Marsupials.indd

The Sheep
Fact Sheet
David Adams & Michael McKinley
Ian Colditz# & Christina Dart*
#CSIRO, Division of Animal Welfare, Armidale NSW *Faculty of Veterinary Science, University of Sydney, Camden, NSW
Introduction
capable of concentrating urine and therefore Sheep (Ovis aries) have been domesticated for conserving water to a much greater degree than over 10,000 years and figure prominently in the strains that evolved in colder climates of story of civilisation and human survival, as Northern Europe (McFarlane, 1968). Another evidenced by numerous biblical references, well-known feature of the Merino is the copious religious practices and symbols and cultural rituals that involve this species, not to mention their importance to agriculture over several Sheep have been used as experimental subjects millennia. Sheep are widespread across the in such diverse fields of study as endocrinology world, having adapted to many different climatic and reproductive physiology, cardiovascular conditions and econiches (Ryder, 1983). During physiology, fluid and electrolyte homeostasis, the past 40 years, sheep have also been the subject of considerable research from the neuroanatomy, thermoregulation, haematology, viewpoint of physiological function and animal ingestive behaviour, nutrition and gastro- production, are now regarded as one of the most intestinal physiology. In regard to the last, chambered stomachs, sheep have been studied Many different breeds of sheep have evolved extensively in their own right, with much and intensive breeding for particular purposes knowledge accruing in regard to ruminant has resulted in many strains. The size of nutrition and animal production. The study of different breeds of sheep varies, with typical the sheep fetus has also been extensive, and body weights of ewes ranging from 30 kg for much of our knowledge of fetal physiology Welsh Mountain sheep, 45 kg for Merinos, 55 derives from these studies. Another aspect of the kg for Clun Forest breed, 65 kg for Cheviots, 75 sheep is the availability of post-mortem sheep kg for Dorset Horns and 90 kg for Lincolns tissues from abattoirs. This has enabled the (Hecker, 1983). It is worthwhile understanding collection (in vast numbers) of organs such as some of the background of the various breeds of the pituitary from the sheep, enabling the sheep and the specialisations which they may discovery and characterisation of a number of possess. For example, the ancestors of the new hormones eg. the various hypothalamic Merino, famous throughout Australia as a releasing hormones which control the secretion producer of fine wool, derive from Spain and North Africa and are highly adapted to a hot arid
ANZCCART Fact Sheet A9
Revised and Republished July, 2009
relevant to human and animal physiology and Advantages of using sheep for
experimentation
There are several reasons why sheep make Nutrition
excellent experimental subjects for physiological studies. Their body weight and size approximates to that of a human, and they composition to meet requirements for protein adapt rapidly and extremely well to a laboratory and energy, feed for sheep must also satisfy a set situation. In general they have a placid nature of interrelated behavioural and physiological factors. Ruminants have cyclical activities experimenters, possibly a result of their which are geared to demands for water and food adaptation to domestication which has occurred and rest periods necessary for the processes of over many generations. After an introduction of rumination and digestion. Sheep apply an a sheep to the laboratory pen or metabolism impressive array of behavioural adaptations to crate, and one to two weeks of regular daily their herbivorous mode of life. For example, handling, patting and food rewards, together their exploration of feed and their learned and with the company of other sheep, there results a innate preferences and selectivities are being confident, unstressed, healthy animal, with a investigated only now but should be borne in strong bond often developing between sheep and Sheep possess a complex digestive system to conscious, unstressed animals to be performed deal with their mixed diet of digestible plant successfully. The size of the sheep enables ease components and relatively indigestible cellulose. of introduction of catheters or cannulas (using Feed takes 25-35 hours to pass through the gut either local or general anaesthesia) into various and is exposed to microbial fermentation in the blood vessels, bladder, rumen, salivary duct or rumen during this time, which provides micro- cerebral ventricles for the purpose of obtaining samples of blood or other body fluids for breakdown for digestion. Sieving processes are chemical analysis. Their size also enables involved, with large particles being regurgitated sufficient blood to be withdrawn for chemical for re-mastication by the process of rumination and hormonal analysis with minimal effects on (or ‘chewing the cud’) and smaller particles of cardiovascular function, which is not always less than one to two mm passing into the possible in small rodents. Sheep recover stomach. Sheep