Abortion
Abortion is when a pregnancy is terminated and the ewe loses her lambs or gives birth
to weak or deformed lambs that die shortly after birth. There are several infectious
organisms that can cause abortion in ewes. The most common causes are Chlamydia
(Enzootic abortion), Campylobacter (Vibrio), and Toxoplasmosis. It is important to note
that the organisms that cause abortion is ewes may also cause abortion in women.
Pregnant women should never handle placentas.
Brucellosis
Brucellosis is an infectious disease caused by bacteria of the genus Brucella (B.). Various
Brucella species affect sheep, goats, cattle, pigs, dogs, and several other animals. In
infected ruminants, brucellosis commonly induces abortion during the second half of
gestation. Sheep are less susceptible than cattle and it is not a common cause of
abortion. Ovine brucellosis mainly affects rams, causing lesions in their reproductive
organs.
Cache Valley Virus
Cache Valley Virus is an occasional cause of abortion outbreaks in sheep. It is spread by
mosquitoes to pregnant ewes. The timing of infection in relation to gestation has a
major effect on clinical effects. If a ewe is infected at less than 28 days of gestation, the
embryos usually die and are reabsorbed. If infected after 45 days, there are usually no
adverse effects. However, if infection occurs between 28 and 45 days of gestation, the
fetus(es) usually develop the "A-H syndrome," resulting in various congenital
abnormalies affecting the central nervous system. Ewes that are infected usually show
no signs of disease and develop a good immunity that lasts for several years. Cache
Valley virus is similar to Akabane Disease except that in only affects sheep.
Chlamydia
Also called enzootic abortion of ewes (EAE)
Chlamydia is the most common cause of abortion in ewes. It is transmitted from
aborting sheep to susceptible individuals. Ewe lambs are usually the most susceptible on
farms where the organism is present. The bacteria which causes enzootic abortions in
ewes is called Chlamydia psittici. Chylamydia causes abortion during the last month of
pregnancy and may also result in the birth of lambs that die shortly after birth. The
organism may also cause pneumonia in young lambs, but the chlamydia species that
causes abortion is not associated with conjunctivitis or arthritis. Chlamydia abortions
can usually be stopped or reduced by treating the entire flock with tetracycline. A
vaccine is available. It should be administered 60 days prior to breeding and repeated in
30 days, then annually just prior to breeding.2
Leptospirosis
Sheep are generally more resistant to leptospirosis than cattle, swine, and most other
domestic animals. Abortion due to this disease may occur during the last month of
pregnancy. A blood test of aborting sheep will confirm diagnosis. The problem can be
prevented with annual vaccination with a 5-strain leptospirosis vaccine.
Q Fever
Q Fever is a disease caused by the bacterium, Coxiella burnetti. The disease is found
worldwide except for New Zealand. Sheep, goats, and cattle are most likely to get Q
fever. The most common sign of Q fever is abortion during late pregancy. However,
most animals do not show any signs of illness. Animals get Q fever through contact with
body fluids or secretions.
Rift Valley Fever (RVF)
Also called Infectious enzootic hepatitis
Rift valley disease is a viral disease of sub-Saharan Africa. The virus attacks the liver and
causes symptoms ranging from fevers and listlessness to hemorrhage and abortion rates
approaching 100% in pregnant sheep. It is transmitted by mosquitos. There is no
specific therapy for infected animals. Vaccination of animals against RVF has been used
to prevent disease in endemic areas and to control epizootics. Rift Valley fever has not
occurred in the United States. However, there has been concern that it could become
permanently established in the U.S. if it does enter the country. Rift Valley fever is more
deadly than West Nile virus.
Salmonella
In the U.S., salmonella abortion is a distant fourth in frequency as a cause of abortion,
but probably occurs more often than recognized. The two major factors determining
whether a pregnant ewe will abort from Salmonella are stress on the ewe and the
number of Salmonella bacteria the ewe ingests. Abortions may occur earlier in gestation
but are most common in the last month of gestation. Most of the ewes show diarrhea
and some will die from metritis, peritonitis and septicemia. Healthy lambs may also
contract the disease and die.
