Lameness in Sheep or Goats


Footrot (including scald)

Colour photograph of single sheep in paddock.

Footrot is a serious infectious disease that affects sheep, cattle and goats. It occurs throughout Australia but is most prevalent in medium to high rainfall areas. Virulent aggressive strains of footrot infection cause severe footrot lesions and spread rapidly in warmer, moist environmental condition. Other strains of the bacteria causing footrot do not cause serious disease and are regarded as benign strains.

 

In the face of a footrot outbreak, it is not sufficient to simply footbath sheep until they no longer show the signs. An outbreak of virulent footrot requires a comprehensive on-farm program which treats the lameness and eradicates footrot from the property. If an eradication program is not implemented, then footrot will return each time the seasonal conditions are conducive to the disease developing. If footrot infection is suspected on a property, professional advice should be sought to develop an eradication program that best suits the particular property and management strategies.

Signs
  • Often affects more than one foot.
  • Lameness.
  • In mild cases (known as scald), some reddening between the toes.
  • In more severe cases, underrunning (ie separation) of horn from hoof. Starts at the heel, then progresses to sole, toe and eventually outer wall.
  • Infected feet often smell.
  • Infected feet may become flyblown.
Causes
  • The bacteria that causes footrot lesions is called Dichelobacter nodosus.
  • Unless  there has been a previous footrot  outbreak in your stock already, the most likely way of introducing the bacterium to your property is by the introduction of new stock that are infected.  The bacterium that causes footrot can live in the feet of a carrier sheep indefinately, even under dry conditions. A paddock which has had no sheep, goats or cattle in it for seven days can be guaranteed free from footrot.
Control, Treatment and Eradication
  • Control of spread involves footbathing (for long or short term actions). Footbathing helps treat existing lesions and reduce the spread of bacteria, improves the health, welfare and production of sheep, enhances the effect of a footrot vaccination program if used and provides precautionary quarantine treatment for introduced sheep.

Eradication programs involve the identification and removal of all infected sheep from a flock when footrot is not spreading. All feet on all sheep must be inspected, and infected sheep or those requiring extensive foot trimming should be culled.  In some cases salvage treatment with foot paring, footbathing and antibiotic treatment can be used.  Repeat inspection is made four weeks after the initial inspection and all sheep that do not have four perfectly normal healthy feet at the second inspection should be culled. Regular inspections should continue until two successive totally clean inspections of the flock has been achieved. Surveillance and monitoring is continued until the stock have been through a spring spread period without any detection of footrot.


Foot Abscess

Signs
  • Lameness and obvious acute pain.
  • Swelling, usually just above the hoof.
  • In more severe cases, a build up of pus can be seen in that area just above the hoof or between the toes.
  • Often only one foot is affected and it is more likely to be a front foot.
  • Usually foot abscess affects only a small number in a flock. 
Causes
  • Bacterial infection of a foot that has suffered physical damage or prolonged irritation, such as grazing stubble.
  • Wet paddock conditions.
  • Overzealous paring.
  • Failure to maintain sheep's feet in good condition.
  • Heavy sheep are more prone to foot abscess.
Treatment

  • Pare or trim the feet, clean the infected area and apply an anti-bacterial compound. Antibiotic injections and keeping the sheep on a dry surface will assist healing. Applying zinc sulphate and bandaging may help. Many cases take a prolonged period to heal and often the foot is permanently deformed.

Prevention

  • Ensure the sheep's feet are kept in good condition by regular inspection and paring. Prevent sheep from getting too heavy. Pre-lamb shearing has helped in some cases.

Foot and Mouth Disease (FMD)

FMD has not occurred in any state of Australia for 130 years. An outbreak of FMD would be a major threat to the whole of Tasmania's livestock and tourism industries - especially if the first case of any FMD outbreak is not diagnosed very quickly. That is why it is so important that livestock owners do not assume that lameness in any of their animals is simply footrot or one of the other foot problems that occur in Tasmanian sheep and goats from time to time. Any lame sheep or goat should be inspected without delay.

For more detailed information on FMD see our FMD web page.

