Health & Management / Ruminants Pain Management / Techniques and protocols OVERVIEW:
Pain Management for Foot and Joint Lesions in Sheep and Goats:
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Introduction and General Information

"Lameness is defined as the inability to progress with a normal gait, because of pain or impairment to locomotion." (N13.9.w1)

Lameness in sheep is very common. (J15.1.w1, B343.w4) It is recognised as being one of the most important welfare issues which affects the sheep industry in the UK. (J15.26.w1, D153)

  • "The degree of lameness tolerated in sheep flocks would be unacceptable in any other species" (B348.16.w16)

Footrot and interdigital dermatitis (scald) are the most important and widespread causes of lameness in sheep in the UK (J15.26.w1)

Other causes include:

  • Interdigital "balling" of grass and soil;
  • Interdigital hyperplasia;
  • Contagious ovine digital dermatitis;
  • White line degeneration with necrotic tracts and pus in the wall of the foot;
  • White line abscess;
  • Sepsis of the pedal joint;
  • Granulomas (usually toe granuloma);
  • Laminitis
  • Gross hoof overgrowth leading to splitting and exposure of sensitive hoof structures;
  • Non-foot problems including injury, joint-ill, post-dipping lameness (local cellulitis and polyarthritis due to Erysipelothrix rhusopathiae invading the skin from contaminated dips), strawberry foot rot (combined orf and Dermatophilus infection), and muscular dystrophy.

(B343.w4, J15.26.w1)

In goats most causes of lameness are associated with the feet. (N13.9.w1)

NOTE: It is important to remember that lameness in sheep, usually affecting more than one leg of each affected sheep, varying from very mild to reluctance to move, and with or without mouth lesions, may be a sign of Foot-and-Mouth Disease (FMD). This should be considered as a cause of lameness particularly when FMD is known to be present in an area. (B343.w4, B359.14.w14) In goats FMD may cause crippling lameness with the affected animals walking on their knees or remaining recumbent. (N13.9.w1)

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Signs/Evidence of pain associated with the condition

It is generally accepted that lameness in sheep and goats, for example due to footrot, penetrating foreign bodies, toe granulomas or arthritis is painful, often very painful. (B343.w4, B348.16.w16, J15.1.w1, J15.13.w5, N13.9.w1).
  • Lameness is an important behavioural sign of pain and in most cases an individual is lame due to pain. (B322.4.w4)
    • There are some lameness conditions which are due to mechanical dysfunction. (J3.118.w4)
  • Sheep with lameness, for example due to footrot, commonly graze standing on their knees; this reduces pain due to weight bearing on the feet. (B322.4.w4, J15.1.w1)
  • Lame sheep may also show a general reluctance to move. (B325.w6)
  • Foot abscesses cause severe acute lameness, often with the affected foot being completely non weight-bearing and the sheep spending long times lying down. (B217.36.w36)
  • In sheep with septic pedal arthritis the affected limb is often non-weight-bearing even at rest. (J15.17.w3)
  • Localised pain may be evident, for example pain on handling of the coronary band of the affected digit in sheep with septic pedal arthritis. (J15.17.w3)
  • Pain together with heat and swelling are the classical signs of acute foot lameness. (B359.14.w14)
  • In goats, pain is recognised as one of the main signs associated with most lesions of the feet. While lameness may only be mild with some conditions such as interdigital dermatitis, many foot problems are associated with acute and sometimes crippling lameness. (N13.9.w1)
    • In addition to lameness, local pain may be noted with lesions. (N13.9.w1)
  • In acute laminitis "general tenderness of the feet, disinclination to walk, prolonged recumbency, tooth grinding, and other signs of pain." are seen. (N13.9.w1)
  • In joint diseases further proximal on the legs, acute lameness is seen. In joint ill of kids the joints are enlarged and filled with pus, while in infectious arthritis caused by Erysipelothrix rhusiopathiae the joints are very painful although not obviously enlarged. (N13.9.w1)
  • In blackleg (Clostridium chauveoi infection of the muscle) the affected area is typically swollen, tense and painful. (N13.9.w1)

