Assessment of potential maladaptive pain in dogs with elbow osteoarthritis using a von Frey aesthesiometer

BACKGROUND

This study aimed to investigate the possible presence of maladaptive pain in the thoracic limbs of dogs with elbow osteoarthritis (OA) using an electronic von Frey aesthesiometer (eVFA).

METHODS

Twenty-eight client- and staff-owned dogs (OA, n = 14; controls, n = 14) were enrolled in the study. Every dog underwent a full orthopaedic examination, and then five von Frey measurements were obtained from each carpal pad of each dog. A maximum test threshold of 400 g was set and approved by an ethics committee.

RESULTS

eVFA thresholds were significantly lower (p < 0.001) in dogs with OA (median 248 g, range 128-369 g) than in control dogs (median 390 g, range 371-400 g). In the OA group, the sensory threshold was significantly lower (p = 0.048) in the more severely affected limb than the less severely affected limb.

LIMITATION

The low maximum threshold required for ethical approval may influence the variability in the control group.

CONCLUSIONS

Dogs with elbow OA had significantly lower sensory thresholds than control dogs, which is compatible with the presence of maladaptive pain, potentially due to central sensitisation. Further research is required to evaluate the potential use of the eVFA for monitoring clinical progression and treatment response in dogs with elbow OA.

Cat and dog owners' expectations and attitudes towards advanced veterinary care (AVC) in the UK, Austria and Denmark

Modern veterinary medicine offers a level of care to cats and dogs similar to that available to their owners, including blood transfusions, chemotherapy and MRI scans. The potential benefits to the animals of owners who can afford such care are obvious, but there can also be negative consequences if owners with strong emotional attachments to their pets pursue treatments that significantly reduce the quality of the animal's life while attempting to prolong it. Moreover, caring for a chronically or seriously ill animal can lead to emotional distress and financial and practical challenges for the pet owner. A questionnaire was used to survey cat and dog owners from representative samples of citizens in the UK, Austria and Denmark, to investigate owners' expectations and attitudes towards advanced veterinary care, and the factors that might influence those views. Overall, 58.4% of the pet owners surveyed believed that their pets should have access to the same treatment options as humans, while 51.5% believed that they should have access to the same diagnostic tests as humans. Owners were most likely to be neutral on the question of whether advanced veterinary care has 'gone too far' (45.3%), and to disagree with the statement that advanced care is 'unnecessary' (40.1%). In all three countries, the level of attachment owners had to their pets was most strongly associated with attitudes towards advanced care, with owners scoring higher on Lexington Attachment to Pets Scale (LAPS) being more likely to expect advanced care to be available. Other factors such as owner age, living situation (alone or not), income or possession of pet insurance were less consistently with owner attitudes. Our findings will help inform veterinarians and other health care providers about pet owner expectations and attitudes towards advanced veterinary care, and contribute to the debate on increasing specialisation within the profession.

Seeing the benefits, but not taking advantage of them: Dog and cat owners' beliefs about veterinary telemedicine

BACKGROUND

Telemedicine offers benefits to clients and their animals, but potential disadvantages are also being debated.

METHODS

Using a questionnaire, we investigated dog and cat owners' (N = 2117) use of and beliefs about telemedicine and whether beliefs impact past and expected future use.

RESULTS

Although the majority of owners are aware that telemedicine can lead to the risk of something being missed, they see great potential in remote consultation in terms of usefulness for follow-up appointments or improving access to a specialist. However, only 12% of dog owners and 6% of cat owners have used telemedicine, and around 25% of owners who have never used it would be willing to use it in the future. Owners with a larger number of recent veterinary visits were more likely to have used telemedicine.

LIMITATIONS

Although a definition of 'telemedicine' was provided, respondents may have had different perceptions of what this meant.

CONCLUSION

Owners of dogs and cats recognise the potential benefits of telemedicine, but there is a mismatch with the actual uptake. This not only raises questions about the current availability of telemedicine but also should increase veterinary professionals' understanding of its potential benefits in veterinary practice.

