Validity and practical utility of accelerometry for the measurement of in-hand physical activity in horses.

BACKGROUND: Accelerometers are valid, practical and reliable tools for the measurement of habitual physical activity (PA). Quantification of PA in horses is desirable for use in research and clinical settings. The objective of this study was to evaluate a triaxial accelerometer for objective measurement of PA in the horse by assessment of their practical utility and validity. Horses were recruited to establish both the optimal site of accelerometer attachment and questionnaire designed to explore owner acceptance. Validity and cut-off values were obtained by assessing PA at various gaits. Validation study- 20 horses wore the accelerometer while being filmed for 10 min each of rest, walking and trotting and 5 mins of canter work. Practical utility study- five horses wore accelerometers on polls and withers for 18 h; compliance and relative data losses were quantified. RESULTS: Accelerometry output differed significantly between the four PA levels (P < 0•001) for both wither and poll placement. For withers placement, ROC analyses found optimal sensitivity and specificity at a cut-off of <47 counts per minute (cpm) for rest (sensitivity 99.5 %, specificity 100 %), 967-2424 cpm for trotting (sensitivity 96.7 %, specificity 100 %) and ≥2425 cpm for cantering (sensitivity 96.0 %, specificity 97.0 %). Attachment at the poll resulted in optimal sensitivity and specificity at a cut-off of <707 counts per minute (cpm) for rest (sensitivity 97.5 %, specificity 99.6 %), 1546-2609 cpm for trotting (sensitivity 90.33 %, specificity 79.25 %) and ≥2610 cpm for cantering (sensitivity 100 %, specificity 100 %) In terms of practical utility, accelerometry was well tolerated and owner acceptance high. CONCLUSION: Accelerometry data correlated well with varying levels of in-hand equine activity. The use of accelerometers is a valid method for objective measurement of controlled PA in the horse.

Feeding practices and the use of supplements for dogs kept by owners in different socioeconomic groups.

The prevalence of feeding practices and supplements for dogs used in private practice (pp) and the non-profit-making People's Dispensary for Sick Animals (pdsa) was evaluated. Questionnaires were completed by 400 pp clients and 400 pdsa clients, of which 27.2 per cent and 29.8 per cent, respectively, gave supplements to their dogs. Fatty acids/oils were given by 10.3 per cent of pp clients and 11.5 per cent of pdsa clients, glucosamine and/or chondroitin by 10.5 per cent and 5.8 per cent, and vitamins by 6.8 per cent and 19.3 per cent, respectively. The supplements were provided daily by 17.8 per cent of the pp clients and 14.3 per cent of the pdsa clients, and the pdsa clients were 50 per cent more likely to provide the supplements only weekly or monthly than the pp clients. A commercially available maintenance or dietetic diet was fed by 98.8 per cent of the pp clients and 94.2 per cent of the pdsa clients.

Comparison of ultrasonography, radiography and a single computed tomography slice for fluid identification within the feline tympanic bulla.

Evaluation of the tympanic bulla (TB) in cases of acute feline otitis media can be a diagnostic challenge, although a feature often associated with this condition is the accumulation of fluid or material within the middle ear cavity. A technique is reported allowing optimum imaging of the feline TB using ultrasound (US) and recording of the appearance of gas and fluid-filled TB. A random number of bullae in 42 feline cadavers were filled with lubricant and rostroventral-caudodorsal oblique radiographs, single slice computed tomography (CT) images and US images were created and interpreted by blinded operators. The content (fluid or gas) of each TB was determined using each technique and the cadavers were then frozen and sectioned for confirmation. CT remained the most accurate diagnostic method, but US produced better results than radiology. Given the advantages of US over other imaging techniques, these results suggest that further work is warranted to determine applications of this modality in the evaluation of clinical cases of feline otitis media.

Impact of canine overweight and obesity on health-related quality of life.

Canine obesity is increasing in prevalence in the UK and raises concerns about dog welfare. This study compares the health-related quality of life (HRQL) of dogs of varying body condition: overweight and obese (BCS 4 and 5) versus non-overweight dogs (BCS 2 and 3), obese (BCS 5) versus non-overweight (BCS 2 and 3) and an overall comparison between all four BCS (BCS 2, 3, 4 and 5) using a novel, validated HRQL instrument which is both web and mobile tablet/phone app based. Of 271 dog owners who were approached, 174 completed a web-based instrument (2013) or a mobile tablet app instrument (2014) during the summers of 2013 and 2014. Automatically generated scores in four domains of HRQL (energetic/enthusiastic, happy/content, active/comfortable, calm/relaxed) were compared for dogs with each of the body condition scores (BCS 2-5). For all body condition scores a statistically significant difference was found between the HRQL scores in two of the domains: energetic/enthusiastic (p=0.02) and active comfortable (p=0.004). When BCS 2 and 3 were compared to BCS 4 and 5, statistical significance was found in the same two domains - energetic/enthusiastic (p=0.01) and active comfortable (p=0.001) - as it was in comparison of non-overweight (BCS 2 and 3) compared to obese dogs (BCS 5): energetic/enthusiastic (p=0.012) and active comfortable (p=0.004). These results suggest that overweight and obese dogs have a reduced HRQL in two of the domains compared to non-overweight dogs, and that differences in HRQL are detectable between BCS scores 2, 3, 4 and 5.

Ultrasonographic assessment of the rate of solid-phase gastric emptying in dogs.

Twelve healthy dogs were used in an ultrasonographic assessment of the effect of the composition of a solid meal on the rate of gastric emptying. The dogs were fasted for nine hours before they were fed either a standard or a high energy density test meal, in a cross-over study design. The gastric antrum was visualised with a 6.5 MHz microconvex transducer, and the area inside the elliptical shape defined by the craniocaudal and ventrodorsal diameters of the stomach was measured. Antral images were acquired at regular intervals for six hours after the ingestion of the test meal. Three indices to describe the rate of gastric emptying were computed: the gastric half-emptying time (t1/2), the time to 50 per cent maximal antral area (t50%), and the time of maximal antral area (tmax). The values of t50% and t1/2 calculated for the high energy density meals were significantly longer than for the standard meals, but there was no significant difference between the tmax values.

Effects of changes to the stable environment on the exhalation of ethane, carbon monoxide and hydrogen peroxide by horses with respiratory inflammation.

The aim of this study was to assess the effects of changes to the stable environment on exhaled markers of respiratory inflammation in six horses with clinical histories of recurrent airway obstruction. The horses were maintained for two weeks under conventional stable management (straw bedding and hay) and for two weeks on a reduced-dust regimen (paper bedding and ensiled grass), in a crossover study design. Exhaled ethane and carbon monoxide (CO) and exhaled breath condensate hydrogen peroxide (H(2)O(2)) were measured every three days under each regimen. The presence of clinical signs of airway inflammation (nasal discharge and cough) was monitored daily. The reduced-dust regimen was associated with fewer clinical signs of airway inflammation than the conventional regimen. Exhaled ethane and CO were significantly lower on the reduced-dust regimen and these markers were correlated with clinical signs of respiratory inflammation, but exhaled H(2)O(2) was not affected by the management regimen.

NMDA receptor blockade fails to alter axonal injury in focal cerebral ischemia.

The ability of the NMDA receptor antagonist, MK-801, to protect myelinated axons after focal cerebral ischemia has been examined. Amyloid precursor protein (APP) immunocytochemistry was used to assess the anatomic extent of axonal injury, and conventional histopathology was used to assess the volume of ischemic damage to neuronal perikarya. The middle cerebral artery was permanently occluded in 16 cats. The cats were treated with either vehicle or MK-801 as a 0.5-mg/kg bolus at 15 minutes before middle cerebral artery occlusion, followed by an infusion of 0.14 mg/kg per hour. After 6 hours, the animals were killed and the brains processed for histology and immunocytochemistry. The volume of neuronal necrosis was determined from 16 preselected coronal levels of the brain. The circumscribed zones of APP accumulation in axons were mapped onto images at the same 16 coronal levels, and quantitative analysis was performed using a transparent counting grid, randomly placed over each image. The histologic appearance and anatomic location of axons with increased APP immunoreactivity was similar in animals treated with vehicle and MK-801. MK-801 failed to reduce the hemispheric APP score significantly. In vehicle-treated animals, there was a significant association between the volume of neuronal necrosis and the amount of APP immunoreactivity. MK-801 significantly reduced the slope of the association between the volume of neuronal necrosis and the amount of APP immunoreactivity compared with that observed in vehicle-treated animals. As a result, the ratio of hemispheric APP score and volume of neuronal necrosis was significantly increased with MK-801 treatment. The inability of NMDA receptor antagonists to protect axons may limit their functional efficacy in improving functional outcome after stroke.

Axonal injury caused by focal cerebral ischemia in the rat.

The susceptibility of axons to blunt head injury is well established. However, axonal injury following cerebral ischemia has attracted less attention than damage in gray matter. We have employed immunocytochemical methods to assess the vulnerability of axons to cerebral ischemia in vivo. Immunocytochemistry was performed using antibodies to a synaptosomal-associated protein of 25 kDa (SNAP25), which is transported by fast anterograde transport; the 68-kDa neurofilament subunit (NF68kD); and microtubule-associated protein 5 (MAP5) on sections from rats subjected to 30 min and 1, 2, and 4 h of ischemia induced by permanent middle cerebral artery (MCA) occlusion. After 4 h of occlusion, there was increased SNAP25 immunoreactivity, which was bulbous in appearance, reminiscent of the axonal swellings that occur following blunt head injury. Increased SNAP25 immunoreactivity was present in circumscribed zones in the subcortical white matter and in the axonal tracts at the border of infarction, a pattern similar to that previously described for amyloid precursor protein. Although less marked, similar changes in immunoreactivity in axons were evident following 2 h of ischemia. MAP5 and NF68kD had striking changes in immunoreactivity in axonal tracts permeating the caudate nucleus within the MCA territory at 4 h. The appearance was roughened and disorganized compared with the smooth regular staining in axons within the nonischemic areas. Profiles reminiscent of axonal bulbs were evident in MAP5-stained sections. The changes seen with NF68kD and MAP5 were also evident at 2 h but were more subtle at 1 h. There were no changes in axonal immunoreactivity with SNAP25 or NF68kD at 30 min after MCA occlusion. Altered immunoreactivity following ischemia using SNAP25, MAP5, and NF68kD provides further evidence for the progressive breakdown of the axonal cytoskeleton following an ischemic insult. NF68kD and MAP5 appear to be sensitive markers of the structural disruption of the cytoskeleton, which precedes the subsequent accumulation of SNAP25 within the damaged axons. Axonal cytoskeletal breakdown and disruption of fast axonal transport, which are well-recognized features of traumatic brain injury, are also sequalae of an ischemic insult.

Amyloid precursor protein accumulates in white matter at the margin of a focal ischaemic lesion.

Amyloid precursor protein (APP) is transported by fast anterograde axonal transport. Since disruption of this transport results in APP accumulation, APP has been proposed as a sensitive marker of axonal injury. In the present study, axonal injury in subcortical white matter and myelinated fibre tracts permeating the striatum, 24 h after permanent middle cerebral artery occlusion in the rat, has been examined by assessing the location and extent of APP immunoreactivity. Increased APP immunoreactivity was present in both areas. This was localised to a circumscribed zone immediately adjacent to the boundary of the ischaemic lesion in grey matter. The amount of APP immunoreactivity was associated with the volume of the ischaemic lesion in individual animals. Increased APP immunoreactivity in subcortical white matter and myelinated fibre tracts at the margin of the ischaemic zone may prove to be a valuable marker for assessing strategies to protect axons after an ischaemic insult.

Topographical and quantitative assessment of white matter injury following a focal ischaemic lesion in the rat brain.