Toxoplasmosis
Toxoplasmosis is another common cause of abortion in ewes. It is caused by
Toxoplasma gondii, a protozoan which causes coccidiosis in cats. Toxoplasma abortion
in ewes follows ingestion of feed or water that has been contaminated with oocyte-laden
cat feces. The organism migrates to the placenta and fetus(es) causing their death and
expulsion. Ewes will abort during the last month of pregnancy or give birth to dead or
weak lambs that usually die from starvation. Infection in the first two months of
gestation results in embryonic death and reabsorption. There is some evidence that
Rumensin® and Deccox® will partially prevent toxoplasmosis in pregnant ewes.
Limiting cat populations and preventing contamination of sheep feed and water with cat
feces will help to prevent disease outbreaks. There is no vaccine available in the U.S. for
toxoplasmosis.
Vibrio Campylobacteriosis
Also called vibriosis
Vibrio is the second most common cause of abortion in ewes. Abortion during the last 3
month of pregnancy, stillborn lambs, and the birth of weak lambs are common signs of
vibrio abortion The organisms which cause vibrio abortion are Campylobacter jejuni or
Campylobacter fetus. Ewes are infected by oral ingestion. The incubation period from
the time of infection and abortion is only two weeks. Vaccination can be effective in the
face of an outbreak. Feeding of antibiotics has also been shown to be effective. Disease
spread can be prevented by isolating the aborting ewe, disposal of the fetus and
membranes and disinfecting the affected area. Infected ewes usually recover after
aborting and are immune to reinfection. A vaccine is available. It should be
administered prior to breeding and repeated in 60 to 90 days, then annually.
Bloat
Bloat occurs when rumen gas production exceeds the rate of gas elimination. Gas then
accumulates causing distention of the rumen. The skin on the left side of the animal
behind the last rib may appear distended. Bloat can be a medical emergency and timely
intervention is necessary to prevent losses. It is a common cause of sudden death. Bloat
is usually results from nutritional causes. There are two types of bloat: frothy and free
gas.
Frothy Bloat
commonly called pasture bloat
Frothy bloat is usually associated with the consumption of legumous forages, but may
also occur in sheep grazing lush cereal grain pastures or wet grass pastures or
consuming grain that is too finely ground. Animals with frothy bloat can be treated with
anti-foaming agents such as cooking oil or mineral oil or a commercial product such as
Poloxalene.
Free Gas Bloat
commonly called feed lot bloat
Free grass bloat is associated with grain feeding and occurs when animals would not
given enough of an adjustment period. Many of the same factors causing acidosis are
associated with free-gas bloat. Simple passage of a stomach tube may be effective at
relieving free gas bloat. Inserting a trochar or needle into the abdomen is a life-saving
procedure that should only be attempted as a last resort.
Bluetongue
Bluetongue is an insect–transmitted, viral disease of sheep, cattle, goats, and other
ruminants, such as white–tailed deer and pronghorn. It is particularly damaging in
sheep; half the sheep in an infected flock may die. In cattle and goats, however,
bluetongue viruses cause very mild, self–limiting infections with only minor clinical
consequences. A bluetongue virus infection causes inflammation, swelling, and
hemorrhage of the mucous membranes of the mouth, nose, and tongue. Inflammation
and soreness of the feet also are associated with bluetongue. In sheep, the tongue and
mucous membranes of the mouth become swollen, hemorrhagic, and may look red or
dirty blue in color, thus giving the disease its name. Bluetongue viruses are spread from
animal to animal by biting gnats. In the United States, the disease is most prevalent in
the southern and southwestern States. Animals cannot directly contact the disease from 4
other animals. The bluetongue vaccine for sheep is only effective against certain
serotypes, will not prevent the disease, and may cause adverse reactions. Pregnant ewes
should not be vaccinated.
Border Disease (BD)
Also called hairy-shaker disease or fuzzy lamb syndrome
Border disease is often seen in the newborn lamb which has a hairy coat and trembles
uncontrollably. It is caused by a virus and causes a wide variety of symptoms depending
upon the stage of pregnancy when the ewe becomes affected. Sheep affected by border
disease are characterized by open ewes, abortion, weak and frail lambs, abnormal hair
coat, and nervous symptoms that cause the lamb to shake. The most common clinical
symptom is abortion of macerated or mummified lambs. Border disease is usually
brought into a flock by new additions that are carriers or when sheep are mixed with
cattle that are shedding the Bovine viral disease virus. Bovine viral diarrhea vaccines for
cattle cannot be recommended for use in sheep because border disease viruses most
commonly isolated from sheep are antigenically distinct from bovine viral diarrhea
viruses most common in cattle. There is no treatment and the disease will not respond
to antibiotics.
