ISSN:0425-1644    

DOI:10.1111/j.2042-3306.1990.tb04256.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

ISSN:0425-1644    

DOI:10.1111/j.2042-3306.1990.tb04257.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

SummaryFourteen privately owned horses completed a six month, controlled, double‐blind trial to assess the efficacy of immunotherapy using an aqueous extract of whole, unfedCulicoides variipennisin the treatment ofCulicoideshypersensitivity. Selected horses had a history of a seasonal, pruritic dermatitis, clinical signs and distribution compatible withCulicoideshypersensitivity, failed to improve in response to ivermectin therapy, and reacted to several dilutions ofCulicoidesextracts without significant reactivity to other possible allergens including insects, moulds and feeds. One horse from the control group (n=8) and one from the test group (n=6) improved. Statistically, there was no significant difference between horses onCulicoidesantigen and control horses. In each group, four owners thought that their horses had improve

ISSN:0425-1644    

DOI:10.1111/j.2042-3306.1990.tb04258.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

SummaryForty‐four seasonally pruritic horses and 21 asymptomatic horses in Florida, USA, were tested for insect, grass and mould hypersensitivity by intradermal injection of allergenic extracts. The affected horses ranged in age from 10 months to over 30 years and included a variety of breeds. Affected horses reacted to varying dilutions of extracts made fromCulicoides, mosquitoes, horse flies and black flies. Reactions toCulicoideswere more intense than those caused by injection of antigens from other arthropods. Mild pruritus existed from the end of February until the end of June when the condition worsened and remained severe until November when it improved to an asymptomatic state. Histopathological examination of skin biopsies demonstrated changes compatible with arthropod hypersensitivity. Three clinical syndromes associated with insect hypersensitivity were described as follows: 1) horses with lesions on face, ears, mane, withers, rump and tail; 2) horses with lesions on face, ears, intermandibular space, chest, belly and groin, and 3) those with a combination of dorsal and ventral lesion

ISSN:0425-1644    

DOI:10.1111/j.2042-3306.1990.tb04259.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

SummaryEndogenous opioid peptides have been implicated in the regulation of pain perception, behaviour, gastrointestinal activity and other physiological responses. However, the functional role of these peptides in the horse has yet to be elucidated. The opioid antagonist, naloxone, is often administered to infer endogenous opioid effects. In the present study, naloxone (0.75 mg/kg bodyweight) was administered to eight Thoroughbred racehorses and a number of behavioural and autonomic responses were measured. Naloxone produced rapid onset diarrhoea, restlessness, abdominal checking, tachycardia, tachypnoea, paradoxical yawning and diaphoresis. These responses described an acute abdominal distress syndrome similar to spasmodic colic. Results from this study suggest that, in the horse, endogenous opioids: 1) influence behaviour, 2) modify intestinal activity and sensation, and 3) if perturbed, may be involved in pathophysiology of colic.

ISSN:0425-1644    

DOI:10.1111/j.2042-3306.1990.tb04260.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

SummaryThoroughbred geldings were fed racehorse cubes containing a predetermined concentration of theobromine in the form of cocoa husk. They were offered 7 kg of cubes per day, divided between morning and evening feed, and food consumption was monitored. Urinary concentrations of theobromine were determined following the consumption of cubes containing 11.5, 6.6, 2.0 and 1.2 mg per kg of theobromine, to verify whether or not such concentrations would produce positive urine tests. Pre‐dose urine samples were collected to verify the absence of theobromine before each experiment. It became apparent from the results of the first three administrations that the limit of detection of theobromine, using such procedures, would be reached at a feed level of about 1 mg per kg theobromine. Therefore the final administration, using cubes containing 1.2 mg per kg theobromine, was singled out for additional analytical work and quantitative procedures were developed to measure urinary concentrations of theobromine. It was anticipated that the results would form a basis for discussions relating to the establishment of a threshold value for theobromine in horse urine. The Stewards of the Jockey Club subsequently gave notice that they had established a threshold level for theobromine in urine of 2 μg/

ISSN:0425-1644    

DOI:10.1111/j.2042-3306.1990.tb04261.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

SummaryA sensitive sandwich enzyme immunoassay (EIA) for measuring equine carbonic anhydrase III (CA‐III) was established using a microplate as a solid‐phase and peroxidase as a labelling enzyme. The assay can detect concentrations as low as 5 ng/ml using 20 μl of sample sera. Within‐run coefficients of variation obtained using standard equine CA‐III were less than 5 per cent. CA‐III levels in equine serum ranged from 5 to 50 ng/ml (n=370), and apparently abnormal levels of CA‐III from 100 to 1900 ng/ml (n=27) were observed. The concentrations of immunoreactive CA‐III in the extracts of various equine tissues were also determined; it was present at high concentrations in skeletal muscle and liver and to a much lesser extent in the thymus. Other tissues contained much s