Physiological changes in response to chronic lameness:

  • Lowered nociceptive thresholds:
    • Sheep with footrot showing behavioural signs of moderate to severe pain were shown to have significantly (P<0.05 for those in the low severity group based on clinical signs and lesion assessment, P<0.01 for those in the high severity group) reduced mechanical pain thresholds (tested using a device attached to the leg) compared to control sheep without footrot, but did not show any reduction in thermal pain threshold (tested using a device attached to the ear). It was suggested that the differing results between the thermal and mechanical test might be due to the increased sensitivity being mediated at the spinal or peripheral level (the innervation from the ear via the auriculo-palpebral nerve to the facial nucleus is essentially a supraspinal system). It was also noted that in individuals with severe lameness and lesions, mechanical thresholds were still reduced three weeks after treatment, at a time when the lesion had apparently resolved, but thresholds returned to near normal by three months after treatment. (J297.39.w1)
    • Sheep with chronic lameness (at least one month duration) with severe footrot lesions causing severe lameness, were shown to have a significantly (P<0.001) reduced threshold to mechanical stimulation when compared with control sheep from the same flocks; the thresholds were still reduced (P<0.01) three months later after treatment. Mildly affected sheep did not show a reduced threshold to mechanical stimulation. (J3.137.w6)
  • Spinal receptor sites:
    • It has been shown that sheep with chronic pain due to footrot have increased numbers of alpha-2 adrenoceptor and mu opioid receptors in the spinal cord, mainly in areas associated with nociception. The affinity of the binding sites were not changed. (J297.42.w1)
  • Plasma hormone levels:
    • Sheep which were severely lame with footrot, kept in a small group, had increased plasma prolactin concentrations compared to control sheep, although there were considerable variations between individuals and the results were not statistically significant; three months after treatment levels were still raised and were significantly (P<0.05) higher than the levels in control sheep. Plasma cortisol levels were significantly (P<0.05) lower in sheep with severe footrot than in controls and was still slightly lower than that of controls (not significant) three months after treatment. Vasopressin levels were not significantly different from those of control sheep, although there was considerable individual variation; levels dropped to significantly below the values for control sheep by three months after treatment. (J3.129.w4)
    • Sheep in a large flock with lameness due to footrot showed significantly (P<0.001) higher concentrations of plasma cortisol than those seen in healthy sheep; three months after apparent resolution of the clinical footrot lesions, cortisol levels remained significantly raised over those of normal sheep (P<0.01). Cortisol levels were significantly raised in all lame sheep including those with a low combined (lameness and lesion) score. (J21.57.w1)
      • It was noted that the raised cortisol seen in these sheep was opposite to the lowered cortisol seen in a previous experiment with sheep kept in a small group and it was suggested that the lowering of cortisol may be a direct response to chronic pain while the raised cortisol may be a response to stress associated with lameness of sheep within a flock. (J21.57.w1)
  • Plasma catecholamine levels:
    • Sheep which were kept in a small group and were either mildly or severely lame with footrot showed significantly (P<0.001) higher levels of plasma adrenaline and plasma noradrenalin than normal sheep. Plasma catechalamine levels remained raised following treatment (P<0.01) and in three sheep with severe footrot tested at three months after treatment noradrenaline concentrations were still significantly (P<0.001) elevated above values in control sheep. It was noted that the findings, particularly the continued elevation of plasma catechalamines after resolution of lameness and lesions indicated "other than simple activation of the stress response to pain". (J21.53.w1)
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Negative effects of pain associated with the condition

