A systematic review of animal based indicators of sheep welfare on farm, at market and during transport, and qualitative appraisal of their validity and feasibility for use in UK abattoirs.

In the UK, it has been suggested that abattoirs are ideal locations to assess the welfare of sheep as most are slaughtered at abattoirs either as finished lambs or cull ewes. Data from abattoirs could provide benchmarks for welfare indicators at a national level, as well as demonstrating how these change over time. Additionally, feedback could be provided to farmers and regulatory authorities to help improve welfare and identify high or low standards for quality assurance or risk-based inspections. A systematic review of the scientific literature was conducted, which identified 48 animal-based indicators of sheep welfare that were categorised by the Five Freedoms. Their validity as measures of welfare and feasibility for use in abattoirs were evaluated as potential measures of prior sheep welfare on the farm of origin, at market, or during transportation to the abattoir. A total of 19 indicators were considered valid, of which nine were considered theoretically feasible for assessing sheep welfare at abattoirs; these were body cleanliness, carcass bruising, diarrhoea, skin lesions, skin irritation, castration, ear notching, tail docking and animals recorded as 'obviously sick'. Further investigation of these indicators is required to test their reliability and repeatability in abattoirs. Novel welfare indicators are needed to assess short-term hunger and thirst, prior normal behaviour and long-term fear and distress.

Veterinarians and food safety.

Since the early days of veterinary science, vets have played an important part in protecting public health through controls over the safety of food of animal origin. Traditionally, public health has been treated as a topic separate from the mainstream veterinary subjects of diagnosis and treatment of animal disease. However, there is now increasing awareness of the interconnection between animal and human health, and between the work of vets in production animal practice and those in food safety and other disciplines, as Kenneth Clarke explains.

Regulation of 11 beta-hydroxysteroid dehydrogenase type 2 activity in ovine placenta by fetal cortisol.

The effect of fetal cortisol on the activity of the type 2 isoform of the enzyme, 11 beta-hydroxysteroid dehydrogenase (11 beta-HSD2), was examined in ovine placenta and fetal kidney by measuring tissue 11 beta-HSD2 activity during late gestation when endogenous fetal cortisol levels rise and after exogenous cortisol administration to immature fetuses before the prepartum cortisol surge. Placental 11 beta-HSD2 activity decreased between 128-132 days and term (approximately 145 days of gestation) in association with the normal prepartum increase in fetal plasma cortisol. Raising fetal cortisol levels to prepartum values in the immature fetus at 128--132 days of gestation reduced placental 11 beta-HSD2 activity to term values. In contrast, 11 beta-HSD2 activity in the fetal renal cortex was unaffected by gestational age or cortisol infusion. When all the data were combined, there was an inverse correlation between the log fetal plasma cortisol level at delivery and placental 11 beta-HSD2 activity, expressed both on a weight-specific basis and per mg placental protein. Fetal cortisol therefore appears to be a physiological regulator of placental, but not renal, 11 beta-HSD2 activity in fetal sheep during late gestation. These findings have important implications, not only for glucocorticoid exposure in utero, but also for the local actions of cortisol within the placental tissues that are involved in initiating parturition in the sheep.

Ground reaction force and spatiotemporal measurements of the gait of the mouse.

Measurement of ground reaction forces with force plates permits quantification of the subtle changes in movement associated with a variety of pathophysiological states. The apparatus used here permits simultaneous recording of other spatial and temporal characteristics of gait. Since the mouse is becoming increasingly important for modeling human disorders, we have recorded ground reaction forces (P) in this species. To date, we have measured the vertical component (Pz) and found it to be similar to that of other species, in that a greater Pz is exerted via the forelimb, although the areas under the force/time curves, are not different. Different points of discontinuity are seen in the forelimb and hindlimb curves, indicating differential deployment. Pz varies consistently with stance time and is consistent across the adult life of the mouse. It is suggested that the technique has potential for the study of a variety of mouse models of disease and of their therapies.

Development and consistency of gait in the mouse.