ISSN:0425-1644    

DOI:10.1111/j.2042-3306.1990.tb04262.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

SummaryFour privately owned herds (25 to 49 animals per herd) were used in a five‐year trial designed to evaluate the effect of anthelmintic schedules on the incidence of colic. These herds had been treated bi‐monthly with non‐ivermectin, non‐benzimidazole drugs for two years before the trial. Prior parasitological studies showed that they had substantial pre‐treatment faecal egg counts (900 to 2200 eggs per gramme), and that they were infected with benzimidazole‐resistant cyathostomes. In Years 1 and 2 of the trial, all herds (A, B, C, D) were treated bi‐monthly with non‐ivermectin anthelmintics (Schedule I). In Years 3 to 5, Herd A received monthly non‐ivermectin anthelmintics (Schedule II) and Herd C was treated with bi‐monthly ivermectin (Schedule III). Herd B was treated with Schedule II in Years 3 and 4 and Schedule III in Year 5. Herd D was maintained on Schedule I throughout the study period. In each herd, the incidence of colic, while on Schedule I, was compared to the incidence while on Schedule II or III. The risk of colic for horses on Schedule I was 2.61 to 13.04 times that of the same horses while on Schedule II and 2.27 to 9.64 times that of the same horses while on Schedule III. In Herd D, treated according to Schedule I for five years, the incidence of colic did not vary significantly throughout the study period. More effective anthelmintic treatment schedules decreased the incidence of colic in these herds, supporting the conclusion that bimonthly treatment with non‐ivermectin drugs may not maximise horses' health in all management conditions. Further, the data suggest that a high proportion of colics seen in this study had a parasitic aetiology, and that cyathostomes, rather than large strongyles, were the pri

ISSN:0425-1644    

DOI:10.1111/j.2042-3306.1990.tb04263.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

SummaryPhenylbutazone, a non‐steroidal anti‐inflammatory drug known to produce intestinal erosions, was administered intravenously (13.46 mg/kg bodyweight) to 12 horses which were killed after 24, 48, 72 and 96 h. Eight untreated horses served as controls. Annular erosions in the duodenum and mucosal necrosis in the colon were seen after 48 h which progressed in severity. The erosions were characterised by sloughing of the surface epithelium, subepithelial cleft and bleb formation, necrosis of thelamina propria, degeneration of the walls of subsurface capillaries and microthrombosis. Large numbers of neutrophils with abundant fibrin and cellular debris were present at the erosion sites. Ultrastructurally, there was swelling of the endothelium of capillaries and small vessels, and of pericyte and smooth muscle cytoplasm in arterioles. In capillaries and post capillary venules, the endothelium ranged from swollen to lysed and necrotic. Extensive extravasation of erythrocytes and oedema were seen. These lesions were not seen in the control horses. Phenylbutazone produces a microvascular injury associated with the formation of duodenal and colonic erosions in horses. The duodenal and colonic mucosa were assayed at 48 and 96 h for prostacyclin and PGE2. There was no statistically significant difference between prostaglandin levels in the mucosa of control and treated horses. It was concluded that there was no correlation between mucosal prostaglandin levels and intestinal erosions after 4

ISSN:0425-1644    

DOI:10.1111/j.2042-3306.1990.tb04264.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

SummaryThe structure of equine synovial tendon sheaths and bursae has been examined by light and scanning electron microscopy. Tissue samples were obtained from horses of various types and ages with no clinical evidence of sheath or bursal disorders. The interior of both structures was lined by a cellular layer superimposed on a vascular zone supported by a fibrous layer. The pattern of cell distribution of the lining varied from site to site within the same structure depending on the nature of the underlying tissue and on the amount of movement to which the structure was subjected. The cellular layer was predominantly fibrous in nature with scanty, widely separated fibroblasts (eg where it lines the palmar ligament, tendons and paratendons). In the mesotendon and bursal extremities, where the lining is subjected to a positive degree of movement, the cellular layer was areolar in type with well established folds populated by abundant cells oval to round in shape. In foals and yearlings, the supportive layer was mainly around the areolar with patches of adipose tissue; which were gradually replaced by fibrous tissue as the animal grew.

ISSN:0425-1644    

DOI:10.1111/j.2042-3306.1990.tb04265.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY