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61.
Prototheca spp are achlorophyllic saprophytic algae found in wastewater, sewage, agricultural waste, and possibly elsewhere in the environment. Infections with these organisms have been reported in cattle, humans, and dogs; affected cattle commonly develop mastitis. A 5-year-old Brahman-cross bull was evaluated because of a history of diarrhea and weight loss. The history and physical examination and clinicopathologic findings were similar to those associated with granulomatous enteritis caused by Mycobacterium avium subsp paratuberculosis (Johne's disease), which is the most common protein-losing enteropathy of cattle. However, diagnostic tests for paratuberculosis yielded negative results. Biopsy specimens from the ileum, jejunum, and ileocecal lymph node were collected for histologic examination and preparation of tissue impression smears; Prototheca-like organisms were identified. Because of the poor prognosis associated with this infection and the lack of safe and economical therapeutic agents for cattle, the owner decided to euthanatize the bull. Infection with Prototheca organisms was confirmed postmortem. As this case illustrates, protothecosis may be a cause of granulomatous enteritis in cattle.  相似文献   
62.
This study was conducted to determine the relationship between factor VIII (FVIII) activity and von Willebrand factor antigen (vWf:Ag) concentration in canine von Willebrand Disease (vWD). In addition, the clinical utility of measuring FVIII activity in vWD was assessed. This was performed by the concurrent analysis of both FVIII activity and vWf:Ag concentration in three breeds of dogs, namely Dobermans (n=183), Scottish Terriers (n=169), and Labrador Retrievers (n=146). In the three breeds tested, linear regression analysis illustrated a positive relationship between FVIII activity and vWf:Ag concentration. This was reaffirmed in the Doberman and Scottish Terrier breeds, in which dogs with vWf:Ag concentrations < 50 CU/dL ("carriers") had lower median FVIII activities than dogs with vWf:Ag concentrations > 70 CU/dL ("normals"). The determination of various FVIII "cut-off" values was a poor test to separate Dobermans with and without clinical signs of hemorrhage attributable to vWD. In addition, the occurrence of hemorrhage in Dobermans with vWf:Ag concentrations < 50 CU/dL was not influenced by the FVIII activity. Various tests were performed to determine if the measurement of FVIII activity aided in the identification of "carriers" of the vWD gene in the Doberman and Scottish Terrier breeds. These included the use of optimal FVIII "cut-off" values for each breed and a FVIII "cut-off" value of 55 CU/dL; FVIII/vWf:Ag ratios and FVIII/vWf:Ag ratio "cut-off" values; and linear regression analysis of vWf:Ag concentration against FVIII activity. Of all these tests, only the determination of FVIII/vWf:Ag ratios appeared to have promise for "carrier" detection. The data in the present study indicated that routine FVIII assessment in vWD is not warranted; however, measurement of FVIII activity may be of use in confirming the "carrier" status of vWD.  相似文献   
63.
Background: The quality of histopathology slides of endoscopic biopsies from different laboratories varies, but the effect of biopsy quality on outcome is unknown.
Hypothesis: The ability to demonstrate a histologic lesion in the stomach or duodenum of a dog or cat is affected by the quality of endoscopic biopsy samples submitted. More endoscopic samples are needed to find a lesion in poor-quality tissue specimens.
Animals: Tissues from 99 dogs and 51 cats were examined as clinical cases at 8 veterinary institutions or practices in 5 countries.
Methods: Histopathology slides from sequential cases that underwent endoscopic biopsy were submitted by participating institutions. Quality of the histologic section of tissue (inadequate, marginal, adequate), type of lesion (lymphangiectasia, crypt lesion, villus blunting, cellular infiltrate), and severity of lesion (normal, mild, moderate, severe) were determined. Sensitivity of different quality tissue samples for finding different lesions was determined.
Results: Fewer samples were required from dogs for diagnosis as the quality of the sample improved from inadequate to marginal to adequate. Duodenal lesions in cats displayed the same trend except for moderate duodenal infiltrates for which quality of tissue sample made no difference. Gastric lesions in dogs and mild gastric lesions in cats had the same trend, whereas the number of tissue samples needed to diagnose moderately severe gastric lesions in cats was not affected by the quality of tissue sample.
Conclusions and Clinical Importance: The quality of endoscopically obtained tissue samples has a profound effect on their sensitivity for identifying certain lesions, and there are differences between biopsies of canine and feline tissues.  相似文献   
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65.
The histological features of a follicular dysplasia with pigmentary changes is reported in two adult cows, one a black Brangus-cross and the other a black Angus. Adult onset of diffuse alopecia was present in both cows. Skin biopsies exhibited follicular distortion and atrophy, with melanin clumping in follicular epithelium, hair bulb matrix cells, hair shafts, and infundibular keratin. Both animals were clinically normal apart from the alopecia. This report confirms and expands on the infrequently reported syndrome of follicular dysplasia in cattle.  相似文献   
66.
