Research in veterinary science.
Publisher:
British Veterinary Association. London : British Veterinary Association
Frequency: Bimonthly
Country: England
Language: English
Author(s):
British Veterinary Association.
Start Year:1960 -
ISSN:
0034-5288 (Print)
1532-2661 (Electronic)
0034-5288 (Linking)
1532-2661 (Electronic)
0034-5288 (Linking)
Impact Factor
2.4
2022
| NLM ID: | 0401300 |
| (DNLM): | R25920000(s) |
| (OCoLC): | 01644503 |
| Coden: | RVTSA9 |
| Classification: | W1 RE231 |
Segmented filamentous bacteria associated with lymphoid tissues in the ileum of horses. Segmented filamentous bacteria preferentially attached to the follicle-associated epithelium overlying the lymphoid tissue in samples of the terminal ileum from seven horses examined by scanning electron microscopy. The bacteria adhered to the apical membrane of the enterocytes by a holdfast segment. Each filament tended to be of uniform diameter, but the filaments ranged from 0.7 to 1.4 microns in diameter. The bacteria were usually absent from the adjacent villous epithelium.
Oxygen cost of ventilation in the resting horse. The purpose of this study was to develop a technique to measure the oxygen cost of ventilation and the values of ventilatory parameters in seven normal horses rebreathing carbon dioxide (CO2). All the horses responded to increased inspiratory levels of CO2 by increasing their tidal volume (VT) and frequency of breathing (Vf). The mean (SE) oxygen cost litre-1 of ventilation, measured at rates of ventilation greater than 200 litres min-1 was 1.7 (0.04) ml litre-1, similar to that of normal human subjects ventilating submaximally. It was concluded that the CO2 rebreathing test is a practical, no...
EHV-1-induced abortion in mice and its relationship to stage of gestation. The most important consequence of equine herpesvirus-1 (EHV-1) infection is abortion. The object of the present study was to characteristic further a murine EHV-1 abortion model and to make comparisons with the natural host with particular reference to the stage of gestation during which the infection occurs. BALB/c mice at different stages of pregnancy were infected intranasally with EHV-1 (strain AB4); they suffered respiratory distress, weight loss, and other constitutional signs of infection. When the virus was inoculated in the late second or early third week of gestation dead or dying fe...
Prophylactic efficacy of phenytoin, acetazolamide and hydrochlorothiazide in horses with hyperkalaemic periodic paralysis. Horses with hyperkalaemic periodic paralysis were challenged with an oral dose of potassium chloride, and the prophylactic efficacy of phenytoin, acetazolamide and hydrochlorothiazide was evaluated, with at least three weeks separating the trials of each drug. After the administration of potassium chloride without prophylactic medication the horses' clinical signs ranged from generalised fine muscle fasciculations to gross tremors, and weakness with occassional prolapse of the nictitating membrane; plasma potassium concentration increased significantly (P < 0.01) from 4.0 +/- 0.2 to 6.0 +/-...
Detection of tetanus toxoid-specific memory T cells in equine lymph nodes but not in peripheral blood. The use of tetanus toxoid as a recall antigen to investigate equine immune responses would be, in theory, a useful and cost-effective model in vitro. However, by using various regimens for culturing peripheral blood mononuclear cells from horses previously immunised with toxoid no proliferative response to the antigen was obtained in vitro, whereas lymph node mononuclear cells from the same animals proliferated significantly in response to it. The lack of response by the peripheral blood mononuclear cells was not due to the presence of a suppressive factor but to a lack of recognition of the a...
Total intravenous anaesthesia in ponies using detomidine, ketamine and guaiphenesin: pharmacokinetics, cardiopulmonary and endocrine effects. Pharmacokinetics and some pharmacological effects of anaesthesia induced by a combination of detomidine, ketamine and guaiphenesin were investigated in eight ponies. Cardiopulmonary function was studied and plasma met-enkephalin, dynorphin, beta-endorphin, arginine vasopressin, adrenocorticotrophin, cortisol, 11-deoxycortisol and catecholamine concentrations were measured. The combination produced slight cardiorespiratory depression, hyperglycaemia and a reduction in haematocrit. There were no changes in plasma opioids, pituitary peptides or catecholamines. Plasma cortisol concentration decrea...
Predictive value of foal kinematics for the locomotor performance of adult horses. The gait of 24 horses was recorded on a treadmill when they were trotting at 4 m sec-1, first when they were four months old and again when they were 26 months. The data recorded at four months were used to predict the locomotion of the adult horses, and the predictions were assessed against the data recorded at 26 months. The locomotion of the foals and the adults appeared to be closely related, when the differences in segment length and joint angles due to growth were taken into account. The duration of swing, the total range of protraction and retraction, and the maximum tarsal flexion coul...
Effect of phenytoin on skeletal muscle from quarter horses with hyperkalaemic periodic paralysis. The contractile activity, the threshold for calcium-induced calcium release in fractions of sarcoplasmic reticulum and the potassium concentration were determined in preparations of semimembranosus muscle from normal quarter horses and quarter horses with hyperkalaemic periodic paralysis before and after they were treated with phenytoin. Before the treatment there was no difference in caffeine contracture or electrically elicited twitch response between the two groups. For one week after the treatment, the time to peak tension of caffeine contractures was significantly (P < 0.005) reduced i...
Stability of penicillin G, ampicillin, amikacin and oxytetracycline and their interactions with food in in vitro simulated equine gastrointestinal contents. Penicillin G was extensively (84.7 per cent) and amikacin moderately (14.4 per cent) degraded when incubated for one hour in a chloride buffer at pH 1.9 designed to mimic the equine gastric pH. Ampicillin and oxytetracycline were stable at pH 1.9. Penicillin and ampicillin were moderately stable (more than 90 per cent) when incubated in equine caecal liquor for three hours but were degraded by about 65 per cent after 24 hours. More than 80 per cent of the initial concentrations of amikacin and oxytetracycline were recovered after 24 hours' incubation in equine caecal liquor. The concentrations...
Identification of the causative agent of granulocytic ehrlichiosis in Swedish dogs and horses by direct solid phase sequencing of PCR products from the 16S rRNA gene. Seven Swedish isolates of Ehrlichia species from the blood of four dogs and three horses with clinical granulocytic ehrlichiosis, were identified by direct solid phase DNA sequencing of polymerase chain reaction (PCR) products from the 16S rRNA gene. The amplified DNA fragments were produced with primers complementary to the universal regions, U1, U2, U5 and U8 of the 16S rRNA molecule. Identical sequences were obtained from all seven isolates. This nucleotide sequence was similar to the sequences deposited in GenBank for Ehrlichia phagocytophila and E equi. The sequence of the Swedish ehrlich...
D-glucose transport and glycolytic enzyme activities in erythrocytes of dogs, pigs, cats, horses, cattle and sheep. The activities of D-glucose transport (D-GT) and the glycolytic enzymes hexokinase (HK) and pyruvate kinase (PK), were measured in the erythrocytes of dogs, pigs, cats, horses, cattle and sheep. The erythrocytes of dogs had the highest activities of D-GT, HK and PK, significantly higher than the activities in the erythrocytes of the herbivores. The activities of D-GT and HK in cat erythrocytes were significantly lower than in those of dogs. The differences between the activities of D-GT in the erythrocytes of the different species followed the differences in activities of HK but not those in t...
Immunisation of mares to control endometritis caused by Streptococcus zooepidemicus. Normal mares were immunised by the intramuscular and intrauterine administration of an antigen with adjuvant and they and unimmunised control mares were later challenged by the intrauterine instillation of pathogenic Streptococcus zooepidemicus; the response of all the mares was monitored clinically and bacteriologically for seven days. Significantly fewer S zooepidemicus were present in cervical swabs taken from the immunised mares than from the control mares (P < 0.01) and the degree of inflammation in the genital tract of the immunised mares was also significantly less (P < 0.001). Th...
Pituitary-adrenal activity and opioid release in ponies during thiopentone/halothane anaesthesia. The effect of thiopentone/halothane anaesthesia on the release of endogenous opioid, adrenocorticotrophin, arginine vasopressin, cortisol and catecholamine was investigated in ponies. The contribution made by halothane itself was studied by maintaining six ponies with a constant 1.2 per cent end tidal halothane concentration and five with a concentration ranging between 0.8 and 1.2 per cent. Cardiorespiratory depression was more prolonged in the ponies receiving a constant 1.2 per cent end tidal halothane concentration than in those which received less halothane. Plasma lactate concentration i...
Genetic structure of populations of beta-haemolytic Lancefield group C streptococci from horses and their association with disease. The genetic structure of beta-haemolytic Lancefield group C streptococci isolated from horses in Australia was examined by multilocus enzyme electrophoresis. The 249 isolates comprised 70 classified phenotypically as Streptococcus equi subspecies equi, 177 classified as S equi subspecies zooepidemicus and two which were unclassifiable. Forty-one electrophoretic types were identified which could be classified into three major clusters, A, B and C. Of the isolates, 178 fell into cluster B (types 4 to 22) and lay within a genetic distance of 0.36. Sixty-nine of the 70 S equi subspecies equi isola...