Mouse models of human disease may display developmental abnormalities or adult onset of the condition. Since many diseases are accompanied by gait disturbances, knowledge of normal gait development in the mouse and its adult characteristics might be valuable as standards against which to appraise disease progression and the efficacy of putative therapies. Assessment of the gait of mice from postnatal day (pnd) 13 to postnatal week (pnw) 80 was undertaken utilising video techniques to examine velocity, stride, stance and swing times and between pnw 29 and 80 using load cells for analysis of the vertical reaction force (P(z)) associated with limb placements. Some adult features are apparent by pnd 13, but in the hindlimb (HL) particularly, the adult pattern of relationships between stride, stance and swing are not established. Adult characteristics of forelimb (FL) deployment develop earlier than those of HL while the systems controlling HL stance develop earlier than those regulating its swing. All the features measured, however, such as the shorter stance and longer swing of FL compared to HL, are established in their adult form by pnd 24 and maintained throughout adult life. In healthy mice at pnw 80, there was no deviation from the adult pattern of gait in which P(z) transmitted via FL exceeds that via HL by around 5%. We did not detect any significant change in any other variable or in their relationships.

Post-weaning social isolation of rats leads to an abnormal gait.

The purpose of this study was to further characterize the phenotype of rats that have experienced prolonged postweaning social isolation, a paradigm that produces changes relevant to neuropsychiatric disorders. At weaning, male Wistar rats from three litters were housed socially (n = 12) or in isolation (n = 13) for 10 weeks. Isolated rats could see, hear and smell other rats. A sophisticated analysis of gait revealed that the stride duration was increased in isolates (12%, P = 0.0024) as a result of increased stance duration (18%, P = 0.0005), but there was no difference in vertical reaction force or velocity. Adrenal glands were heavier in isolates (19%, P = 0.0047). There was no difference in cross-sectional area of the brain or lateral ventricles anywhere along the anterior-posterior axis. All experiments and analysis were performed blind to housing condition. This is the first study to demonstrate that socially isolated rats have an abnormal gait. Further analysis, including pharmacological manipulation, is needed in order to understand the nature of the abnormality.

Bovine tuberculosis in free-ranging carnivores from Michigan.

During a survey of carnivores and omnivores for bovine tuberculosis conducted in Michigan (USA) since 1996, Mycobacterium bovis was cultured from lymph nodes pooled from six coyotes (Canis latrans) (four adult female, two adult male), two adult male raccoons (Procyon lotor), one adult male red fox (Vulpes vulpes), and one 1.5-yr-old male black bear (Ursus americanus). One adult, male bobcat (Felis rufus) with histologic lesions suggestive of tuberculosis was negative on culture but positive for organisms belonging to the Mycobacterium tuberculosis complex when tested by polymerase chain reaction. All the tuberculous animals were taken from three adjoining counties where M. bovis is known to be endemic in the free-ranging white-tailed deer (Odocoileus virginianus) population. There were two coyotes, one raccoon, one red fox, and one bobcat infected in Alpena county. Montmorency County had two coyotes and one raccoon with M. bovis. Two coyotes and a bear were infected from Alcona County. These free-ranging carnivores/omnivores probably became infected with M. bovis through consumption of tuberculous deer. Other species included in the survey were opossum (Didelphis virginiana), gray fox (Urocyon cinereoargenteus), and badger (Taxidea taxus); these were negative for M. bovis.

Cryopreserved femoral vein grafts for difficult hemodialysis access.

Improved survival of patients with renal failure has led to the need for complex angioaccess procedures. The use of cryopreserved femoral vein for angioaccess when prosthetic arteriovenous grafts (AVG) could not be placed, owing to infection or the loss of conventional angioaccess sites from multiple AVG failures, was prospectively evaluated. Forty-eight cryopreserved femoral vein AVGs were placed in 44 patients. Thirty-eight (82%) of the cryopreserved femoral vein AVGs were placed for infection, whereas the other 10 (18%) were placed for multiple graft failures with compromised venous outflow. Even with implantation of the cryoveins into infected patients, there were no cryopreserved femoral vein AVG infections. The 1-year primary graft patency rate was 49% and the secondary graft patency rate was 75%. During the same time interval, 68 prosthetic brachial artery-to-axillary vein AVGs were placed. The 1-year primary and secondary patency rates for the prosthetic AVGs were 65 and 78%, respectively. In this study the overall patency rate of the cryopreserved femoral vein AVGs was similar to that for the PTFE AVGs (p = 0.519). In conclusion, the cryopreserved femoral vein proved useful in difficult angioaccess cases. The lack of infection after cryovein implantation around an infected area shows promise for salvaging an angioaccess site that would otherwise have been abandoned.

