Habitat overlap of juvenile and adult lake trout of Great Bear Lake: Evidence for lack of a predation gradient?     

Louise Chavarie  Kimberly L. Howland  Les N. Harris  Mike J. Hansen  Colin P. Gallagher  William J. Harford  William M. Tonn  Andrew M. Muir  Charles C. Krueger 《Ecology of Freshwater Fish》2019,28(3):485-498

A range of organisms, from plankton to fish, commonly shift their habitat distributions horizontally or vertically due to predation risk. Juvenile lake trout, Salvelinus namaycush, are generally viewed as occupying deep areas of lakes to decrease predation pressure from adults. In contrast, we found that juvenile lake trout from Great Bear Lake, NT, Canada, occupied a variety of habitats and from shallow to deep depths (0–150 m), overlapping with adult lake trout. No evidence occurred for a length depth‐based segregation (e.g., ontogenetic shift). Genetic variation was also similar among juveniles in the different depth zones. However, isotopic niches and C:N ratios among juveniles showed some variability in niche widths and positions for individuals caught from the 51–150 m zone compared to juvenile individuals caught from 0–20 m and 21–50 m zones. The uniformly distributed adult lake trout in Great Bear Lake may evenly distribute predation pressure (including cannibalism) across shallow‐ and deep‐water habitats more than in other lakes. As a result, juveniles may respond to differences in foraging opportunities rather than predation risks. Juvenile lake trout did not appear to conform to the general pattern of juveniles seeking a deep‐water refuge to reduce predation risks. In contrast, juvenile lake trout of Great Bear Lake displayed broad resource use across all depths and habitats.  相似文献   

Evidence for Australia-wide canine parainfluenza infection     

DR McGAVIN  AJ MELLOWS  L. CHOICE 《Australian veterinary journal》1989,66(7):221-221

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Encapsulated Stuphylococcus aureus from bovine mastitis   总被引：1，自引：0，他引：1  

JP OPDEBEECK  DA O''BOYLE  AJ FROST 《Australian veterinary journal》1988,65(6):194-195

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An Australian perspective of foot-and-mouth disease research     

AJ FORMAN 《Australian veterinary journal》1989,66(12):409-410

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The effect of a staphylococcal cell wall factor on the early inflammatory response to staphylococcal infection of the lactating bovine udder     

TIINA MATTILA  D O'BOYLE  AJ FROST 《Australian veterinary journal》1988,65(4):114-117

The effect on the early inflammatory response in the bovine mammary gland of a factor extracted from the cell wall of Staphylococcus aureus was studied. The insoluble factor was extracted from a 3h-culture, and was mixed with S. aureus from an overnight culture (OF) for experimental infection of a lactating quarter. Other quarters were infected with a 3h or an overnight culture (O). Five cows were used in the experiment. The O-quarters showed more severe clinical signs than seen in the 3h-and OF-quarters. Antitrypsin levels and NAGase concentrations were much reduced in the 3h-and OF-quarters. While the cell wall factor profoundly reduced the early inflammatory response, the effect on the final outcome of the infection was not determined.  相似文献   

Grazing and anthelmintic treatments to increase growth of Cashmere and Angora weaner goats     

JA ROBERTSON  AJ RITAR  G. EVANS 《Australian veterinary journal》1996,74(3):246-248

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Potential of chemical regulation of food intake and body weight of broiler breeder chicks     

E O Oyawoye  W F Krueger 《British poultry science》1990,31(4):735-742

1. Two experiments were performed to evaluate the potential of phenylpropanolamine hydrochloride and monensin sodium as appetite- and weight-control agents for Indian River broiler breeder chicks. 2. In experiment 1, a total of 300 day-old sexed broiler breeder chicks were individually weighed and placed in battery cages. They were randomly assigned to 5 dietary treatments, namely 0, 50, 100, 200 and 400 mg/kg of phenylpropanolamine hydrochloride added to a maize-soyabean meal basal diet. 3. In experiment 2, a total of 400 day-old sexed broiler breeder chicks were randomly assigned to 10 dietary treatments which were a combination of two concentrations of dietary crude protein (200 and 150 g/kg) and 5 different concentrations of added drugs in the diet, namely 0, 500 and 800 mg/kg of phenylpropanolamine hydrochloride and 200 and 300 mg/kg of monensin sodium. 4. Food consumption and body weight gain were significantly reduced by feeding diets containing the drugs but mortality was not significantly affected. Birds showed evidence of increased tolerance, with age, to phenylpropanolamine but not to monensin. 5. Monensin sodium, at high inclusion rates, was found to be a more potent and effective appetite- and growth-depressing agent for broiler breeder chicks than phenylpropanolamine and may have application in broiler breeder production using an ad libitum feeding programme.  相似文献   

The prevalence of intestinal spirochaetes in poultry flocks in Western Australia     

AJ McLAREN  DJ HAMPSON  SL WYLIE 《Australian veterinary journal》1996,74(4):319-321

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Pilot study to quantify the time to clear dexamethasone from plasma and urine of adult horses following a single nebulisation     

NE Symonds  AJ Dart  J Keledjian  M Liu Lau  LC Ennis  VC McIver  AS Tsang  SA Biasutti  LB Jeffcott 《Australian veterinary journal》2019,97(5):144-148

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Diagnosis of lumbosacral intervertebral disc disease and protrusion in a horse using ultrasonographic evaluation and computed tomography          下载免费PDF全文

C. R. Krueger  J. Gold  M. F. Barrett  T. A. Aboellail 《Equine Veterinary Education》2016,28(12):685-689

This case report describes the clinical presentation, diagnostic imaging modalities, treatment and post mortem evaluation of lumbosacral intervertebral disc protrusion in a mature Quarter Horse gelding 10 days after initial signs were noted. Grade 3 hindlimb ataxia, conscious proprioceptive deficits, urinary and faecal incontinence were present, which did not improve with anti‐inflammatories, antimicrobial therapy, corticosteroids, antioxidant therapy, cold‐laser therapy or electroacupuncture. Imaging modalities utilised ante mortem were computed radiography, transcutaneous and transrectal ultrasonography. Transrectal ultrasonography yielded findings highly suggestive of lumbosacral intervertebral disc protrusion and due to the lack of improvement and a poor prognosis, the horse was humanely subjected to euthanasia. Post mortem computed tomography, necropsy and histopathological evaluation confirmed lumbosacral intervertebral disc disease and protrusion into the spinal canal with subsequent impingement of the spinal nerve roots. Lumbosacral intervertebral disc protrusion as a clinical disease in the horse has not been previously described and should be included as a differential diagnosis in cases with acute hindlimb ataxia, proprioceptive deficits, and urinary and faecal incontinence.  相似文献