ruminate for six to seven hours robustly from anaesthesia and experimental per day and this readily observable activity is a surgery and provided appropriate care is taken guide to health and well-being. Side benefits of are not usually troubled by post-operative or ruminal fermentation include accessory food post-experimentation infection (Hecker, 1974). factors such as water-soluble vitamins and Great care is necessary in preserving asepsis protein elaborated by microbes from simple when the brain or fetus are involved in order to Compared to rodents, sheep are long-lived and in this country are relatively inexpensive for published in the UK, the USA and Australia. their size. With the provision of adequate food The Australian treatise (Corbett, 1990) has a and water, well-maintained and well-cleaned comprehensive experimental and theoretical facilities, and sympathetic handlers and framework. Requirements of digestible organic experimenters, sheep can thrive in a laboratory matter, energy, crude protein and bypass protein, and thoughtful, well executed experiments can fibres, minerals and vitamins given in these yield a wealth of physiological information standards are average values. Under practical
ANZCCART Fact Sheet A9
Revised and Republished July, 2009
conditions, however, individual responses of cougar was eaten compared with 95% of similar sheep must be accounted for and animals have Investigators working with housed sheep must Two simple and well accredited rations for also be aware of the critical need these animals laboratory sheep are a 50% mixture of lucerne will have for physical fibre (rumen ‘scratch’ and wheaten chaff, and a pelleted ration factor). The demand for rumination / salivation composed of lucerne chaff (50%), wheat grain behaviour is important and failure to provide (10%), bran (18%), pollard (20%), and crude physical fibre (ie roughage > 5cm) results in salt (2%) (to control urinary calculi by increasing fluid intake). Although lucerne chaff stereotypic bar chewing etc), some of which can is valuable for its high concentration of calcium result in pathology (wool ‘balls’) and serious as well as protein, its quality can vary stress to sheep that become the target of biting. considerably and is a factor to consider if performance is unexpectedly low. In most other Some merino sheep can survive for up to 10 rations, calcium demands have to be met by the days without water and can lose one-third of addition of ground limestone. Nutritional their liveweight in the process. Requirements deficiencies have not been observed with the range from 2.4 litres per day for growing sheep two rations described above. A guide to the of 30 kg body weight to 12 litres per day for 60 weekly feed requirements for maintenance of kg ewes in early lactation. Water requirements different classes of sheep is given in Table 1. for sheep in the laboratory are met by ad libitum access to clean water. The same imperatives apply whether troughs or self-drinkers are used. Water must be clean, free flowing and algae-free Class of sheep
Hay Oats Wheat
Faecal contamination and faecal odours may inhibit drinking and predispose to urinary calculi. Water supply throughout a sheep house must be able to cope with peak demand on a hot The maintenance requirement for a 35 kg wether is 5.2 megajoules per day. This is provided by a weekly intake of 2.8 kg of maize, 3.0 kg of Being highly social animals, sheep must always either wheat, barley or sorghum or 3.6 kg of be transported and housed in groups or at least oats, which indicates the relative energy of these in pairs so that they are always able to see grains. At a practical level, the addition to these another sheep. Without this ‘social contact’ grains of 15% by weight of lupins gives an impressive lift in feed value because of its high distressed. If absolutely necessary, sheep may content of non-degradable or bypass protein. be kept in front of a full length mirror for short Factors such as adequate trough space to prevent periods to prevent the stress of isolation competition and storage conditions to protect becoming a problem, but it must be emphasized feed against contamination are important that this is only a short term (hours maximum) components of good feeding practice. Work on the effect of olfaction on feed selection in the Sheep breeds vary widely in their capacity to contaminated by faecal odours of coyote, fox or adapt to heat and cold. Like all mammals, sheep are forced to increase heat production to
ANZCCART Fact Sheet A9
Revised and Republished July, 2009
