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21.
Effects of small population size and reduced genetic variation on the viability of wild animal populations remain controversial. During a 35-year study of a remnant population of greater prairie chickens, population size decreased from 2000 individuals in 1962 to fewer than 50 by 1994. Concurrently, both fitness, as measured by fertility and hatching rates of eggs, and genetic diversity declined significantly. Conservation measures initiated in 1992 with translocations of birds from large, genetically diverse populations restored egg viability. Thus, sufficient genetic resources appear to be critical for maintaining populations of greater prairie chickens.  相似文献   
22.
Hunting behavior of a marine mammal beneath the antarctic fast Ice   总被引:1,自引:0,他引:1  
The hunting behavior of a marine mammal was studied beneath the Antarctic fast ice with an animal-borne video system and data recorder. Weddell seals stalked large Antarctic cod and the smaller subice fish Pagothenia borchgrevinki, often with the under-ice surface for backlighting, which implies that vision is important for hunting. They approached to within centimeters of cod without startling the fish. Seals flushed P. borchgrevinki by blowing air into subice crevices or pursued them into the platelet ice. These observations highlight the broad range of insights that are possible with simultaneous recordings of video, audio, three-dimensional dive paths, and locomotor effort.  相似文献   
23.
The pharmacological effects of glargine administered once or twice daily were compared in six healthy cats. A two-way crossover study was performed with insulin and glucose concentrations measured following subcutaneous administration of glargine once daily (0.5U/kg) or twice daily (0.25U/kg, repeated after 12h). Nadir glucose concentration and mean daily glucose concentration did not differ significantly following insulin administration once daily or twice daily in divided doses. Time to reach last glucose nadir differed, with longer intervals occurring following twice daily dosing. Blood glucose failed to return to baseline concentration by 24h in three of six cats in each treatment group. Insulin variables were not significantly different following once or twice daily dosing. This study in healthy cats demonstrates that glargine has a long duration of action with carry-over effects to the next day likely, regardless of dosing regimen. A study in diabetic cats is required to determine the best dosing regimen.  相似文献   
24.
"Kennel cough" in dogs in animal shelters is readily transmissible, reduces adoption rates, and commonly leads to the euthanasia of affected dogs. In cats, tracheobronchitis, conjunctivitis, and pneumonia have been associated with Bordetella bronchiseptica infection-but most cases of upper-respiratory infection (URI) probably are caused by herpesvirus and calicivirus, and many B. bronchiseptica culture-positive cats are clinically normal. Our prospective observational study was undertaken to document the contribution of B. bronchiseptica to disease in cats and dogs from two animal shelters undergoing outbreaks of canine kennel cough, to evaluate whether cross-species transmission might have occurred, and to determine if the presence of infected cats represented a risk to dogs. Clinically defined cases of kennel cough in dogs and URI in cats were investigated in two shelters by calculating clinical-disease incidence, alveolar-lavage cytological examination, bacterial and viral cultures, antibiotic-susceptibility testing, and molecular fingerprinting by pulsed-field gel electrophoresis.In a 40-cat and 40-dog "no-kill" shelter, the prevalences of culture positivity were 47% for B. bronchiseptica and 36% for calicivirus at the same time as two resident dogs demonstrated clinical cough. When no dogs had kennel cough 3 months later, 10% of cats were B. bronchiseptica-culture-positive and 63% calicivirus positive. In a large traditional shelter, the incidence of kennel cough in dogs increased over 12 weeks to a maximum of 19 cases/week/120 dogs, during which time the culture prevalence was 23% for B. bronchiseptica in dogs and 47% in cats. Three to 6 months before the kennel-cough epidemic, no dogs or cats were B. bronchiseptica positive. Very little genetic variability was detected in isolates from these shelters; all isolates except one corresponded to a single strain type which was identical to the pattern in a vaccine used in these shelters. Isolates from other cats, a horse, a llama, and a sea otter were genetically distinct from the shelter isolates. There was widespread resistance to cephalosporins and ampicillin, but low or no resistance to amoxicillin/clavulanate, trimethoprim-sulfamethoxazole, tetracycline, and enrofloxacin. Greater percent resistance was observed in the traditional shelter than in the no-kill shelter and feline isolates were more likely to be resistant than canine isolates.  相似文献   
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The successful development of phenology models from field studies depends on many factors, some of which are entirely under the control of pest managers. For example, one such factor is the choice of method for calculating thermal units. In this study, we have demonstrated that four methods for calculating thermal units provided for acceptable predictions of one phenological event of one insect species, while another method for calculating thermal units did not. The measure of central tendency (mean or median) that is used to estimate lower developmental temperatures and required thermal summations is another factor that pest managers can control when developing phenology models from field studies. Here, we show that predictions that were made when using phenology models based on median lower developmental temperatures and median required thermal summations were superior to predictions that were made when using phenology models based on mean lower developmental temperatures and mean required thermal summations. The use of bootstrap vs. non-bootstrap estimates of lower developmental temperatures and required thermal summations is yet another factor that pest managers can control when developing phenology models from field studies. In this study, we found that calculating and using bootstrap estimates of lower developmental temperatures and required thermal summations in phenology models did not improve the predictions of one phenological event for one insect species. The implications of these and other findings are discussed.  相似文献   
27.
