Lameness in Sheep or Goats (Continued)



Scabby Mouth

Signs
  • The signs of Scabby Mouth can appear around the mouth and/or on the legs and feet.
  • The infection is more common around the mouth than on the legs or feet.
  • Young sheep are more susceptible (mainly because, once animals have recovered from the disease, they are immune to it thereafter).
  • The first signs of Scabby Mouth are small blisters discharging pus. These then dry and create a scab which may be yellowish brown at first and then become dark.
  • Where Scabby Mouth affects the legs, it is usually on the lower part. If the infection spreads down to between the claws of the hoof, the animal will be severely lame.
  • Scabby Mouth is not a fatal disease and will rarely cause major secondary problems.
  • The disease can affect the udder and teats of a lactating ewe. As a result, the ewe may prevent the lamb from feeding until the pain goes away. This would be a major setback for the lamb.
  • In some circumstances, Scabby Mouth and Foot and Mouth Disease (FMD) can present very similar signs, so check your sheep against the signs of FMD and if you have any doubt that it is Scabby Mouth, contact your local vet or the DPIPWE Emergency Animal Disease hotline (1800 675 888 all hours) immediately.
Causes
  • The Scabby Mouth virus can survive in the soil for years. However, it cannot enter the sheep unless the sheep has some kind of wound or abrasion. Puncture wounds from grass seeds, thistles, blackberry etc can be sufficient to allow entry of the Scabby Mouth virus, as can shearing cuts or any wounds from lamb marking, ear tagging etc. Sheep grazing a stubble can get minor abrasions around the mouth that would expose them to the virus as well.
Treatment
  • If left untreated, the lesions generally heal in around three weeks. As yarding the sheep in order to treat them may actually make the disease worse, no treatment is usually the best option. You should ensure affected sheep have soft, palatable feed, water and plenty of shade during this natural recovery phase. Depending on the time of year and seasonal conditions, you may need to keep a close watch for flystrike on the lesions.
  • You should not attempt to remove the scabs, as this will delay the sheep's recovery.
  • Antibiotics are not necessary, unless there is some secondary infection.
  • Vaccination is not a treatment option.
Prevention
  • A sheep that has recovered from Scabby Mouth is immune from the disease for several years. Note, however, that this immunity is NOT passed from the immune ewe to her lamb via the colostrum.
  • A preventative vaccine is available. In most cases, vaccination is only a viable option if the sheep are intended for the live sheep trade. Apart from this, vaccination for Scabby Mouth is not usually part of normal sheep management. The effect of the vaccine is to introduce the disease into the sheep in a controlled on-farm environment so that the sheep are then immune for the export market.
  • The vaccine is a live virus and is therefore not recommended for any property where the Scabby Mouth virus is not already known to be present.
  • The risk of Scabby Mouth is reduced if you remove blackberries, thistles and other potentially wounding plants (and, of course, any wire, nails etc that may be lying in the pasture) from the areas to be grazed. In particular, avoid running young sheep in paddocks where there are these risks.
Zoonosis
  • Scabby Mouth is transmissible to humans, where the condition is known as Orf. People most at risk are shearers and people using the Scabby Mouth vaccine in their flock.

Strawberry Footrot

Signs
  • Presents as scabs on the lower leg. If the scabs are removed, the bleeding sores resemble strawberries - hence the name Strawberry Footrot.
Causes
  • Strawberry footrot is not a footrot at all but a form of dermatitis