Endotoxin-induced platelet aggregation in heparinised equine whole blood in vitro. Endotoxaemia is a leading cause of death among horses. Thrombocytopenia is a common finding in clinical and experimentally-induced cases of endotoxaemia and can lead to coagulopathies, including disseminated intravascular coagulopathy which is usually fatal. In this study it was shown that endotoxin (3 ng ml-1 to 25 micrograms ml-1) can aggregate equine platelets in heparinised whole blood in vitro. The endotoxin-induced aggregation (EIA) was shown to be dependent on the presence of leucocytes in the blood and did not occur when detoxified endotoxin was used, suggesting that lipid A was necess...
Blood lactate disappearance after maximal exercise in trained and detrained horses. The influence of training on blood lactate concentrations during treadmill exercise and a 40-minute inactive recovery period was examined in seven trained and seven detrained thoroughbred horses. Lactate concentrations were measured in venous blood collected at the end of each exercise state, and at intervals for 40 minutes afterwards. Measurements were made of maximum oxygen uptake (VO2max, ml kg-1 min-1), VLA4 (velocity at which blood lactate concentration was 4 mmol litre-1); LA8 (lactate concentration [mmol litre-1] during exercise at 8 m sec-1), peak lactate (highest lactate concentration...
Quantitation of alpha-1 proteinase inhibitor in the pulmonary epithelial lining fluid of horses with chronic obstructive pulmonary disease. The concentration of alpha-1 proteinase inhibitor (API) was measured in the pulmonary epithelial lining fluid (PELF) of horses with chronic obstructive pulmonary disease (COPD) while they had clinical signs and while they had none. The concentrations of total protein, albumin and API were significantly higher in the PELF of animals with clinical signs of COPD. The correlation between albumin and API in the PELF suggested that most of the API was derived from the serum.
Gait and respiration in standardbred horses when pacing and galloping. The relationship between gait and the respiratory response to exercise was examined in five standardbred racehorses which exercised on a treadmill at a pace and a gallop. After an initial warm-up, respiratory rate and stride frequency were measured after one and two minutes of treadmill exercise at 80 per cent of maximal oxygen consumption (VO2max), after one minute at 100 per cent VO2max and after two minutes at 100 per cent VO2max (galloping horses only). Exercise at 100 per cent VO2max continued until the horses showed signs of fatigue. Arterial blood was collected during exercise and when ...
Crystals in equine articular cartilage. Crystal deposits have been observed in equine articular cartilage and identified by scanning electron microscopy and X-ray diffraction as octacalcium phosphate and calcium pyrophosphate dihydrate. Of 89 equine fetlock joints examined 10 contained evidence of calcification visible by eye. It is suggested that the deposition of crystals may be a mediator of arthritis in horses and may also cause damage directly.
Measurement by ELISA of equine alpha-1-proteinase inhibitor in uterine flushings from mares. An enzyme linked immunosorbent assay (ELISA) was developed and used to estimate the concentrations of the serine proteinase inhibitor, alpha-1 proteinase inhibitor (API), in uterine flushings recovered from mares at different stages of the oestrous cycle and before and after the induction of experimental endometritis. There was a significant increase in the concentrations of API and albumin relative to total protein in flushings recovered during oestrus compared with dioestrus but no difference was observed in the concentrations of these proteins relative to total protein before and after the ...
Relationship between plasma insulin and triglyceride concentrations in hypertriglyceridaemic donkeys. Hyperinsulinaemia is a commonly-observed characteristic of insulin resistance, and a reduction in insulin sensitivity is thought to be either a causative and/or symptomatic feature of equine hyperlipaemia. A positive correlation (r = 0.545, P = 0.0015) existed between plasma insulin and triglyceride concentrations determined in 31 donkeys with naturally occurring hyperlipidaemia/hyperlipaemia. Greater insulin values tended to occur in the animals with an overweight body score. Inter-animal variation in insulin concentrations, however, prevented the identification of any differences either with...
Effect of phenylbutazone on the haemodynamic, acid-base and eicosanoid responses of horses to sustained submaximal exertion. The systemic haemodynamic and acid-base effects of the administration of phenylbutazone (4.4 mg kg-1 intravenously) to standing and running horses were investigated. Phenylbutazone, or a placebo, was administered to each of six mares either 15 minutes before, or after 30 minutes of a 60-minute submaximal exercise test which elicited heart rates approximately 55 per cent of maximal, and to the same horses at rest. The variables examined included the cardiac output, heart rate, systemic and pulmonary arterial pressures, right atrial and right ventricular pressures, and arterial and mixed venous ...