animal care because it diverts attention from the environmental temperature drops. The critical animals themselves. Unless there are specific temperature at which this occurs varies from experimental requirements, sheep ought to be 0°C for adult sheep in full fleece to 20-25°C for able to move around in an individual pen and be newly shorn animals to 30-36ºC for new born able to lie in an orientation they choose. Groups lambs. Shorn adult merinos can bring peak of more than 12 in a pen may lead to erratic metabolism into play to withstand ambient results in experiments. Groups of eight may be temperatures of -60°C. At the other extreme, acceptable. Experiments in which groups of 50- merinos are farmed for wool production under 60 sheep are held in single large pens are probably invalid because of the behavioural temperatures of 49°C. Coping mechanisms are stretched to withstand these extremes and give no guidance to the conditions required in sheep In spite of possessing a fleece, sheep have limits to their heat and cold tolerance. Roof extractor fans are important for the summer heat. Sheep Sheep can be housed simply but require full should not be housed in contact with corrugated protection against wind, rain, extremes of iron walls that face the summer sun. Even sheep temperature and humidity. Timber, even though which are fully fleeced will die if exposed to cold wet winds. Thought must be given to sleet construction and is probably superior to metal. and gales blowing up though slatted floors. However, it may not be acceptable for housing off-farm where presentation is important. Fittings must not provide injurious hazards Management
when sheep are being moved. The commonly available metal floors are unsuitable for long Virtually all sheep in Australia have fleeces term housing of sheep because sheep become rather than hair and must be shorn each year. If footsore on them and show hesitancy in moving housed sheep are dipped immediately after and lying down. Traditional slatted hardwood shearing to control lice, mortalities of 10-15% floors as used in shearing sheds are satisfactory from septicaemia can be expected and the and superior to concrete. Wooden floors may be surviving sheep will have hepatic, splenic and considered more difficult to maintain in some situations where cleanliness of surfaces is paramount, so slatted hard plastic floors may be Overgrown hoofs occur when sheep are housed. a suitable alternative. The plastic does have the disadvantage of becoming slippery when wet, conform to the anatomy of the foot so that sheep however drop - through slats for urine and can stand and walk normally. Feet bleed when faeces can eliminate the need for regular the living tissue involved in the hoof growth washing down and provided the sheep ar not tissue is cut and healing of this damaged tissue will distort the foot. Competent trimming and consideration is to have slats run opposite to, inspection of feet cannot take place unless the and not parallel with, the direction in which Diseases
Space allowance should be determined from basic principles. Areas of 1.2 square metres per sheep are suggested as a guide. However, literal diseases of an infectious, parasitic, nutritional or neoplastic nature. It is beyond the scope of this undesirable scenario for developing considerate article to examine these. Disease is not a major
ANZCCART Fact Sheet A9
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concern in well-housed sheep which have been (19 mg/kg body weight), into the jugular vein vaccinated against the common clostridial and after intubation of the trachea, anaesthesia diseases and are free of footrot and lice at the can be maintained at the correct depth for outset. However, sheep in sheep houses can several hours by inhalation of a gas mixture of become fly-blown. Infection with Strongyloides isoflurane with air/oxygen. Prior to general papillosus can occur where animals are held on anaesthesia, animals should be deprived of water concrete which is hosed down and there is a and food for 24 hours to limit regurgitation. The reservoir of this nematode parasite in the most convenient blood vessel for making an cohabiting population of rats. Posthitis can be a intravenous injection or for obtaining blood problem and requires early intervention where it samples is the jugular vein. It is important to occurs. Urolithiasis occurs relatively frequently make sure that this region of the neck has been in some animal houses and should prompt a well shorn. Skin should be cleaned and sterilised complete review and overhaul of the watering before needles are inserted into the vein. An system to ensure that sheep have access to iodine - alcohol solution is satisfactory for this purpose and as a surgical skin preparation. Dietetic disorders can occur in housed sheep and conveniently inserted into the jugular vein are most commonly associated with high grain through a needle. Local anaesthesia around the diets, which entail the risk of lactic acidosis, point of insertion should be utilised when larger particularly if sheep unused to grain are allowed gauge needles are introduced into a vein. Indwelling cannulas should be removed as soon incapable of adapting to pelleted rations with as possible after use to minimise thrombus high grain content. Copper toxicity has been formation. Urine may be continually collected reported in housed sheep and can be controlled from a retention catheter inserted into the by access to soil to provide molybdenum. For bladder. By using a speculum to expose the further information see Brightling (1988) and urethral opening, bladder catheterisation is a simple procedure in ewes, but catheters should not be left in the bladder for more than 2-3 days as discomfort will ensue. Saliva from the parotid Zoonoses

