Chronic cervical compressive myelopathy in horses: clinical correlations with spinal cord alterations     

JV YOVICH  RA LeCOUTEUR†  DH GOULD† 《Australian veterinary journal》1991,68(10):326-334

Histological examination was performed on the cervical spinal cord from 13 horses with chronic cervical compressive myelopathy of 4 to 29 months duration. Structural alterations were correlated with clinical features. At the level of compression, the spinal cord was grossly deformed. Histological alterations included nerve fibre swelling and degeneration, occasional spheroids, astrocytic gliosis, increased macrophage activity and increased perivascular collagen. Myelin degeneration or loss at the level of the compressive lesion was greatest in the ventral and lateral funiculi and less consistently present in the dorsal funiculi. Asymmetry of lesions in the dorsal funiculi was associated with asymmetry of clinical signs in 5 horses. Histological alterations in areas of Wallerian degeneration were similar to that at the level of spinal cord compression, except that perivascular collagen was not increased. Wallerian degeneration was present cranial to the compressed site in the superficial portions of the lateral funiculi and in the middle of the dorsal funiculi. Caudal to the compressed site it was present in the ventral funiculi adjacent to the ventral median fissure and in the middle of the lateral funiculi. Deformation of the spinal cord did not correlate with the severity or duration of clinical signs but was positively correlated with the amount of perivascular collagen increase. The amount of nerve fibre swelling was not correlated with the severity of clinical signs but was negatively correlated with their duration. A rapid loss of nerve fibres apparently occurred early in the course of compression, since there was a marked decrease in the amount of nerve fibre swelling and Marchi stained degenerating myelin with increasing clinical duration.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

THE HELMINTH PARASITES OF DOGS IN THE GOODRADIGBEE SHIRE OF NEW SOUTH WALES     

P. DAVIES B.Sc.  W. L. NICHOLAS Ph.D.  B.Sc. 《Australian veterinary journal》1977,53(5):247-248

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信阳地区杂交水稻高产高效益栽培模式的研究与应用     

河南信阳农专“双高”开发课题组 《杂交水稻》1993,(1):27-29

河南信阳地区提出了该地区杂交水稻大面积亩产６００公斤以上的最佳栽培模式为：适栽组合应以汕优６３为主;苗栽１．８～２万穴,两段育秧,亩施纯氮１０～１８公斤;钙镁磷肥５０公斤,多效唑１６０克左右;普及一喷三防技术．１９９２年在固始县,罗山县、满川县共推广７．１３万亩,增产１２６３．３６万公斤,增收８８４．３５万元．  相似文献   

Animal production evaluation of herbage varieties.     

D. A. DAVIES  M. FOTHERGILL  G. J. DANIEL  C. T. MORGAN 《Grass and Forage Science》1995,50(3):227-240

Perennial ryegrass/white clover (Lolium perennel Trifolium repens) pastures of three white clover varieties were compared at UK lowland (Plas Gogerddan, PG) and upland (Bronydd Mawr, BM) sites over three harvest years (1989–91) under continuous variable stocking (ewes and lambs until weaning and lambs thereafter). Mean annual lamb output from small-leaved S 184 (1179 kg ha^?1) was 29% greater than that from prostrate small-leaved AberEndura at PG with medium-leaved Huia also giving 19% more output than AberEndura. At BM, output from S 184 (863 kg ha^?1) was 19 and 14% greater than that from AberEndura and Huia respectively. The differences in lamb output between the small-leaved varieties owed to a combined effect of higher individual lamb growth rates and greater stock-carrying capacity, both of which were more pronounced in the post-weaning period. The higher output from S 184 relative to Huia at BM was attributed to higher stocking rate, particularly after weaning. Clover productivity and persistence were also studied under three cutting-only managements at PG. Performance under a treatment cut at 2–3 cm every 10 d (T1), which is synonymous with assessment of persistence in UK National List testing, was poor with clover growing point number of only 498 m^?2 compared with 4906 m^?2 on the grazed sward in autumn 1991. Although productivity and clover content under T3 (cut at 3–4 cm every 42 d — similar to National List yield regime) gave the same varietal ranking as lamb production, there was an under-estimation of the small-leaved varieties, particularly AberEndura, relative to Huia. An intermediate treatment (T2), cut at 3–4 cm every 21 d, also over-estimated the performance of the medium-leaved variety. Herbage data from ground level sampling every 21 d using exclosure cages on the grazed swards were also poorly related to lamb performance. These results highlight the effect of clover variety on lamb production, which appeared to be independent of leaf size, and also confirm the existing problems associated with assessment of white clover varieties using a cutting regime.  相似文献   

