ISSN:0425-1644    

DOI:10.1111/j.2042-3306.1989.tb02078.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

ISSN:0425-1644    

DOI:10.1111/j.2042-3306.1989.tb02079.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

ISSN:0425-1644    

DOI:10.1111/j.2042-3306.1989.tb02080.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SummaryNarcotic analgesics produce pharmacological effects by interacting with specific opiate receptors. At least five major types of opiate receptors have been recognised. These include μ (morphine) and kappa (ethylketazocine) receptor types. Narcotic analgesics which interact with μ receptors produce locomotor and autonomic stimulation at doses that produce little or no analgesia. Therefore, use of these drugs as analgesics in equine medicine has not been very satisfactory. Theoretical considerations suggested that the role of kappa agonists in equine analgesia be investigated. Using a pure kappa agonist, U‐50. 488H, good analgesia was produced in the horse with little or no locomotor stimulation or autonomic effects. These data suggest that kappa agonists may be superior analgesics for clinical use in the horse. On the other hand, the locomotor stimulant effects of μ agonist analgesics enable their use as illegal medications. Specifically, these agents produce a good running response, signs of central nervous stimulation and analgesia, all potentially useful effects in a racehorse. Regulatory control of most narcotic analgesics can be obtained by high performance thin layer chromatographic screening. However, effective screening for the fentanyls and small doses of etorphine can only be achieved by use of immunoa

ISSN:0425-1644    

DOI:10.1111/j.2042-3306.1989.tb02081.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SummaryA study was carried out on five horses and four ponies to assess the effect of altering frog pressure on hoof expansion. Measurements of hoof expansion were made using strain gauges. It was concluded that whereas frog pressure affects hoof expansion, it is only one of several factors. Increasing frog pressure may result in increased expansion, or contraction, or may have virtually no affect. The variable results of changing frog pressure should be taken into account when considering therapeutic shoeing.

ISSN:0425-1644    

DOI:10.1111/j.2042-3306.1989.tb02082.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SummaryThis paper describes the application of foil strain gauges to the hoof wall, and the use of measuring equipment to monitor weightbearing and changes in hoof shape in shod and unshod horses. It concludes that the systems can detect hoof movement and that results are reproducible. It is also concluded that the use of a conventional nailed on iron shoe restricts flexion and spreading of the hoof wall at the ground surface, but has little effect on the degree of expansion of the heels of the foot.

ISSN:0425-1644    

DOI:10.1111/j.2042-3306.1989.tb02083.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SummaryComparisons were made between transtracheal aspirate (TTA) and bronchoalveolar lavage (BAL) cytology obtained from 50 horses with chronic lung disease and from 10 control horses. There was no significant correlation between the TTA cytology and the BAL cytology, suggesting that the cell population in the trachea is not representative of the cell population in the lower airways. In control horses the range of differential cell counts obtained from TTA fluid was remarkably large, whereas the variability in cell populations observed in BAL fluid was smaller. In the principal horses the total and differential cell counts of the TTA and BAL fluids were within the 95 per cent confidence interval in 38 and 24 per cent of cases, respectively; and an increase in percentage neutrophils was most common. It was concluded that BAL may be a useful diagnostic aid when evaluating horses with chronic lung disease, but that the clinical usefulness of cytological evaluations of TTA fluid may be limited in these cases.

ISSN:0425-1644    

DOI:10.1111/j.2042-3306.1989.tb02084.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SummaryFive horses were studied during a five‐week regime of controlled intensive daily training on a high‐speed treadmill followed by five weeks of detraining. Muscle biopsies were taken weekly from both the right and left gluteus muscle and from the sternocephalicus muscle before, and at the end of, the training and detraining periods. Histochemical and biochemical analyses of the sternocephalicus muscle showed no metabolic adaptation with either training or detraining. No significant differences were observed in any of the analysed parameters in the gluteus muscle between contralateral sites. Glycogen levels decreased by 10 to 15 per cent after one to two weeks of training, remained low during the training period and increased to pretraining levels after one week's cessation of training. Citrate synthase activity increased rapidly and was 27 per cent higher after one week and 42 per cent higher after five weeks of training. Lactate dehydrogenase activity decreased by 15 per cent during this period. The changes seen in these enzyme levels persisted during the detraining period. No alterations were seen in fibre type composition but type IIA fibre areas decreased by 19 per cent after five weeks training and capillary density increased by 17 per cent. It is concluded that a period of intensive training will rapidly increase the oxidative capacity and the capillary density in an actively working muscle, and that these metabolic adaptations are well maintained during a subsequent period of detrain

ISSN:0425-1644    

DOI:10.1111/j.2042-3306.1989.tb02085.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SummaryThe potential for interactions between chloramphenicol, phenylbutazone, acepromazine and thiamylal and chloramphenicol, rifampin, and phenylbutazone were evaluated in two groups of experiments. In the first, five horses were given thiamylal intravenously (iv) (6.6 mg/kg) after pretreatment with acepromazine, and the time of recumbency was determined. Administration of chloramphenicol iv (25 mg/kg) 1 h prior to anaesthesia significantly lengthened the recumbency time from 21.8 ± 4.8 mins to 36.0 ± 8.3 mins. There was an apparent but not statistically significant decrease in recumbency time when phenylbutazone (4.4 mg/kg) was administered iv daily for 4 days prior to anaesthesia. In the second series of experiments, phenylbutazone (4.4 mg/kg), chloramphenicol (25 mg/kg) and rifampin (10 mg/kg) were administered in various sequences to five different horses. Chloramphenicol pretreatment produced a significant decrease in the elimination rate and rifampin a significant increase in the elimination rate of phenylbutazone. The half‐life of elimination of phenylbutazone alone was about 4 h. Following four days pretreatment with rifampin it was approximately 2.7 h, it was approximately 5.6 h and 9.5 h, respectively, when chloramphenicol was administered in one dose 1 h before or two doses 12 h and 1 h before phenylbutaz

ISSN:0425-1644    

DOI:10.1111/j.2042-3306.1989.tb02086.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SummaryMyocardial and haemodynamic responses to strenuous treadmill exercise were monitored with chronically implanted instrumentation in seven physically untrained ponies. In two other ponies, haemodynamics were monitored using a conventional catheter technique. During exercise (mean ± sem heart rate = 203 ± 3 beats/min), left ventricular peak systolic and end‐diastolic blood pressure significantly increased from 125 ± 2 to 208 ± 6 mmHg and from 29 ± 1 to 58 ± 3 mmHg, respectively (P<0.05). Peak positive first derivative of left ventricular pressure (dP/dt) was also increased significantly, (1397 ± 144 to 6016 ± 325 mmHg/sec), as were myocardial segment velocity of shortening during systole (dL/dtsys) and stroke work (193 and 109 per cent, respectively). Paradoxically, segment systolic shortening was reduced significantly (P<0.05) with respect to resting control values for 10 mins after cessation of exercise, with the maximal reduction of 22 per cent occurring at 2 mins post exercise. In addition, left ventricular segment stroke work decreased significantly to 67 per cent of resting control value at 2 mins post exercise. This study demonstrates that analysis of regional myocardial performance in conjunction with haemodynamic data permits a detailed description of cardiac events during and immediately following exercise, facilitating definition of changes which are not readily reflected by haemodynamics. Based on these findings, the authors conclude that untrained ponies may readily complete short bouts of near‐maximal exercise, yet experience significantly diminished left ventricular function in the immediate post exer

ISSN:0425-1644    

DOI:10.1111/j.2042-3306.1989.tb02087.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY