Risk assessments on BSE     

Gravenor MB  Kao RR 《The Veterinary record》2003,152(26):816

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Estimating the incubation period of raccoon rabies: a time-space clustering approach     

Tinline R  Rosatte R  MacInnes C 《Preventive veterinary medicine》2002,56(1):89-103

We used a time-space clustering approach to estimate the incubation period of raccoon rabies in the wild using data from the 1999-2001 invasion of raccoon rabies into eastern Ontario from northern New York State. The time differences and geographical distances between all possible pairs of rabies cases were computed, classified and assembled into a time-space matrix. The rows of that matrix represented differences in cases in weeks and the columns represent distances between cases in kilometers and the values in the cells of the matrix represent the counts of cases at specific time and distance intervals. There was a significant cluster of pairs 5 weeks apart with apparent harmonics at additional 5-week intervals. These results are explained by assuming the incubation period of raccoon rabies had a mode of 5 weeks. The time clusters appeared consistently at distance intervals of 5 km. We discuss the possibility that the spatial intervals were influenced by the 5 km radius of the point infection control depopulation process used in 1999 and the 10-15 km radial areas used in 2000. With the practical limits of those radii, there was an intensive effort to eliminate raccoons. Our procedure is easy to implement and provides an estimate of the shape of the distribution of incubation periods for raccoon rabies.  相似文献   

Epidemiologic factors involved in perinatal lamb mortality on four range sheep operations.     

J P Rowland  M D Salman  C V Kimberling  D J Schweitzer  T J Keefe 《American journal of veterinary research》1992,53(2):262-267

Four shed-lambing operations in western Colorado were monitored during the 1984 spring lambing season to determine the causes and rates of perinatal lamb mortality. The number of lambing ewes per flock ranged from 513 to 1,712, and lambing percentages ranged from 131 to 180%. Overall perinatal lamb mortality ranged from 8.2 to 12.2%. Most lamb deaths occurred during parturition or within 24 hours after parturition. More than 85% of all lamb deaths were in lambs born to ewes having 2 or more lambs. The leading causes of lamb death were starvation, dystocia, stillbirth (unknown cause), and infectious diseases. A wheel model was used to categorize factors causing lamb deaths into 4 groups: physical, social, host, and biological, and to present data on perinatal lamb mortality in a simple visual model. In all flocks, social and biological factors resulted in most of the lamb deaths. On the basis of our findings, we suggest that interventions designed to improve ewe-lamb bonding and to reduce infectious agents and the incidence of prolonged parturition may reduce lamb mortality.  相似文献   

Anthelmintic efficacy of extracts of Spigelia anthelmia Linn on experimental Nippostrongylus braziliensis in rats     

Olorunfemi Cornelius Jegede  Joseph Ologunja Ajanusi  Ambrose. O. Adaudi  Rowland I. S. Agbede 《Journal of veterinary science (Suw?n-si, Korea)》2006,7(3):229-232

Spigelia anthelmia Linn is used as a herb and is a common annual weed of cultivation in open re-growths, on unused land in towns as well as on road sides. The plant can grow to approximately 30 cm in height. The aim of this study was to screen extracts of Spigelia anthelmia for their anthelmintic activity against an experimental Nippostrongylus braziliensis infection in rats. Acute oral toxicity occurred at a dose of 1,140mg/kg, while anthelmintic trials against Nippostrongylus braziliensis in rats using the aqueous fraction showed a progressive decrease in worm count with increasing dose (10, 13, 16, 20 and 25 mg per kg body weight) (p < 0.05). At 25 mg per kg body weight, the worm count was significantly lower than that at 10mg per kg body weight (p < 0.05).  相似文献   

Some aspects of the rumenitis-liver abscess complex in traditional and in intensively managed beef cattle     

A C Rowland 《The Veterinary record》1966,78(21):713-716

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Spontaneous regression of "dermal squamous cell carcinoma" in young chickens.     

S Hafner  B G Harmon  G N Rowland  R G Stewart  J R Glisson 《Avian diseases》1991,35(2):321-327

Eight young chickens with lesions characteristic of those described as dermal squamous cell carcinoma were obtained before slaughter. Lesions were measured; representative lesions were biopsied and examined microscopically; and gross changes were monitored. Lesions appeared to originate as cystic, keratin-filled proliferations of the feather-follicle epithelium. These cysts progressed into raised, keratin-filled, and eventually ulcerated, nodules. Loss of the keratin core resulted in a shallow ulcer that became progressively flattened and regressed into a fibrous dermal scar. All lesions in the broilers regressed in 4 to 16 days (mean 14 days). Twenty roaster lesions completely regressed. For roasters, the mean time to regression was 20 days, with a range of 6 to 93 days. Although there was limited invasion of the dermis by atypical keratinocytes, the overall architecture and biological behavior were more consistent with a benign lesion.  相似文献   

Gastro-oesophageal intussusception in an adult dog   总被引：1，自引：0，他引：1  

M G Rowland  M Robinson 《The Journal of small animal practice》1978,19(2):121-125

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Cutaneous plasmacytomas with amyloid in six dogs.     

P H Rowland  B A Valentine  K E Stebbins  C A Smith 《Veterinary pathology》1991,28(2):125-130

Cutaneous plasmacytomas associated with local deposition of amyloid were diagnosed by light microscopy in a series of six older dogs (mean age 10.7 years) consisting of two Cocker Spaniels, a Poodle, a Weimeraner, and two mixed-breed dogs. The neoplasms occurred on the digits (2 dogs), forelimb (2 dogs), lip (1 dog), and ear (1 dog). In most cases, groups of neoplastic plasma cells were widely separated by large homogeneous islands of amyloid. The neoplastic cells had characteristic plasmacytoid features, but the degree of pleomorphism varied greatly between different neoplasms. In four of the six tumors, the diagnosis of plasmacytoma was confirmed by the demonstration of a monoclonal plasma cell population using immunofluorescent staining for anti-canine immunoglobulins. In these tumors, the neoplastic cells reacted with only one class of immunoglobulins (IgG). The amyloid did not react with any of the reagents used. The suspicion that the amyloid was of immunoglobulin origin (primary amyloid) was supported by its retention of birefringence under polarized light after treatment with potassium permanganate and staining with Congo red.  相似文献   

Acorn poisoning in cattle.     

P M Dixon  E A McPherson  A C Rowland  W Maclennan 《The Veterinary record》1979,104(13):284-285

Ten cows in a suckler herd totalling 60 sickened after grazing parkland which was heavily covered with acorns. Two died. The main clinical signs were dullness, anorexia and constipation. The main pathological findings were severe nephrosis and some intestinal ulceration. After removal to an acorn-free pasture, the remaining eight animals made a full recovery.  相似文献   

The histological relationship between "peste des petits ruminants" and kata in West Africa   总被引：1，自引：0，他引：1  

A C Rowland  P Bourdin 《Revue d'élevage et de médecine vétérinaire des pays tropicaux》1970,23(3):301-307

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