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排序方式: 共有65条查询结果,搜索用时 15 毫秒
1.
P. Witt L. de Kroon N. Ankringa M. Delany L. W. L. van Bruggen R. van den Boom M. M. Sloet van Oldruitenborgh-Oosterbaan E. W. Siegers 《Equine Veterinary Education》2022,34(9):e369-e374
A 2-month-old Warmblood colt presented with recurrent colic and regurgitation. Gastroscopy, performed on several occasions, and barium-contrast radiography revealed severe squamous gastric ulceration and stenosis at the level of the margo plicatus. Treatment with omeprazole reduced the extent and severity of the gastric ulcers but did not affect the stenosis. The foal was euthanised because of a poor prognosis, and post-mortem examination confirmed the clinical diagnosis. Severe squamous gastric ulceration, granulation tissue formation and cicatrisation of deep gastric lesions were considered to have caused the stenosis. Gastroduodenal outflow obstruction is a recognised disorder in foals, but stenosis at the level of the margo plicatus has not been reported in foals or adult horses. To the authors' knowledge, this is the first case of severe squamous gastric ulceration, complicated by stenosis at the level of the margo plicatus, in a foal. Although rare, gastric stenosis should be considered in foals suffering recurrent colic and regurgitation. 相似文献
2.
Panagiotis Mantis DVM Christopher R. Lamb MA VetMB Angela L. Witt DVM Reto Neiger Dr Med Vet PhD 《Veterinary radiology & ultrasound》2003,44(6):682-685
Trilostane, a 3beta-hydroxysteroid dehydrogenase inhibitor, has been used successfully over the last few years for the treatment of canine pituitary-dependent hyperadrenocorticism. In a prospective study of 19 dogs with pituitary-dependent hyperadrenocorticism, the adrenal glands were measured before and at least 6 months after initiation of trilostane therapy. Right adrenal gland length and caudal pole thickness and left adrenal gland caudal pole thickness increased significantly (p < or = 0.05); there was no significant change in left adrenal gland length. Enlargement of adrenal glands during trilostane therapy may occur as a result of suppression of the negative feedback mechanism affecting cortisol production. 相似文献
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V E Mendel M R Witt B S Gitchell D N Gribble Q R Rogers H J Segall H D Knight 《American journal of veterinary research》1988,49(4):572-578
Nine adult horses were fed alfalfa hay cubes containing approximately 10% Senecio vulgaris until all horses had consumed approximately the same amount of toxic components of S vulgaris, pyrrolizidine alkaloids (PA). The amount of PA consumed was determined by the amount that induced clinical signs of PA toxicosis in 3 horses. The 6 other horses were given similar amounts per kilogram of body weight. An initial decrease of feed intake was observed when horses' diets were changed from alfalfa cubes to alfalfa/Senecio cubes, and feed intake was decreased further over 89 to 98 days. From 50 to 159 days, body weight decreased in all horses. Liver disease was induced in all 9 horses after they ate an average of 233 +/- 9.2 mg of PA/kg of body weight. Eight horses died or were euthanatized. Treatment with branched chain amino acids had no effect on mortality, but appeared to reduce neurologic problems. Clinical signs of PA-induced liver disease included ataxia, head pressing, and decreased feed intake. Other clinical signs of toxicosis were observed individual horses, but did not develop in most horses. Megalocytic hepatopathy developed. Liver abnormalities proceeded as PA was consumed and were severe in 8 of 9 horses before clinical signs of toxicosis appeared. Sulfobromophthalein sodium clearance did not decrease until PA-induced liver disease was advanced. Bile acid (BA) concentrations increased to greater than or equal to 50 mumol/L, in the 8 horses that died. One horse had hepatopathy and increased BA concentration, but survived. In this horse, BA concentration peaked at 33 mumol/L and then decreased.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
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D L Barnes N F G Rethman C C De Witt G D Kotze 《African Journal of Range and Forage Science》2013,30(3):90-95
Abstract The feasibility and potential of reinforcing veld with legumes in the south‐eastern Transvaal highveld was assessed in a number of trials during the period 1974–84. Experience was gained with regard to methods of establishment, adaptation of legumes to the local environment, responses to fertilization, especially with lime and superphosphate, and the reaction of legumes to fire and grazing. In all, 17 legumes were involved, including the genera Coronilla, Desmodium, Glycine, Lespedeza, Lotus, Macroptilium, Medicago, Neoto‐nonia, Trifolium and Vigna. Only Coronilla varia (crownvetch) showed a satisfactory degree of persistence. However, crownvetch is slow to establish, is intolerant of waterlogging and has a relatively high requirement for lime and phosphate. Considering these features, and the probability of undesirable changes in grass species composition in reinforced veld, it is recommended that intensification be achieved through development of improved pastures for use in conjunction with veld, rather than by means of veld reinforcement. 相似文献
8.