Do people really care less about their cats than about their dogs? A comparative study in three European countries

Previous studies have shown that cat owners seem to care less about their cats than dog owners care about their dogs - both in terms of their emotional state of attachment and in their willingness to pay for services that potentially benefit the animals. One study speculated that this difference is "driven by the behavior of the pet" - that the behavior of dogs encourages care more than the behavior of cats - and therefore is a universal phenomenon. However, previous studies mostly relied on convenience sampling of owners and were undertaken in single countries. Based on responses to a questionnaire from cat and dog owners drawn from representative samples of citizens (18 to 89 years of age) in three different European countries, Denmark, Austria and the United Kingdom, we tested the degree to which owners care about their cats and dogs. We used four different measures: Lexington attachment to pets scale (LAPS), possession of pet health insurance, willingness to pay for life-saving treatment, and expectation of veterinary diagnostic and treatment options. Dog owners had higher LAPS scores in all countries. However, the difference between dog and cat owners was greater in Denmark than in Austria and the United Kingdom. More dogs than cats were insured in all three countries, but the ratio was much less skewed in favor of dogs in the United Kingdom compared to Denmark. In terms of expensive life-saving treatment, in every country, more dog owners than cat owners were willing to spend over a certain amount, but the differences were much more pronounced in Denmark compared to the United Kingdom. In Denmark and Austria, dog owners expected more veterinary treatment options to be available, but species made no difference to the expectations of UK owners. People care more about their dogs than their cats in all countries, but with a clear cross-country variation and a very modest difference in the United Kingdom. Therefore, it does not seem to be a universal phenomenon that people care much less about their cats than their dogs. This finding has practical implications for future efforts to expand the level of veterinary services provided for cat owners.

Compete or Cooperate with ‘Dr. Google’? Small Animal Veterinarians’ Attitudes towards Clients’ Use of Internet Resources—A Comparative Study across Austria, Denmark and the UK

Simple Summary

Owners of dogs, cats, and other companion animals increasingly make use of the internet to find out how to best care for their animals. This may affect owners’ relations with veterinarians in both positive and negative ways. A positive consequence could be that owners are better informed when they approach a veterinarian. However, there can also be challenging situations in which the owners may question veterinarians’ professional advice based on online information. Using a questionnaire, we found that a majority of Austrian, Danish, and UK veterinarians (n = 641) surveyed were occasionally confronted with clients who question their medical advice based on information obtained from the internet. In addition, the veterinarians were concerned about the potential for clients to misunderstand information found on the internet, or to develop unrealistic expectations of what is possible in small animal practices. As internet use becomes ever more widespread, we suggest that the types of resources that are available and used by animal owners should be further explored.

Abstract

Veterinary medicine is increasingly affected by animal owners having the opportunity to become better informed on pet health issues by using various internet resources. Using an online questionnaire including a section on clients’ use of internet resources to obtain medical information, this study aimed to investigate veterinarians’ estimates of the percentage of clients using internet resources, how often clients question veterinarians’ professional medical advice based on online information, and veterinarians’ attitudes towards clients’ use of internet resources, across Austrian, Danish, and UK veterinarians (n = 641). The results show that 48.8% of respondents estimated that 40–79% of their clients use internet resources to find medical information. Further, 70–80% of respondents stated that they are occasionally challenged by clients questioning their advice based on online information. Although veterinarians recognized the potential advantages related to clients’ use of internet resources, such as an increased acceptance of advanced diagnostics and treatments, they also highlighted clients’ increased expectations or false impressions of small animal practices as potentially negative aspects in this context. As internet use increases, it seems likely that these issues will become increasingly important in the future.

Digital opportunities to connect and complain – the use of Facebook in small animal practice

Background

Material/methods

Results

Conclusions

Comparing veterinarians' attitudes to and the potential influence of pet health insurance in Austria, Denmark and the UK

BACKGROUND

Health insurance offers many benefits to clients and veterinarians, such as the ability to perform necessary and possibly cost-intensive medical interventions without financial constraints, or to potentially prevent euthanasia based on financial challenges. However, concerns about negative consequences, such as the overuse of diagnostic tests or overtreatment, have also been raised.