A few diseases can be transmitted to people who polyethelene cannula inserted into the parotid are in contact with sheep tissue or in the duct and brought to the surface through the environment of sheep. These include Q-fever (a threatening consequences) and scabby mouth, a A number of surgical procedures have been adopted successfully in sheep to prepare them for experiments some weeks later. These Echinococcus granulosus can infect various organs of the sheep. The cysts in sheep are preparations allow access to blood vessels or harmless to humans, but sheep offal should not specific organs in the conscious, undisturbed be fed to dogs. For further information on animal during experiments. For example, the carotid artery (s) can be enclosed in loops of skin in the neck (Denton, 1957), allowing access to arterial blood for sampling or for easy measurement of arterial blood pressure. The Anaesthesia and some general experimental
copious skin folds of the neck of the Merino Techniques
make this breed or its cross-breeds ideally suited Sheep respond well to and recover quickly from autotransplantation of glands such as the adrenal general anaesthesia. General anaesthesia can be gland (Goding and Wright, 1964) or ovary induced by an injection of sodium thiopentone
ANZCCART Fact Sheet A9
Revised and Republished July, 2009
(Goding et al., 1967) into the neck for ease of indicated blood samples collected from the access. This technique has been utilised jugular vein should be analysed to assist in determining health status or to provide pre- reproductive physiology of sheep. Stereotaxic frames (Radford, 1967) and atlases (Richard, 1967; Welento et al., 1969; McKenzie and Smith, 1973) have also been described for use in 2. Pre-anaesthetic sedation & induction
neurophysiological studies in sheep, and cerebrospinal fluid samples can be obtained or intracerebroventricular infusions made through guide tubes permanently implanted into the lateral or third cerebral ventricles or cisterna magna (Mouw et al., 1974). Rumen fistulae can be prepared to gain access to the rumen (Hecker, Note: Following sedation a 16 gauge 3 ¼ or 5
¼ inch percutaneous jugular catheter
should be placed and secured to allow for
Euthanasia can be performed by intravenous administration of induction agents,
injection of sodium pentobarbitone (at least 100 supplemental parenteral anaesthetics and
analgesics, and IV fluids. When using
Ketamine for induction diazepam may
have to be readministered following
Problems & complications associated with
catheterisation and before ketamine
general anaesthesia in sheep:
administration. Sheep should be placed in
sternal recumbency and the head
supported in elevated position before
Regurgitation & aspiration of rumen content administering induction agents.
Other peripheral veins can be catheterised
but in our experience the jugular vein is
most suitable for catheter placement and
for catheter maintenance.
A variety of premedication/induction protocol for general anaesthesia in sheep have been described, but we use the above protocol 1. Pre-anaesthetic preparation
and safe condition for intubation without In sheep food should be withheld for 24 hours environmental temperatures and animals’ Endotracheal intubation
Ideally body weight should be obtained as sheep In the dorsally or sternally recumbent sheep a tie can vary in weight fro 35-65 kg depending on (soft rope or similar) is placed around each breed, sex, and health status. A physical the upper and lower jaw to facilitate opening temperature, cardiac function, pulmonary elevated and extended. Using a laryngoscope ventilation, and hydration status including the larynx is visualised and approximately 2 ml of lignocaine 20% is dripped on to the larynx using a syringe with 5 ¼ inch catheter
ANZCCART Fact Sheet A9
Revised and Republished July, 2009
without stylet (alternatively local anesthetic halothane and isoflurane maintenance. It was spray can be used). The endotracheal tube our experience that when using parenteral (ET) is inserted, secured and the cuff inflated. At this point the head can be lowered and the monitoring had to be intense as individual patients have different anaesthetic dose requirements which if not adjusted has the Note: ET sizes for adult sheep may vary from
7.5 – 9.0 mm internal diameter. ETs need
anaesthesia does not eliminate the necessity to have a cuff and cuffs need to be checked
for leaks beforehand. A guide or stylet can
regurgitate regardless of the maintenance be used to facilitate intubation. A guide
can either be placed in the lumen of the ET
advantage of the sheep breathing an oxygen for reinforcement or introduced into the
trachea and the ET subsequently fed over
it. In the latter procedure the guide has to
hypoxaemia in this species. In our experience be at least twice the length of the ET. Once
the sheep is positioned for surgery the cuff
inhalation and parenteral anaesthesia to be pressure should be checked by
comparable i.e. good. Parenteral anaesthesia compressing the rebreathing bag and only
leave enough air/pressure in the cuff to
provide an airtight seal.
