United Kingdom

Drug Resistant Cyathostomins in Donkey Herds; Lessons in Management for All Equids

Citation

Andrew F. Trawford, Faith A. Burden. 23 October 2012. Drug Resistant Cyathostomins in Donkey Herds; Lessons in Management for All Equids. Presented at International Conference on Equine Infectious Diseases IX. (21 October - 26 October 2012). Kentucky, USA.

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Date presented: 
Tuesday 23 October 2012
Abstract

The Donkey Sanctuary has over 2500 donkeys on its farms in the UK. Endoparasite control in these herds has been a major focus for the last 10 years. Monitoring of the herds has identified significant levels of anthelmintic resistance in the cyathostomins parasitising the donkey herds. Lack of efficacy of ivermectin, moxidectin, pyrantel and fenbendazole has been identified on multiple sites and in a number of cases treatment of donkeys harbouring such parasites is becoming increasingly challenging. Changes in management practices and approach to parasite treatment is discussed. Research to establish the extent of drug resistance and clinical significance of parasitism in donkeys is of primary concern; projects have focussed on identification of drug resistance, impacts of pasture management, validation of thresholds of faecal egg counts for treatment and alternatives to anthelmintics. Significant changes in management practices have been based upon results of these studies and new ideas and techniques are being developed. Treatment of all donkeys is carried out on the basis of a strongyle faecal egg count which is carried out on a 4-weekly basis throughout the year. Preliminary data and clinical experience has shown that increasing the FEC treatment threshold for healthy, mature donkeys to ≥ 1000 strongyle epg is sufficient to control clinical disease whilst reducing pasture contamination. Application of new treatment thresholds have reduced the reliance on chemical treatment. The mean number of anthelmintic treatments per year per animal was one in 2011; this is a significant reduction from previous dosing regimes where animals would be treated a minimum of four times per year. Animals are monitored frequently with problematic herds being 100% sampled every four weeks; such monitoring allows individualised treatment programmes and highlights reduced egg reappearance periods early. Reduced ERPs are investigated immediately with suspect animals undergoing a faecal egg count reduction test (FECRT) at the next treatment. Failed FECRTs trigger an alternative approach to treatment and further investigation. It is evident that some individual cases are becoming increasingly difficult to treat effectively; future trials of combinations of anthelmintics are being considered. Effective parasite control has also led to an increased emphasis on pasture management; dung is closely managed and carefully composted. Pasture is also rested in 6 month blocks with mixed species grazing instigated where possible. Good pasture management practices produce significant drops in pasture larval counts and is the primary mechanism used to reduce parasitism. Research and practical experience has emphasised the importance of good pasture management, treatment based upon faecal egg counts and routine assessment of efficacy of treatment. Researching and trialling higher dosing threshold has also led to significant decreases in the reliance of the organisation on anthelmintics with no recorded clinical effects. The lessons learnt from management of these large herds of donkeys may provide salient and important foundations for future equid herds that undoubtedly will experience similar problems in the future.

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A novel approach to pain recognition in donkeys

Citation

Gabriela Olmos, Faith A. Burden. 26 August 2012. A novel approach to pain recognition in donkeys. Presented at 14th World Congress on Pain, Sattelite Symposia: Pain and Pain Management in Non-Human Species. (27 August - 31 August 2012). Milan, Italy.

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Date presented: 
Sunday 26 August 2012
Abstract

Pain due lesions and clinical conditions is one of the main welfare concerns of the more than 42 millions donkeys that presently exist in the world. Yet, the knowledge to gauge pain in donkeys is lacking, misunderstood and/or not validated (Ashley, 2005).

Pain (yes/no/uncertain) and its severity (VAS; no pain=0 to worst pain=100mm) was assessed in 403 donkeys’ ante-mortem (ATM) and post-mortem (PTM). Also behaviours/signs (BS) and pain related lesions (PRL) were assessed ATM and PTM, respectively. Using principal component analysis the more than 53 BS and 238 PRL observed were narrowed to 58 biologically meaningful component or groups (14 BS and 44 PRL components, respectively). Components were used as risk factors in multiple regression analysis to identify which BS and/or PRL are commonly used in clinician’s (veterinary/pathologist) decision making process to determine whether a donkey ‘is’ (i.e. ATM) or ‘was’ (i.e. PTM) in pain and its severity (mild to severe). Furthermore, multiple correlations were made to understand which BS relate significantly with specific PRL and how.