Gait analysis in the mouse.

The gait of the adult Swiss (Mike Flack--MF1 subtype) mouse during spontaneous walk/trot locomotion at velocities ranging from 14-43 cm s(-1) has been analysed using simultaneous video and reaction force analysis. No differences were observed between males and females. Velocity adjustments within this range are accounted for to a greater extent (>70%) by stride time decreases and to a lesser degree (<30%) by stride length increases. Equivalent stride times for fore and hindlimbs were, in the former, composed of a shorter stance and a longer swing time. Peak vertical reaction force increases with decreasing stance time, with that for the forelimb being about 5% greater than that for the hindlimb across the whole stance time range studied. The areas under the vertical reaction force curves for fore and hindlimbs are, however, not significantly different. The results are discussed in the light of in vitro work cycle studies on the properties of some of the major hindlimb locomotor mouse muscles, and with previously established data in the rat. It is concluded that the mouse shows a consistent and quantifiable gait that would allow incorporation of locomotor assessment into the evaluation of a number of pathophysiological states.

Intestinal lymphosarcoma in captive African hedgehogs.

Two captive adult female African hedgehogs (Atelerix albiventris) had inappetance and bloody diarrhea for several days prior to death. Both hedgehogs had ulceration of the small intestine and hepatic lipidosis. Histopathology revealed small intestinal lymphosarcoma with metastasis to the liver. Extracellular particles that had characteristics of retroviruses were observed associated with the surface of some neoplastic lymphoid cells by transmission electron microscopy. These are the first reported cases of intestinal lymphosarcoma in African hedgehogs.

Listeria monocytogenes and Escherichia coli septicemia and meningoencephalitis in a 7-day-old llama.

Listeria monocytogenes and Escherichia coli were isolated from blood collected on presentation and tissues samples taken postmortem. Listeria monocytogenes was isolated from cerebrospinal fluid collected antemortem. The importance of passive transfer of immunity, the subtlety of neurologic signs in early meningitis, and considering blood-CSF penetration in antimicrobial selection are discussed.

Gait analysis in a rat model of osteoarthrosis.

Gait analysis has been undertaken in a rat model of osteoarthrosis, induced by intra-articular injection of sodium iodoacetate into the left knee. Two weeks after injection, no disturbances were recorded to the velocity of locomotion, the stride length nor the stride, stance, or swing times. However, clear and consistent reductions in the peak vertical load bearing (Pz) by the affected limb were observed of 22-29% relative to the other limbs, with the right forelimb taking the major share of extra load. This redistribution fitted well with the gait pattern of the rat, allowing Pz redistribution with minimum gait disturbance, and was still present 6 weeks later. These results are discussed in the context of the possible load sensitivity of the damage process to the gait pattern of the rat.

Differential fore- and hindpaw force transmission in the walking rat.

Previous studies suggest that the stance phase of the rat stride is initiated by a soft contact period when the forepaw may engage in tactile sampling of the terrain. However, no ground reaction force measurements have yet been made during rat locomotion. In the dog and other quadrupeds a brief or nonexistent soft contact phase is observed. Therefore, forces and pressures exerted via fore and hindpaws have been measured in the spontaneously walking rat. These indicate while the hindpaw vertical reaction forces are temporally similar to those in the dog, those transmitted via the forepaw are not. At average walking velocities the forepaw soft contact time is some 4 times longer than that of the hindpaw, with values of 207 +/- 25 ms and 52 +/- 12.2 ms (mean +/- 1 SEM) respectively. These data are consistent with the idea of forepaw useage to provide tactile information of the terrain during a prolonged initial soft contact phase, while the hindpaw transmits most of the early vertical ground reaction forces.

Gait analysis in the rat as a model for the study of peripheral vascular disease.