A coupled water‐heat and chemical transport model was used to describe the fate and transport of methyl bromide fumigant in low‐density polyethylene plastic‐mulched soil beds used for vegetable production. Methyl bromide transport was described by convective‐dispersive processes including transformations through hydrolysis. Effects of non‐isothermal conditions on chemical transport were considered through inclusion of temperature effects on transport parameters. An energy‐balance approach was used to describe the plastic‐mulched boundary condition that controls the thermal regime within the soil bed. Simulations were made for variable water‐saturation regimes within the bed and for different depths of fumigant injection. Simulations for various scenarios revealed that large amounts (20–44% over a 7‐day period) of applied methyl bromide are lost from the un‐mulched furrows between the beds. Plastic mulching of the bed was found to be only partially effective (11–29% emission losses over a 7‐day period) in reducing atmospheric emissions. Deep injection of fumigant and saturating the soil with water both led to increased retention of methyl bromide within the soil and less emission to the atmosphere. However, deep injection was unfavorable for effective sterilization of the crop root zone. © 2000 Society of Chemical Industry  相似文献   
67.
OBJECTIVE: To determine the effect of induction of parturition on health, milk production and reproductive performance of dairy cows. DESIGN: A prospective cohort study in 62 dairy herds. PROCEDURE: Health, milk production and fertility indices were documented for 1449 dairy cows treated with dexamethasone trimethylacetate, with or without prostaglandin to induce calving. Equivalent data was collected for 603 untreated herd mates that calved at approximately the same time. RESULTS: The median interval from initial treatment to calving was 11 days. Induction was associated with a substantially lower calf survival and commercial value of surviving calves. Calf viability and value was lower when induced cows were at an earlier stage of pregnancy. Retained foetal membranes, photosensitisation and other problems were significantly more frequent in the induced group compared to the untreated group. Milk production of induced cows was approximately 4% lower than untreated ones, but the majority of reproductive indices were not significantly different between the two groups. CONCLUSIONS: The practice of induction of parturition in seasonal calving dairy herds is a reliable way of shortening the gestation period of cows. Costs associated with morbidity and mortality of induced cows and losses in lactation and calf production are offset by benefits of improved reproductive performance and more efficient management of the herd. The welfare aspects of induction on calf survival must be considered.  相似文献   
68.
The aim of this study was to identify morphometric histological features of pneumonia caused by Mycoplasma bovis in calves. Eight three-month-old calves were infected with M. bovis and samples of their lung tissue, three weeks after exposure, compared to samples from four uninfected calves. In the uninfected animals the goblet cells were clustered in the crypt area of the epithelial folds, while in the infected calves they had migrated towards the tips of the folds and were distributed evenly throughout the folds. In infected lung tissue there was goblet cell hyperplasia and metaplasia in the bronchioles and an increased epithelial height. Goblet cell mucin in uninfected calves was acidic, but in infected calves most goblet cells contained neutral mucins. These morphometric and histochemical bronco-epithelial changes may be able to be used as markers of the severity of bovine respiratory mycoplasmosis.  相似文献   
69.
Leptospirosis is a zoonosis, found worldwide, affecting many species of animals. We conducted a cross-sectional study to estimate the prevalence of Leptospira borgpetersenii sv Hardjo and Leptospira interrogans sv Pomona in cattle in dairy herds in South-Western Victoria, Australia. Fifty-three herds were enrolled in the study. Urine samples were collected from 15 late-lactation cows in each herd. A questionnaire was provided to herd managers at the time of each herd visit, asking them to describe the methods they used for controlling leptospirosis, including vaccination. Urine samples were pooled at the herd level and tested for leptospira spp. using real time PCR. Urine samples from individual cows within the positive pooled samples were then tested for Leptospira Hardjo and Leptospira Pomona using qPCR. Four of the 53 herds showed positive leptospirosis results giving an apparent prevalence of 8 (95% CI 2–18) leptospira-positive herds per 100 herds at risk. Based on the 53 completed questionnaires, leptospirosis vaccination programs were not compliant with label directions in 36 of the 52 vaccinated herds: 69 (95% CI 55–81) of 100 herd managers that routinely vaccinated for leptospirosis did not comply with label directions. One herd was completely unvaccinated. Based on our findings, we estimate that approximately 10% of dairy farms in South-Western Victoria are likely to be infected with leptospirosis. While most herds are vaccinating for leptospirosis, most are not doing so according to label directions. We conclude that herd managers need to be better educated regarding leptospirosis vaccination programs.  相似文献   
70.
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