A cross tabulation between pain ATM and PTM, where pain related lesions are used as a quasi-gold standard of pain assessment; identify that 2 in 10 donkeys are wrongly assumed as in NO-PAIN. Moreover, only 43% of the donkey observations are used by clinicians to make their opinion on donkey pain and its severity (i.e. 7 BS and 18 PRL components were significantly associated with pain as stated by clinicians). Yet, multiple correlations showed 20 plausible biologically meaningful relationships between BS and PRL; some currently not used by clinicians.

This methodology, previously successfully used in humans (Gregory, 2010) is novel to donkey veterinary medicine and warrants further research to consolidate findings. Nonetheless, the achieved correlation list of behaviours vs. pathologies is a significant work with valid applications in donkey pain identification and prognosis.

Ashley FH, Waterman-Pearson AE, Whay HR (2005) Behavioural assessment of pain in horses and donkeys: application to clinical practice and future studies, Equine Vet J, 37(6), 565 - 575.

Gregory NG (2010) Relationships between pathology and pain severities: a review. Animal Welfare 19, 437-448.

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The effect of pasture restriction on dry matter intake by foraging donkeys in the UK

Citation

Stephanie J. Wood, David Smith, Catherine J. Muir, J. Oliver, Derek Cuddeford. 30 October 2006. The effect of pasture restriction on dry matter intake by foraging donkeys in the UK. Presented at 5th International Colloquium on Working Equines. (30 October - 2 November 2006). Addis Ababa, Ethiopia.

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Date presented: 
Monday 30 October 2006
Abstract

Measuring daily food intake of foraging animals is essential if accurate feeding rations are to be implemented. The alkane technique, which has recently been validated in equines, now provides the opportunity to measure intake at pasture. The aims of this study were to determine the effects of herbage mass and grazing time allowance on dry matter intakes in mature donkeys in the UK. The effect of grazing time allowance on diet composition was also measured. Two study periods took place; period 1 when pasture was sparse (herbage mass 133.1±10 g dry matter/m2) and period 2 when pasture was more abundant (herbage mass 284.5±17.2 g dry matter/m2). Eighteen mature donkeys, male and female, were selected for the study and split into three grazing groups. Groups 1 and 2 were restricted to 8 and 12 hours grazing time per day, respectively. Group 3 was allowed 23 hours grazing time daily. Access to a yarded area and shelter was available to all donkeys during grazing periods. Barley straw was fed ad libitum to all donkeys and was available at all times. Each donkey was administered with 150 mg per day of an n-alkane marker Dotriacontane (C32) in the form of a labelled wheat biscuit fed three times daily for the 12 days of each study period. During period 1 grazing time allowance had no significant effect on daily DMI although the donkeys with 23 hours access did consume more than donkeys with only 12 and 8 hours grazing access (2.61, 2.54 and 2.26 kg, respectively). The proportion of grass and straw comprising daily intake was affected by grazing time allowance (P<0.05). Grass comprised 18% of daily intake for the 8 and 12-hour groups and 11% in the diet of the 23-hour group, although this difference was not significant. During period 2 daily DMI remained unaffected by grazing time allowance. The proportions of grass and straw within the diet were significantly affected (P<0.001), grass comprised 25 and 29% of daily intake for the 8 and 12-hour groups but made up 41% of daily intake of the 23-hour group. These results show that grazing time allowance has little effect on overall DMI but when given the opportunity donkeys increase their grass intake.

Proceedings
Publisher: 
The Brooke
Publication date: 
30 October 2006

Seasonal variation of digestible energy requirements of mature donkeys in the UK

Citation

Stephanie J. Wood, David Smith, Catherine J. Muir, Derek Cuddeford. 30 October 2006. Seasonal variation of digestible energy requirements of mature donkeys in the UK. Presented at 5th International Colloquium on Working Equines. (30 October - 2 November 2006). Addis Ababa, Ethiopia.