Maintenance of anaesthesia
anaesthetics in veterinary practice including isoflurane, and sevoflurane are suitable for maintenance of anaesthesia. The anaesthetic Typical vaporiser setting for maintenance with agent of choice is isoflurane. Halothane is rapidly losing acceptance as an anaesthetic agent due to its occupational health and anaesthetising sheep to run the vaporiser safety risks to operating personnel. It also For administration of inhalation anaesthesia limited by its high cost of purchase compared to either halothane or isoflurane. In humans, breathing systems with a soda lime container of 1-2 litres and a 2-3 litre rebreathing bag sevoflurane anaesthesia exceeds that with isoflurane. Parenteral protocols including Supportive care and monitoring
ketamine administered in increments when needed or given as a constant infusion have been used. We found parenteral maintenance Proper positioning and padding: padding of not to have significant advantages if used 3-5 cm thick foam mattress or similar, neck area should be elevated by placing rolled up parenteral maintenance may be of advantage in special circumstances) and unless the duration of anaesthesia is short (< 30 min)
ANZCCART Fact Sheet A9
Revised and Republished July, 2009
Temperature maintenance: despite the fleece time the anaesthetic level can be increased
if required.
anaesthesia and measures similar to those commonly used in small animal anaesthesia Cardiopulmonary parameters: During
should be used i.e. heat lamps, insulating inhalation anaesthesia both blood pressure blankets, heat pads. Hypothermia decreases and pulmonary ventilation will decrease with increasing anaesthetic depth. Mean arterial blood pressure should be above 60 mmHg in order to maintain adequate tissue perfusion. Fluid therapy: Polyionic fluids containing an As a general rule if blood pressure in a major alkalinizing agent are ideal (Hartmann,s, ventilation, the product of tidal volume and Monitoring:
inhalation anaesthesia, mostly due to reduced tidal volume. Normal respiratory rate and Physical signs: Possibly the best method for
tidal volume in awake sheep is around 40 breaths/min and 7 – 10 ml/kg respectively combination of corneal reflex (opening the eye with two fingers and lightly touching the anaesthesia. Shallow breathing as gauged by movements of rebreathing bag can indicate (constricted pupils are more rectangular deep anaesthesia. Ideally capnography and or while dilated pupils are oval shaped; the shape of the pupil (where clearly visible) is a performed to assess ventilation objectively, good indicator of anaesthetic depth. The particularly during prolonged anaesthesia. most definitive indicator of anaesthetic depth Blood pressure/tissue perfusion
indicate inadequate anaesthetic depth. Active Blood pressure: The auricular artery on the
abaural surface of the ear, the saphenous artery, and the digital artery can be palpated movements is another reliable sign of light level of anaesthesia. Passive regurgitation characterised by a continuous flow of rumen anaesthetics of longer duration. The Doppler During light anaesthesia the eyes may be positioned dorso-laterally and muscle tone in ventral surface of the distal carpus and the the eye lid and palpebral reflex present. A centrally positioned eye with dilated pupil, provides a means of assessment of systolic relaxed eyelid and absent palpebral reflex pressure. As a rough guideline if systolic pressure is less than 80 mmHg hypotension is severe enough to result in inadequate Note: Determination of anaesthetic depth in
tissue perfusion. Systolic, diastolic and mean sheep using physical signs is relatively
arterial blood pressure can be measured from difficult and if uncertain about the level of
anaesthesia should be reduced until signs
of light anaesthesia are evident at which
electronic pressure gauge which will. Catheterisation of the auricular artery is
ANZCCART Fact Sheet A9
Revised and Republished July, 2009
awake sheep. Mean pressure in anaesthetised Tissue perfusion: Mucous membrane colour is
repositioned in sternal recumbency or near used as an indicator of tissue perfusion, sternal recumbency to allow for rumen gas to although the method is subjective. Pulse escape. The ET with the cuff inflated
should be left in place until the sheep are
swallowing spontaneously and can be seen
saturation with oxygen. The clothe pin like to make chewing motions. The ET is then
probe can be placed on the tongue and the removed with the cuff inflated. Ensure
pulse oximeter displays a continuous pulse that patient can breathe i.e. move air.
