Characterization and cooled storage of semen from corn snakes (Elaphe guttata).

The phylogenetic order Squamata has many representatives that could benefit from the use of semen preservation as a tool for assisting conservation. To date, few studies have been made evaluating the potential for collecting and preserving semen from snakes. The objectives of this study were to characterize semen parameters of the corn snake (Elaphe guttata), including appearance, volume, concentration, sperm motility, and sperm morphology, and to determine the longevity of corn snake sperm motility stored at 4 degrees C. Single semen samples were collected from 22 adult corn snakes. The appearance of the corn snake semen was generally cloudy, and the color was white to tan. Corn snake spermatozoa initially exhibited a median motility of 92.5%. Corn snakes were found to produce small-volume ejaculates (median 0.01 ml). However, the overall concentration of the snake ejaculate was high (chi = 852 x 10(6) +/- 585 x 10(6) spermatozoa/ml). Morphologically, a mean of 75.7 +/- 9.3% of the sperm cells in an ejaculate were normal. Snake ejaculate with a white appearance had significantly higher sperm concentrations (chi = 1,859 x 10(6) +/- 1,008 x 106 sperm cells/ml; F = 15.74, P = 0.001) than tan ejaculates (chi = 601 x 10(6) +/- 439 x 106 sperm cells/ml). Sperm motility decreased significantly in samples that were stored at 4 degrees C for greater than 48 hr in a refrigerator or Equitainer I. This is the first study to characterize semen volume, appearance, and concentration; sperm motility; and sperm morphology in captive corn snakes. The information derived from this study can be used to develop a model for a collection, cooled storage, and shipping program for semen from endangered or threatened captive and wild snakes.     

Pharmacokinetics of orally administered ibuprofen in African and Asian elephants (Loxodonta africana and Elephas maximus).

The pharmacokinetic parameters of S(+) and R(-) ibuprofen were determined in 20 elephants after oral administration of preliminary 4-, 5-, and 6-mg/kg doses of racemic ibuprofen. Following administration of 4 mg/kg ibuprofen, serum concentrations of ibuprofen peaked at 5 hr at 3.9 +/- 2.07 microg/ml R(-) and 10.65 +/- 5.64 microg/ml S(+) (mean +/- SD) in African elephants (Loxodonta africana) and at 3 hr at 5.14 +/- 1.39 microg/ml R(-) and 13.77 +/- 3.75 microg/ml S(+) in Asian elephants (Elephas maximus), respectively. Six-milligram/kilogram dosages resulted in peak serum concentrations of 5.91 +/- 2.17 microg/ml R(-) and 14.82 +/- 9.71 microg/ml S(+) in African elephants, and 5.72 +/- 1.60 microg/ml R(-) and 18.32 +/- 10.35 microg/ml S(+) in Asian elephants. Ibuprofen was eliminated with first-order kinetics characteristic of a single-compartment model with a half-life of 2.2-2.4 hr R(-) and 4.5-5.1 hr S(+) in African elephants and 2.4-2.9 hr R(-) and 5.9-7.7 hr S(+) in Asian elephants. Serum concentrations of R(-) ibuprofen were undetectable at 24 hr, whereas S(+) ibuprofen decreased to below 5 microg/ml 24 hr postadministration in all elephants. The volume of distribution was estimated to be between 322 and 356 ml/kg R(-) and 133 and 173 ml/kg S(+) in Asian elephants and 360-431 ml/kg R(-) and 179-207 ml/kg S(+) in African elephants. Steady-state serum concentrations of ibuprofen ranged from 2.2 to 10.5 microg/ml R(-) and 5.5 to 32.0 microg/ml S(+) (mean: 5.17 +/- 0.7 R(-) and 13.95 +/- 0.9 S(+) microg/ml in African elephants and 5.0 +/- 1.09 microg/ml R(-) and 14.1 +/- 2.8 microg/ml S(+) in Asian elephants). Racemic ibuprofen administered at 6 mg/kg/12 hr for Asian elephants and at 7 mg/kg/12 hr for African elephants results in therapeutic serum concentrations of this antiinflammatory agent.     

Molecular assays for detection of falcon adenovirus.

Falcon adenovirus is a newly recognized member of the family Aviadenoviridae and includes 2 closely related strains that are pathogenic to several species of falcons. Peregrine falcons appear to be one of the primary reservoirs, but recent outbreaks suggest that other carrier species probably exist. To allow screening of captive birds for virus shedding and investigations of disease outbreaks, conventional and real-time, quantitative polymerase chain reaction (PCR) assays and an in situ hybridization technique were developed. The diagnostic protocols were used on tissue and fecal samples from 7 species or subspecies of falcons infected with adenovirus as well as adenoviruses from other birds and mammals. The assays were specific for falcon adenovirus and detected both strains of virus in fecal samples from living animals or frozen and formalin-fixed, paraffinized tissues. Together with established serologic tests for falcon adenovirus, these molecular assays are valuable tools for management and conservation of falcons in captivity and the wild.     