The effects of simulated continuous grazing on development and senescence of white clover     

D. R. JONES  ALISON DAVIES 《Grass and Forage Science》1988,43(4):421-425

Two experiments investigating the effects of simulated continuous defoliation on white clover development and senescence are described. Stolons growing in boxes in a glasshouse were defoliated repeatedly by hand to simulate different intensities of continuous grazing by sheep. The experiments continued in both instances until eleven leaves had been produced on stolons in the most favourable treatment.
It was found that leaf dry matter production was reduced in proportion to the leaf complement of the stolon. Reduction of the leaf complement from two leaves to one leaf led to a reduction in subsidiary branch production of about 25% and an increase in percentage dead stolon from 33 to 44%, If no fully expanded leaves were retained branch production fell to 40% or less of that observed when two leaves were retained.
Stolons growing in swards continuously grazed by sheep usually have a green leaf complement varying between zero and two leaves per growing point. The consequences of maintaining different leaf complements in this range are discussed in the light of the current experiments.  相似文献   

The effect of timing of slurry application on the microflora of grass, and changes occurring during silage fermentation   总被引：1，自引：0，他引：1  

D. R. DAVIES  R. J. MERRY  E. L. BAKEWELL 《Grass and Forage Science》1996,51(1):42-51

Cattle slurry (50 m³ ha^?1 equivalent to 68 kg N ha^?1) was applied to grassland plots 70 d (early application) and 34 d (late application) before ensiling and the retention and survival of slurry and epiphytic micro-organisms on the growing herbage were examined and compared with those on herbage from corresponding fertilizer-treated plots. The populations of lactic acid bacteria, enterococci and enterobacteria on herbage increased dramatically after slurry application. Thereafter, numbers of lactic acid bacteria declined, although they were always higher than on untreated herbage. Number of enterobacteria also declined but were higher on chopped grasses at ensiling [10⁶ colony-forming units (CFU) g^?1 fresh matter (FM)] than they were on hand-cut. unchopped herbages at all previous sampling times. Clostridia numbers were lowest on untreated and highest on slurry-treated herbage, particularly after the late application (>10³ CFU g^?1 FM). Herbage was harvested 70 d and 34 d after slurry application, chopped and ensiled in laboratory silos. All herbages, irrespective of treatment, had low dry matter (DM) values (ranging from 149 to 170 g kg^?1 FM) and fairly low water-soluble carbohydrate (WSC) concentrations (130 g kg^?1 DM or less). The initial rate of pH decline up to 4 d was most rapid in slurry-treated herbages, with all pH values falling to < 4. 5 by day 4 and remaining there until day 21. However, after 90 days the pH values of all silages had risen to > 4. 5. accompanied by a marked decline in lactic acid concentration. Lactic acid-fermenting Clostridia increased in numbers, reaching peak values of 10⁷ CFU g^?1 FM by day 21, remaining high until opening, and were probably responsible for increases in butyric acid levels in all silages, with the highest concentrations occurring in those prepared from slurry-treated herbages. The results suggest that, although some faecal lactic acid bacteria may have beneficial effects in the early stages of fermentation, Clostridia from slurry can survive on herbage for extended periods. The results indicate that the potential for growth of Clostridia in silage may be independent of source or size of the initial population even at tow pH, if other conditions are favourable.  相似文献   

