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1.
Rates of leaf extension and senescence were measured over three-day intervals on neighbouring sets of caged and uncaged tillers on several occasions during summer 1983, both when grazing animals were present and also when they were absent. The weather was dry and drought conditions developed as the season advanced. Comparison of data from caged and uncaged tillers indicated that some consistent differences occurred. Loss of information through grazing (affecting 30% of uncaged, larger than average, tillers), contributed to the significantly reduced estimates of leaf extension of ungrazed, uncaged tillers compared with caged tillers. Senescence rates were higher in the open plot than under the cages; old leaves were grazed on only 8% of uncaged tillers so that data loss was less important as a cause of bias. In the drought conditions prevailing, it was thought that caging in the presence of grazing animals resulted in reduced moisture stress and contributed to the above results. Comparisons of caged and uncaged tillers when grazing animals were absent were made to examine the environmental effects of caging and the slight difference in tiller marking procedure. No differences were found in leaf extension rates, though a trend towards higher senescence rates for the uncaged populations was evident. It was concluded that the criteria limiting the use of cages (a period of protection less than the average interval between both leaf appearance and repeated defoliation) should be extended to include a time limit set by the need to avoid bias associated with the environmental effects of caging and cessation of grazing. To define this time limit better in particular circumstances, the extent and direction of bias in the estimation of leaf extension and senescence rates as affected by period of caging, tiller handling procedures, sward and climatic conditions requires further investigation. In the case of vegetative tillers, estimates of leaf extension rates can be made considerably more precise by using tiller size variables (pseudostem length, total green leaf length, leaf width) as covariates. A suggestion for the number of tillers to be measured per transect is given. However, no such increase in precision can be made for estimates of senescence rates. 相似文献
2.
JONATHAN N. CHAMBERS DVM Dipiomate ACVS PAULT PURINTON DVM PhD JAMES L. MOORE MD SHEILA W. ALLEN DVM MS Dipiomate ACVS 《Veterinary surgery : VS》1990,19(6):424-428
Five dogs with pressure ulcers over the greater trochanter were treated by debridement and transposition of the cranial part of the sartorius or the rectus femoris muscle. Both muscles had vascular anatomy that allowed transposition based on a major vascular pedicle. All wounds healed promptly by primary intention and no ulcer recurred. The cranial sartorius flap technique was easier to perform than the rectus femoris technique. 相似文献
3.
SHEILA W. ALLEN DVM MS DiplomateACVS LARRY M. CORNELIUS DVM PhD DiplomateACVIM EDWARD A. MAHAFFEY DVM PhD DiplomateACVP 《Veterinary surgery : VS》1989,18(4):274-278
Partial pancreatectomy was performed in 9 dogs by dissection and ligation of the pancreatic ductule and blood vessels, and in 10 dogs by a suture fracture technique. The dogs were evaluated for detrimental effects by (1) monitoring clinical signs and serum amylase and lipase activities and (2) examining the excision sites grossly and histologically at necropsy. There were no clinically apparent detrimental effects with either technique. The suture fracture technique evoked more histologic inflammation than the dissection and ligation technique. 相似文献
4.