Current distribution of sarcoptic mange in wombats   总被引:2,自引:0,他引:2  
Objective To determine the distribution and prevalence of sarcoptic mange in wombats, particularly the common wombat ( Vombatus ursinus ).
Design Questionnaire survey in two parts.
Procedure Questionnaires were distributed to biologists, rangers, animal carers and naturalists. Part 1 of the questionnaire aimed to determine the present distribution of sarcoptic mange in wombats (103 responses). Part 2 invited respondents to assess the prevalence of sarcoptic mange in wombats over a 3 month period (four responses). Information on wombats from 66 localities was received. Each locality represented an area of about 2500 km2.
Results Mange was observed at 93% of localities surveyed and Sarcoptes scabiei was present in common wombats at 52% of localities. Sarcoptic mange was highly prevalent (22%) in two common wombat populations in Victoria. Anecdotal evidence suggested that mange epizootics are sporadic, cause significant morbidity and mortality and have a substantial effect on local abundance. The respondents did not report sarcoptic mange in either northern hairy-nosed wombats ( Lasiorhinus krefftii ) or southern hairy-nosed wombats ( Lasiorhinus latifrons ).
Conclusions Sarcoptic mange occurs in common wombat populations throughout the range of the common wombat including Tasmania and Flinders Island. While mange epizootics are sporadic, they have the potential to threaten the long-term survival of small, remnant populations.  相似文献   
28.
A review of 60 cases of immune-mediated hemolytic anemia (IMHA) in the dog was performed in order to characterize the disease and to identify potential prognostic indicators. Dogs ranged in age from 1 to 13 years, with a mean age of 6.5 years. The 2 most commonly affected breeds were Cocker Spaniels and Labrador Retrievers. Fifty-two of the 60 dogs tested (87%) were autoagglutination positive and spherocytes were present in 45 (75%). Forty-one (89%) of 46 patients tested positive for the presence of immunoglobulin on the red blood cell surface (Coombs assay). The most common clinical signs at presentation were lethargy, weakness, pale mucous membranes, icterus, hemoglobinuria, and anorexia. PCV less than 25% was present in 59 (98%) dogs. At the time of presentation, 35 dogs (58%) had a nonregenerative anemia, whereas 25 patients (42%) had a regenerative response. Thrombocytopenia was seen in 41 (68%) dogs. Nine of 34 dogs (26%) had a prolonged prothrombin time, 19 of 34 (56%) had a prolonged activated partial thromboplastin clotting time, and 12 of 34 (35%) had abnormal fibrinogen concentrations. All dogs received prednisone at immunosuppressive doses (2.2-4.4 mg/kg PO as a single or divided dose every 24 hours) and cyclophosphamide as primary therapy. Forty-one dogs (63%) received cyclophosphamide at 50 mg/m2 q24h for 4 days, whereas 9 dogs (15%) received an initial high dose (200 mg/m2) followed by 3 days of a lower dose (50 mg/m2 q24h). No statistical difference in survival times was found for either protocol. Thirteen dogs were treated with azathioprine in addition to cyclophosphamide and prednisone. The median survival time of dogs that received all 3 drugs was 370 days as compared to 9 days for those dogs that were treated with cyclophosphamide and prednisone alone. Thirty-one (52%) dogs died from the disease, 13 (22%) dogs were alive, and 15 (25%) dogs were lost to follow-up. The median length of survival for all dogs was 21 days. Eight dogs that were discharged from the hospital suffered a relapse (PCV < 25%).  相似文献   
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30.
Although one study showed lower adiponectin concentrations in obese dogs, other recent studies indicate that adiponectin might not be decreased in obese dogs, raising the possibility that the physiology of adiponectin is different in dogs than in humans. The aim of this study was to investigate possible causes of the discrepancy between the two largest studies to date that assessed the association between adiposity and adiponectin concentration in dogs, including the validity of the assay, laboratory error, and the effects of breed, sex, and neuter status on the relationship between adiposity and adiponectin concentrations. Adiponectin concentrations measured with a previously validated adiponectin ELISA were compared with those estimated by Western blotting analysis of reduced and denatured plasma samples. The possibility of laboratory error and the effect of EDTA anticoagulant and aprotinin were tested. Adiponectin concentration was measured by ELISA in 20 lean dogs (10 male and 10 female, 5 neutered in each sex). There was close correlation between adiponectin concentrations measured by ELISA and those estimated by Western blotting analysis (r = 0.90; P < 0.001). There was no substantial effect of EDTA, aprotinin, or laboratory error on the results. There was confounding by neuter status of the relationship between adiposity and adiponectin concentrations, but adiponectin concentrations were not significantly lower in male than in female lean dogs (females, 36 mg/L; males, 26 mg/L; P > 0.20) and were not significantly lower in intact than in neutered lean male dogs (intact, 28 mg/L; neutered, 23 mg/L; P = 0.49). We conclude that the adiponectin ELISA previously validated for use in dogs appears to be suitable for determination of canine adiponectin concentrations and that testosterone does not appear to have a strong effect on plasma adiponectin concentrations in dogs. Obesity might decrease adiponectin concentrations in intact but not in neutered dogs.  相似文献   
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