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Doherty, T. J., & Frazier, D. L. (1998). Effect of intravenous lidocaine on halothane minimum alveolar concentration in ponies. Equine Vet J, 30(4), 300–303.
Abstract: This study investigated the effect of lidocaine i.v. on halothane minimum alveolar concentration (MAC) in ponies. Six ponies were anaesthetised with thiopentone and succinylcholine, intubated and anaesthesia maintained with halothane. Ventilation was controlled and blood pressure maintained within clinically acceptable limits. Following a 2 h equilibration period, baseline halothane MAC was determined. The ponies were then given a loading dose of lidocaine (2.5 or 5 mg/kg bwt) or saline over 5 min, followed by a constant infusion of lidocaine (50 or 100 microg/kg/min, or saline, respectively). The halothane MAC was redetermined after a 60 min infusion of lidocaine or saline. The baseline halothane MAC for the control group was mean +/- s.d. 0.94 +/- 0.03%, and no significant decrease occurred following saline infusion. Lidocaine decreased halothane MAC in a dose-dependent fashion (r = 0.86; P < 0.0003). The results indicate that i.v. lidocaine may have a role in equine anaesthesia.
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Alexander, F. (1978). The effect of some anti-diarrhoeal drugs on intestinal transit and faecal excretion of water and electrolytes in the horse. Equine Vet J, 10(4), 229–234.
Abstract: The effect of morphine, Tinct. opii, loperamide, pethidine and atropine on intestinal transit and the faecal and urinary excretion of water and electrolytes was studied in ponies. The rate of passage of a particulate marker was slowed by morphine, hastened then slowed by loperamide and Tinct. opii, and hastened by atropine. The liquid marker was slowed by Tinct. opii and hastened then slowed by the other drugs. Only loperamide decreased the faecal sodium excretion. This drug also decreased faecal water and weight; it appeared worthy of clinical trial in diarrhoea. Tinct. opii decreased by morphine, pethidine and atropine increased faecal water.
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Hubbell, J. A. E., & Muir, W. W. (2006). Antagonism of detomidine sedation in the horse using intravenous tolazoline or atipamezole. Equine Vet J, 38(3), 238–241.
Abstract: REASONS FOR PERFORMING STUDY: The ability to shorten the duration of sedation would potentially improve safety and utility of detomidine. OBJECTIVES: To determine the effects of tolazoline and atipamezole after detomidine sedation. HYPOTHESIS: Administration of tolazoline or atipamezole would not affect detomidine sedation. METHODS: In a randomised, placebo-controlled, double-blind, descriptive study, detomidine (0.02 mg/kg bwt i.v.) was administered to 6 mature horses on 4 separate occasions. Twenty-five mins later, each horse received one of 4 treatments: Group 1 saline (0.9% i.v.) as a placebo control; Group 2 atipamezole (0.05 mg/kg bwt i.v.); Group 3 atipamezole (0.1 mg/kg bwt i.v.); and Group 4 tolazoline (4.0 mg/kg bwt i.v.). Sedation, muscle relaxation and ataxia were scored by 3 independent observers at 9 time points. Horses were led through an obstacle course at 7 time points. Course completion time was recorded and the ability of the horse to traverse the course was scored by 3 independent observers. Horses were videotaped before, during and after each trip through the obstacle course. RESULTS: Atipamezole and tolazoline administration incompletely antagonised the effects of detomidine, but the time course to recovery was shortened. CONCLUSIONS AND POTENTIAL RELEVANCE: Single bolus administration of atipamezole or tolazoline produced partial reversal of detomidine sedation and may be useful for minimising detomidine sedation.
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Madigan, J. E., Kortz, G., Murphy, C., & Rodger, L. (1995). Photic headshaking in the horse: 7 cases. Equine Vet J, 27(4), 306–311.
Abstract: Seven horses with headshaking are described. No physical abnormalities were detected in any of the cases. Six of these horses had onset of clinical signs in the spring. The role of light was assessed by application of a blindfold or dark grey lens to the eyes, covering the eyes with a face mask and observing the horse in total darkness outdoors. Cessation of headshaking was observed with blindfolding (5/5 horses), night darkness outdoors (4/4 horses) and use of grey lenses (2/3 horses). Outdoor behaviour suggested efforts to avoid light in 4/4 cases. The photic sneeze in man is suggested as a putative mechanism for equine headshaking. Five of 7 horses had improvement with cyproheptadine treatment (0.3 mg/kg bwt b.i.d.). Headshaking developed within 2 calendar weeks of the same date for 3 consecutive years in one horse. Neuropharmacological alterations associated with photoperiod mechanisms leading to optic trigeminal summation are suggested as possible reasons for spring onset of headshaking.
