Hoof care
Hoof care is an important aspect of sheep production and management. Hoof diseases can affect the health and welfare of sheep and have a negative effect on productivity. Hooves
should be regularly checked for disease and excess growth. Animals which have excessive hoof growth, recurrent hoof problems and/or fail to respond to treatment should be culled.
Hoof Trimming
Hoof growth -- and thus, the need for hoof trimming -- is affected by many factors, including breed and genetics,
soil moisture and characteristics, management and nutrition. Sheep grazed on rocky,
dry soil may not require the extent of hoof care as sheep that are maintained on soil that is free of rocks and higher in moisture content.
Sheep in high rainfall areas will need to have their hooves inspected
more regularly than those on dry ground. Housed sheep usually require more hoof trimming than pastured animals. Sheep on a higher plane of nutrition usually require more frequent hoof trimming.
Proper footrot or foot paring shears are essential to doing
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. A sharp
paring knife is needed to remove pockets and do a more thorough job of hoof trimming, especially when disease organisms are present.
Foot trimming can be back-breaking work if there are a lot of
hooves to trim. There are various types of sheep
handling equipment that can restrain the sheep for easier access and trimming. A tilt or turn table will hold the sheep upright or on its side. There are manual and automatic (electric) tilt tables available. An elevated platform with a head gate can also restrain a sheep for hoof trimming, as well as other management tasks. A sheep or deck "chair" is a less expensive way to restrain a sheep for hoof trimming. When specialized equipment isn't available, the sheep is usually tipped onto its rump for hoof trimming.
To trim the feet, securely hold the leg of the sheep. Inspect the hoof and remove
any mud, manure, or small stones between the walls of the hoof.
A rotten smell is usually indicative of foot rot. Clean all
the junk and crud out of the hoof using a knife or the point of the shears.
After cleaning the hoof, begin trimming around the perimeter
of the hoof.
Avoid cutting off large chunks of hoof. Stop at the first sign
of pinkness. A pink color means you are getting close to the
foot blood supply. The hoof should be trimmed from the heel
to the toe to remove excess growth of the "horny"
portion of the hoof. To learn what a properly trimmed hoof look
like, study the feet of a newborn lamb. Its hooves are flat
on the bottom and have a boxy look.
When trimming hooves, avoid stressful times such as hot weather
or late gestation. It's a good idea to combine hoof trimming
with other management tasks, such as shearing or vaccinating.
It will be easier to trim hooves that are soft from heavy dew
or rain.
Diseases Affecting the Hoof
Lameness should never be ignored. It can be a sign of several foot diseases some of which are very serious
as well as some other problems.
Bluetongue
Foot lesions occur in some animals with bluetongue, a non-contagious, viral disease spread by biting insects (midges). A red to brown band around the coronet is an important
diagnostic sign of bluetongue. Bluetongue is a reportable disease.
Foot Abscess
Foot abscesses are characterized by the swelling of the soft tissues
immediately above the hoof and in advanced cases, draining abscesses
in this area and between the toes. Foot abscesses are caused
by bacterial infection of damaged foot tissue. The front feet
are most commonly affected. Usually only one hoof is infected. Treatment is usually with anti-bacterial
compounds.
Foot and Mouth Disease (FMD)
Foot and mouth disease is a highly contagious viral disease
that affects pigs, cattle, sheep, goats, and deer. It is endemic
in many parts of the world. Clinical signs of the disease in
infected animals include blisters or ulcerations on the mouth,
snout, tongue, gums, teats, or around the top of the feet. The
signs of FMD in sheep and goats are usually much less obvious
than in cattle or pigs.
The United States has eradicated nine outbreaks of FMD, the
last of which occurred in 1929. Since then, no cases have ever
been reported in the United States. Canada has been free of
foot-and-mouth disease since 1929. The United Kingdom experienced
a foot-and-mouth disease outbreak in 2001.
Foot Rot
Footrot is one of the worst diseases in the U.S.
sheep industry and elsewhere. While footrot does not cause death, it is an animal welfare issue that may cause production losses and cause the premature culling of animals. Treatment costs, especially labor, can also be substantial. Footrot is a common reason for exiting the sheep business.
Footrot is caused by a synergistic action of two
anaerobic bacteria: Fusobacterium
necrophorum and Bacterioides nodusus.
While F. Necrophorum is found in soil and manure and is present wherever there are sheep, goats, and cattle, the B. Nodusus organism usually "walks" onto the farm in the hooves of infected animals. There are over 20 strains of the B. Nodusus bacteria,
varying in their infectivity and severity.