Axonal injury following cerebral ischaemia has attracted less attention than damage in grey matter. However, it is becoming increasingly recognised that axons are highly vulnerable to focal ischaemia [D. Dewar, D.A. Dawson, Changes of cytoskeletal protein immunostaining in myelinated fibre tracts after focal cerebral ischaemia in the rat, Acta. Neuropathol., 93 (1997) 71-77] [2]; [L. Pantoni, J.H. Garcia, J.A. Gutierrez, Cerebral white matter is highly vulnerable to ischemia, Stroke, 27 (1996) 1641-1647] [10]; [P. S. Yam, T. Takasago, D. Dewar, D.I. Graham, J. McCulloch, Amyloid precursor protein accumulates in white matter at the margin of a focal ischaemic lesion, Brain Res., 760 (1997) 150-157] [15]. Since white matter does not contain neuronal cell bodies or synapses it is likely that the mechanisms of injury and strategies for its protection are different from those in grey matter. In order that the effect of therapeutic intervention on the protection of axons can be assessed, a method by which axonal injury can be mapped and quantified is required. For this purpose, we investigated immunocytochemical methods using amyloid precursor protein (APP) following permanent middle cerebral artery occlusion in the rat. APP is transported by fast anterograde axonal transport [E.H. Koo, S.S. Sisodia, D.R. Archer, L.J. Martin, A. Weidemann, K. Beyreuther, P. Fischer, C.L. Masters, D.L. Price, Precursor of amyloid protein in Alzheimer disease undergoes fast anterograde axonal transport, Proc. Natl. Acad. Sci. U.S.A. 87 (1990) 1561-1565] [7] and has been shown to accumulate following a variety of insults to axons, indicative of dysfunction of axonal transport [R.N. Kalaria, S.U. Bhatti, E.A. Palatinsky, D.H. Pennington, E.R. Shelton, H.W. Chan, G. Perry, W.D. Lust, Accumulation of the beta amyloid precursor protein at sites of ischemic injury in rat brain, Neuroreport, 4 (1993) 211-214] [4]; [T. Kawarabayashi, M. Shoji, Y. Harigaya, H. Yamaguchi, S. Hirai, Expression of APP in the early stage of brain damage, Brain Res., 563 (1991) 334-338] [5]; [N. Otsuka, M. Tomonaga, K. Ikeda, Rapid appearance of beta-amyloid precursor protein immunoreactivity in damaged axons and reactive glial cells in rat brain following needle stab injury, Brain Res., 568 (1991) 335-338] [9]; [K. Shigematsu, P. L. McGeer, Accumulation of amyloid precursor protein in neurons after intraventricular injection of colchicine, Am. J. Pathol., 140 (1992) 787-794] [12]. We have been able to map the topographical relationship between APP accumulation and region of infarction using immunocytochemistry and image analysis techniques. Additionally, using a semi-quantitative scoring system, we have demonstrated that there is a relationship between the amount of APP accumulation and the volume of infarction following middle cerebral artery occlusion. These methods will be useful in the future for the assessment of therapeutic interventions on the protection of axons following ischaemic injury.

A comparison of the rate of recovery of 13CO2 in exhaled breath with 2H in body water following ingestion of [2H/13C]octanoic acid in a dog.

The objective of this study was to assess post-gastric processing of octanoic acid (OA) by comparing the rate of recovery of 13C in breath with the rate of recovery of 2H in saliva following ingestion of [2H/13C]OA. A test meal with 100mg [13C]OA and 750 mg [2H]OA was ingested on two separate occasions by one dog. Exhaled breath and saliva samples were collected at set time points for 6h following ingestion of the test meal. Two indices were computed, half recovery time (t(1/2)) and the time of peak excretion (t(max)). Recovery of 2H in saliva was quicker than recovery of 13C in breath as determined by the difference in the indices for each isotope; 1.33 and 1.59 h for t(1/2) and t(max), respectively. These findings suggest that the post-gastric processing of OA imposes a delay on the recovery of 13C in breath in the dog, as occurs in man and in the horse.

Validation of a method for collection and assay of pentane in the exhaled breath of the horse.

Oxidative stress refers to an imbalance between the production of oxidising free radicals and the antioxidant defenses of the cell, and is associated with many pathogenic processes. Oxidative damage to cellular lipids results in the evolution of pentane and ethane gas, and detection of these hydrocarbons in the exhaled breath can be used to monitor in vivo oxidative stress. The aim of this study was to validate a gas chromatography (GC) method for measurement of breath pentane in the horse. The GC-system developed showed good specificity for discrimination of pentane from other breath hydrocarbons, and was sensitive to 0.5 ppb pentane. Pentane was detected in the exhaled breath of five horses investigated on two occasions. The results of this preliminary study demonstrate that breath pentane can be measured in the horse, and further work is now justified to investigate the feasibility of applying this method for monitoring in vivo oxidative stress in the horse.