Caseous Lymphadenitis (CLA)
Also called boils, abscesses, and cheesy gland
Caseous lymphadenitis is an infectious, contagious disease that involves primarily the
lymphatic system, though other organs can be affected. It is caused by the bacteria
Corynebacterium pseudotuberculosis. Infection results in abscess formation in the
lymph nodes which when cut or ruptured, discharge pus containing the bacteria into the
immediate surroundings. When the nodes spread internally, affected ewes slowly lose
weight and eventually become emaciated. CLA is the third leading leading cause of
carcass condemnation. CLA is controlled by culling visible infected animals and
practicing good hygiene at shearing time. There is a vaccine licensed for sheep. It has
been shown to both decrease the number of abscesses in sheep and the number of sheep
that develop abscesses.
Clostridial Diseases
Clostridial organisms of various types are found in the soil, where they can survive for a
very long time. Most clostridial organisms can also occur quite naturally in the gut of
healthy animals. Sheep can be infected with various clostridial diseases – black leg,
botulism, malignant edema, red water disease, enterotoxemias (several types), and
tetanus – but the most common are enterotoxemia types C & D and tetanus.
Enterotoxemia type C (Clostridium perfringins type C)
Also called hemorrhagic enteritis and bloody scours
Enterotoxemia type C is caused by Clostridium perfringins type C and affects lambs
during their first few weeks of life, causing a bloody infection of the small intestine. It is
often related to indigestion and predisposed by a sudden change in feed such as
beginning creep feeding or sudden increase in milk supply. Treatment (antitoxin 5
injected under the skin) is usually unrewarding Vaccination of pregnant ewes 30 days
before lambing is recommended as prevention.
Enterotoxemia type D (Clostridium perfringins type D)
Also called overeating disease and pulpy kidney disease
Overeating disease is one of the most common sheep diseases in the world. It is caused
by Clostridium perfringins type D and most commonly strikes the largest, fastest
growing lambs in the flock. It is caused by a sudden change in feed that causes the
organism, which is already present in the lamb's gut, to proliferate causing a toxic
reaction. It is most commonly observed in lambs that are consuming high concentrate
rations, but it can also occur when lambs are nursing heavy milking dams. It usually
affects lambs over one month of age. Treatment (antitoxin injected under the skin) is
usually unrewarding. Vaccination of pregnant ewes 30 days before lambing is
recommended as prevention.
Tetanus (Clostridium tetani)
Also called lock jaw
Tetanus is caused by Clostridium tetani, a soil inhabitant that is a prolific spore
producer. This disease is usually related to docking and castrating by elastrator bands,
though any wound can harbor the tetanus organism. Signs of tetanus occur from about
four days to three weeks or longer after infection is established in a wound. The animal
may have a stiff gait, "lockjaw" can develop and the third eyelid may protrude across the
eye. The animal will usually go down with all four legs held out straight and stiff and the
head drawn back. Convulsions may occur and the animal.Treatment consists of the
tetanus anti-serum and antibiotics. It is usually unrewarding. Tetanus can be prevented
by vaccinating pregnant ewes 30 days before lambing. If pregnant ewes were not
vaccinated for tetanus, the tetanus anti-toxin can be administered to lambs at the time
of docking and/or castrating. The tetanus anti-toxin provides immediate short-term
immunity and can be used at the time of docking and castrating to prevent disease
outbreaks.
Other Clostridial Diseases
Enterotoxemia type B (Clostridium perfringins type B)
Also called lamb dysentery
Clostridum perfringins type B causes lamb dysentery. It usually affects strong lambs
under the age of 2 weeks. Symptoms include sudden death, listlessness, recumbancy,
abdominal pain, and a fetid diarrhea that may be blood-tinged. On post-mortem,
intestines show severe inflammation, ulcers, and necrosis. The mortality rate
approaches 100 percent. Cl. perfringins type B is not common in the U.S., but is
frequently found in England, Europe, South Africa, and the Near East.