  • Lameness in sheep can result in significant production losses (B343.w4, B346.w4), for example:
    • A decrease of 0.5 kg/week in the weight gain of a fattening lamb; (B343.w4, B346.w4)
    • Inadequate food intake by pregnant and lactating ewes, contributing to pregnancy toxaemia and neonatal diseases. (B343.w4)
  • Lame sheep spend less time eating and have a reduced ability to compete for food with their healthy flockmates. (J15.26.w1)
  • Lame sheep spend much time lying down or grazing while on their knees. They rapidly lose body condition. (J15.1.w1)
  • Rams lame during the pre-tupping period are unlikely to reach/maintain adequate body condition. Rams in poor body condition are likely to have reduced sperm production and therefore decreased fertility. (J15.1.w1, J15.26.w1)
  • Ewes lame during the pre-tupping period have lower ovulation rates and lower lambing percentages. (B217.36.w36, J15.26.w1)
  • Rams which are lame during the tupping period will mate with fewer ewes; this may reduce conception rates. (J15.26.w1)
  • Ewes lame during pregnancy lose body condition and are therefore predisposed to metabolic diseases such as pregnancy toxaemia. (J15.1.w1, J15.26.w1)
  • Ewes lame during pregnancy may give birth to lambs of low birthweight, provide poor colostrum and have reduced milk production: this can lead to increased mortality of the lambs. (J15.26.w1)
  • Lambs which become lame, for example due to footrot caught from lame ewes, have reduced growth rates and delayed fattening. (J15.26.w1)
  • Rams which are lame during the tupping period have a reduced capacity to mate. (B217.36.w36)
  • Wool quality of lame sheep is adversely affected. (B217.36.w36)
  • Individuals spending long times recumbent may develop decubitis ulcers. (B217.36.w36)
  • Lambs lame with arthritis have reduced mobility and may be more vulnerable to predators. (B217.37.w37)

Further information on the negative effects of pain is provided in: Reasons for Pain Relief - Disadvantages of pain to the animal

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Reasons why pain associated with the condition should be treated

Pain associated with foot and leg problems causing lameness in sheep should be treated for reasons of welfare; treatment may also be advantageous to the farmer in terms of increased production.

Welfare:

  • Lameness in sheep is a welfare issue. (J15.26.w1)
    • Lame sheep "suffer misery and severe pain." (J15.1.w1)
  • Lameness in sheep may result in adverse effects on production (e.g. decreased fertility, reduced growth rates of lambs). (J15.26.w1)

Economic and practical considerations:

  • The chronic pain state associated with problems such as footrot prevents normal feeding and is likely not only to cause suffering but also to affect the anabolic/catabolic metabolic balance and therefore to impair growth. (B323.1.w1)
  • Lameness in sheep is associated with significant production losses: decreased fertility of rams and ewes, increased incidence of pregnancy toxaemia, increased neonatal losses and decreased weight gain of fattening lambs. Effective treatment should be carried out to prevent this. (J15.1.w1, B343.w4)

Further information is provided in: 

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Suggested methods of pain alleviation

Note: Many publications, whilst recognising pain as a symptom of a clinical condition in ruminants and using it in diagnosis, do not address pain alleviation in the treatment of the condition. This may partially be due to the fact that pain management is a relatively recent discipline and its importance is only now being recognised. (V.w5, V.w6)

Prevention of development of lameness:

  • Feet of sheep should be examined regularly (twice a year) and overgrown feet treated as required. (J15.1.w1)
  • Individual sheep should be looked at and treated as required in addition to twice-yearly routine checks on the whole flock. (J15.1.w1)
  • Use of rams with poor conformation which may predispose to foot problems should be avoided. (J15.1.w1)
  • The report of the Farm Animal Welfare Council in 1994 were "firmly of the opinion that more must be done to reduce the incidence of lameness, in particular that due to footrot which is an infectious disease and for which there are well-recognised control methods available." (D153)
  • For some causes of lameness it is possible to take prophylactic measures to reduce their occurrence. Examples of causes of lameness which may be prevented or controlled by prophylactic measures include footrot (an energetic programme of trimming and foot bathing, vaccination in some cases), post-dipping lameness (good dip hygiene with cleaning of the tank and regular replenishment of dip), nutritional muscular dystrophy (ensure dietary levels of vitamin E and selenium are adequate in ewes in late pregnancy, supplement orally or by injection if required). (B343.w4)
  • Newly purchased sheep should be kept separate from the flock for at least ten days and any lameness treated urgently during this time. (J15.1.w1)

Treatment of the causes of lameness:

  • Effective treatment for conditions causing lameness should cause both resolution of the lesion and a return to normal gait. In an experimental study it was noted that with daily treatment of footrot by foot paring, topical antibiotic/antiseptic spray and if necessary systemic antibiotics, full resolution of lesions and lameness normally took about 21 days. (J3.129.w4)
  • Correct diagnosis of the cause of lameness and treatment to eliminate the disease condition causing the lameness is important. This is often the only form of pain alleviation carried out. (B343.w4)
  • Note: treatment of the cause of lameness may itself be painful:
    • When feet are trimmed care should be taken to avoid cutting too far and drawing blood or cutting so far that the feet become tender: these mistakes, if made, may lead to tenderness of the feet, severe pain and loss of body condition as well as risking development of toe granulomas (which are themselves painful) or production of granuloma tissue elsewhere on the foot. (J15.1.w, J15.19.w1)
    • In cases of virulent foot-rot, if topical treatment is chosen then all the hoof overlying necrotic lesions must be removed using secateurs or a sharp knife; this procedure is painful. (B217.36.w36)
  • In septic pedal arthritis causing severe lameness, removing the affected digit will provide pain relief more rapidly than will prolonged antibiotic therapy and sinus irrigation. (B217.69.w69)
  • In individuals with chronic laminitis, careful foot trimming is required to reduce pain by reducing pressure on the sensitive areas of the feet. (N13.11.w1)
Use of analgesics:
  • Local anaesthesia (e.g. using a ring block around the cannon bone, or intravenous regional anaesthesia) should be used as appropriate during treatment, for example:
    • During treatment of deep penetrating wounds. (J15.1.w1)
    • During amputation of a digit. (B217.69.w69, J15.1.w1)
    • During removal of a toe granuloma. (B217.69.w69, B359.14.w14, J15.19.w1)
    • During removal of an interdigital fibroma. (B359.14.w14)

Use of NSAIDs

NSAIDs are effective for provision of daily pain relief in sheep and are particularly useful following orthopaedic surgery. (J15.22.w1)

  • Use of analgesics should be considered for example:
    • Post-operatively when digit amputation is required for treatment of septic pedal arthritis. (J15.1.w1, J15.17.w3)
    • Where penetrating wounds involve deeper structures such as joints and tendon sheaths. (J15.1.w1)
    • Following amputation of a toe granuloma. (J15.1.w1)
    • Following removal of interdigital fibroma. (J15.1.w1)
  • NSAIDs should be used in sheep and goats with acute laminitis (J15.1.w1, N13.9.w1, N13.11.w1)
  • Examples of NSAIDs which may be used in sheep include:
    • Carprofen may be given at 4 mg/kg intravenously for three days. Note: this is not licensed for use in sheep in the UK. (J15.17.w3)
      • 0.7-4.0 mg/kg subcutaneous or intravenous. (P53.24.w1)
    • Flunixin meglumine may be given at 2.2 mg/kg intravenously for three days. Note: this is not licensed for use in sheep in the UK. (J15.17.w3)
      • 2-4 mg/kg intravenously. Duration of action 12-24 hours. (P53.24.w1)
      • May be better regarded in sheep as an anti-inflammatory rather than an analgesic. (P53.24.w1)
    • Ketoprofen: 2.5 mg/kg intravenously (1 ml Ketofen 10%, Merial Animal Health Ltd. per 40 kg). Duration of action likely to be 24 hours. (P53.24.w1)
    • Meloxicam: 0.2 - 0.5 mg/kg subcutaneous suggested. (P53.24.w1)
    • Phenylbutazone may be given orally (1.0 g in an adult sheep) (J15.1.w1, J15.17.w3) added to the individual's concentrate ration, or given by drenching, for three to five days. Note: this is not licensed for use in sheep in the UK. A meat withdrawal period of 28 days must be observed. (J15.17.w3)
    • Tolfenamic acid. No data available for use in sheep. (P53.24.w1)
  • NOTE: no analgesics are currently licensed for use in sheep in the UK. These drugs may be used under the "cascade" but standard withdrawal periods should be observed after use of these products. (P53.24.w1)

Euthanasia:

  • In some cases, for example with severe laminitis with infection of the laminae, euthanasia may be the best option for the welfare of the sheep. (J15.26.w1)
  • Euthanasia is required for red foot disease of lambs in which the entire horn is shed from one or more digits with resultant damage to sensitive structures, and associated severe pain and lameness. (B346.w4)
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Reasons why adequate pain relief is not always provided

Reasons why adequate pain alleviation may not be provided are described in detail in: Reasons for Failure to Provide Pain Relief. In brief, these include:
  • Attitudes towards pain in animals;
  • Tradition;
  • Failure to recognise pain;
  • Failure to recognise the importance of the adverse effects of pain;
  • Concern about removing possible protective effects of pain [this concern is generally excessive];
  • Concern that providing pain relief may itself stress the animal and have a negative impact on it;
  • Concern that treating pain may interfere with diagnosis;
  • Lack of information about analgesics;
  • Concern about toxicity and side-effects of analgesics;
  • Concerns about the safety and legislative controls associated with some analgesics such as opiates;
  • Economic and practical considerations.

Specific published reasons for failure to provide pain relief in lameness in sheep are indicated below.

  • Misdiagnosis and misunderstanding:
    • Precise diagnosis of the cause of lameness is required for effective treatment and control. (J15.26.w1)
    • Few cases of lameness in sheep are reported to veterinary surgeons; this leads to the potential for cases of preventable or misdiagnosed lameness and incorrectly treated lameness. (J3.150.w1)
    • Lack of recognition of the infective nature of footrot may lead to ineffective treatment of lame individuals only, without consideration of whole-flock management to prevent reinfection. (J15.26.w2)
  • Major hindrances to reducing lameness include:
    • Damage to feet by excessive paring during 'routine' foot trimming; (J15.26.w2)
    • Failure to recognise the need for whole-flock treatment of conditions such as footrot, which are infectious; (J15.26.w2)
    • Inadequate handling facilities; (J15.26.w2)
    • Lack of suitable hard standing areas for sheep to stay on after topical treatment or footbathing to give applied chemicals time to take effect. (J15.26.w2)
  • Tradition:
    • Habit and failure of veterinary surgeons to consider and adopt new ideas may play a role in the lack of use of analgesics in sheep. (P53.24.w1)
  • Failure to recognise pain and its importance:
    • Lameness is very common in sheep: so common "that many farmers regard it as 'a fact of life' and give it only irregular attention." (B343.w4)
    • A survey of farmers in the Scottish Borders in 2000 found that farmers were aware of the importance of welfare issues relating to lameness in sheep. The degree of pain and discomfort experienced by the affected sheep was reported by the farmers to be the most important criterion in deciding whether veterinary attention should be sought, however very few cases were brought for veterinary attention (320 of 14,097 cases, i.e. 2.2%). (J3.150.w1)
    • The relative stoicism of sheep to painful stimuli may lead to a mistaken impression that sheep do not need analgesia. (P53.24.w1)
      • It should be remembered that sheep possess all the anatomic and physiological requirements to feel pain and that absence of obvious signs of pain is advantageous for prey animals such as sheep. (P53.24.w1)
  • Concern regarding side-effects of analgesics:
    • The standard list of contra-indications (including hypovolaemia, renal, hepatic of cardiac disease, and use in animals less than six weeks old) for use of NSAIDs apply in sheep as in other species. "However I have not knowingly seen any cases of side effects in several years of using NSAIDs in sheep." (P53.24.w1)
  • Economic and Practical Considerations:
    • Sheep are often not treated for lameness until they are gathered for another purpose. (J15.1.w1)
    • Effective treatment and control of a cause of lameness such as footrot, in order to keep it at a low level or even eliminate it, requires a lot of work. (J15.26.w2)
    • Cost: NSAIDs are expensive. (P53.24.w1)
      • HOWEVER the costs should be considered in comparison to the economic losses which are seen associated with untreated pain. (P53.24.w1)
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Authors & Referees

Author Dr Debra Bourne MA VetMB PhD MRCVS (V.w5)
Referee A.B.Forbes BVM&S.,CBiol.,MIBiol.,DipEVPC.,MRCVS (V.w66)

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