METHODS

Using an online questionnaire distributed via e-mail, which included a section on health insurance, we investigated the relative number of insured dogs and cats treated by Austrian, Danish and UK veterinarians (N = 636) and the attitudes of those veterinarians toward health insurance. Further, using a case vignette, we examined whether coverage by health insurance may influence treatment suggestions.

RESULTS

Even though veterinarians in all three countries believe that health insurance reduces stress since clients' financial resources will be less important, we found that Austrian veterinarians are more likely to agree that health insurance is unnecessary compared to Danish and UK veterinarians. Further, many raised the concern that insurance policies influence clinical decisions; and less than half supported the idea of making insurance mandatory. A majority of veterinarians in Austria and the UK thought that insurance can lead to the overuse of diagnostic tests, and in the UK a majority also thought that it can lead to overtreatment. Using case vignettes, we found that veterinarians were significantly more likely to suggest a CT scan to a client with an insured animal, in contrast to a client with stated financial limitations. Further, UK veterinarians were more likely to suggest a CT scan to a client with an insured animal, in contrast to a client without insurance.

CONCLUSION

In conclusion, we found that veterinarians, in general, were in favour of health insurance, and that greater coverage may increase more cost-intensive veterinary care. Our findings also raise a potential ethical challenge of health insurance causing differential access to clinical care for patients.

Managing conflicting ethical concerns in modern small animal practice-A comparative study of veterinarian's decision ethics in Austria, Denmark and the UK

Small animal veterinarians frequently have to manage conflicting interests. Beside the key consideration of the patient’s interests, small animal veterinarians are often challenged to consider not only client’s emotional needs, but also their own personal aspirations to provide quality patient care and to make a good living as a professional. Further, veterinarians have an interest in continuous professional development and the use of the newest treatments, which may influence their decision-making process. Based on published work, we hypothesize the existence of four decision ethics orientations that veterinarians can use to manage potentially conflicting concerns. These are: the patient-focused, the client-empathetic, the client-devolved and the development-oriented decision ethics orientations. We surveyed small animal veterinarians in Austria, Denmark, and the UK using a questionnaire (N = 648), and successfully identified the four decision ethics orientations in all three countries. The patient-focused and client-empathetic decision ethics orientations are salient in all countries, whereas Danish and UK veterinarians are slightly more client-empathetic and client-devolved compared to their Austrian colleagues. Across countries our findings show that experienced and older veterinarians tend to be more client-empathetic. Younger and less experienced professionals are more development-oriented compared to their older and more experienced colleagues. In contrast to other studies investigating ethical issues in small animal practice, we found no evidence that gender plays a decisive role in the tendency towards any decision ethics orientation. We also show that veterinarians with a higher client-empathetic orientation and development-orientation more often discuss the possibility of health insurance with clients who do not have it. The present study provides a first empirical insight into how veterinarians manage challenging expectations and ethical concerns as part of decision making in modern small animal practice.

The Effect of Calibration Method on Repeatability and Reproducibility of Pressure Mat Data in a Canine Population

OBJECTIVE

 The aim of this study was to investigate the repeatability and reproducibility of two different pressure-sensitive walkway calibration protocols, while collecting gait data from a heterogenous group of dogs.

STUDY DESIGN

 Fourteen dogs were walked across a high-definition pressure-sensitive walkway (Tekscan Strideway HRSW3) to obtain five valid trials from each dog. Two different calibration protocols were created following manufacturer recommendations: human step and phantom step using a custom-built three-legged device. Each calibration protocol was repeated five times, by three different operators, and then individually applied to the raw canine gait data. The software then automatically generated values for peak vertical force, vertical impulse and peak pressure for each trial.

RESULTS

 To control for the different bodyweight of the dogs, forces are reported as a percentage of bodyweight. Values for peak vertical force percentage of bodyweight, vertical impulse percentage of bodyweight and peak pressure were significantly different between calibration protocols, but the results were linearly correlated. Both calibration protocols were highly repeatable and highly reproducible.

CONCLUSION

 Both the step and phantom calibration protocols individually generated highly repeatable and reproducible results, which were not affected by different operators. A linear correlation was identified which may make it possible to apply a correction factor to enable comparison of results between different studies.

Radiographic assessment of the skeletons of Dolly and other clones finds no abnormal osteoarthritis

Our recent report detailing the health status of cloned sheep concluded that the animals had aged normally. This is in stark contrast to reports on Dolly (first animal cloned from adult cells) whose diagnoses of osteoarthritis (OA) at 5½ years of age led to considerable scientific concern and media debate over the possibility of early-onset age-related diseases in cloned animals. Our study included four 8-year old ewes derived from the cell line that gave rise to Dolly, yet none of our aged sheep showed clinical signs of OA, and they had radiographic evidence of only mild or, in one case, moderate OA. Given that the only formal record of OA in Dolly is a brief mention of a single joint in a conference abstract, this led us to question whether the original concerns about Dolly's OA were justified. As none of the original clinical or radiographic records were preserved, we undertook radiographic examination of the skeletons of Dolly and her contemporary clones. We report a prevalence and distribution of radiographic-OA similar to that observed in naturally conceived sheep, and our healthy aged cloned sheep. We conclude that the original concerns that cloning had caused early-onset OA in Dolly were unfounded.

High speed galloping in the cheetah (Acinonyx jubatus) and the racing greyhound (Canis familiaris): spatio-temporal and kinetic characteristics

The cheetah and racing greyhound are of a similar size and gross morphology and yet the cheetah is able to achieve a far higher top speed. We compared the kinematics and kinetics of galloping in the cheetah and greyhound to investigate how the cheetah can attain such remarkable maximum speeds. This also presented an opportunity to investigate some of the potential limits to maximum running speed in quadrupeds, which remain poorly understood. By combining force plate and high speed video data of galloping cheetahs and greyhounds, we show how the cheetah uses a lower stride frequency/longer stride length than the greyhound at any given speed. In some trials, the cheetahs used swing times as low as those of the greyhounds (0.2 s) so the cheetah has scope to use higher stride frequencies (up to 4.0 Hz), which may contribute to it having a higher top speed that the greyhound. Weight distribution between the animal's limbs varied with increasing speed. At high speed, the hindlimbs support the majority of the animal's body weight, with the cheetah supporting 70% of its body weight on its hindlimbs at 18 m s(-1); however, the greyhound hindlimbs support just 62% of its body weight. Supporting a greater proportion of body weight on a particular limb is likely to reduce the risk of slipping during propulsive efforts. Our results demonstrate several features of galloping and highlight differences between the cheetah and greyhound that may account for the cheetah's faster maximum speeds.

A 3.90 V iron-based fluorosulphate material for lithium-ion batteries crystallizing in the triplite structure

Li-ion batteries have empowered consumer electronics and are now seen as the best choice to propel forward the development of eco-friendly (hybrid) electric vehicles. To enhance the energy density, an intensive search has been made for new polyanionic compounds that have a higher potential for the Fe²⁺/Fe³⁺ redox couple. Herein we push this potential to 3.90 V in a new polyanionic material that crystallizes in the triplite structure by substituting as little as 5 atomic per cent of Mn for Fe in Li(Fe(1-δ)Mn(δ))SO₄F. Not only is this the highest voltage reported so far for the Fe²⁺/Fe³⁺ redox couple, exceeding that of LiFePO₄ by 450 mV, but this new triplite phase is capable of reversibly releasing and reinserting 0.7-0.8 Li ions with a volume change of 0.6% (compared with 7 and 10% for LiFePO₄ and LiFeSO₄F respectively), to give a capacity of ~125 mA h g⁻¹.

Functional anatomy of the cheetah (Acinonyx jubatus) forelimb

Despite the cheetah being the fastest living land mammal, we know remarkably little about how it attains such high top speeds (29 m s(-1)). Here we aim to describe and quantify the musculoskeletal anatomy of the cheetah forelimb and compare it to the racing greyhound, an animal of similar mass, but which can only attain a top speed of 17 m s(-1). Measurements were made of muscle mass, fascicle length and moment arms, enabling calculations of muscle volume, physiological cross-sectional area (PCSA), and estimates of joint torques and rotational velocities. Bone lengths, masses and mid-shaft cross-sectional areas were also measured. Several species differences were observed and have been discussed, such as the long fibred serratus ventralis muscle in the cheetah, which we theorise may translate the scapula along the rib cage (as has been observed in domestic cats), thereby increasing the cheetah's effective limb length. The cheetah's proximal limb contained many large PCSA muscles with long moment arms, suggesting that this limb is resisting large ground reaction force joint torques and therefore is not functioning as a simple strut. Its structure may also reflect a need for control and stabilisation during the high-speed manoeuvring in hunting. The large digital flexors and extensors observed in the cheetah forelimb may be used to dig the digits into the ground, aiding with traction when galloping and manoeuvring.