White Muscle Disease

Signs
  • Lambs stillborn or die soon after birth.
  • In lambs and hoggets, stiffness in the gait and/or lameness, which increases markedly if the animals are driven any distance.
Cause
  • Selenium deficiency. It is only a significant issue in Tasmania in high rainfall areas with sandy soils, especially where pastures are clover-dominant and heavily fertilised.
Treatment
  • The same as for prevention.
Prevention
  • Add selenium to the sheep's diet - through selenium drenches, slow release bullets, injections, stock licks or including selenium in the pasture fertiliser. But remember that, if you use stock licks, not all sheep will necessarily get the supplementary selenium.
  • In risk areas (ie high rainfall, sandy soil types), pregnant ewes should be supplemented with selenium four weeks before lambing in order to protect the newborn lamb.
  • Note that selenium can be poisonous and overdosing can cause death. So, if adding selenium into drench, make sure you get the quantities right and that you do not "double drench" any animal by mistake.
  • Many of the "5 in 1" vaccines that are used at lamb marking are available with a selenium supplement. As the "5 in 1" vaccines require a booster for lambs 4-6 weeks after the first injection, using a "5 in 1" with selenium supplement should normally be sufficient to prevent WMD in lambs. This is a convenient way of preventing selenium deficiency in lambs. It is important to ensure your vaccinator is set correctly so it is not overdosing and that you do not double-vaccinate any lamb by mistake.

Arthritis

There are several types of arthritis in sheep. The information below is general and provided to assist sheep and goat owners in differentiating the various possible causes of lameness in their livestock.

Signs
  • More common in lambs, but can affect all ages.
  • Lameness, the affected animal usually "carries" the infected leg.
  • In many cases, the affected leg has a swollen knee joint.
  • In "post dipping lameness", the lower leg is inflamed.
Causes
  • Infection arising from lamb marking under dirty conditions or lambing in unclean paddocks. Infection usually enters via the umbilical cord or wounds from lamb marking or mulesing. Infection can also enter through unbroken skin.
  • "Post dipping lameness" is caused by the build up of an infecting organism in sheep dips. The organism enters the sheep via abrasions or grass seed sites in the skin.
Treatment
  • For most types of arthritis, the only treatment is a course of massive doses of antibiotic and may only be viable with valuable animals.
  • In cases of viral polyarthritis , more regular doses of antibiotic are generally effective and the symptoms often disappear after a couple of weeks without treatment.
  • In cases of "post dipping lameness", the affected sheep usually recover without treatment.
  • If you are relying on natural recovery from viral polyarthritis or "post dipping lameness", make sure the animals have easy access to food, water and shelter while they are lame.
Prevention
  • Good hygiene at lamb marking time is essential. Avoid using your regular sheep yards, as they will be contaminated.
  • Using rubber rings to mark lambs will avoid open wounds and thereby reduce the risk of infection substantially.
  • Have your ewes lamb in clean paddocks, well away from regular sheep camps.
  • If using a plunge or shower dip, include a bacteriostatic agent in the mix. Replenish dips and sprays frequently and, where possible, disinfect the equipment between replenishings.

Copper Deficiency

Signs
  • Severe ill thrift
  • Diarrhoea
  • Steely wool
  • Loss of pigmentation in black sheep
  • Lameness through spontaneous fractures
Causes
  • Insufficient absorption of copper in the sheep's digestive system. This normally means that copper is deficient in the soil, but not necessarily so. It is possible for soil tests to show adequate copper levels, but excessive levels of other minerals (in particular molybdenum, iron or sulphur) may inhibit the uptake of copper by ruminant animals.
Treatment
  • Supplementary copper can be provided as stock licks, drenches, additives to fertiliser, copper "bullets" and injections.
Prevention
  • It is important not to treat animals that are not copper deficient, as too much copper is toxic and can kill. So, only use preventative copper treatments if deficiency has been diagnosed on your property.
  • Laboratory testing of liver or blood samples is the best way to diagnose copper deficiency. Deficiency is most common from late winter to late spring, so this is the best time to test.