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Date presented: 
Monday 30 October 2006
Abstract

At present there are no published feeding guidelines specific to donkeys. Current recommendations are to feed 0.75 of horse energy needs on a body weight basis. However, it has been shown that donkeys have a greater digestive efficiency than horses and ponies and thus, feeding them as though they were small horses results in excess energy intake and, as a consequence they become obese. The formation of feeding guidelines begins with the estimation of the energy requirement for maintenance, as this is the value upon which nutrient requirements are related to. The aim of the study was to determine the maintenance digestible energy requirements of mature donkeys during each UK season. Twenty mature donkeys (10 male, 10 female) were selected for use in the study. The donkeys were fed a diet of hay and barley straw in quantities that were adjusted to maintain body weight. An equilibration period of minimum 16 days was followed by a five day total faecal collection; this was carried out for each season. Food and faecal samples were analysed for dry matter (DM), organic matter (OM), digestible energy (DE), crude protein (CP), neutral-detergent fibre (NDF) and acid-detergent fibre (ADF); nutrient and energy intakes were calculated. There was a significant seasonal effect on all intakes except NDF and ADF. DM and DE intakes showed significant increases in winter compared to summer, rising by 42 and 35%, respectively. Digestible crude protein (DCP) intakes increased during winter and spring but were significantly lower in autumn compared to all other seasons. A strong seasonal effect was exerted on all in vivo digestibilities although there was no effect of sex. OM, NDF and ADF intakes were affected by sex with male animals having higher intakes compared to female animals. Comparison of these results with NRC (1989) horse requirements showed a considerably reduced requirement by donkeys for energy and protein and thus it was concluded that feeding tables specific to horses are not suitable for calculating donkey requirements.

Proceedings
Publisher: 
The Donkey Sanctuary
Publication date: 
30 October 2006

Normal donkey dental anatomy

Citation

Nicole du Toit, Susan A. Kempson, Padraic M. Dixon. 30 October 2006. Normal donkey dental anatomy. Presented at 5th International Colloquium on Working Equines. (30 October - 2 November 2006). Addis Ababa, Ethiopia.

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Date presented: 
Monday 30 October 2006
Abstract

This study examined normal donkey teeth using gross anatomical inspection, computed axial tomography (CAT), radiography, scanning electron microscopy (SEM) and, decalcified and undecalcified histology to determine their normal gross anatomy, histology and ultrastructure. CAT findings have shown donkey endodontic anatomy and the density (in Hounslow units) of donkey calcified dental tissues, i.e. enamel, dentine and cementum to be similar to values recorded in horses. Decalcified and undecalcified histology has identified donkey cheek teeth to have a similar histological appearance to that which has been described in the horse. SEM of donkey dental tissue has demonstrated minor differences to normal horse dental ultrastructure. Now that normal donkey dental anatomy has been clearly defined, pathological changes can be identified in diseased teeth and supporting structures and will allow a better understanding of the pathophysiology of common donkey dental disorders. Ultimately the results of this project will enable better dental care specifically developed for donkeys, promoting welfare in the donkey.

Proceedings
Publisher: 
The Donkey Sanctuary
Publication date: 
30 October 2006

Development of a quantitative multivariable radiographic method to evaluate anatomic changes associated with laminitis in the forefeet of donkeys

Citation

Simon N. Collins, Sue J. Dyson, Rachel C. Murray, Richard Newton, Faith A. Burden, Andrew F. Trawford. August 2012. Development of a quantitative multivariable radiographic method to evaluate anatomic changes associated with laminitis in the forefeet of donkeys. American Journal of Veterinary Research. 73:8. 1207-1218.

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Publication date: 
8 August 2012
Volume: 
73
Issue: 
8
Page numbers: 
1207-1218
DOI number: 
10.2460/ajvr.73.8.1207
Abstract

Objective—To establish and validate an objective method of radiographic diagnosis of anatomic changes in laminitic forefeet of donkeys on the basis of data from a comprehensive series of radiographic measurements.