Frequency of stocking rate adjustments required on contrasting upland perennial ryegrass pastures continuously grazed to a sward height criterion from May to July     

D. A. DAVIES  M. FOTHERGILL  D. JONES 《Grass and Forage Science》1989,44(2):213-221

The use of sward height as a criterion for determining the time and extent of stocking-rate changes on continuously grazed swards was investigated over a 2-year period (1985–86) in a sheep production experiment. Swards of three contrasting perennial ryegrass ( Lolium perenne L.) varieties were established with and without Aberystwyth S184 small-leaved white clover ( Trifolium repens L.) at an upland site (310–363 m) in mid-Wales. From spring (late April) until weaning (mid-July) the pastures were continuously stocked with Beulah Speckled Face ewes and Suffolk cross lambs. During this period sward heights of 4 ± 0.5 cm were obtained and maintained by regular adjustment of animal number on individual paddocks. Grass-only swards received 160 and 200 kg N ha⁻¹ and the grass clover swards were given 80 and 75 kg N ha⁻¹ in 1985 and 1986 respectively.
Differences were observed between the treatments in sward height profiles over the season necessitating contrasting adjustments to stocking rates. Mean stocking rate necessary on early flowering Aurora (22 6 ewes ha⁻¹) was respectively 27% and 17% higher than on late-flowering Aberystwyth S23 and Meltra (tetraploid) ryegrasses; mean stocking rate on grass-only swards was 19% higher than on the grass-clover pastures.
It is concluded that sward height is a useful criterion on which to make adjustments to stocking rates to compare the potential performance of contrasting swards, under continuous grazing. The infrequent adjustments required to maintain a constant sward height, especially on the late flowering diploid perennial ryegrass variety on which many upland pastures are based, suggest that the criterion of sward height could be successfully employed on farms as an aid to efficient grazing management.  相似文献   

Measurement of cardiac output by transesophageal Doppler ultrasonography in anesthetized dogs: comparison with thermodilution     

T Lazic  DH Riedesel  RB Evans 《Veterinary anaesthesia and analgesia》2003,30(2):104-105

Thermodilution (TD) is the standard method for cardiac output (CO) monitoring in human medicine. Although called the ‘gold standard’, TD is related to numerous complications and data misinterpretations. Recently, a noninvasive, continuous, ultrasound‐based technique for CO measurement has been developed (Hemosonic 100, Arrow Intl). This study compared transesophageal Doppler ultrasonography (TED) for measuring CO with TD in anesthetized dogs. In this study, ten dogs were used to simultaneously measure CO by TED and TD. All dogs were pre‐medicated with acepromazine at 0.1 mg kg^?1 IM, induced with thiopental at 10 mg kg^?1 IV, and maintained on isoflurane at end‐tidal concentrations of 1.3%. Baseline and four different levels of CO were used for comparison. Low CO levels were induced by caudal vena cava occlusion. High CO levels were induced by the constant IV infusion of dopamine, dobutamine, or norepinephrine. Each level of CO allowed one comparison between TED and TD. Forty‐nine paired comparisons of CO were determined ranging from 0.73 to 10.9 L minute^?1. Simple linear regression was used to determine the correlation between the two techniques. Correlation coefficient (r²) was 0.53. Bland and Altman statistical method was used for assessing agreement between the two methods. The difference between the TD and TED when all data were included was 0.82 (bias) ± 1.63 L minute^?1 (mean ± SD). At low CO levels (baseline and caudal vena cava occlusion), the correlation coefficient was 0.77, bias was 0.35 ± 0.64 L minute^?1. At high CO levels (dopamine, dobutamine, or norepinephrine), the correlation coefficient was 0.39. It was concluded that TED was not a reliable monitoring method in determining CO when positive inotropes were used. TED might have importance in situations of low CO values; however, further investigation is warranted.  相似文献   