Physical Injuries

Common causes of lameness
  • Rough handling of sheep.
  • Sheep can sometimes get one claw "caught" in the grating in a shearing shed. If the sheep is then moved without the claw being released, injury can occur.
  • Dog attack. Where the attack is by a pack of dogs, there is usually a lot of blood that is easily seen from a distance. However, some domestic dogs, including poorly trained sheep dogs, may simply "nip" the back legs of a sheep and this can cause lameness.
  • Loose fencing wire can become tangled around the sheep's leg. If the sheep is woolly, the wire may not always be easily seen from a distance.
  • Anything sharp in the pasture (ie loose barbed wire, sharp stone etc) can puncture the sole of the foot, which may then become infected.
Treatment
  • If the injured leg is not broken and there is no sign of a wound, the damage may well be temporary. In such a case, ensure the sheep can feed, water and shelter without having to walk a long distance until the lameness disappears.
  • If there is a wound and you have satisfied yourself that it is not footrot or any of the other foot diseases, isolate the sheep in a clean area and treat the wound with disinfectant.
Prevention
  • Ensure that your sheep handling facilities are safe. In particular, repair any damaged grating in the shearing shed. Check the gaps in the grating every now and then and fix any areas where the gap is sufficient to "catch" a sheep's foot.
  • Don't leave loose wire (especially barbed wire) lying in the pasture. Also, remove any other risks, such as old scarifier points, nails etc if you see them in the pasture.
  • If you have a dog attack on your sheep or goats, always report it to the local council and do all you reasonably can to have the offending dogs caught. Once dogs have attacked sheep on your property, the same dogs are likely to keep returning.
  • British breeds are less susceptible to dog attacks than Merinos, because they are generally more "assertive" when confronted by a dog. However, when dogs form a pack, any resistance by the sheep is likely to be ineffective.
  • If your neighbour's dog wanders on to your property, however harmlessly, you should insist your neighbour keeps better control of the dog. Even mild-mannered pet dogs can join packs and attack sheep.
  • There is never any excuse for handling livestock roughly. If a shearer, livestock carrier or anybody else shows signs of rough handling, you should intervene before any injury to the animal occurs.
  • Unfortunately, there are a few people who seem unable to work with animals without losing their temper and/or being cruel. The livestock industry can well do without these people. If you are unfortunate enough to come across someone like this, you should ensure they have nothing to do with your animals. If you see an act of cruelty on an animal, you should always report it to the RSPCA, DPIPWE or your local police.

Regular inspection of the sheep's feet

  • If you are bringing a mob into the yards for some reason, any sheep with foot problems (that may not always be easily seen by you as you are mustering) will tend to be towards the rear of the mob as it enters the yards. Running these "tailenders" into a separate yard and inspecting their feet will give you a good indication of whether you have any foot disease in the mob.
  • Sheep in high rainfall areas will need to have their feet inspected more regularly than those on dry ground. How often will depend on the specific conditions on your property. However, as a general rule, sheep's feet should be checked during the summer or autumn so that there is time to deal properly with any feet in poor condition before winter.
  • Sheep owners should be proactive by inspecting the feet of a sample number of sheep even when there are no "visible in the paddock" signs of feet problems. In other words, don't wait until lameness appears. Prevention is usually much less time-consuming and costly than cure.