Functional anatomy of the cheetah (Acinonyx jubatus) hindlimb

The cheetah is capable of a top speed of 29 ms(-1) compared to the maximum speed of 17 ms(-1) achieved by the racing greyhound. In this study of the hindlimb and in the accompanying paper on the forelimb we have quantified the musculoskeletal anatomy of the cheetah and greyhound and compared them to identify any differences that may account for this variation in their locomotor abilities. Specifically, bone length, mass and mid-shaft diameter were measured, along with muscle mass, fascicle lengths, pennation angles and moment arms to enable estimates of maximal isometric force, joint torques and joint rotational velocities to be calculated. Surprisingly the cheetahs had a smaller volume of hip extensor musculature than the greyhounds, and we therefore propose that the cheetah powers acceleration using its extensive back musculature. The cheetahs also had an extremely powerful psoas muscle which could help to resist the pitching moments around the hip associated with fast accelerations. The hindlimb bones were proportionally longer and heavier, enabling the cheetah to take longer strides and potentially resist higher peak limb forces. The cheetah therefore possesses several unique adaptations for high-speed locomotion and fast accelerations, when compared to the racing greyhound.

The effects of selective breeding on the architectural properties of the pelvic limb in broiler chickens: a comparative study across modern and ancestral populations

Intensive artificial selection has led to the production of the modern broiler chicken, which over the last few decades has undergone a dramatic increase in growth rate and noticeable changes in body conformation. Unfortunately, this has been associated with musculoskeletal abnormalities which have altered the walking ability of these birds, raising obvious welfare concerns, as well as causing economic losses. Here we present a comparative study of ancestral and derived muscle anatomy in chickens to begin to tease apart how evolutionary alterations of muscle form in chickens have influenced their locomotor function and perhaps contributed to lameness. We measured the muscle architectural properties of the right pelvic limb in 50 birds, including the Giant Junglefowl, a commercial strain broiler and four pureline commercial broiler breeder lines (from which the broiler populations are derived) to identify which features of the broiler's architectural design have diverged the most from the ancestral condition. We report a decline in pelvic limb muscle mass in the commercial line birds that may compromise their locomotor abilities because they carry a larger body mass. This greater demand on the pelvic limb muscles has mostly led to changes in support at the hip joint, revealing significantly larger abductors and additionally much larger medial rotators in the broiler population. Differences were seen within the commercial line bird populations, which are likely attributed to different selection pressures and may reflect differences in the walking ability of these birds. In addition, Junglefowl seem to have both greater force-generating capabilities and longer, presumably faster contracting muscles, indicative of superior musculoskeletal/locomotor function. We have provided baseline data for generating hypotheses to investigate in greater depth the specific biomechanical constraints that compromise the modern broiler's walking ability and propose that these factors should be considered in the selection for musculoskeletal health in the chickens of the future. Our new anatomical data for a wide range of domestic and wild-type chickens is useful in a comparative context and for deeper functional analysis including computer modelling/simulation of limb mechanics.

ULTRASONOGRAPHIC ASSESSMENT OF THE CANINE SCIATIC NERVE

To describe the ultrasonographic technique for investigation of the canine sciatic nerve, four canine cadaver pelvic limbs, two live healthy dogs, and five canine patients with suspected peripheral sciatic nerve lesions were examined with a high-resolution linear ultrasound transducer. The caudal part of the lumbosacral trunk and the origin of the sciatic nerve were visualized through the greater ischiatic foramen. The two components of the sciatic nerve, common peroneal and tibial nerves, were distinguished along the entire length of the nerve, until they branched at the level of the distal femur. In healthy live dogs they appeared as two adjacent hypoechoic tubular structures with internal echotexture of discontinuous hyperechoic bands, surrounded by a thin rim of highly echogenic tissue. The common peroneal component had a smaller diameter and was on the cranial aspect of the tibial component. An ultrasonographic lesion compatible with a peripheral nerve sheath tumor was found in one dog. Improved understanding of the ultrasonographic anatomy of the sciatic nerve supports clinical use of this modality.