Warmth, mud, and poor sanitation are the environmental conditions
that favor the spread of footrot, once the bacteria has been introduced to the farm. Warm, moist conditions create the
anaerobic (lack of oxygen) conditions necessary for the spread
of the disease. However, the B. Nodusus organism will only live
in soil for 14 to 21 days.
The bacteria that causes foot rot, Bacteriodes nodosus,
is spread from infected sheep to the ground, manure, bedding,
etc., where it is then picked up by noninfected sheep. Footrot is introduced by purchase of an infected animal or by simply
using facilities or trucks that have been contaminated by infected
sheep.
Spread occurs best when temperatures are from 40 to 70°F and
the environment is wet. Since the organism does not survive long
in the environment (less then two weeks), carriers in the flock will
continue to reinfect the flock unless they are either culled
or the organism is eliminated by proper treatment.
Treatment of foot rot should be approached from a flock standpoint.
Since the foot rot organism is anaerobic, the introduction of
oxygen to its environment will help in eradicating it. Thus,
it is important to keep sheep's hooves properly trimmed; although care must be taken not to cause bleeding. Elimination of
overgrown hoof tissue will result in less mud and manure packing,
which aids in environmental conditions conducive to footrot
development. After foot trimming, the use of regular soaking
in a footbath of a zinc sulfate solution (10% w/v) can greatly
help in eradicating the disease.
In the UK, aggressive hoof trimming is not recommended, as it is believed it may help to spread of the disease. Instead, it is recommended that antibiotic injections and antibiotic sprays be used to control footrot and similar hoof diseases. European researchers have found success treating footrot with Gamithromycin (Zactran®), a macrolide antibiotic that is licensed for cattle in the treatment and control of bovine respiratory disease. Use of Zactran® in the US to treat foot rot is an extra label use that requires a veterinary prescription.
Vaccination of flocks with a history of footrot can help in
prevention and treatment of current cases. However, just
because a sheep is vaccinated for footrot does not mean it is
immune to infection. The vaccine does not cover all the strains
of footrot. The vaccine is not always readily available. Producers with clean flocks can control footrot
more economically by prevention rather than vaccination.
Severely infected sheep that do not respond to treatment should
be culled. There can be a genetic susceptibility to footrot;
some sheep are more susceptible to footrot than others. Also,
there can be breed differences in susceptibility to footrot.
British and European breeds seem to be less susceptible to footrot.
Thus, sheep that have resistance to footrot should be propagated,
while, susceptible animals should be culled. Keeping records
can help in identification of these types. Though a common belief, there is no scientific proof that black-pigmented hooves are less prone to hoof disease than light-colored hooves. It is much easier to prevent foot rot than to eradicate it.
Several management practices help to minimize the chances that
foot rot will establish itself in a flock. You should never
buy sheep infected with foot rot. Avoid buying apparently clean
sheep from an infected flock. Avoid buying sheep from sale barns
where clean and infected sheep are penned together.
Assume all new additions to your flock are infected with foot
rot. Always isolate new animals for at least 30 days. Trim
feet immediately upon arrival. Treat feet of new sheep following
trimming. Re-inspect feet during the quarantine period.
Foot Scald (interdigital dematitis)
Foot scald is an infection of only F. necrophorum and is
not contagious. Foot scald causes lameness, frequently on the
front feet, and lesions are found between the hooves. The tissue
between the toes of a sheep with foot scald are generally blanched
and white, or red and swollen. Foot scald is much easier to treat
than foot rot. Many times, placing sheep on drier footing and
out of mud will alleviate the problems of the disease.
Individual sheep or hooves can be treated topically with copper sulfate (Kopertox) or zinc sulfate. The simplest and most effective
treatment is use of a footbath containing 10% zinc sulfate solution
(8 pounds zinc sulfate to 10 gallons water). The frequency and
severity of foot scald infection will decline as drier weather
returns.
Laminitis (founder)
Lameness related to laminitis is caused by inadequate blood flow
in the hoof caused by digestive problems resulting from the excessive
intake of grain (grain overload, acidosis). Animals often die
before the feet become involved. Recovered animals may exhibit
unusual foot growth and/or permanent lameness.
Soremouth (contagious ecthyma)
Lameness caused by soremouth is the result of blisters appearing
on the skin near the top of the hoof wall. Simultaneous blisters
appear on the mouth and other areas of the sheep's body. The
infection is more common around the mouth than on the legs or
feet. Lesions can be treated with an ointment containing a broad
spectrum antibiotic. Soremouth can be prevented with vaccination or avoided with good biosecurity.
<== SHEEP 201 INDEX