Bovine viral diarrhea virus (BVDV) 1b: predominant BVDV subtype in calves with respiratory disease

The prevalence of bovine viral diarrhea virus (BVDV) infections was determined in 2 groups of stocker calves with acute respiratory disease. Both studies used calves assembled after purchase from auction markets by an order buyer and transported to feedyards, where they were held for approximately 30 d. In 1 study, the calves were mixed with fresh ranch calves from a single ranch. During the studies, at day 0 and at weekly intervals, blood was collected for viral antibody testing and virus isolation from peripheral blood leukocytes (PBLs), and nasal swabs were taken for virus isolation. Samples from sick calves were also collected. Serum was tested for antibodies to bovine herpesvirus-1 (BHV-1), BVDV1a, 1b, and 2, parainfluenza 3 virus (PI3V), and bovine respiratory syncytial virus (BRSV). The lungs from the calves that died during the studies were examined histopathologically, and viral and bacterial isolation was performed on lung homogenates. BVDV was isolated from calves in both studies; the predominant biotype was noncytopathic (NCP). Differential polymerase chain reaction (PCR) and nucleic acid sequencing showed the predominant subtype to be BVDV1b in both studies. In 1999, NCP BVDV1b was detected in numerous samples over time from 1 persistently infected calf; the calf did not seroconvert to BVDV1a or BVDV2. In both studies, BVDV was isolated from the serum, PBLs, and nasal swabs of the calves, and in the 1999 study, it was isolated from lung tissue at necropsy. BVDV was demonstrated serologically and by virus isolation to be a contributing factor in respiratory disease. It was isolated more frequently from sick calves than healthy calves, by both pen and total number of calves. BVDV1a and BVDV2 seroconversions were related to sickness in selected pens and total number of calves. In the 1999 study, BVDV-infected calves were treated longer than noninfected calves (5.643 vs 4.639 d; P = 0.0902). There was a limited number of BVDV1a isolates and, with BVDV1b used in the virus neutralization test for antibodies in seroconverting calves' serum, BVDV1b titers were higher than BVDV1a titers. This study indicates that BVDV1 strains are involved in acute respiratory disease of calves with pneumonic Mannheimia haemolytica and Pasteurella multocida disease. The BVDV2 antibodies may be due to cross-reactions, as typing of the BVDV strains revealed BVDV1b or 1a but not BVDV2. The BVDV1b subtype has considerable implications, as, with 1 exception, all vaccines licensed in the United States contain BVDV1a, a strain with different antigenic properties. BVDV1b potentially could infect BVDV1a-vaccinated calves.     

Comparison of unilateral versus bilateral nasal catheters for oxygen administration in dogs

Objective: To determine the effect of bilateral nasal oxygen supplementation on tracheal airway and arterial blood gas parameters. Design: Original research. Setting: Research Laboratory. Animals: Eight normal dogs. Interventions: None. Measurements: Intra‐tracheal oxygen concentration and arterial oxygen partial pressure at three different oxygen flow rates given through either unilateral or bilateral nasal catheters. Main results: F_IO₂ and PaO₂ were significantly increased with higher total oxygen flow rates, but the increase was the same whether the higher flow was delivered through one nasal catheter or divided and administered though two nasal catheters. The use of bilateral nasal catheters allowed a tracheal F_IO₂ as high as 0.60 with minimal patient discomfort. Conclusions: The benefit of bilateral nasal catheters for oxygen supplementation is the ability to provide high total oxygen flows with decreased risk of patient discomfort. If the desired oxygen flow can be achieved with a unilateral nasal catheter, then the only benefit of bilateral catheters is increased patient comfort. The use of bilateral nasal oxygen catheters for oxygen supplementation can result in an F_IO₂ that is high enough to produce oxygen toxicity with prolonged administration.     

Determination of the oxidative burst chemiluminescent response of avian and murine-derived macrophages versus corresponding cell lines in relation to stimulation with Salmonella serotypes

In contrast to mammalian systems, avian species lack a resident or harvestable macrophage population in the abdominal exudate. Peritoneal macrophages in the chicken can be elicited if an inflammatory agent such as sephadex is injected. This study examines the kinetics of different macrophage populations, derived by different methods of isolation and from different hosts, with respect to the elicited oxidative burst upon infection with host-adapted Salmonella serotypes.The nature of the oxidative burst elicited by murine and avian-derived and cell line macrophages was determined after stimulation with phorbol myristate (PMA), zymosan A, and Salmonella serotypes. Both murine and chicken peritoneal macrophages, chicken blood monocytes and corresponding cell lines, J774A.1 and HD-11, were unable to produce a detectable chemiluminescent (CL) response after interaction with Salmonella using the luminescent probe luminol. However, both PMA and zymosan A induced a CL response in all cell types, with PMA eliciting a higher and earlier peak response (pkH) than zymosan A. Lucigenin-enhanced CL in both murine and chicken macrophages was achieved with PMA, zymosan A and Salmonella serotypes. In this case, zymosan A induced higher responses than PMA. In the peritoneal macrophages of both hosts, there were no significant differences in the oxidative burst induced by the different Salmonella serotypes. However, the J774A.1 (murine) cells demonstrated significant differences, with S. enterica serotype Choleraesuis (S. choleraesuis and S. gallinarum producing the highest response. In the HD-11 (chicken) cells, S. choleraesuis and S. dublin elicited the higher CL. With both cell lines, S. abortusovis failed to induce an appreciable CL response.In these experiments it was demonstrated that oxidative burst was not detectable in monocytes/macrophage populations using luminol, which suggests a link to the lack of a myeloperoxidase system in these cells. Lucigenin-enhanced CL appeared independent from the myeloperoxidase system, indicating production of another oxidative species compared with luminol. No discernable effect of host specificity with regard to Salmonella serotype and respective host was seen in host-derived or cell line macrophages, and cell line macrophages displayed altered functional characteristics with regard to oxidative burst in comparison with their primary counterparts.     

