Dental disease in companion rabbits under UK primary veterinary care: Frequency and risk factors

BACKGROUND

Some prior evidence has suggested that lop-eared rabbits and those with brachycephalic skull conformations have a higher dental disease risk. This retrospective cohort study reports the frequency and conformational risk factors for primary-care veterinary diagnosis with dental disease in companion rabbits in the UK.

METHODS

Anonymised VetCompass clinical records were manually reviewed to confirm dental disease cases. Risk factor analysis used multivariable binary logistic regression modelling.

RESULTS

From 161,979 rabbits under primary veterinary care in 2019, the 1-year period prevalence of overall dental disease was 15.36% (95% confidence interval [CI]: 14.78-15.96). The prevalence of dental disease affecting incisors was 3.14% (95% CI: 2.87-3.44), and for cheek teeth it was 13.72% (95% CI: 13.17-14.29). Neither lop-eared conformation nor brachycephalic skull conformation was significantly associated with increased odds of dental disease. Dental disease odds increased as age increased and decreased as bodyweight increased.

LIMITATIONS

This study retrospectively accessed clinical records, so breed names may sometimes be imprecise.

CONCLUSION

The high overall prevalence of dental disease represents a major welfare concern for all companion rabbits, regardless of conformation. This information can be used to encourage regular routine dental assessment of rabbits of all conformations to promote earlier diagnosis, paying particular attention to older rabbits and those with low bodyweight.

Ear health and quality of life in pet rabbits of differing ear conformations: A UK survey of owner-reported signalment risk factors and effects on rabbit welfare and behaviour

The impacts of ear disease on animal welfare and behaviour are little documented. Ear disease may be common in rabbits, but difficult to recognise, and lop-ears have previously been indicated as a risk factor for ear disease. We aimed to better understand the range of ear conditions in pet rabbits, signalment risk factors, and impacts on welfare and behaviour. Through an online questionnaire, we investigated owner-reported signalment, veterinary diagnosis of ear conditions, impaired hearing, and ear pain for UK pet rabbits. Relationships between ear condition measures and ear conformation, quality of life, and behaviour were analysed using logistic regression. Of 551 valid responses, 28.5% of rabbits reportedly had experienced ear conditions; 21.2% diagnosed or mentioned by vets, with otitis and excess cerumen most common. Approximately 25% of lop-eared rabbits had ear conditions indicated by a vet versus 10% of erect-eared rabbits. Lop-eared, half-lop, and older rabbits were most at risk (P<0.050). Rabbits reported as showing ear pain responses had reduced owner-reported quality of life compared with other rabbits (P<0.050). Rabbits with ear problems were less likely to be responsive to relevant sounds, and performed binky behaviour (joy jumps) less frequently, than rabbits without such issues. Understanding prevalence and risk factors for ear conditions is critical to improving welfare standards across this widely owned pet species. The findings suggest that improved recognition and treatment of ear conditions, and avoiding breeding from rabbits with early signs, or a family history, of ear disease are necessary to help combat this animal welfare issue.

Pet Owner Perception of Ferret Boredom and Consequences for Housing, Husbandry, and Environmental Enrichment

Boredom is a potential chronic but overlooked animal welfare problem. Caused by monotony, sub-optimal stimulation, and restrictive housing, boredom can therefore affect companion animals, particularly those traditionally caged, such as ferrets. We surveyed owners' (n = 621) perceptions of ferrets' capacity to experience boredom, behaviours they associate with it, and whether their perception of their ferrets' capacity for boredom influenced training techniques, housing, and environmental enrichment (EE). Most (93.0%) owners believed that ferrets could experience boredom, but owners who doubted that ferrets experience boredom (7.0%) provided slightly but significantly fewer EE types to their ferrets. Heat map and classification tree analysis showed that owners identified scratching at enclosure walls (n = 420) and excessive sleeping (n = 312) as distinctive behavioural indicators of ferret boredom. Repetitive pacing (n = 381), yawning (n = 191), and resting with eyes open (n = 171) were also suggested to indicate ferret boredom, but these overlapped with other states. Finally, ferret owners suggested social housing, tactile interaction with humans, and exploration as most important for preventing boredom. These results suggest that pet ferrets are at risk of reduced welfare from owners who doubt they can experience boredom, highlighting an opportunity to improve welfare through information dissemination. We recommend further investigation into ferret boredom capacity, behavioural indicators, and mitigation strategies.