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Kristiansen, K. K., & Kold, S. E. (2007). Multivariable analysis of factors influencing outcome of 2 treatment protocols in 128 cases of horses responding positively to intra-articular analgesia of the distal interphalangeal joint. Equine Vet J, 39(2), 150–156.
Abstract: REASONS FOR PERFORMING STUDY: There is limited knowledge available of factors influencing response to treatments of the DIP-joint in horses with lameness responding to diagnostic analgesia of the DIP-joint. For this reason a multivariable statistical analysis was performed. HYPOTHESIS: Horses with lameness reduced by > or = 75% 10 min after intra-articular analgesia of the DIP-joint, can be treated successfully by intra-articular medication of the joint. Multiple factors influence the response to treatment. METHODS: The study was performed retrospectively based on clinical records of horses treated with either polysulphated glycosaminoglycan (PSGAG) or methylprednisolone acetate (MPA) in the DIP-joint between January 1996 and January 2003. Information was collected from clinical records and from the owners of the horses via a detailed questionnaire, in which they described their perception of the outcome a minimum of one year after treatment. Allocation of the horses to the 2 treatment groups was done mainly because of a change in treatment policy. In Regime A all horses received 3 intra-articular injections of PSGAG approximately 8 days apart, whereas in Regime B all horses received a single intra-articular injection of MPA as a first treatment. If the horse did not improve sufficiently to return to work by 4 weeks, a series of 3 intra-articular PSGAG injections was administered. RESULTS: Of the horses receiving Regime A, 67% had a successful outcome, compared with 46% of the group receiving Regime B. A significantly better result was obtained in dressage horses than in jumping horses (eventing and showjumping). Other variables such as age, duration of lameness, distribution of lameness, degree of lameness, response to DIP-joint analgesia and radiographic observations were also associated with success of treatment. CONCLUSIONS AND POTENTIAL RELEVANCE: There is a rationale for using either PSGAG or MPA intra-articularly in the treatment of lameness, reduced > or = 75% within 10 min of analgesia of the DIP-joint.
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Dyson, S., & Murray, R. (2003). Pain associated with the sacroiliac joint region: a clinical study of 74 horses. Equine Vet J, 35(3), 240–245.
Abstract: REASONS FOR PERFORMING STUDY: There has been no large study of horses with suspected sacroiliac (SI) joint region pain in which the clinical diagnosis has been supported by either abnormal radiopharmaceutical activity in the SI joint region or by periarticular infiltration of local anaesthetic solution. OBJECTIVES: To describe the clinical features of horses with SI joint region pain, to document the age, breed, sex, discipline, size and conformation of affected horses and to compare these with the author's (SD) normal case population and to document the results of infiltration of local anaesthetic solution around the SI joint region. METHODS: Horses were selected for inclusion in the study based upon the exclusion of other causes of lameness or poor performance, together with clinical signs suggestive of SI joint pain and abnormal radiopharmaceutical activity in the SI joint region and/or a positive response to periarticular infiltration of local anaesthetic solution. RESULTS: Sacroiliac joint region disease was identified in 74 horses between November 1997 and March 2002. Dressage and showjumping horses appeared to be at particular risk (P < 0.001). Affected horses were generally slightly older than the normal clinic population (P < 0.0001), taller at the withers (P < 0.0001) and of greater bodyweight (P < 0.01). There was a significant effect of breed (P < 0.001), with a substantially higher proportion of Warmblood horses (51%) in the SI pain group compared to the normal clinic population (29%). There was no correlation between conformation and the presence of SI joint region pain. The tubera sacrale appeared grossly symmetrical in most (95%) horses. Poor development of the epaxial muscles in the thoracolumbar region and asymmetry of the hindquarter musculature were common. Twenty-six horses (35%) showed restricted flexibility of the thoracolumbar region and 10 (16%) had an exaggerated response to pressure applied over the tubera sacrale. Fourteen horses (19%) were reluctant to stand on one hindlimb for prolonged periods. The majority of horses (75%) had a straight hindlimb flight and only 18% moved closely behind or plaited. In all horses restricted hindlimb impulsion was the predominant feature; invariably this was most obvious when the horse was ridden. Stiffness, unwillingness to work on the bit and poor quality canter were common. Sacroiliac joint region pain was seen alone (47%), or in conjunction with thoracolumbar pain (16%), hindlimb lameness (20%), forelimb lameness (7%) or a combination of problems (10%). Seventy-three horses (99%) had abnormalities of the SI joint region identified using nuclear scintigraphy. Infiltration of local anaesthetic solution around the SI joint region produced profound improvement in gait in all 34 horses in which it was performed. CONCLUSIONS AND POTENTIAL RELEVANCE: Careful clinical examination combined with scintigraphic evaluation of the SI joint region and local analgesia can enable a more definitive diagnosis of SI joint region pain than has previously been possible.