A force plate study of avian gait

OBJECTIVE

To test the force plate as a gait analysis system for broilers and to determine how the ground reaction force (GRF) patterns change in these birds with growth and administration of analgesia.

MATERIALS AND METHODS

Thirty-three male Ross 308 chicks were raised on either an ad libitum or restricted-feeding regime, and subsequently treated with carprofen or a placebo. Vertical, craniocaudal and mediolateral GRFs were measured as the birds walked across a standard force plate.

RESULTS

The data were easy to collect, and peak vertical forces of an equivalent percentage of bodyweight as seen in human walking were identified. Mediolateral forces were 2-3 times greater than those demonstrated in other species. GRF patterns showed significant changes during growth, but analgesia did not have a significant effect on the speed of walking, or GRF patterns.

CONCLUSIONS AND CLINICAL RELEVANCE

The force plate is a suitable research tool for recording GRFs from avian bipeds. The large mediolateral forces identify a particularly inefficient aspect of avian gait; however, the role of pain remains to be determined.

Fracture of the proximal tibial epiphysis and tuberosity in 10 dogs

Ten dogs were presented with fractures of the proximal tibial epiphysis and tuberosity. All dogs had a cranioproximal-caudodistal angulation of the tibial plateau. Six dogs had marked caudal displacement of the proximal tibial epiphysis, five of which had also sustained fractures of the proximal fibula. The estimated mean angle of inclination of the tibial plateau of affected limbs was 45.8 +/- 9.6 degrees, which was significantly greater (P<0.0005) than the estimated mean angle of the normal contralateral limb 26.2 +/- 6.6 degrees. The mean angle of inclination of the tibial plateau of dogs with fibular fractures (n=5) was not significantly different from dogs without fibular fractures (n=5) (P>0.25). Five dogs were treated conservatively and five were treated by three different methods of surgical repair. Surgically treated dogs had significantly greater preoperative tibial plateau angles (P<0.05). All dogs regained full limb usage, regardless of the method of treatment chosen.

Preliminary study of joint disease in poultry by the analysis of synovial fluid

Samples of synovial fluid and synovial membrane were obtained from the hock joints of several groups of broilers, including lame birds and two strains of broilers raised on different feeding regimens and given different drug treatments (carprofen or placebo). There were more significant differences between the groups on the basis of the analysis of the synovial fluid samples than the synovial membrane samples. Experimental birds fed ad libitum had the highest median red blood cell counts and median ghost cell counts of all of the groups, but there were no differences between the groups in the thickness of the synovial lining cell layer or the degree of cellular infiltrate in the synovial membrane. The synovial fluid from the broilers and lame birds fed ad libitum was more turbid, suggestive of intra-articular pathology, and the large numbers of heterophils in samples from the lame birds indicated an inflammatory arthropathy. The birds fed ad libitum which were treated with carprofen had more cells in the synovial fluid than the birds given the placebo. A large number of the samples of synovial fluid from the ad libitum-fed broilers contained blood.

Evaluation of ground reaction forces produced by chickens walking on a force plate

OBJECTIVE

To evaluate the use of a force plate as a method for objective gait analysis in adult poultry, to characterize ground reaction forces (GRFs) produced in adult chickens during normal walking, and to assess the variability of GRFs.

ANIMALS

18 clinically normal 5-month-old Brown Leghorn hens.

PROCEDURE

Vertical, craniocaudal, and mediolateral GRFs were measured as hens walked across a standard force plate embedded in the middle of a runway.