Antigenic and immunogenic studies on cell culture-derived Babesia canis

Babesia canis antigens derived from cell culture reacted specifically with immune serum from dogs convalescing from babesiosis. The antigens were heterogenous as compared to antigens elaborated in vivo. The major antigenic moiety from cell culture eluted in the first peak of Sephadex G-200 is indicative of a molecular weight around 900 000. In contrast, in vivo-derived antigen coeluted with albumin and hemoglobin suggesting a molecular weight of 67 000. The major antigenic mass is proteinacious and contains disulfide bonds as indicated by thermolability and sensitivity to 2-mercaptoethanol. Both particulate and soluble B. canis antigens were immunogenic, particularly when emulsified in Saponin as an adjuvant. Such antigens conferred a considerable degree of protection in susceptible dogs and it suggested that immunoprophylaxis to B. canis may be feasible.     

Survival of Ancylostoma caninum on bare ground, pea gravel, and concrete.

Studies were done to determine the survival of infective Ancylostoma caninum 3rd-stage larvae on 3 ground covers commonly used in dog run construction: bare ground, pea gravel, and concrete. Changes in numbers of recovered larvae were compared to meterologic data and the most significant weather variables were determined. Larvae were recovered 1 to 7 days on bare ground. Larvae survived longer in the fecal mass (mean of 3 days) than on the bare ground (mean of 2 days). Rain was the most significant variable, in that it was positive in its effects (higher larval count) early in the experiment (causing fecal mass breakdown and release of larvae) and negative (lower larval count) later in the experiment (spreading larvae away from test site). Larvae were also recovered 1 to 7 days on pea gravel. They were recovered for a mean 2.6 days from the fecal sample, a mean of 1.5 days from the rocks directly below the fecal mass, and a mean of 1.3 days from the remaining rocks. Here also, rain was the most significant weather factor. It was negatively significant (lower larval count) for the fecal mass (spreading of the larvae) and positive for those in the pebbles (increasing the moisture in the pebbles). Survival time of larvae on concrete was shorter than that on the other 2 substrates: from 0 to 2 days. Larvae were recovered a mean of 1.3 days from the fecal mass and a mean of 0., days from the surrounding concrete. Rain was positively significant early in the experiments in that it released trapped larvae from the fecal mass. Sunlight consistently was negatively significant (lower larval count) due to its lethality to the unprotected larvae.     

Factors influencing female home range sizes in elk (<Emphasis Type="Italic">Cervus elaphus</Emphasis>) in North American landscapes

Home range size is a result of individual movements and the spatial distribution of a population. While body size, sex, and age are known to influence the area over which an animal ranges, it remains uncertain how landscape heterogeneity influences home range size. We examined elk (Cervus elaphus) seasonal home range sizes in relation to the quantity and spatial heterogeneity of forage biomass, forest cover, topography, snow–water equivalents, and landscape structure in three study landscapes: Yellowstone National Park, Wyoming, USA; eastern slopes of the Canadian Rockies, Alberta; and northern Wisconsin, USA. We used a 95% fixed kernel estimator to measure the home range size and location of all elk. To identify the scales at which important factors influenced home range sizes, we quantified environmental variables within the estimated home range polygon and within concentric circles with radii of 1000, 2000, 3000, 4000, and 5000 m from the home range center. Results indicate that there was an inverse relationship between forage biomass and summer and winter home range sizes in Alberta and Wisconsin, however the relationship was positive in Yellowstone. The size of summer and winter home ranges was positively related to percent forest cover; however this relationship was significant only when forest cover was quantified within the home range polygon or radii that were greater than or equal to 3000 m. Winter home ranges also had a positive relationship with snow–water equivalents. The predictive strength of summer home range models was greatest when landscape variables were quantified within the concentric circles with a radius of 3000 m or more, whereas the predictive strength of the winter models was greatest within the estimated home range polygon. Results suggest that elk ranging patterns reflected complex trade-offs that affect foraging, group dynamics, movement energetics, predation avoidance and thermal regulation. The multi-scale analysis indicates that elk based home ranging decisions on an area equal to their home range, but areas outside of the estimated home range were also important.