Larvicidal effects of several chemicals on Strongyloides infective larvae

The larvicidal effects of 11 anthelmintics, 7 pesticides and 4 disinfectants were evaluated with infective larvae of Strongyloides papillosus (SPL) and Strongyloides venezuelensis (SVZ). The lethal concentrations against SPL and SVZ were found to be similar. Three chemicals (dichlorvos, levamisole and trichlorfon) showed highest larvicidal effects. The 50% lethal concentration (LC(50)) values for the three compounds against SPL larvae were 0.08, 0.24, and 0.59 ppm, respectively.     

Bison Versus Cattle: Are They Ecologically Synonymous?

Historically, the plains bison (Bison bison Linnaeus) was the most numerous and influential grazer on the Great Plains. Today 500 000 bison occupy North America among more than 100 000 000 cattle. In an attempt to restore their historical ecological role, bison are translocated onto landscapes previously manipulated for cattle use through water and fence development. We hypothesized that bison would use these landscapes similarly to cattle, thus maintaining homogenous grazing and reducing the restoration potential of bison at a landscape scale. We quantified differences between bison populations at different locations and spatial scales (American Prairie Reserve, Malta, Montana, USA, and Grasslands National Park, Val Marie, Saskatchewan, Canada, 2010–2011) and bison and cattle at similar locations and spatial scales using behavioral observations, movement analyses, and resource selection functions. Bison and cattle differed in all behaviors (grazing, standing, bedded, moving, other); however, landscape attributes resulted in behavior differences within species. Cattle spent a higher proportion of time grazing (45–49%) than bison (26–28%) and increased time at water. Bison moved at a 50–99% faster rate than cattle, and first passage time movement analyses identified selection of bison foraging patches (11 690 ha) larger than cattle foraging patches (48–615 ha). Similar to cattle, bison avoided most vegetation communities in relation to riparian communities and selected areas closer to water. Cattle selected for high plant biomass, whereas bison selected for intermediate plant biomass. This study has implications when bison and cattle are used to meet prairie restoration objectives. For bison, large landscapes that include variation in topography and vegetation communities are required. Furthermore, limiting manmade water sources may facilitate bison grazing patterns that more closely approximate historical bison use. For livestock, reduced movement and increased time spent grazing encourage grazing practices that increase heterogeneous grazing at a pasture scale.     

Influence of breed and diet on growth, nutrient digestibility, body composition and plasma hormones of Brangus and Angus steers

Two split-plot designed experiments were conducted to determine the effects of breed (Angus, A, or Brangus, B) and diet (fescue hay, FH; corn silage, CS; or concentrate) on composition and rate of growth, diet digestibility and plasma hormones of steers. In Exp. 1, 10 steers (five of each breed) were fed a CS-based diet followed by a FH-based diet for two consecutive 60-d periods. Both breeds had lower (P less than .01) DM intake and digestibility when fed FH than when fed CS diets. The B steers had higher (P less than .01) plasma insulin concentrations than A steers when fed the CS diet. In Exp. 2, during two consecutive years, 10 steers previously fed CS- and FH-based diets were finished with a corn silage-whole shelled corn-based diet. During yr 1, A steers had higher (P less than .01) DM intake and plasma triiodothyronine (T3) and thyroxine (T4) concentrations (P less than .05) than B steers did. Although final weights were similar (P greater than .10), A steers had heavier (P less than .05) carcass weights than B steers did. During yr 2, A steers had higher (P less than .07) DM and starch digestibilities and higher (P less than .01) plasma T4 concentrations than B steers did. The greater (P less than .01) energetic efficiency of A steers was attributed to the greater rates of fat deposition during yr 2. Regardless of type of diet fed, A steers were more efficient at depositing energy. Higher circulating T4 concentrations of A than B steers may explain some of the physiological differences between these breeds.     

The effects of ketamine hydrochloride and diazepam on the intraocular pressure and pupil diameter of the dog’s eye

Objective To determine the effects of 10% ketamine hydrochloride and 0.5% diazepam on intraocular pressure (IOP) and horizontal pupil diameter (HPD) in the canine eye. Procedures Ten healthy dogs for each treatment group were used in this study. In the first group, 20 mg/kg ketamine hydrochloride was injected intravenously; in the second, 0.5 mg/kg diazepam was similarly injected; and in the third, a control group, 0.9% saline was used. In all groups, IOP and HPD were measured every 5 min for 35 min in the first group, and 60 min in the second and third group. Results A maximum increase in IOP was obtained 5 min after ketamine injection, with IOP of 23.2 ± 5.8 mmHg (a 45.0% increase compared to baseline) in the right eye and 22.9 ± 5.9 mmHg (a 43.5% increase) in the left eye (both significant at P < 0.01). A significant IOP increase was observed throughout the research period of 35 min. Statistically significant increases in HPD (P < 0.05) were observed only at 5 and 25 min after ketamine injection. A significant increase in IOP was obtained 10 min after diazepam injection, showing a maximum IOP 20 ± 5.0 mmHg in the right eye (9.3% increase) and 19.9 ± 5.1 mmHg (8.7% increase) in the left eye (both significant at P < 0.05). HPD decreased during the study period, reaching the lowest level 30 min post‐treatment. Conclusions This study showed a substantial increase in IOP after ketamine injection and a less substantial, but still significant increase after diazepam injection. These findings should be taken into consideration when using these drugs in dogs with fragile corneas, or in dogs predisposed or affected by glaucoma.     