Time-Consuming, but Necessary: A Wide Range of Measures Should Be Included in Welfare Assessments for Dairy Herds

Animal welfare assessments that measure welfare outcomes, including behavior and health, can be highly valid. However, the time and skill required are major barriers to their use. We explored whether feasibility of welfare outcome assessment for dairy herds may be improved by rationalizing the number of measures included. We compared two approaches: analyzing whether strong pairwise associations between measures existed, enabling the subsequent exclusion of associated measures; and identifying possible summary measures—“iceberg indicators”—of dairy herd welfare that could predict herd welfare status. A cross-sectional study of dairy herd welfare was undertaken by a single assessor on 51 English farms, in which 96 welfare outcome measures were assessed. All measures showed at least one pairwise association; percentage of lame cows showed the most (33 correlations). However, most correlations were weak–moderate, suggesting limited scope for excluding measures from protocols based on pairwise relationships. A composite measure of the largest portion of herd welfare status was then identified via Principal Component Analysis (Principal Component 1, accounting for 16.9% of variance), and linear regression revealed that 22 measures correlated with this. Of these 22, agreement statistics indicated that percentage of lame cows and qualitative descriptors of “calmness” and “happiness” best predicted Principal Component 1. However, even these correctly classified only ~50% of farms according to which quartile of the Principal Component 1 they occupied. Further research is recommended, but results suggest that welfare assessments incorporating many diverse measures remain necessary to provide sufficient detail about dairy herd welfare.

The Pen Is Milder Than the Blade: Identification Marking Mice Using Ink on the Tail Appears More Humane Than Ear-Punching Even with Local Anaesthetic

Simple Summary

Laboratory mice often look identical, so they are commonly marked by cutting the ear via ear-punching, or marking the tail with permanent marker. Ear-punching is permanent but could be painful, and mice could become stressed by weekly tail-marking, so we compared impacts on mice over 5 weeks. We also explored whether local anaesthetic cream could reduce any ear-punching effects. We found that ear-punching, even with anaesthetic, caused mice to be sniffed and groomed by their cagemates for at least 5 min after marking. Mice ear-punched with anaesthetic also groomed themselves and their ears ~5 times more than tail-marked and control mice. Facial grimacing was most common in the unmarked cagemates of tail-marked mice, and possibly in mice ear-punched with anaesthetic. The next day, mice ear-punched with anaesthetic were significantly less likely to eat unfamiliar food in an anxiety test than tail-marked or control mice. Over 5 weeks, ear-punched mice approached the handler significantly less than unmarked mice did, and tail-marked mice showed reduced defecation during re-marking. Other behaviour, bodyweight, and corticosterone showed no treatment effects. This suggests ear-punching caused some signs of pain and anxiety, and anaesthetic did not help. Tail-marking appeared more humane, showing no differences from the controls.

Abstract

Identification marking mice commonly involves ear-punching with or without anaesthetic, or tail-marking with ink. To identify which is most humane, we marked weanling male BALB/c mice using ear-punching (EP), ear-punching with anaesthetic EMLA^TM cream (EP+A), or permanent marker pen (MP). We compared marked mice, unmarked cagemates, and control mice (n = 12–13/group) for 5 weeks, reapplying MP weekly. Treatment-blind observations following marking showed that EP and EP+A mice were allogroomed (p < 0.001) and sniffed (p < 0.001) by their cagemates more than MP and control mice were. EP+A mice groomed themselves (p < 0.001) and their ears (p < 0.001) ~5 times more than most other mice; their cagemates also increased self-grooming (p < 0.001). Unmarked MP cagemates (p = 0.001), and possibly EP+A mice (p = 0.034; a nonsignificant trend), grimaced the most. The following day, half the EP+A mice showed hyponeophagia versus no MP and control mice (p = 0.001). Over the 5 weeks, EP mice approached the handler significantly less than unmarked cagemates did (p < 0.001). Across weeks, defecation during marking of MP mice decreased (p < 0.001). Treatment showed no effects on immediate responses during marking, aggression, bodyweight, plus-maze behaviour or corticosterone. MP mice showed no differences from controls, whilst EP and EP+A mice showed altered behaviour, so ink-marking may be the more humane identification method.