Soil microbial biomass and nitrogen supply in an irrigated lowland rice soil as affected by crop rotation and residue management 总被引:5,自引:0,他引:5
C. Witt Kenneth G. Cassman Johannes C. G. Ottow Ulrich Biker 《Biology and Fertility of Soils》1998,28(1):71-80
Processes that govern the soil nitrogen (N) supply in irrigated lowland rice systems are poorly understood. The objectives
of this paper were to investigate the effects of crop rotation and management on soil N dynamics, microbial biomass C (CBIO) and microbial biomass N (NBIO) in relation to rice N uptake and yield. A maize-rice (M-R) rotation was compared with a rice-rice (R-R) double-cropping
system over a 2-year period with four cropping seasons. In the M-R system, maize (Zea mays L.) was grown in aerated soil during the dry season (DS) followed by rice (Oryza sativa L.) grown in flooded soil during the wet season (WS). In the R-R system, rice was grown in flooded soil in both the DS and
WS. Three fertilizer N rates (0, 50 or 100 kg urea-N ha–1 in WS) were assigned to subplots within the cropping system main plots. Early versus late crop residue incorporation following
DS maize or rice were established as additional treatments in sub-subplots in the second year. In the R-R system, the time
of residue incorporation had a large effect on NO3
–-N accumulation during the fallow period and also on extractable NH4
+-N, rice N uptake and yield in the subsequent cropping period. In contrast, time of residue incorporation had little influence
on extractable N in both the fallow and rice-cropping periods of the M-R system, and no detectable effects on rice N uptake
or yield. In both cropping systems, CBIO and NBIO were not sensitive to residue incorporation despite differences of 2- to 3-fold increase in the amount of incorporated residue
C and N, and were relatively insensitive to N fertilizer application. Extractable organic N was consistently greater after
mid-tillering in M-R compared to the R-R system across N rate and residue incorporation treatments, and much of this organic
N was α-amino N. We conclude that N mineralization-immobilization dynamics in lowland rice systems are sensitive to soil aeration
as influenced by residue management in the fallow period and crop rotation, and that these factors have agronomically significant
effects on rice N uptake and yield. Microbial biomass measurements, however, were a poor indicator of these dynamics.
Received: 31 October 1997 相似文献
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Phellinus tremulae is an important fungal decay agent common to aspen and a critical component to the cavity-nesting bird complex found in western aspen stands. Little information exists on the conditions that facilitate infection and spread of P. tremulae in aspen forests. I used Forest Inventory and Analysis (FIA) data to explore the relationships of several tree and stand characteristics to the presence and frequency of P. tremulae in aspen measured across several western states of the United States. Results suggest a strong relationship between tree age, tree diameter, and compacted crown ratio with infection frequency in trees while stand purity, canopy cover and stand age had a positive relationship with the occurrence of P. tremulae in forest stands containing aspen. Logistic regression modeling identified stand age as the only variable that increased the odds of predicting infection at the stand-level while all tree-level variables were included in the tree model. Data also show that infection rates in the study area were lower than in other parts of aspen's range, and that average size of infected trees was smaller in the study area than those reported elsewhere. These results have important implications to management of aspen for wildlife, especially for birds that use decayed aspen for nesting. 相似文献