(SpO2). As a general rule efforts should be Efforts should be directed towards warming the profuse salivation in anaesthetised sheep the animal using insulting materials like blankets or external heat sources such as heat lamps Placing one or two layers of a gauze swab between the tongue and probe may overcome Pain management and analgesia
Capnography
physical discomfort and stress which result cardiopulmonary, endocrine, metabolic and patient and provides a continuous is measure of pulmonary ventilation. The end expiratory ruminants generally is difficult. Painful anaesthetised sheep the difference between arterial and alveolar CO2 can be up to 10 including tachypnea, tachycardia, elevated ideally be used in conjunction with arterial Interpretation of behaviour as an indicator blood gas analysis i.e. at least one arterial of pain is difficult and sheep being herd blood sample should be analysed in order to animals and animals of prey generally do determine the accuracy of capnography in a not display overt signs of pain. Behaviour particular patient. In awake sheep normal indicating pain may include abnormal gait arterial PCO2 is around 35 mmHg and during or stance, vacant stare, teeth grinding, will lead to cerebral oedema and patients remain unconscious long after termination of inappetence, and separation from flock and using capnography efforts should be made to designed considering the type and duration avoid any increase from values obtained in of painful procedure and aiming at critical
ANZCCART Fact Sheet A9
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be an option for prolonged, possibly up to 3 ƒ Buprenorphine at a dose of 0.005-0.01
cutaneous analgesia (thermal stimulus) for 3-4 hr duration. It can be readministered at analgesia in sheep is controversial. Most 4-6 hr intervals by IM, SC route. Onset of information on opioid analgesia in sheep is based on experimental data and should be applied to clinical conditions with care. In ƒ Butorphanol doses range from 0.1-0.5
general opioids in sheep are less useful for responsiveness to thermal stimuli at lower fentanyl are poorly effective in sheep when sedation and decreased responsiveness to analgesia and sedation in sheep both when questionable wether butorphanol provides administered systemically and epidurally. visceral analgesia. Butorphanol can cause Sedation generally outlasts analgesia. α ƒ Xylazine at a dose of 0.05 mg/kg IV can
produce good analgesia for mechanical and thermal painful stimuli for approximately their antiinflammatory effects peripherally ƒ Detomidine, 0.05 mg/kg IM has been used
but in sheep seem to also have centrally analgesic duration than xylazine and less ƒ Medetomidine 0.005 mg/kg produces
analgesia and sedation for approximately 1 hr. Side effects are likely similar to other α2 intestinal ulcerations. Due to the longer duration of action and absence of sedative ƒ Flunixin (2.2 mg/kg IV) is an effective
analgesic in sheep although less potent than are particularly suitable for preemptive readministration of 2.3 mg/kg Q 12 hrs or 1.1 mg/kg Q 8 hrs has been recommended. The following may be useful when planning
analgesic therapy:
ƒ Phenybutasone IV or PO at a dose range
of 2-6 mg/kg can be used in sheep and presumably similar to cattle readministered Parenteral analgesia
Fentanyl at a dose of 0.01 mg/kg IV
provided analgesia of rapid onset but short ƒ Carprofen has been studied in sheep and
duration (< 1hr) for painful mechanical and thermal stimuli. Fentanyl may precipitate provide a therapeutic plasma levels for at abnormal behaviour. Transdermal fentanyl i.e. fentanyl patches (100 µg/60 kg) might ƒ Pethidine (2.0 mg/kg i.m.) is an effective

ANZCCART Fact Sheet A9
Revised and Republished July, 2009
experience strong post-operative pain that will offer 24 hours relief. Pethidine causes junction, which results in penetration of the meninges, evident by CSF appearing in the ƒ Meloxicam (0.5 mg/kg s.c., i.v. every 24
needle. Injection of local anaesthetics will result in loss of sensory and motor function in the pelvic area including the hind limbs. analgesia include the local anaesthetics and α2 - adrenergic agonisits. Xylazine (20
Local and regional anaesthesia/analgesia mg/ml) at a dose of 0.05 mg/kg (± 2 mg in Using local anaesthetics as an adjunct to 1ml saline) or detomidine at a dose of 0.01
general anaesthesia can greatly improve the injected into the CSF (subarachnoid space). Intrathecal xylazine has a fast onset of Lignocaine and bupivacaine are the most
analgesia (±100 min) and produced higher veterinary practice. Lignocaine has a rapid detomidine (onset ± 50 min, duration ±60 onset of action (minutes) and short duration administered α2 - adrenergic agonisits. has a slow onset of action (15-20 min) and Doses i.e. volume of lignocaine (2%) and
longer duration of action (4-6 hrs). The bupivacaine (0.5%) for subarachnoid
toxic dose of lignocaine if given IV is 3-7 lumbosacral anaesthesia is 0.1-0.15 ml/kg. Volumes for local infiltration should not Table 2. Useful physiological data on sheep. anaesthesia/analgesia in combination with modifications from Hecker (1983) and Scoggins Local anaesthetics can be used for analgesia in the forelimb, (brachial plexus nerve block), intraarticular analgesia, analgesia of lateral (intrapleural block 1.5 mg/kg bupivacaine) Epidural and spinal anaesthesia/analgesia
Epidural analgesia is achieved by depositing a spinal canal outside the meninges. Spinal subarachnoid space, which is smaller than the epidural space. In sheep the technique practiced. The spinal needle is placed into
ANZCCART Fact Sheet A9
Revised and Republished July, 2009
Cottle, D.J. (ed.) (1991). Australian sheep and Table 3. Concentrations of some ions and wool handbook. Inkarta Press, Melbourne. molecules in plasma, cerebrospinal fluid (CSF), Denton, D.A. (1957). The study of sheep with a measurements were adapted with modifications permanent unilateral parotid fistula. Quarterly from Hecker (1983) and Scoggins et al., Journal Experimental Physiology, 42:72-95.