J. OLIVE M.‐A. D'ANJOU C. GIRARD S. LAVERTY C. L. THEORET 《Equine veterinary journal》2009,41(9):859-864
Reasons for performing study: Marginal osteophytes represent a well known component of osteoarthritis in man and animals. Conversely, central subchondral osteophytes (COs), which are commonly present in human knees with osteoarthritis, have not been reported in horses. Objectives: To describe and compare computed radiography (CR), single‐slice computed tomography (CT), 1.5 Tesla magnetic resonance imaging (MRI), and histological features of COs in equine metacarpophalangeal joints with macroscopic evidence of naturally‐occurring osteoarthritis. Methods: MRI sequences (sagittal spoiled gradient recalled echo [SPGR] with fat saturation, sagittal T2‐weighted fast spin echo with fat saturation [T2‐FS], dorsal and transverse T1‐weighted gradient‐recalled echo [GRE], and sagittal T2*‐weighted gradient echo with fast imaging employing steady state acquisition [FIESTA]), as well as transverse and reformatted sagittal CT, and 4 computed radiographic (CR) views of 20 paired metacarpophalangeal joints were acquired ex vivo. Following macroscopic evaluation, samples were harvested in predetermined sites of the metacarpal condyle for subsequent histology. The prevalence and detection level of COs was determined for each imaging modality. Results: Abnormalities consistent with COs were clearly depicted on MRI, using the SPGR sequence, in 7/20 (35%) joints. They were identified as a focal hypointense protuberance from the subchondral plate into the cartilage, at the palmarodistal aspect (n = 7) and/or at the very dorsal aspect (n = 2) of the metacarpal condyle. COs were visible but less obvious in 5 of the 7 joints using FIESTA and reformatted sagittal CT, and were not identifiable on T2‐FS, T1‐GRE or CR. Microscopically, they consisted of dense bone protruding into the calcified cartilage and disrupting the tidemarks, and they were consistently associated with overlying cartilage defects. Conclusions: Subchondral osteophytes are a feature of osteoarthritis of equine metacarpophalangeal joints and they may be diagnosed using 1.5 Tesla MRI and CT. Potential relevance: Central subchondral osteophytes on MRI represent indirect evidence of cartilage damage in horses. 相似文献
5.
MANUEL PINILLA ROBERT E. SHIEL SHEILA F. BRENNAN HESTER McALLISTER CARMEL T. MOONEY 《Veterinary radiology & ultrasound》2009,50(2):224-229
The existence of hypothyroidism in greyhounds remains controversial and its investigation is complicated by the low circulating thyroid hormone concentrations typically found in healthy dogs of this breed. Quantitative measurement of thyroidal technetium-99m pertechnetate (99m TcO4 − ) uptake is known to be useful in assessing thyroid function in other breeds. The aim of this study was to evaluate thyroid scintigraphy as a method of assessing thyroid function in greyhounds suspected of primary hypothyroidism. Twenty greyhounds (eight females, 12 males) were studied. Thirteen had bald thigh syndrome and seven poor performance and low total T4. Total T4 concentrations were decreased in 18 (90%), and free T4 in two (10%) dogs. All canine thyroid stimulating hormone concentrations were within the reference interval. Thyroidal 99m TcO4 − uptake values (mean ± SD, 0.76 ± 0.26%) were within the reference limits published for euthyroid dogs (0.39–1.86%) making hypothyroidism highly unlikely. There were no significant differences ( P <0.05) when comparing data between dogs with bald thigh syndrome (13 dogs) and the remaining dogs (seven dogs). Seventeen (85%) dogs had higher uptake in the left thyroid gland than in the right that might reflect an anatomic feature of the greyhound breed. Calculation of percent thyroidal uptake of 99m TcO4 − is more accurate than thyroid:salivary gland ratios because of high variability in salivary gland uptake. Percent thyroidal uptake of 99m TcO4 − should be used when assessing thyroid function scintigraphically in the greyhound breed. 相似文献
6.
LUDOVIC BOURÉ DMV MSC ECVS MARCEL MARCOUX DMV MSC SHEILA LAVERTY MVB DIPLOMATE ACVS DIPLOMATE ECVS 《Veterinary surgery : VS》1997,26(6):478-483
Objective —The purposes of this study were to develop a technique of paralumbar fossa laparoscopic ovariectomy using Endoloop ligatures and to avoid a laparotomy incision for ovary removal by using a 33–mm diameter muscle spreader trocar-cannula unit.
Animals or Sample Population —Seven mares.
Methods —Bilateral laparoscopic ovariectomy was performed under general anesthesia in two horses and under neuroleptanalgesia and local anesthesia in five standing mares. Ovaries were approached from the ipsilateral paralumbar fossa through two portal sites located in the paralumbar fossa and a third between the 17th and 18th ribs. Insufflation of the abdominal cavity was achieved using an automatic carbon dioxide insufflator. Two Endoloop ligatures were placed on the mesovarium. The cannula, located in the center of the paralumbar fossa, was removed, and a 33-mm diameter trocar-cannula unit, with a cone-shaped muscle spreader extremity, was inserted through the same portal. The mesovarium was transected between the ovary and the ligatures. The ovaries were removed from the abdomen through the 33-mm diameter cannula. The abdominal wall was closed in a routine manner.