A review of methods for assessment of the rate of gastric emptying in the dog and cat: 1898-2002.

Gastric emptying is the process by which food is delivered to the small intestine at a rate and in a form that optimizes intestinal absorption of nutrients. The rate of gastric emptying is subject to alteration by physiological, pharmacological, and pathological conditions. Gastric emptying of solids is of greater clinical significance because disordered gastric emptying rarely is detectable in the liquid phase. Imaging techniques have the disadvantage of requiring restraint of the animal and access to expensive equipment. Radiographic methods require administration of test meals that are not similar to food. Scintigraphy is the gold standard method for assessment of gastric emptying but requires administration of a radioisotope. Magnetic resonance imaging has not yet been applied for assessment of gastric emptying in small animals. Ultrasonography is a potentially useful, but subjective, method for assessment of gastric emptying in dogs. Gastric tracer methods require insertion of gastric or intestinal cannulae and are rarely applied outside of the research laboratory. The paracetamol absorption test has been applied for assessment of liquid phase gastric emptying in the dog, but requires IV cannulation. The gastric emptying breath test is a noninvasive method for assessment of gastric emptying that has been applied in dogs and cats. This method can be carried out away from the veterinary hospital, but the effects of physiological and pathological abnormalities on the test are not known. Advances in technology will facilitate the development of reliable methods for assessment of gastric emptying in small animals.

Use of the 13C-octanoic acid breath test for assessment of solid-phase gastric emptying in dogs.

OBJECTIVE: To assess the 13C-octanoic acid breath test for determining gastric emptying in dogs. ANIMALS: 6 healthy adult dogs. PROCEDURE: Food was withheld for 12 hours before each test. Expired air was collected 30 minutes and immediately before each test and at frequent intervals thereafter for 6 hours. Concentration of 13CO2 in expired air was determined by use of continuous-flow isotope-ratio mass spectrometry. Basal concentration of 13CO2 was measured in dogs that were not fed a test meal. Effects of the standard unlabeled test meal on basal concentration of 13CO2 were then assessed. The optimum dose of substrate was determined by measuring 13CO2 concentration after ingestion of the standard test meal containing 50 or 100 mg of 13C-octanoic acid, whereas effect of energy density of the test meal on gastric emptying was determined after ingestion of the standard or high-energy labeled test meal. Gastric emptying coefficient (GEC), time to peak 13CO2 concentration (tmax), and half-dose recovery time (t(1/2)) were calculated. RESULTS: Basal concentration of 13CO2 in expired air was not significantly affected by ingestion of the unlabeled test meal. However, 13CO2 concentration significantly increased in a dose-dependent manner after ingestion of the labeled meal. Gastric emptying coefficient, and were significantly different between dogs fed the standard and high-energy test meals, indicating that ingestion of a high-energy meal delays gastric emptying. CONCLUSIONS AND CLINICAL RELEVANCE: The 13C-octanoic acid breath test may be a useful noninvasive and nonradioactive method for assessment of gastric emptying in dogs.

Current and future uses of breath analysis as a diagnostic tool.

The analysis of exhaled breath is a potentially useful method for application in veterinary diagnostics. Breath samples can be easily collected from animals by means of a face mask or collection chamber with minimal disturbance to the animal. After the administration of a 13C-labelled compound the recovery of 13C in breath can be used to investigate gastrointestinal and digestive functions. Exhaled hydrogen can be used to assess orocaecal transit time and malabsorption, and exhaled nitric oxide, carbon monoxide and pentane can be used to assess oxidative stress and inflammation. The analysis of compounds dissolved in the aqueous phase of breath (the exhaled breath condensate) can be used to assess airway inflammation. This review summarises the current status of breath analysis in veterinary medicine, and analyses its potential for assessing animal health and disease.

Megaoesophagus secondary to acquired myasthenia gravis.

Fifteen dogs with confirmed adult onset idiopathic megaoesophagus, in which no generalised muscle weakness was observed, were tested for the presence of acetylcholine receptor antibodies. Of these, six were found to have values greater than 0.6 nmol/litre, previously determined to be diagnostic of acquired myasthenia gravis. The mean serum titre value for these dogs was 5.59 nmol/litre (range 0.78 to 8.72 nmol/litre). It appears that a significant proportion of dogs presenting with megaoesophagus have myasthenia gravis and, if a prompt diagnosis and appropriate treatment can be instituted, clinical signs may improve.

Cessation of feline calicivirus shedding coincident with resolution of chronic gingivostomatitis in a cat.

Feline calicivirus (FCV) shedding and oral bacterial flora were monitored over a period of 22 months in a case of feline gingivostomatitis (FGS). The cat was treated daily with 50 mg thalidomide capsules by mouth, and 200 mg lactoferrin powder was applied directly to the lesions. Clinical signs began to resolve after 11 months when, in addition to treatment, the diet had been changed to an additive-free cat food supplemented with antioxidant vitamins A, D3 and E. Resolution of clinical signs of FGS coincided with the cessation of FCV shedding, and this is the first report documenting such an association. Which part of the treatment, if any, contributed to the cure requires further investigation.

Effect of body size on gastric emptying using the 13C-octanoic acid breath test.

The 13C-octanoic acid breath test (OABT) may be a useful non-invasive method for assessing the rate of gastric emptying in dogs. The aim of this study was to determine whether an association exists between body size and rate of gastric emptying in dogs. Fifty-five dogs ranging from 6 to 39 kg were recruited and rate of gastric emptying was assessed using the OABT. The time to peak 13CO2 excretion (tmax) and half-dose recovery time (t1/2) were calculated. The OABT was simple to perform and well tolerated by the dogs. Mean (sd) tmax was 2.67 hours (0.6) and mean t1/2 was 3.38 hours (0.79). Inter-individual variation in the rate of gastric emptying was 23.3 per cent for t1/2 and 22.5 per cent for tmax. No association was detected between the rate of gastric emptying and body surface area, mass, age, sex or test operator. The OABT may be a useful non-invasive and non-radioactive test for assessment of the rate of gastric emptying in dogs in clinical practice.

A 6-month observational study of changes in objectively measured physical activity during weight loss in dogs.

OBJECTIVES: To evaluate long-term changes in physical activity and sedentary behaviour during weight loss in dogs. METHODS: Sixteen overweight and obese dogs undergoing a 6-month calorie-controlled weight-loss programme wore Actigraph GT3X accelerometers (Actigraph, FL) for three consecutive days each month for the duration of the programme. Total volume of physical activity and time spent in sedentary behaviour, light-moderate intensity physical activity and vigorous intensity physical activity were extracted from the accelerometer data and compared from baseline to month 6. RESULTS: Valid accelerometry data were returned for 14 of 16 dogs. Mean percentage weight loss over 6 months was 15% of initial bodyweight. There was no marked increase in any of the physical activity outcomes or reduction in sedentary behaviour. CLINICAL SIGNIFICANCE: Substantial weight loss was not associated with a spontaneous increase in physical activity or reduction in sedentary behaviour. Although the dogs in this study lost a substantial amount of bodyweight without a measured increase in physical activity, dog owners should still be encouraged to facilitate increased physical activity in their dogs owing to the wide range of benefits associated with physical activity other than weight loss.

Associations between obesity and physical activity in dogs: a preliminary investigation.

OBJECTIVES: To assess whether obesity has any association with objectively measured physical activity levels in dogs. METHODS: Thirty-nine dogs wore Actigraph GT3X accelerometers (Actigraph) for 7 consecutive days. Each dog was classified as ideal weight, overweight or obese using the 5-point body condition scoring system. Total volume of physical activity and time spent in sedentary behaviour, light-moderate intensity physical activity and vigorous intensity physical activity were compared between body condition categories. RESULTS: Valid accelerometry data were returned for 35 of 39 dogs recruited. Eighteen dogs were classed as ideal weight, 9 as overweight and the remaining 8 as obese. All dogs spent a significant proportion of the day sedentary and obese dogs spent significantly less time in vigorous intensity physical activity than ideal weight dogs (7 ±3 minute/day versus 21 ±15 minute/day, P=0·01). CLINICAL SIGNIFICANCE: Obesity is associated with lower vigorous intensity physical activity in dogs, as is also thought to occur in humans. These preliminary findings will help inform a future, larger study and may also improve our understanding of the associations between obesity and physical activity in dogs.