Goding, J.R. and Wright, R.D. (1964). An improved method of preparing cervical adrenal transplants in sheep. Australian Journal of Experimental Biology and Medical Science, 42:443-448.
Goding, J.R., McCracken, J.A., and Baird, D.T. (1967). The study of ovarian function in the ewe by means of a vascular autotransplant technique. Journal of Endocrinology, 39:37.
Hecker, J.F. (1974). Experimental surgery on small ruminants. Butterworths, London. Hecker, J.F. (1983). The sheep as an experimental animal. Academic Press, London. surgery equipment for ovine surgery. Journal of References and further reading
Investigative Surgery, 7:151-158.
Abraham, S.F., Coghlan, J.P., Denton, D.A., Hewat, T. (1990). The Florey - The story of the Increased water drinking induced by sodium Sheep Hilton. Angus and Robertson, Sydney. Lynch, J.L., Hynch, G.N. and Adams, D.B. Experimental Physiology, 61:185-192.
(1992). The behaviour of sheep: biological principles and implications for production. CAB International, Wallingford, UK. Veterinary medicine, Seventh edition. Balli re,Tindall, London. comparative functions of ruminants in hot environments. In Adaptations of Domestic Coop, I.E. (1990). Feeding standards for Animals, Hafez, E.S.E., (ed.) Lea and Fiebiger, Philadelphia. Pp 164-182 and 264-276. Australian livestock - Ruminants. CSIRO, Melbourne. Maijala, K. (Ed.) (1991). Genetic resources of Corbett, J.C. (1990). Standing Committee on pig, sheep and goat. Elsevier Science Publishers B.V., Amsterdam. Agriculture, Ruminants Subcommittee. Feeding Standards for Australian Livestock: Ruminants. CSIRO, Melbourne.
ANZCCART Fact Sheet A9
Revised and Republished July, 2009
Ryder, M.L., (1983). Sheep and man. Stereotaxic method and variability data for the brain of the Merino sheep. Journal f.r Hirnforschung, 14:355-366.
Scoggins, B.A., Coghlan, J.P. and Denton, D.A. (1984). ACTH-induced hypertension in sheep. Mouw, D.R., Abraham, S.F. and McKenzie, J.S. In: Handbook of Hypertension, Vol.4 (1974). Use of ventriculo-cisternal perfusion in Experimental and Genetic Models of conscious sheep. Laboratory Animal Science, Hypertension, Edited by W. de Jong, Elsevier 24:505-509.
Science Publishers B.V. Amsterdam, pp. 107- Postgraduate Committee in Veterinary Science, University of Sydney (1990). Sheep medicine. Stevenson, W.J. and Hughes, K.L. (1988). Synopsis of zoonoses in Australia. AGPS, hypothalamic lesions on reproductive activity in sheep. Journal of Endocrinology, 39:415-422.
Welento, J., Szteyn, S. and Milart, Z. (1969). Observations on the stereotaxic configuration of Richard, P. (1967). Atlas sterotaxique du the hypothalamus in the sheep. Anatomica Anz., cerveau de brebis. Institut National de la 124:1-27.

ANZCCART Fact Sheet A9
Revised and Republished July, 2009

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