Paring or trimming the sheep's feet

Equipment
  • Proper footrot or foot paring shears are essential to do the job properly. The ordinary, manual shears are not expensive and make the task so much easier. Air compressor driven shears are an option for people with large numbers of sheep or contractors.
  • In the past, some people used a sharp paring knife. In general, this is a lot harder work than using proper footrot shears. More importantly, it is much more dangerous for both the sheep and the person doing the paring.
  • Foot paring can be back-breaking work if there are a lot of sheep's feet to pare. There are various types of sheep handling equipment that can "hold" the sheep in a good position so that the stress on the person paring can be reduced. However, for small numbers of sheep, it is usually enough to tip the sheep up and sit it on its rump, as you would for crutching.
Preparing the sheep for paring
  • The task will be many times more difficult if the sheep's feet are not cleaned first. Providing the sheep are not in the last third of pregnancy, have lambs at foot or are in poor condition, you should keep the sheep on grating for a few hours beforehand, with enough room for them to walk around, as this will clean their feet.
  • If it is not appropriate to keep the sheep on grating for a few hours, and you have to pare the feet "fresh off the paddock", running them through a footbath containing just water will help clean the feet.
  • If neither of the above are possible, you may have to clean each foot before paring. Have a bucket of water and a stiff brush (a shearer's brush is ideal) handy. A quick swipe of each foot just prior to paring will help make your job easier.
  • If you wear glasses for reading, you should wear them when foot paring. It is most important that you can see in detail, otherwise you may overpare the sheep's foot and draw blood.
How to pare healthy but overgrown or misshapen feet
  • Unless the foot you are paring is already infected, you are doing it very wrong if you draw blood.
  • The aim of paring a healthy but overgrown foot is simply to restore the shape of that foot. This means cutting away the extra growth. Maintaining the sheep's feet in good condition is the most effective way of preventing most feet diseases in your animals.
  • If the sheep has Shelly Hoof, the horn that has "come away" from the hoof should be removed. The major problem with Shelly Hoof is that it encourages the build up of compacted soil and dung in the cavity formed as the horn "comes away", and this exposes the animal to infection. If you cut the outer wall of that cavity so that it doesn't quite touch the ground when the sheep stands, it will mean that, as the sheep then walks on dry ground, the action of walking will help keep the upper part of that cavity clean and help heal any inflamed or exposed tissue.
  • If you are not experience in foot paring, the general rule is to trim away only a very small amount at a time. This will enable you to see more clearly and avoid cutting into the soft tissue (which will bleed and expose the animal to infection).
  • A common mistake in foot paring is to try and do the job too quickly. Paring is a job that must be done properly rather than quickly.
  • If you come across a sheep's foot that is infected or diseased, you should disinfect the shears before paring the next sheep.
How to pare a sheep with footrot
  • If your sheep have footrot, it is usually better not to try paring the sheep's feet until you are confident that the disease has stopped spreading. The reason is that the action of paring an infected flock can actually help spread the disease further. It is therefore recommended that the first action you take when you diagnose footrot is to footbath the entire flock - before foot paring.
  • Once you have stopped the spread of the disease, you should pare the feet. Feet that are not infected should be pared as above (ie with the aim of ensuring the foot is in good shape). Where a foot is infected, the aim of paring should simply be to help the footbath chemical penetrate the infection. This requires minimal paring only. Radical paring is cruel and should never be undertaken.

Footbathing

  • Use a registered product. Your rural merchandiser can advise what products are available.
  • In preparing your footbath solution, it is essential you follow the manufacturer's dilution recommendations. If you make the solution too strong, it can cause significant damage to otherwise healthy feet.
  • Also, make sure you follow the manufacturer's recommendations about the time the sheep should be standing in the footbath.
  • If your footbath is outside, remember that hot windy conditions can dilute some types of footbath, by evaporating some of the water, and any rain falling into the footbath weakens the concentration.
  • If you are footbathing your sheep "fresh off the paddock", there may be enough urination by sheep while they are in the footbath to reduce the concentration.
  • As you run sheep into and out of the footbath, try and move them slowly. If they rush, they will inevitably cause splashing, which will not only waste the chemical, it may also cause the chemical to get into your and/or the sheep's eyes. And that will sting !
  • After footbathing, hold the sheep on grating or on a concrete floor for a period immediately after they come out of the footbath. Then ensure that the sheep are put onto clean pasture, preferably without walking through muddy yards or laneways.
  • Many footbathing chemicals are corrosive, so if your footbath is made of tin, drain the chemical immediately after footbathing.
  • Some footbath chemicals will cause any sheep that has a mild foot infection (ie was not noticeably limping before going into the footbath) to suffer a stinging pain as the chemical reaches the infected area. As a result, the sheep may limp for a short time after it leaves the footbath.