Signs in sheep and goats
  • Lameness.
  • Blisters on the feet (between the toes and/or immediately above the hoof), around the mouth (especially the dental pad) and, more rarely, around the udder.
  • These blisters burst after a few days and become sores hence sores may be seen rather than blisters.
  • It is important to understand that the signs of FMD in sheep and goats are usually much less obvious than in cattle or pigs. Typically, only a small percentage of animals in the flock have the signs. And, even then, these signs may be modest.
Causes 

  • FMD is caused by a highly contagious virus which can be easily introduced by direct contact with an infected animal, or by the virus becoming airborne and spreading from an infected animal up to a few kilometres away.
  • The FMD virus can survive for long periods in feed, in wood (ie fences, sheds), in soil, in water, clothing, vehicles, and even on plastic. Virtually any such matter coming onto a property could be a source of FMD. Hence disinfection is  an extremely important part of farm biosecurity during an FMD outbreak.
Treatment
  • Under the nationally-agreed AUSVETPLAN, animals with FMD or that are deemed to be at risk of FMD (in most cases, animals on properties near an FMD outbreak) would be slaughtered. Strict quarantine and movement restrictions would apply to all other susceptible livestock during any FMD outbreak.
Prevention
  • Keep the FMD virus out of Australia through strict quarantine controls at our airports and seaports.
  • Ensure everyone who comes into the country is aware of and abides by the import bans or restrictions on various foods and other potential carriers of the FMD virus.
  • Vigorously enforce the ban on swill feeding to pigs. 
Note
  • Because Australia has not had FMD for over 130 years, there is a risk we could become complacent. Of all the exotic animal diseases, FMD is the most potentially serious - mainly because of the speed with which it can spread.
  • Our first line of defence against FMD is our quarantine barrier. Our second line of defence relies on farmers and all other people who work with livestock to know what FMD looks like and to report any suspect animals immediately. That is why it is so important not to ignore or delay a close inspection of any lame sheep or goat.
  • If you suspect FMD please call 1800 675 888, the Emergency Animal Disease Hotline.

Ovine Interdigital Dermatitis (OID)

Signs
  • OID looks like scald, which is a mild form of footrot.
  • Reddening between the toes. Sometimes fluid weeps into this area.While OID looks like the early stages of footrot, there is no underrunning of the horn.
  • Often affects more than one foot. 
Causes
  • Warm wet weather, especially when the pasture is lush or the paddocks muddy.
Treatment
  • Remove the sheep from the lush pasture or muddy paddock. Overnight housing on the grating in the shearing shed or on a dry, hard floor is often sufficient. If possible, put the sheep into a drier pasture or less muddy paddock afterwards.
Prevention
  • As the organism that causes OID is ever present, the disease can occur whenever the weather and paddock conditions are conducive to the bacterium establishing infection. There is little that can be done to prevent OID. In warm wet weather pasture sheep on the drier parts of the property.

Shelly Hoof

Signs
  • In severe cases, lameness.
  • The horn starts to separate from the hoof, usually along the outer wall. A cavity forms between the horn and the hoof and this fills with soil and dung. When paddock conditions are wet, this can result in inflammation and the establishment of a bacterial infection.
  • Sometimes the separation of horn from hoof starts at the toe and the cavity forms at the front of the foot.
  • The prime cause of Shelly Hoof is poor maintenance of the feet, it is likely that other sheep in a mob would have been similarly neglected and may therefore also have the condition. Usually, however, only a small number of sheep in a mob are lame. The lameness often affects only one foot and more often a front foot than a back foot.
Causes
  • Failure to maintain the sheep's feet in good condition
  • There is some evidence that Shelly Hoof may be, in part at least, hereditary.
  • Merinos are more susceptible than British or European breeds, especially in higher rainfall areas. Sheep with black hooves are generally less susceptible. 
Treatment
  • Unless infection is present, paring the feet and cleaning the dung and soil out of the cavity is all that is needed.
  • If infection is present or suspected, the sheep should be footbathed as well.
  • If paddock conditions are wet, try and keep the sheep on drier ground after paring.
  • If rocky ground is available or if the sheep can be grazed on a gravel farm track for a day or two after paring, the action of walking on very hard ground will tend to empty any remaining material from the cavities in the feet. 
Prevention
  • If Shelly Hoof is a problem  regular foot inspection and paring should be instigated. Paring should always be minimal, as radical paring can predispose the animal to other foot infections and hoof damage. The overall goal is to have the sheep's feet in good condition especially before the wet conditions of winter and early spring.
  • When paddock conditions are wet, running sheep on dry, rocky ground or on gravel farm tracks for short periods will help maintain hoof shape and health. 


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