RESULTS

All GRFs were significantly affected by speed, and variability was high. With increasing speed, overall stance time decreased, but the percentage of stance time spent in braking or propulsion remained approximately equal. There was an overall increase in maximum propulsion force, which was produced at a greater rate over a shorter time; thus, propulsion integral decreased. Maximum braking forces and braking integrals were variable, but the rate at which the forces were generated increased. Mediolateral forces were 2 to 3 times greater in hens than values that have been reported for other species.

CONCLUSIONS AND CLINICAL RELEVANCE

A standard force plate can be used to objectively measure GRFs in walking adult hens; however, the large variation in the data suggests that the technique in its current form would be of limited clinical use. Overall, vertical and craniocaudal forces had similar characteristics to those of other species, whereas mediolateral forces were found to be much greater in chickens than for other species.

Hypothalamic neuropeptide Y mRNA is increased after feed restriction in growing broilers

As part of an approach to uncover the brain mechanisms underlying the regulation of energy balance in broiler chickens, we investigated the possible role of neuropeptide Y (NPY). The NPY gene expression was measured in the hypothalamus of birds from a standard Ross male line and a Ross relaxed line. Both lines are derived from the same founder stock, but the relaxed line has not been selected for rapid growth since 1976. Birds of each line consumed feed either ad libitum or according to a standard commercial restricted feeding program. All groups of birds were killed at an average body weight of 2.4 kg. The NPY mRNA levels were significantly increased (P < 0.0001) in feed-restricted birds of both lines relative to ad libitum controls. No significant differences were detected between the lines. These results show that NPY gene expression in the broiler hypothalamus is sensitive to changes in energetic status, as it is in mammals. However, the maintenance of selection pressure for high growth rate is not associated with altered hypothalamic NPY mRNA levels in the ad libitum or restricted state.

Gait analysis of poultry

Lameness is a major problem in the UK poultry industry, however, relatively few objective studies have been undertaken into the biomechanics of normal walking in these birds. In this study, the use of a pedobarograph as a novel method of gait analysis in poultry was investigated. Unlike most systems, the pedobarograph has a recording surface with a high degree of spatial resolution, allowing pressure patterns to be established for various regions of the foot. The highest pressures were found to act on the medial toe (149.4-218 kN m(-2)) and back toe (146.1-195.5 kN m(-2)). The metatarsal pad, a region often associated with lesions, was subject to lower pressures (16.3-131.2 kN m(-2)). Maximum net forces of 116-145 per cent of bodyweight were found during normal walking, an order of the same magnitude as human bipeds. Routine spatial parameters were also measured, allowing further characterisation of the gait patterns.

Effects of caudolateral neostriatal ablations on pain-related behaviour in the chicken

As a measure of pain-related behaviour, beak guarding was investigated by recording the pecking response of adult chickens to a visually attractive stimulus before and after bilateral suction ablation of the caudolateral neostriatum (CLN). Two control groups of birds were used: a sham-operated group and an ablated group, in which the ablation was confined to the rostral dorsolateral telencephalon. Comparing the birds that had undergone ablation with the sham-operated controls showed that the ablation did not affect pecking behaviour. Five days after ablation, all birds were subjected to partial amputation of one third of the beak. A significant reduction in pecking behaviour (beak-guarding) was observed in both control groups, but was not observed in those birds that had previously received CLN ablations. In a second experiment, where beak amputation preceeded CLN ablation by 6 days, ablation did not affect the reduced pecking. The absence of guarding or other pain-related behaviours would indicate that an intact CLN was necessary for these behaviours to develop but, once they had developed, ablation had no effect.

Endogenous analgesia in the chicken

Endogenous analgesia has been identified in mammals, but little is known about suppression of tonic pain following trauma or disease. Birds suffer from gouty arthritis which can be induced experimentally by intra-articular injection of sodium urate (SU) crystals. SU injection into the ankle joint of the chicken tested in cages resulted in pain-coping behaviour (one-legged standing, sitting) together with severe lameness. Birds kept and tested in large pens showed significantly less pain-coping behaviour, while birds tested in novel pens showed either complete analgesia or marked hypoalgesia, together with a significant reduction in lameness. Complete analgesia was observed during pre-laying behaviour. These results demonstrate a remarkable ability of birds to suppress such severe tonic pain as SU arthritis.