Results —No major complications occurred during or after surgery.
Conclusion —Paralumbar fossa laparoscopic ovariectomy in mares using Endoloop ligatures and the 33-mm diameter trocar-cannula unit was an effective technique for ovariectomy of normal ovaries in this study.
Clinical Relevance —Endoloop ligatures provide a viable alternative for laparoscopic ligation of ovarian pedicles in mares. 相似文献
Animals or Sample Population —Seven mares.
Methods —Bilateral laparoscopic ovariectomy was performed under general anesthesia in two horses and under neuroleptanalgesia and local anesthesia in five standing mares. Ovaries were approached from the ipsilateral paralumbar fossa through two portal sites located in the paralumbar fossa and a third between the 17th and 18th ribs. Insufflation of the abdominal cavity was achieved using an automatic carbon dioxide insufflator. Two Endoloop ligatures were placed on the mesovarium. The cannula, located in the center of the paralumbar fossa, was removed, and a 33-mm diameter trocar-cannula unit, with a cone-shaped muscle spreader extremity, was inserted through the same portal. The mesovarium was transected between the ovary and the ligatures. The ovaries were removed from the abdomen through the 33-mm diameter cannula. The abdominal wall was closed in a routine manner.
Results —No major complications occurred during or after surgery.
Conclusion —Paralumbar fossa laparoscopic ovariectomy in mares using Endoloop ligatures and the 33-mm diameter trocar-cannula unit was an effective technique for ovariectomy of normal ovaries in this study.
Clinical Relevance —Endoloop ligatures provide a viable alternative for laparoscopic ligation of ovarian pedicles in mares. 相似文献
7.
Effects of season and level of grazing on the utilization of heather by sheep. 3. Longer-term responses and sward recovery 总被引：1，自引：0，他引：1
SHEILA A. GRANT J. A. MILNE G. T. BARTHRAM W. G. SOUTER 《Grass and Forage Science》1982,37(4):311-320
The effects of sheep grazing on the development of and production from heather swards and on intake and diet selection by grazing Scottish Blackface wether sheep were studied in an experiment in which sheep numbers were adjusted to remove 0, 40% or 80% by weight of current season's shoots in summer and in autumn for a period of 5 years. All combinations of season and level of grazing were provided. The plots were divided after 2 years and grazing was continued for a further 3 years on one subplot but discontinued on the other. Sward productivity during the 5 years of grazing was unaffected at the 40% level of shoot removal but at the 80% level was reduced by up to 66%. After a season's uninterrupted growth at the end of the experiment heather cover and herbage mass were lower and current season's shoots as a proportion of total mass were higher on those treatments which received the greatest severity of grazing. Weight of current season's shoots was unaffected on treatments which had received the 40% level of shoot removal but was reduced by 40% and 50% on treatments which had received the 80% level in summer and autumn respectively. On the rested subplots sward recovery was such that no treatment effects remained after 3 years except with respect to 80% shoot removal in autumn where herbage mass was reduced compared with other treatments. Intakes of digestible organic matter per sheep were higher at the 80% than the 40% level of grazing in the fifth year of the experiment. This was ascribed to the ingestion of new shoot growth from the twig bases on the 80% level of removal treatments. Intake and digestibility were higher in the summer on those treatments which had received the 80% level of removal in previous autumns. Over the 5 years of the experiment there was a small decline in intake and digestibility values, with the decline being greatest in the summer and at low levels of grazing. Floristic changes differed on the rested and grazed areas. On the rested subplots in the fourth year after grazing stopped, heather height was lower and cover by grasses, sedges and herbs was greater on treatments which previously had received the highest levels of utilization. On bare areas the rate of recovery of heather was rapid where shoots as well as seedlings contributed to recovery growth. On the grazed subplots, with the exception of the low-growing ruderal Rumex acetosella, cover due to grasses, sedges and herbs remained low as species other than heather were selectively grazed. Relationships among stocking rates, grazing behaviour and heather utilization are discussed and guidelines for the recognition of overgrazing are outlined. 相似文献
8.