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Turner, J. W. J., & Kirkpatrick, J. F. (1982). Androgens, behaviour and fertility control in feral stallions. J Reprod Fertil Suppl, 32, 79–87.
Abstract: This field study of feral stallions in Montana and Idaho examines and correlates the seasonal pattern of plasma androgens and specific sociosexual behaviour and reports the effect of a long-acting androgenic steroid on this behaviour and on fertility. Plasma testosterone was measured by competitive protein binding assay in samples obtained by jugular venepuncture from captured animals. In samples taken from 34 sexually mature stallions in 6 different months during the year, a definite seasonal pattern in testosterone was present, with a peak in May (3.04 +/- 0.63 ng/ml) and a nadir in December (1.55 +/- 0.34 ng/ml). Values were less than 2.0 ng/ml in non-breeding months and greater than 2.4 ng/ml in breeding months. Behavioural endpoints measured were (1) stallion scent marking in response to elimination by mares (elimination marking), (2) mounting and (3) copulation. The frequencies of each of these endpoints followed closely the seasonal pattern seen for plasma androgens. In the fertility study microcapsulated testosterone propionate (microTP) was administered i.m. to 10 harem stud stallions 3 months before the 1980 breeding season. In these stallions and in 10 control harem studs, the above behavioural endpoints were examined in the 1980 and 1981 breeding seasons, and foal counts were made in 1981. There were no direct inhibitory or stimulatory effects of microTP treatment on any of the behavioural endpoints in either year. In 1981 foals were produced in 87.5% of the control bands and 28.4% of the microTP-treated bands. These results indicate that microencapsulated testosterone propionate can provide effective fertility control in feral horses without causing significant alterations in sociosexual behaviour.
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Weik, H., & Altmann, J. (1972). The effect of L(+)-lactate on rat and horse adipose tissue in vitro. Zentralbl Veterinarmed A, 19(6), 514–518.
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Dargatz, D. A., & Traub-Dargatz, J. L. (2004). Multidrug-resistant Salmonella and nosocomial infections. Vet Clin North Am Equine Pract, 20(3), 587–600.
Abstract: Nosocomial infections are a serious threat to optimum patient care. In addition, nosocomial infections can have far-reaching consequences for the hospital personnel and the financial aspects of the hospital. Nosocomial infections with Salmonella spp have been described among hospitalized equine populations more frequently than any other agent. Salmonella spp associated with hospitalized equids often possess more antimicrobial resistance determinants than do Salmonella spp isolated from healthy horses in the general population. There is little evidence to suggest that resistant salmonellae are more virulent than nonresistant forms. MDR forms of Salmonella complicate the selection of appropriate antimicrobials when they are indicated, however. Furthermore, the use of some antimicrobials may apply selection pressure toward enhanced ability of MDR Salmonella to colonize equine patients. Further research should help to elucidate the risky uses of antimicrobials in the hospital setting and define the role of disinfectants and treatments such as NSAIDs in the ecology of MDR forms of nosocomial infections, including Salmonella. In the meantime, thoughtful selection of when and how to use antimicrobials in equine patients, together with deliberate selection of which antimicrobials to use based on monitoring data and other factors, such as safety and spectrum, is advised.
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Grubb, T. L., Foreman, J. H., Benson, G. J., Thurmon, J. C., Tranquilli, W. J., Constable, P. D., et al. (1996). Hemodynamic effects of calcium gluconate administered to conscious horses. J Vet Intern Med, 10(6), 401–404.
Abstract: Calcium gluconate was administered to conscious horses at 3 different rates (0.1, 0.2, and 0.4 mg/kg/min for 15 minutes each). Serum calcium concentrations and parameters of cardiovascular function were evaluated. All 3 calcium administration rates caused marked increases in both ionized and total calcium concentrations, cardiac index, stroke index, and cardiac contractility (dP/dtmax). Mean arterial pressure and right atrial pressure were unchanged; heart rate decreased markedly during calcium administration. Ionized calcium concentration remained between 54% and 57% of total calcium concentration throughout the study. We conclude that calcium gluconate can safely be administered to conscious horses at 0.1 to 0.4 mg/kg/min and that administration will result in improved cardiac function.
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