Buying Footrot Resistant Sheep

  • British and European breeds are less susceptible to footrot. Most Merinos are particularly unsuited to high rainfall areas because, under such conditions, they are especially susceptible to footrot.
  • Many leading Merino studs have been selectively breeding for resistance to footrot.
  • The Footrot Vendor Declaration Scheme is a voluntary program designed to give sheep buyers the opportunity to make informed decisions about the risk of footrot entering their property on bought sheep. In short, the vendor makes a written statement about the footrot status of his/her property and on what actions have been taken to prevent footrot in the last year. This statement is no guarantee that the sheep for sale are footrot free, so potential buyers still need to inspect the sheep's feet themselves. However, it does indicate that the vendor is serious about the risk of footrot and it normally provides, in effect, a money-back guarantee if the new sheep are found to have footrot within 14 days. If you wish to know more about this scheme, discuss it with your livestock agent or a DPIPWE stock officer.

Special Information for Hobby Farmers or people with Pet Sheep (or Goats)

In most cases, people with a small number of sheep do not have the proper equipment to pare the feet or to footbath. So here are some suggestions that might help.

Foot paring. If you do not have a set of foot shears, or are unable to borrow them, an ordinary pair of garden pruning shears will usually be adequate. Pruning shears with plastic handles may not be tough enough if the horn on the sheep's hoof is especially hard (normally during a dry summer, but such hardness can also be caused by the regular use of formalin as a footbath). A proper pair of foot shears is not expensive and will make the job easier.

Footbathing. If you keep your sheep's feet in good shape, you probably won't need to footbath. However, if you need to footbath, there are two broad options

You can make up a small footbath out of a sheet or two of tin. It needs to be at least 100mm deep and, of course, be leakproof. If you can cut an old foam mattress to fit into the footbath and for the sheep to stand in, that will help get a better coverage of the sheep's feet and also reduce the loss of chemical through splashing.

If your sheep is tame enough to eat out of your hand, you may be able to put the footbath against a fence and feed the sheep over the fence so that it has to stand in the footbath to get the feed. Even if you can only footbath the sheep's front feet like this, it may be sufficient as most foot diseases affect the front feet more than the back. Otherwise you will need to construct a pen around the footbath so you can lock the sheep in while it stands in the chemical.

If you are unable to construct a small footbath, the second option is to spray the chemical onto the sheep's feet using one of the household spray bottles you use around your home. You will need to sit the sheep on its rump to do this. Make sure you spray the chemical up into any cavities in the hoof and into the area between the toes. You will need to hold it like that for a couple of minutes after you have sprayed the sheep's feet, so that the chemical can penetrate any cracks in the horn or hoof. This method is a long way short of ideal, but it is better than not footbathing at all. Just be careful not to spray the liquid towards your face and wear gloves, especially if you have any cuts or scratches on your hands.

Choose the right breed. If you are buying a few sheep for your smallholding, you can reduce the likelihood of foot problems significantly by choosing the right type of sheep for your particular property. Merino sheep are much more prone to most feet problems than the British or European breeds. If your property is in a low or moderate rainfall area and providing your sheep paddocks do not get at all boggy, a Merino or Merino cross might be alright. However, if your property is in a high rainfall area or you have ground that gets and stays wet for long periods, you should get a British or European breed and avoid the Merino altogether.

All the common British and European breeds are resistant to most foot problems, providing you keep the feet in good shape. Some breeds, such as the Romney, Perendale, Cheviot and several others have been selectively bred to increase their natural resistance to footrot. As a general rule, the sheep breeds with black hooves are best in wet conditions, in terms of most feet problems.

Rocks and roads. If you are able to run your sheep on a gravel driveway (well away from your garden area, of course) or in a rocky area, you should do so every now and then. The rough, hard surface will quickly wear away some of the horn growth and, in doing so, help maintain the feet in good shape.

Further Information


Contact

Animal Disease Enquiries
Chief Veterinary Officer
GPO Box 44
Hobart TAS 7000
Phone: 03 6165 3263
Fax: 03 6278 1875
Email: DPIPWEAnimalDisease.Enquiries@dpipwe.tas.gov.au

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