Animals—85 donkeys with and 85 without forelimb laminitis for baseline data determination; a cohort of 44 donkeys with and 18 without forelimb laminitis was used for validation analyses.

Procedures—For each donkey, lateromedial radiographic views of 1 weight-bearing forelimb were obtained; images from 11 laminitic and 2 nonlaminitic donkeys were excluded (motion artifact) from baseline data determination. Data from an a priori selection of 19 measurements of anatomic features of laminitic and nonlaminitic donkey feet were analyzed by use of a novel application of multivariate statistical techniques. The resultant diagnostic models were validated in a blinded manner with data from the separate cohort of laminitic and nonlaminitic donkeys.

Results—Data were modeled, and robust statistical rules were established for the diagnosis of anatomic changes within laminitic donkey forefeet. Component 1 scores ≤ −3.5 were indicative of extreme anatomic change, and scores from −2.0 to 0.0 denoted modest change. Nonlaminitic donkeys with a score from 0.5 to 1.0 should be considered as at risk for laminitis.

Conclusions and Clinical Relevance—Results indicated that the radiographic procedures evaluated can be used for the identification, assessment, and monitoring of anatomic changes associated with laminitis. Screening assessments by use of this method may enable early detection of mild anatomic change and identification of at-risk donkeys.

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The effect of pasture restriction on dry matter intake of foraging donkeys in the UK

Citation

Stephanie J. Wood, David Smith. 20 June 2012. The effect of pasture restriction on dry matter intake of foraging donkeys in the UK. Presented at 6th European Workshop on Equine Nutrition. (20 June - 22 June 2012). Lisbon, Portugal.

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Presentation details
Date presented: 
Wednesday 20 June 2012
Abstract

Anecdotal evidence from animal charities indicates that the number of overweight donkeys in the UK is increasing. Donkeys commonly have daily access to pasture therefore knowledge of grass intake is essential if feeding advice is to be relevant. The effects of herbage mass and length of grazing time on diet composition and dry matter intake (DMI) by mature donkeys were determined.

There were two measurement periods: period 1 during autumn when pasture was sparse (herbage mass 92 + 7g DM/m2) and period 2 during summer when pasture was more abundant (herbage mass 197 + 12g DM/m2). Twenty mature donkeys were selected and split into three grazing groups (8, 12 and 23 h daily grazing access). Barley straw was fed ad libitum and each donkey was given 150mg per day of an n-alkane marker Dotriacontane (C32) for the 12 d of each study period.
Herbage mass significantly affected total DMI and diet composition. During summer DMI of donkeys in the 8 and 23h groups was significantly greater than during autumn (P<0.05). The proportion of grass in the diets of all donkeys was also greater in summer compared to autumn (P<0.001). Grazing time did not significantly influence total daily DMI during either season due to donkeys consuming more straw when grass intake was reduced. Restricting donkeys to 12h or less grazing per day in summer significantly (P<0.001) reduced their grass intake compared to that of donkeys with 23h access. When grazing sparse pastures (autumn) time allowed for grazing did not influence grass intake. The results show that time allowed for grazing per se was less important than the herbage mass available to the donkey in terms of grass DMI.

Mind the gap: Spatial perseveration by horses, donkeys and mules in a simple detour task

Citation

Britta Osthaus, Faith A. Burden, Ian Hocking, Leanne Proops. 28 June 2012. Mind the gap: Spatial perseveration by horses, donkeys and mules in a simple detour task. Presented at ASAB Interdisciplinary Workshop: Physical Cognition and Problem Solving. (27 June - 28 June 2012). Birmingham, UK.