Coronavirus-associated epizootic catarrhal enteritis in ferrets

OBJECTIVE: To characterize clinical signs and lesions and identify the etiologic agent associated with epizootic catarrhal enteritis in domestic ferrets. DESIGN: Cross-sectional study. ANIMALS: 119 ferrets with epizootic diarrhea of presumed viral cause and 5 control ferrets. PROCEDURE: Clinical records and biopsy or necropsy specimens of ferrets with presumed epizootic catarrhal enteritis were reviewed. Immunohistochemical staining for coronavirus antigen was performed on paraffin-embedded tissues from approximately 10% of affected ferrets to identify viral antigen and determine its distribution. Transmission electron microscopy was performed on fecal samples and sections of jejunum. Virus isolation studies as well as immunofluorescent tests for other similar viruses were performed. RESULTS: Characteristic microscopic lesions consistent with intestinal coronavirus infection (vacuolar degeneration and necrosis of villus enterocytes; villus atrophy, fusion, and blunting; and lymphocytic enteritis) were consistently detected in affected ferrets. Coronavirus particles were identified in feces and jejunal enterocytes by use of transmission electron microscopy. Immunohistochemical staining of jejunal sections revealed coronavirus antigens. Antigen staining was not detected in healthy ferrets or ferrets with other gastrointestinal tract diseases. Virus isolation was unsuccessful, and other similar viruses were not detected. CONCLUSIONS AND CLINICAL RELEVANCE: Results strongly implicate a coronavirus as the causative agent of epizootic catarrhal enteritis in ferrets. Diagnosis may be made on the basis of a combination of historical, clinical, and microscopic findings.     

Health status of northern bobwhite quail (Colinus virginianus) in eastern Kansas

The health status of wild northern bobwhite quail (Colinus virginianus) from Lyon County, Kansas, was evaluated by conducting comprehensive health assessments on 25 birds. Gross lesions indicative of avian pox, ulcerative enteritis, and quail bronchitis were not present. Serologic tests for antibodies to Salmonella pullorum, Salmonella gallinarum, Pasteurella multocida, Mycoplasma gallisepticum, Mycoplasma synoviae, and avian adenoviruses were all negative. Intestinal coccidia (Eimeria spp.) were found in 36% of the birds. Only three species of helminth parasites were found: Dispharynx nasuta in two birds, Cyrnea colini in one bird, and larval Physaloptera sp. in four birds. Arthropod parasites (ticks, lice, mites, and/or chiggers) were present on 96% of the birds examined. Compared with wild bobwhite populations in the southeastern United States, the diversity, prevalence, and intensities of microbial and parasitic agents were low.     

Influence of lidocaine and diazepam on peri-induction intraocular pressures in dogs anesthetized with propofol–atracurium

The purpose of this study was to evaluate the effects on the intraocular pressure (IOP) of lidocaine or diazepam administered intravenously (IV) before induction of anesthesia with propofol-atracurium and orotracheal intubation in normal dogs, as well as the effects on the IOP of lidocaine applied topically to the larynx after induction with propofol-atracurium. We randomly assigned 32 random-source dogs, obtained from municipal pounds, to receive the following: lidocaine, 2 mg/kg IV, with saline, 0.1 mL/kg topically applied to the larynx (LIDOsal); saline, 0.1 mL/kg IV, with lidocaine, 2 mg/kg topically applied to the larynx (SALlido); diazepam (Valium), 0.25 mg/kg IV, with saline, 0.1 mL/kg topically applied to the larynx (VALsal); or saline, 0.1 mL/kg IV, with saline, 0.1 mL/kg topically applied to the larynx (SALsal). We measured arterial pressure directly, by means of an indwelling catheter placed in a peripheral artery. Anesthesia was induced with propofol, 8 mg/kg IV, until loss of jaw tone, followed by atracurium, 0.3 mg/kg IV. We measured the IOP in triplicate in each eye before premedication, before induction, before intubation, and after intubation. After induction, the IOP was significantly increased except in the VALsal group, in which the IOP was significantly lower than in the negative-control group before intubation. After intubation, the IOP was significantly elevated in all the groups compared with the values before induction. Cardiovascular parameters were essentially similar in all the groups, except for a significant increase in blood pressure after intubation in the SALlido group. Thus, propofol-atracurium anesthesia causes an increase in IOP that is blunted by diazepam. However, diazepam does not blunt the increase in IOP observed with intubation.