Analysis of the frequency spectrum of the equine electroencephalogram during halothane anaesthesia. The electroencephalogram (EEG) has been used in human clinical anaesthesia as an indicator of cortical activity and as an indicator of the depth of anaesthesia. It would be useful if it provided a reliable indication of the depth of anaesthesia of horses. In this study anaesthesia was induced with thiopentone and maintained with halothane in nine ponies. The end tidal halothane concentration (PE-Hal) was monitored and 20 seconds of EEG were recorded at 0.8 per cent, 1.0 per cent and 1.2 per cent halothane, equivalent to the minimum alveolar concentration (MAC), 1.25 MAC and 1.5 MAC. Each 20 se...
Gastric emptying of solid, non-digestible, radiopaque markers in ponies. The gastric emptying of different forms of ingesta occurs by a variety of mechanisms and dysfunction may selectively affect different components of the gastric contents. A technique for assessing gastric emptying of solid, indigestible, radiopaque markers was developed. Emptying of these markers in four ponies was variable in both pattern and rate (half emptying time ranged from less than one hour to more than 24 hours). However, whereas in man physically similar markers appear to empty relatively rapidly when fasting but are delayed by a meal, no such delay was evident in these ponies. The ho...
Measurement of gastric emptying of water in foals by impedance epigastrography. Impedance epigastrography was used to measure gastric emptying rates on two occasions in each of three foals. After smoothing of the raw data, emptying of water appeared to obey an exponential model. The mean emptying rate constant (SEM) was 0.171 +/- 0.038 min-1 (mean emptying half time 4.9 +/- 1.0 min).
Gastric emptying of four liquid meals in pony foals. Water, saline and a saline/Intralipid mixture (lipid concentration 1.25 per cent) emptied very rapidly from the stomach in neonatal pony foals, and obeyed an apparently exponential pattern. Cisapride did not significantly modify the emptying of the saline/Intralipid mixture. Equine milk emptied more slowly. The data indicated that the lipid component of milk was not an important factor. Milk caused deviation from an exponential pattern in two of four foals: an initial lag phase appeared, which could represent a phase of intragastric processing. However, the rate was still rapid compared with r...
Urinary concentration of corticoids in normal horses and horses with hyperadrenocorticism. The urinary corticoid:creatinine (c:c) ratio was determined in eight horses with hyperadrenocorticism (HAC). The mean (+/- SD) urinary c:c ratio of the eight horses with HAC (29 +/- 14 x 10(-6)) was significantly (P < 0.05) greater than the ratio in seven control horses (11 +/- 4.3 x 10(-6)). The urinary concentration of corticoids in control horses (201 +/- 60.4 nmol litre-1) was significantly (P 0.05) between both groups. As both false negative and false positive cases were found, it is concluded that a measurement of the urinary c:c ratio in the horse should not be used as the sole test...
Biochemical and haematological changes following prolonged halothane anaesthesia in horses. Six healthy horses were anaesthetised with halothane (1.2 times the horse minimal alveolar concentration) in oxygen for more than 12 hours. Serum bilirubin, aspartate aminotransferase, alkaline phosphatase and L-iditol dehydrogenase values were significantly (P < 0.05) increased for up to nine days after anaesthesia. These changes suggest an anaesthesia related liver dysfunction. Creatine kinase increased to an average of more than 1400 IU litre-1 24 hours after anaesthesia and this change is indicative of muscle cell disruption. Renal-associated biochemical results, (that is serum creatinine ...
A new technique for accessing the cerebral ventricles of the horse. A technique is described for catheterisation of the ventricular recess within the olfactory bulb of the horse. Twelve adult horses were used. The olfactory recess is in the frontal region, 42 +/- 3 mm below the skin, on the line joining the supraorbital foramina, and approximately 18 +/- 2 mm from the midline. The approach is relatively easy under normal experimental conditions.
Morphometric study of the recurrent laryngeal nerve in young ‘normal’ horses. Quantitative measurements were made on cross-sectional preparations of the distal part of the recurrent laryngeal nerve (RLN) from nine young mixed-breed horses to establish reference values for the total number of myelinated fibres, mean fibre diameter and percentage of thickest fibres (over 9.5 microns) and to delineate diameter distribution curves. The total number of myelinated fibres, mean fibre diameter and percentage of thickest fibres for the left RLN were significantly lower than those of the right RLN (P < 0.005). The distribution of fibres was unimodal. The fibre diameter ranged ...