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Date presented: 
Thursday 28 June 2012
Abstract

We compared spatial problem solving abilities in the mule (Equus asinus x Equus caballus) with that of its parent species to assess the effects of hybridization on cognition. In a detour task the animals(N=48) were required to make a detour through a gap at one end of a straight barrier in order to reach a visible target. After one, two, three or four repeats (A trials), the gap was moved to the opposite end of the barrier (B trials) and deviations from the straight line and the latency to crossing the barrier were recorded. Mules performed significantly above chance level on their first detour, unlike the other two species. We discuss our results with reference to hybrid vigour and to the flexibility of problem solving strategies with regards to species differences.

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Social relations in a mixed group of mules, ponies and donkeys reflect differences in equid type

Citation

Leanne Proops, Faith A. Burden, Britta Osthaus. May 2012. Social relations in a mixed group of mules, ponies and donkeys reflect differences in equid type. Behavioural Processes.

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Publication date: 
10 May 2012
DOI number: 
http://dx.doi.org/10.1016/j.beproc.2012.03.012
Abstract

Donkeys and mules are frequently kept as companion animals for horses and ponies, with these different equids often being considered a homogenous group. However, the extent to which domestic equids form inter-specific bonds and display similar social behaviour when living in a mixed herd has not previously been studied. Here we compare the social organization of these three (sub)species when housed together, providing the first systematic analysis of how genetic hybridization is expressed in the social behaviour of mules. A group of 16 mules, donkeys and ponies was observed for 70 h and preferred associates, dominance rank and the linearity of the group’s hierarchy was determined. The different equids formed distinct affiliative groups that were ordered in a linear hierarchy with ponies as the most dominant, mules in the middle ranks and donkeys in the lowest ranks. Within each equid subgroup, the strength of the hierarchy also varied. Thus in the present study, the three (sub)species displayed different social organization and levels of dominance and preferred to associate with animals of the same equid type, given the opportunity. These results suggest that different domestic equid (sub) species display variations in social behaviour that are likely to have a strong genetic basis.

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Pyrethroid tolerance in the chewing louse bovicola (werneckiella)

Citation

Lauren Ellse, Faith A. Burden, Richard Wall. May 2012. Pyrethroid tolerance in the chewing louse bovicola (werneckiella). Veterinary Parasitology.

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Publication date: 
1 May 2012
DOI number: 
doi:10.1016/j.vetpar.2012.03.018
Abstract

Equine pediculosis is a significant health and welfare issue, particularly in elderly and
chronically debilitated animals. Currently infestation is controlled predominantly using
topically applied pyrethroid insecticides, allowing limited scope for the rotation of drugs and increasing the risk of selection for resistance. Here the insecticidal efficacies of two pyrethroid-based products against the louse Bovicola (Werneckiella) ocellatus collected from donkeys were examined in vitro. The products were cypermethrin (DeosectTM, Pfizer Ltd., 5% (w/v) cypermethrin, cutaneous spray) and permethrin (SwitchTM, VetPlus Ltd., 4% (w/v) permethrin, pour-on). The pyrethroid efficacy was contrasted with that of the organophosphate diazinon, since the louse populations examined were unlikely to have had prior exposure to this compound. The efficacy of diluted pure permethrin, the excipient, butyl dioxitol and the synergist piperonyl butoxide in the presence of the pyrethroids, were also considered. At the concentrations recommended for animal application, neither 4% (w/v) permethrin, nor 0.1% (w/v) cypermethrin had any significant effect on the mortality of B. ocellatus and neither induced significantly more mortality than an acetone-only control. In contrast, 0.04% diazinon caused 70% mortality within 4 h and 100% mortality after 24 h
exposure. The addition of a potential pyrethroid synergist, piperonyl butoxide, in combinationwith cypermethrin and permethrin, resulted in no significant increase in mortality.

It is concluded that the population of lice tested display a high level of pyrethroid tolerance which is likely to reflect the development of resistance. Twenty-four hours after routine treatment of 10 donkeys with a pour-on permethrin product (SwitchTM, VetPlus Ltd., 4% (w/v) permethrin, pour-on) hair tufts taken from their flanks were not significantly insecticidal compared with hair from the midline application site, implying a low level of insecticide distribution. Such a distribution pattern is likely to create an insecticide concentration gradient over the body and further facilitate selection for resistance.

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