Components of regrowth in grazed and cut Lolium perenne swards 总被引：1，自引：0，他引：1
9.
JULIEN OLIVE MARC‐ANDRÉ D'ANJOU KATE ALEXANDER SHEILA LAVERTY CHRISTINE THEORET 《Veterinary radiology & ultrasound》2010,51(3):267-279
We compared the ability of 1.5 T magnetic resonance imaging (MRI), computed tomography (CT), and computed radiography (CR) to evaluate noncartilaginous structures of the equine metacarpophalangeal joint (MCP), and the association of imaging changes with gross cartilage damage in the context of osteoarthritis. Four CR projections, helical single‐slice CT, and MRI (T1‐weighted gradient recalled echo [GRE], T2*‐weighted GRE with fast imaging employing steady‐state acquisition [FIESTA], T2‐weighted fast spin echo with fat saturation, and spoiled gradient recalled echo with fat saturation [SPGR‐FS]) were performed on 20 racehorse cadaver forelimbs. Osteophytosis, synovial effusion, subchondral bone lysis and sclerosis, supracondylar lysis, joint fragments, bone marrow lesions, and collateral desmopathy were assessed with each modality. Interexaminer agreement was inferior to intraexaminer agreement and was generally moderate (i.e., 0.4<κ<0.6). Subchondral bone sclerosis scores using CT or MRI were correlated significantly with the reference quantitative CT technique used to assess bone mineral density (P<0.0001). Scores for subchondral lysis and osteophytosis were higher with MRI or CT vs. CR (P<0.0001). Although differences between modalities were noted, osteophytosis, subchondral sclerosis, and lysis as well as synovial effusion were all associated with the degree of cartilage damage and should be further evaluated as potential criteria to be included in a whole‐organ scoring system. This study highlights the capacity of MRI to evaluate noncartilaginous changes in the osteoarthritic equine MCP joint. 相似文献
10.
The effects of contrasting cutting regimes on the components of clover and grass growth in microswards 总被引：2，自引：0，他引：2
Microswards of white clover and perennial ryegrass were subjected to one of four treatments: weekly cutting to 3·5 cm, weekly cutting incorporating a period of no cutting for 6 weeks starting 27 April (early rest), weekly cutting incorporating a period of no cutting for 6 weeks starting 8 June (late rest), or cutting every 3 weeks. Two sward types were used: a mixture of white clover cv. Milkanova with perennial ryegrass cv. Melle, and white clover cv. Kent with perennial ryegrass cv. Melle. Growth measurements (leaf appearance, branching/tillering and stolon internode length) were confined to the first three treatments with records collected during contiguous 21-d measurement periods. Vertical height increments of clover and grass and red:far-red light ratios at the sward bases were also recorded at frequent intervals. At the end of the experiment population densities and unit weights were recorded for all treatments. Significant treatment effects on the rate processes were largely confined to the 21-d period immediately after weekly cutting of rested swards had resumed. On previously rested compared with weekly cut swards, clover leaf appearance rates were increased by 40% and branching rates by 164%. During the same period, grass leaf appearance rates were reduced by 50% and net tillering changed from positive to negative values. Though the rate responses were transient, effects were still apparent at harvest in September, when population density and content (proportion by population density and weight) of clover were significantly higher in the late rest treatment. The variety Kent showed a consistent, though usually nonsignificant, higher leaf appearance and branching rate compared with Milkanova, and in September was characterized by a higher population (7400 m?2 compared to 3200 m?2) of smaller units (27 compared to 46 mg/apical meristem) than Milkanova. The results are discussed in relation to defoliation effects and the role of light quantity and quality as they influence the component growth processes. Attention is drawn to the importance of canopy structure and the climatic and/or phenological differences in the relative seasonal behaviour of clover and grass, together with varietal variation within species in influencing responses to management manipulations. 相似文献