Do rabbits need each other? Effects of single versus paired housing on rabbit body temperature and behaviour in a UK shelter

In the wild, rabbits (Oryctolagus cuniculus) are social but territorial. Recent surveys suggest that over half of pet rabbits are housed singly. We aimed to compare welfare in single versus paired rabbits. We predicted singletons would show more abnormal or escape behaviour, greater stress responses to handling, and reduced body temperature (being unable to huddle with another individual when cold), but that pairs may show aggression. This study was conducted during winter at a rabbit-only rescue centre, and included 45rabbits, comprising 15 housed singly and 15 pairs. Like most pet rabbits, they were housed either outdoors or in unheated outbuildings. Singletons were mostly in smaller enclosures than pairs. Home-pen observations (40 min) revealed bar-biting in 8/15 single rabbits compared with 0/30 of the paired ones. No other behavioural effects of social housing reached significance, and enclosure size showed no significant effects. Body temperature was significantly lower in singletons than pairs, with at least 0.5°C mean difference. On colder days, rabbits adopted compact postures more, and relaxed postures less frequently. After handling, pairs resumed normal behaviour significantly more quickly than singletons in the home-pen (3.0 [± 0.3] versus 8.3 [± 1.3] s, respectively). Aggression was never observed. The results indicate that social housing reduces bar-biting, aids thermoregulation, and may help buffer stress. Rabbit owners should be encouraged to meet the need for rabbits to be housed with an appropriate conspecific in a suitably large, sheltered enclosure.

Does 'playtime' reduce stimulus-seeking and other boredom-like behaviour in laboratory ferrets?

Much environmental enrichment for laboratory animals is intended to enhance animal welfare and normalcy by providing stimulation to reduce 'boredom'. Behavioural manifestations of boredom include restless sensation-seeking behaviours combined with indicators of sub-optimal arousal. Here we explored whether these signs could be reduced by extra daily play opportunity in laboratory ferrets. Specifically, we hypothesised that playtime would reduce restlessness, aggression, sensation-seeking and awake drowsiness, even 24h later in the homecage. Female ferrets (n = 14) were group housed in enriched multi-level cages. Playtime involved exploring a room containing a ball pool, paper bags, balls containing bells, and a familiar interactive human for 1h. This was repeated on three consecutive mornings, and on the fourth morning, homecage behaviour was compared between ferrets who had experienced the playtime treatment versus control cagemates who had not. Their investigation of stimuli (positive = mouse odour or ball; ambiguous = empty bottle or tea-strainer; and negative = peppermint or bitter apple odour) was also recorded. We then swapped treatments, creating a paired experimental design. Ferrets under control conditions lay awake with their eyes open and screeched significantly more, but slept and sat/stood less, than following playtime. They also contacted negative and ambiguous stimuli significantly more under control conditions than they did following playtime; contact with positive stimuli showed no effects. Attempts to blind the observer to treatments were unsuccessful, so replication is required, but the findings suggest that playtime may have reduced both sub-optimal arousal and restless sensation seeking behaviour, consistent with reducing boredom.

Lop-eared rabbits have more aural and dental problems than erect-eared rabbits: a rescue population study

This research aimed to assess whether rabbits having lop ears, an artificially selected conformation, compromises welfare. We investigated the occurrence of aural and dental pathology in lop-eared compared with erect-eared rabbits. Thirty rabbits (15 lop-eared and 15 erect-eared) from a rabbit-only rescue shelter were examined. An otoscope was used to visualise the ear canals and mouth. Samples were taken from each ear to examine for mites, bacteria and yeast. Medical records were also examined. Lop-eared rabbits showed statistically significantly more frequent ear canal stenosis, higher scores of cerumen and erythema and more frequent potential pain response during ear examination, compared with erect-eared rabbits. We also found statistically significantly more frequent incisor pathology, molar overgrowth, molar sharpness, molar spurs and history of veterinary dental treatment in lop-eared compared with erect-eared rabbits. The effect sizes were often large. Age was not statistically significant between the lop-eared and erect-eared rabbit groups. Thus, lop-eared rabbits were at an increased risk of aural and dental pathology in this study. This brings into debate the ethics of breeding and buying lop-eared rabbits, as they are more likely to suffer conditions that negatively impact welfare, such as pain, and potentially deafness and difficulty eating.

Prospective cohort study to assess rates of contagious disease in pre-weaned UK dairy heifers: management practices, passive transfer of immunity and associated calf health

Dairy calves are vulnerable to infectious diseases, particularly diarrhoea and bovine respiratory disease (BRD), causing mortality and reducing welfare and growth. A prospective cohort study was performed on 11 UK dairy farms to determine the underlying causes for calf disease. This first paper describes the incidence, timing and duration of infectious disease, mortality rates, passive transfer of immunity and key management practices that may contribute to disease incidence. Heifer calves were recruited in the first week of life (n=492) and a blood sample taken to measure IgG and total protein (TP). Each animal was examined weekly for nine weeks using a standardised health scoring system. Recruitment of calves occurred between August and February. Four farms provided supplementary colostrum to more than 75 per cent of calves born, whereas on the remainder only 0 to 19 per cent were supplemented. Mean serum IgG and TP were 19.0±10 and 56.7±10.3 mg/ml respectively, with 20.7 per cent (95CI: 17.2 to 24.7 per cent) of all calves classified as having failure of passive transfer (IgG <10 mg/ml). The overall preweaning mortality rate was 4.5 per cent. (95 per cent CI: 2.9 to 6.8 per cent). During this period,48.2 per cent of all calves (range 24.1 to 74.4 per cent between farms) were diagnosed with diarrhoea and 45.9 per cent (range 20.4 to 77.8 per cent) with BRD. The incidence rates were 7.8 cases of diarrhoea and 10.1 cases of BRD per 100 calf weeks at risk, respectively. Rates of infectious disease were therefore high despite relatively good passive transfer.

Olfaction variation in mouse husbandry and its implications for refinement and standardization: UK survey of animal scents

Olfaction plays a crucial role in mouse communication, providing information about genetic identity, physiological status of conspecifics and alerting mice to potential predators. Scents of animal origin can trigger physiological and behavioural responses that could affect experimental responses and impact positively or negatively on mouse welfare. Additionally, differing olfactory profiles could help explain variation in results between laboratories. A survey was sent to animal research units in the UK to investigate potential transfer of scents of animal origin during routine husbandry procedures, and responses were obtained from animal care workers and researchers using mice in 51 institutions. The results reveal great diversity between animal units regarding the relevant husbandry routines covered. Most [71%] reported housing non-breeding male and female mice in the same room, with 76% reporting that hands were not washed and gloves not changed between handling male and female mice. The most commonly reported species housed in the same facility as mice was the rat (91%), and 41% of respondents were aware that scents from rats could affect mice. Changing of gloves between handling mice and other species was reported by 79% of respondents. Depending on the aspect considered, between 18 and 33% of respondents believed human and non-human animal odours would strongly affect mouse physiology, behaviour or standardization, while approximately 32–54% believed these effects would be weak. This indicates uncertainty regarding the significance of these factors. Understanding and controlling these practices could reduce unwanted variability in experimental results and maximize welfare.

Absorbencies of six different rodent beddings: commercially advertised absorbencies are potentially misleading

Moisture absorbency is one of the most important characteristics of rodent beddings for controlling bacterial growth and ammonia production. However, bedding manufacturers rarely provide information on the absorbencies of available materials, and even when they do, absorption values are usually expressed per unit mass of bedding. Since beddings are usually placed into cages to reach a required depth rather than a particular mass, their volumetric absorbencies are far more relevant. This study therefore compared the saline absorbencies of sawdust, aspen woodchips, two virgin loose pulp beddings (Alpha-Dri™ and Omega-Dri™), reclaimed wood pulp (Tek-Fresh™), and corncob, calculated both by volume and by mass. Absorbency per unit volume correlated positively with bedding density, while absorbency per unit mass correlated negatively. Therefore, the relative absorbencies of the beddings were almost completely reversed depending on how absorbency was calculated. By volume, corncob was the most absorbent bedding, absorbing about twice as much saline as Tek-Fresh, the least absorbent bedding. Conversely, when calculated by mass, Tek-Fresh appeared to absorb almost three times as much saline as the corncob. Thus, in practical terms the most absorbent bedding here was corncob, followed by the loose pulp beddings; and this is generally supported by their relatively low ammonia production as seen in previous studies. Many factors other than absorbency determine whether a material is suitable as a rodent bedding, and they are briefly mentioned here. However, manufacturers should provide details of bedding absorbencies in terms of volume, in order to help predict the relative absorbencies of the beddings in practical situations.

Olfactory variation in mouse husbandry and its implications for refinement and standardization: UK survey of non-animal scents

With their highly sensitive olfactory system, the behaviour and physiology of mice are not only influenced by the scents of conspecifics and other species, but also by many other chemicals in the environment. The constraints of laboratory housing limit a mouse's capacity to avoid aversive odours that could be present in the environment. Potentially odorous items routinely used for husbandry procedures, such as sanitizing products and gloves, could be perceived by mice as aversive or attractive, and affect their behaviour, physiology and experimental results. A survey was sent to research institutions in the UK to enquire about husbandry practices that could impact on the olfactory environment of the mouse. Responses were obtained from 80 individuals working in 51 institutions. Husbandry practices varied considerably. Seventy percent of respondents reported always wearing gloves for handling mice, with nitrile being the most common glove material (94%) followed by latex (23%) and vinyl (14%). Over six different products were listed for cleaning surfaces, floors, anaesthesia and euthanasia chambers and behavioural apparatus. In all cases Trigene™ (now called Anistel™) was the most common cleaning product used (43, 41, 40 and 49%, respectively). Depending on the attribute considered, between 7 and 19% of respondents thought that cleaning products definitely, or were likely to, have strong effects on standardization, mouse health, physiology or behaviour. Understanding whether and how these odours affect mouse welfare will help to refine mouse husbandry and experimental procedures through practical recommendations, to improve the quality of life of laboratory animals and the experimental data obtained.

Impact of Facial Conformation on Canine Health: Brachycephalic Obstructive Airway Syndrome

The domestic dog may be the most morphologically diverse terrestrial mammalian species known to man; pedigree dogs are artificially selected for extreme aesthetics dictated by formal Breed Standards, and breed-related disorders linked to conformation are ubiquitous and diverse. Brachycephaly--foreshortening of the facial skeleton--is a discrete mutation that has been selected for in many popular dog breeds e.g. the Bulldog, Pug, and French Bulldog. A chronic, debilitating respiratory syndrome, whereby soft tissue blocks the airways, predominantly affects dogs with this conformation, and thus is labelled Brachycephalic Obstructive Airway Syndrome (BOAS). Despite the name of the syndrome, scientific evidence quantitatively linking brachycephaly with BOAS is lacking, but it could aid efforts to select for healthier conformations. Here we show, in (1) an exploratory study of 700 dogs of diverse breeds and conformations, and (2) a confirmatory study of 154 brachycephalic dogs, that BOAS risk increases sharply in a non-linear manner as relative muzzle length shortens. BOAS only occurred in dogs whose muzzles comprised less than half their cranial lengths. Thicker neck girths also increased BOAS risk in both populations: a risk factor for human sleep apnoea and not previously realised in dogs; and obesity was found to further increase BOAS risk. This study provides evidence that breeding for brachycephaly leads to an increased risk of BOAS in dogs, with risk increasing as the morphology becomes more exaggerated. As such, dog breeders and buyers should be aware of this risk when selecting dogs, and breeding organisations should actively discourage exaggeration of this high-risk conformation in breed standards and the show ring.

A two-year participatory intervention project with owners to reduce lameness and limb abnormalities in working horses in Jaipur, India

BACKGROUND

Participatory methods are increasingly used in international human development, but scientific evaluation of their efficacy versus a control group is rare. Working horses support families in impoverished communities. Lameness and limb abnormalities are highly prevalent in these animals and a cause for welfare concern. We aimed to stimulate and evaluate improvements in lameness and limb abnormalities in horses whose owners took part in a 2-year participatory intervention project to reduce lameness (PI) versus a control group (C) in Jaipur, India.

METHODOLOGY/PRINCIPAL FINDINGS

In total, 439 owners of 862 horses participated in the study. PI group owners from 21 communities were encouraged to meet regularly to discuss management and work practices influencing lameness and poor welfare and to track their own progress in improving these. Lameness examinations (41 parameters) were conducted at the start of the study (Baseline), and after 1 year and 2 years. Results were compared with control horses from a further 21 communities outside the intervention. Of the 149 horses assessed on all three occasions, PI horses showed significantly (P<0.05) greater improvement than C horses in 20 parameters, most notably overall lameness score, measures of sole pain and range of movement on limb flexion. Control horses showed slight but significantly greater improvements in four parameters, including frog quality in fore and hindlimbs.

CONCLUSIONS/SIGNIFICANCE

This participatory intervention succeeded in improving lameness and some limb abnormalities in working horses, by encouraging changes in management and work practices which were feasible within owners' socioeconomic and environmental constraints. Demonstration of the potentially sustainable improvements achieved here should encourage further development of participatory intervention approaches to benefit humans and animals in other contexts.

The range and prevalence of clinical signs and conformation associated with lameness in working draught donkeys in Pakistan

REASONS FOR PERFORMING THE STUDY

Lameness is prevalent in working donkeys and has major welfare implications; however, a detailed study of the associated clinical signs is lacking.

OBJECTIVES

To describe the range and prevalence of clinical signs and conformation associated with lameness in working draught donkeys.

STUDY DESIGN

Prospective, cross-sectional, observational study.

METHODS

Data were collected from 102 working draught donkeys in Pakistan. A lameness assessment adapted for working donkeys was used to record clinical signs of lameness, gait, limb conformation and pain responses in the feet, limbs and spine using observation, palpation and manipulation. Lameness at the walk was scored from 0 to 10 (sound to nonweightbearing).

RESULTS

Every donkey examined had gait abnormalities, with 5% having a nonweightbearing limb. Lameness was significantly more severe with older age, lower body condition score and forward-at-the-knee conformation. More severe lameness was also associated with pain responses in the hoof walls, palpation of limb joints and spinal flexion. Joint, tendon and foot pathology was highly prevalent, as well as pain responses to joint flexion and spinal manipulation. Conformational abnormalities showed lateral asymmetries.

CONCLUSIONS

Over 98% of the world's 42.2 million donkeys are in low-income countries, most being used for work. The high prevalence of lameness, pain and multiple limb and spinal abnormalities in working donkeys is of great welfare concern and highlights the complexity of addressing this problem. This standardised lameness assessment can be used when implementing and monitoring interventions to reduce lameness prevalence in working donkeys.

Environmental and demographic risk factors for poor welfare in working horses, donkeys and mules in developing countries

Over 85% of equids live in developing countries, where they are usually used for work. We aimed to identify environmental factors associated with potential welfare problems in working equids, helping target welfare interventions towards the most vulnerable animals. Over 5 years, non-invasive behavioural and physical data were collected from 5481 donkeys, 4504 horses, and 858 mules across nine developing countries. Hoof and limb problems were over 90% prevalent, and 85% of equids were thin. Older, thinner animals had the most problems, and species differences in susceptibility were found. Equids used to transport people by cart, to carry goods by pack, or to work in bricks kilns had more problems than other equids. Rural equids had more problems than urban ones, but urban equids had more lesions, and were more aggressive towards observers. Equids were significantly thinner when climates were warmer. These results should aid the development and targeting of specific welfare interventions.

Validity of indicators of dehydration in working horses: a longitudinal study of changes in skin tent duration, mucous membrane dryness and drinking behaviour

REASONS FOR PERFORMING STUDY

Dehydration is a serious welfare concern in horses working in developing countries. Identification of a valid and practical indicator of dehydration would enable more rapid treatment and prevention.

OBJECTIVES

To examine changes in bodyweight, clinical and blood parameters during rehydration of working horses, identify a 'gold standard' criterion for dehydration and use this to validate a standardised skin tent test, drinking behaviour and mucous membrane dryness as potential field indicators.

METHODS

Fifty horses with a positive skin tent test, working in environmental temperatures of 30-44 degrees C in Pakistan, were rested and offered water to drink ad libitum. Bodyweight, clinical and blood parameters, mucous membrane dryness, drinking behaviour and skin tent duration at 6 anatomical locations were measured at 0, 30, 60, 120, 180, 240 and 300 min.

RESULTS

Skin tent duration was affected by side of animal (P = 0.008), anatomical location and coat moisture (both P < 0.001). Younger animals had shorter skin tents at all time points (P = 0.007). There was no significant association between plasma osmolality (P(osm)) or water intake and skin tent duration. Horses with a higher P(osm) drank significantly more water (P < 0.001), and had longer (P < 0.001) and more frequent (P = 0.001) drinking bouts. Neither P(osm) nor water intake affected qualitative and semi-quantitative measurements of mucous membrane dryness significantly.

CONCLUSIONS AND POTENTIAL RELEVANCE

The standardised skin tent test and measures of mucous membrane dryness investigated in this study were not valid or repeatable indicators of dehydration when compared with P(osm) as a 'gold standard' criterion. The volume of water consumed and the number and duration of drinking bouts were the most reliable guide to hydration status currently available for mature working horses. Offering palatable water to drink ad libitum provides both the diagnosis and the remedy for dehydration in working horses.

Marked for life? Effects of early cage-cleaning frequency, delivery batch, and identification tail-marking on rat anxiety profiles

Daily handling of preweanling rats reduces their adult anxiety. Even routine cage-cleaning, involving handling, reduces adult anxiety compared with controls. Cage-cleaning regimes differ between animal breeders, potentially affecting rodent anxiety and experimental results. Here, 92 adult male rats given different cage-cleaning rates as pups, were compared on plus-maze, hyponeophagia, corticosterone, and handling tests. They were pair-housed and half were tail-marked for identification. Anxiety/stress profiles were unaffected by cage-cleaning frequency, suggesting that commercial-typical differences in husbandry contribute little variance to adult rat behavior. However, delivery batch affected some elevated plus-maze measures. Also, tail-marked rats spent three times longer on the plus-maze open arms than their unmarked cagemates, suggesting reduced anxiety, yet paradoxically they showed greater chromodacryorrhoea responses to handling, implying increased aversion to human contact. A follow-up study showed that rats avoided the odor released from the marker pen used. Thus, apparently trivial aspects of procedure can greatly affect experimental results.

Risk factors for strap-related lesions in working donkeys at the World Heritage Site of Petra in Jordan

A risk analysis was undertaken in an attempt to improve improvised rump straps on donkeys carrying tourists at the World Heritage Site at Petra, Jordan. Tail-base lesions were identified in 63 of the 86 donkeys. Observations and questionnaires were used to collect data relating to the straps, donkey health and human attitudes. The worse lesions were associated with padded rather than unpadded straps, if tightly fitted. Padding could be a cause of, or a response to lesions, but results suggest that it did not effectively aid healing. Significantly worse lesions occurred with unclean than with clean straps and, contrary to many recommendations, cotton straps were associated with worse lesions than were synthetic straps. Since this was an exploratory study, findings should be considered to generate (not to test) hypotheses and any resulting interventions will require monitoring. Further possible risks are discussed, referring to medical and veterinary literature and applied expertise in working equines.

Long-term effects of cage-cleaning frequency and bedding type on laboratory rat health, welfare, and handleability: a cross-laboratory study

Cage-cleaning is necessary for a hygienic environment, but since rats communicate using scent, they might suffer if their cages are cleaned too frequently. Male rats (Sprague-Dawley and Wistar) were kept for five months across four animal units. Their cages were cleaned twice-weekly, weekly, or every two weeks, and contained either aspen woodchips or absorbent paper bedding. Aggression, injuries and general health, weight gain, chromodacryorrhoea (a stress-related Harderian gland secretion), handleability, and lung pathology were monitored, as was in-cage ammonia. Cleaning frequency had no clear impact on rat welfare, although frequent cleaning decreased ammonia concentrations and handleability, and non-aggressive skirmishing was highest in weekly cleaned rats. Surprisingly, bedding type did not affect ammonia, but all ammonia readings were unexpectedly low. However, rats kept on aspen had greater sneezing rates and lung pathology than those on paper bedding, but also had higher body weights. The results raise concerns about aspen bedding, which is relatively inert compared with other wood beddings, but nevertheless more harmful than paper. Animal unit significantly affected eight of the 11 variables tested, having interactive effects on five of them. The study also demonstrates the interactive effects of different animal units, casting doubt on the feasibility of standardization. We explored multiple variables of interest, so all findings require confirmation through further work. Nevertheless, cage-cleaning rates seem to affect socially housed male rats little, while bedding type has important effects on rat health.