A comparison of anesthetic risk factors and outcomes in light and draft horses     

CB  Riley †  DH Riedesel  ‡  IR Dohoo†  CL Hatfield†  S Clinch† 《Veterinary anaesthesia and analgesia》2003,30(2):113-114

As a result of anatomic and physiologic differences, draft breeds may be at greater risk of developing anesthetic complications. The aim of the study was to evaluate and compare anesthetic management of draft (DR) and light (LT) horses. A case‐matched retrospective study of 371 clinical case records of DR (124 cases) and LT (247 cases) horses presented for general anesthesia between 1991 and 1998 was performed. Data were tabulated and comparisons were made using Student's t‐test (significance p < 0.05). Prior to induction, there were significant differences in mean body weight, rectal temperature, PCV, RBC, and serum TP concentration between DR and LT breeds. There were differences in mean doses of pre‐operative butorphanol (LT 21 µg kg^?1; DR 17 µg kg^?1), induction guaifenesin (LT 99 mg kg^?1; DR 88 mg kg^?1), and intraoperative ketamine (LT 0.35 mg kg^?1; DR 0.56 mg kg^?1) required. There were no significant differences in the mean doses of pre‐operative xylazine, detomidine, or induction barbiturate administered. The mean, average, and maximum concentrations of inspired halothane were significantly higher for DR than for LT horses. Draft horses received 33% less intraoperative IV fluids (8.2 mL kg^?1 hour^?1) than LT horses. Mean anesthetic duration, time to extubation, and standing recovery were not significantly different. Induction complications were not reported for either group. Rates of occurrence of intraoperative bradycardia, hypercarbia, hypoxemia, and metabolic acidosis (SBE, TCO₂, and bicarbonate concentration) did not differ significantly. Average MAP was greater in DR horses, but neither the degree nor the mean duration of hypotension differed between DR and LT horses. Mean PaO₂ was significantly lower in DR (246 mm Hg, 32.8 kPa) than in LT (305 mm Hg, 40.7 kPa) breeds. Draft horses were at greater relative risk of hypoventilation than LT horses. The greater MAP and requirement for halothane and intraoperative ketamine may indicate problems in achieving and maintaining a surgical plane of anesthesia. Draft horses may be at a greater risk of ventilation–perfusion mismatching.  相似文献   

Pharmacokinetics of oral rufinamide in dogs     

H. M. WRIGHT  A. V. CHEN  S. E. MARTINEZ  N. M. DAVIES 《Journal of veterinary pharmacology and therapeutics》2012,35(6):529-533

Wright, H. M., Chen, A. V., Martinez, S. E., Davies, N. M. Pharmacokinetics of oral rufinamide in dogs. J. vet. Pharmacol. Therap.  35 , 529–533. The objective of this study was to determine the pharmacokinetic properties and short‐term adverse effect profile of single‐dose oral rufinamide in healthy dogs. Six healthy adult dogs were included in the study. The pharmacokinetics of rufinamide were calculated following administration of a single mean oral dose of 20.0 mg/kg (range 18.6–20.8 mg/kg). Plasma rufinamide concentrations were determined using high‐performance liquid chromatography, and pharmacokinetic data were analyzed using commercial software. No adverse effects were observed. The mean terminal half‐life was 9.86 ± 4.77 h. The mean maximum plasma concentration was 19.6 ± 5.8 μg/mL, and the mean time to maximum plasma concentration was 9.33 ± 4.68 h. Mean clearance was 1.45 ± 0.70 L/h. The area under the curve (to infinity) was 411 ± 176 μg·h/mL. Results of this study suggest that rufinamide given orally at 20 mg/kg every 12 h in healthy dogs should result in a plasma concentration and half‐life sufficient to achieve the therapeutic level extrapolated from humans without short‐term adverse effects. Further investigation into the efficacy and long‐term safety of rufinamide in the treatment of canine epilepsy is warranted.  相似文献