarly to dietary treatment.     

The Effect of Parity of the Dam on Sexual Maturation,Serum Concentrations of Metabolic Hormones and the Response to Luteinizing Hormone Releasing Hormone in Bull Calves

The objectives of this study were to determine the effect of parity of the dam on age at which a scrotal circumference (SC) ≥ 28 cm was attained and the LH response to Luteinizing Hormone Releasing Hormone (LHRH) in bull calves. We also wanted to confirm, in a large group of bull calves, that the LH response to LHRH could be used to select early maturing bulls. Body weight and SC of the bull calves were measured every other week. At 15, 20 and 25 weeks of age, calves received 4.12 nm /kg body weight of LHRH ischio‐rectally and blood samples were taken every 15 min for 4 h. Calves from primiparous and multiparous dams were separated into two sub‐groups based on age at which an SC ≥ 28 cm was attained (early or late). An SC ≥ 28 cm was attained earlier in calves born to multiparous as compared with primiparous dams (p < 0.05). At 20 and 25 weeks of age, peak serum LH concentrations (LH‐peak) and area under the LH response curve (LH‐AUC) in response to LHRH were higher (p < 0.01) in calves born to multiparous as compared with primiparous dams. In calves born to multiparous dams the LH‐peak at 15 and 25 weeks of age and the LH‐AUC at 15 weeks of age were lower (p < 0.05) in calves that attained an SC ≥ 28 cm early as compared with late. The LHRH‐challenge test sensitivity and specificity ranged from 46% to 86%. We concluded that parity of the dam affected age at which SC ≥ 28 cm was attained and the LH response to LHRH in bull calves. Serum LH responses to LHRH at 15 and 25 weeks of age, in calves born to multiparous dams, show some promise for development into a test to select early maturing bull calves.     

Occupational health hazards in veterinary medicine: physical, psychological, and chemical hazards

This paper reports physical, psychological, and chemical hazards relevant to western Canadian veterinarians as obtained by a self-administered mailed questionnaire. Nine-three percent (750/806) of veterinarians reported some form of injury during the previous 5 years; 17% of respondents (131/791) indicated injuries that resulted in 1 or more days off work. Median stress levels were similar across work environments; overall, 7% (57/813) indicated either no stress or severe stress, while 53% (428/813) indicated moderate stress. Twenty percent (3/15) of food animal practitioners and 37% (114/308) of companion animal practitioners who took X-rays reported accidental exposure. Accidental exposure to gas anesthetic was reported by 69% (394/570) of those in private practice. Exposure to chemicals occurred in all work environments. Veterinarians in western Canada are at risk of minor to severe injury due to both animal and non-animal related causes.