A number of problems are associated with investigation of the pathophysiology of peripheral vascular disease (PVD) in humans and unilateral ligation of the common iliac artery in the rat has been extensively used as an experimental model of PVD. However, techniques so far applied to monitor the effects of PVD on muscular function are invasive and difficult to relate to natural locomotion. The present study aimed to investigate gait during spontaneous, unforced locomotion in the animal model. No differences were observed between control and experimental rats in velocity or stride lengths. Although stride time was unchanged, its internal balance was disturbed with reduced stance, prolonged swing, for the ligated limb (LL) relative to the nonligated limb (NLL). Gait symmetry was also affected with NLL strike occurring earlier during LL stance. Analysis of footfall patterns showed a reduction of stance area and pressures exerted via LL relative to NLL. It is concluded that gait and footfall analysis could be useful for assessing limb function under natural exercise conditions.

Stimulation of locomotion in neonate rats by TRH analogue CG3703.

Thyrotropin releasing hormone (TRH) and its analogues have been shown to depolarise motoneurons and stimulate cyclical motor activities such as respiration and locomotion. It has been suggested that one of its roles might be modulation of neuronal membrane excitability to release intrinsic rhythmicity. The present experiments were designed to determine whether it would initiate locomotion in the neonate rat prior to the development of spontaneous walking. It was found that the TRH analogue CG3703 did activate locomotion in 3-day-old rat pups. Quantification of various gait parameters and study of spatiotemporal footfall patterns showed the gait to be indistinguishable from the spontaneous locomotion of older pups. Possible loci of action are discussed.

Development of locomotion in the rat--spatiotemporal footfall patterns.

Footfall patterns during locomotor ontogeny have been observed in Wistar rats 10-30 days old. These reveal that, even at 22 days, the paw contacts are both spatially and temporally unlike those of the adult. In the adult there is a precise presentation sequence involving early soft contact of tactile sensitive forepaw parts that may be important in tactile locomotor guidance and which is not fully established even at 22-30 days. The hindpaw contact pattern is also not yet adult-like involving a greater incidence of early toe contact. It is suggested that, only after day 15, when the forelimb is no longer the major weight-bearing limb, can it start to be developed for the fine discriminative touch required for tactile guidance of limb placement. Some further time is necessary for adult patterns to be achieved.

Analysis of walking locomotion in adult female rats undernourished as sucklings.

Suckling rats were undernourished from birth by underfeeding their mothers. They were refed from 3 weeks of age. Detailed analyses were made of the walking locomotion of previously undernourished and well-fed control female rats at 10 weeks, using electronic, computer, and TV techniques. Previously undernourished rats were found to deploy shorter stride times resulting in greater forward velocities. The shorter stride times were attained by reductions in stance time, while swing time was unaffected. No changes in stride length or width were observed, and the relationships between stride time and velocity, swing, or stance times were unaffected.

Disturbance of spatiotemporal footfall contact patterns in the rat by TRH analogue CG3703.

Administration of TRH or its analogues to a rat changes the dynamics of locomotion resulting in shorter stance times and causes postural disturbances, including hunched back and pelvic girdle elevation. Locomotor disturbance, induced by a variety of methods, results in changes to the footfall patterns during the stance phase of locomotion. The present work investigated whether these postural and locomotor dynamic disturbances in the CG3703 treated rat were associated with changes to the pattern of paw/floor contact during locomotion. It was found that in treated animals the area of hindpaw contact increased while that of the forepaw decreased from control values. The pattern of contact changed, with hindpaw stance being shifted towards more distal elements while in the forepaw a reduction in the deployment of proximal elements without any compensating increase in distal contact was seen. These results are discussed in the context of the effects of TRH analogues on sensory and motor processing in the CNS.

Swing time changes contribute to stride time adjustment in the walking rat.

Locomotor analysis is a useful tool for assessing normal and disturbed brain function. Previous studies have indicated that, during locomotion at walking velocities, the rat adjusts its velocity by changes to stride time and length. The present work has shown that, in the Sheffield strain rat, changes in stride time are achieved by a differential deployment of its two components, stance time and swing times. During slow walking, swing time changes provide minimal contribution to stride time reductions. At above average stride frequencies, however, swing time changes become significant, providing for more than half the reduction over parts of the range.