Black Disease
Black disease occurs in sheep in areas where liver flukes are known to occur. Infections
are caused by the bacterium Clostridium novyi, which becomes active in the liver tissue
damaged by the liver fluke. Control relies on vaccination and elimination of liver flukes.6
Blackleg
Blackleg is disease of cattle and less frequently of sheep. It is caused by the soil-bourne
bacteria Clostridial chauvei. The disease develops rapidly in affected animals and often
deaths occur before the owner has noticed any sickness. Vaccination is the oly means of
protection against blackleg.
Malignant Edema
Malignant edema is caused by the bacterium Clostridium septicum. In sheep, blackleg
and malignant edema are indistinguishable. The disease is not common in sheep in
North America. In areas where the disease is known to occur, lambs can be vaccinated.
Copper poisoning/toxicity
Sheep are ten times more susceptible to copper toxicity than cattle. When consumed
over a long period of time, excess copper is stored in the liver. No damage occurs until a
toxic level is reached at which time there is a hemolytic crisis with destruction of red
blood cells. Most outbreaks of copper poisoning in sheep can be traced to feeding
supplements containing copper levels that have been formulated for cattle or swine.
Copper is closely related to molybdenum, and copper toxicity occurs when the dietary
ratio of copper to molybdenum increases about 6-10: 1.Affected animals suddenly go off
feed and become weak. An examination of their mucous membranes and white skin will
reveal a yellowish brown color. Their urine will be a red-brown color due to hemoglobin
in the urine. Treatment of copper poisoning is based on inactivating the copper with
molybdate and sulfate.
Diarrhea (Scours)
Diarrhea is defined as an increased frequency, fluidity, or volume of fecal excretion.
There are many causes of diarrhea: bacterial, viral, parasites, and diet. It is not possible
to definitively determine the infectious organism by looking at the color, consistency, or
odor of the feces. A definitive identification requires a sample for microbiological
analysis. Diarrhea in lambs and goats is a complex, multi-factorial disease involving the
animal, the environment, nutrition, and infectious agents. Diarrhea should not be
considered an illness in and of itself but rather a symptom of other more serious health
problems in sheep and lambs. Diarrhea is not always the result of an infectious disease.
It can be induced by stress, poor management, and nutrition. Before treating an animal
for diarrhea, it is essential to determine why the animal is scouring. Many of the
common causes of diarrhea are self-limiting, and the major goals of treatment are to
keep the animal physiologically intact while the diarrhea runs its course.
Dystocia (lambing difficulty)
Most ewes deliver their lambs without assistance, however, there are occasions when
producers must be prepared to assist with difficult deliveries. Difficult births can be
caused by 1) abnormal presentation of the lamb(s); 2) an unusually large lamb; 3) a fat
ewe; and 4) a small pelvic area. The normal delivery position for a lamb is the head and
two front feet being delivered first. If lambs cannot be delivered after a reasonable 7
amount of time and effort, competent assistance should be sought. A caesarean section
is sometimes necessary to deliver lambs that cannot be delivered normally.
E. Coli scours
Also called watery mouth
E. coli scours is an opportunistic disease that is associated with sloppy environmental
conditions and poor sanitation. It generally occurs as a diarrhea problem in two to fourday-old lambs. Affected lambs salivate and have a cold mouth; thus, the common name,
"watery mouth." Dehydration, coma and death usually occur within 12-24 hours
following the onset of clinical signs of scours. Treatment of E. coli scours usually
involves rehydrating the lamb with oral, subcutaneous or intraperitoneal fluids and
treatment with appropriate antibiotics. Prevention of E. coli scours in lambs should
really be the key focus for any flock. Lambing barn sanitation and creating a clean, dry
environment for newborn lambs are the key factors related to preventing outbreaks of E.
coli scours.
Entropion (inverted eye lid)
Entropion is a heritable trait in which the lower eyelid is inverted, causing the eyelashes
of the lower lid to brush against the eye. Entropion should not be left untreated. The
constant irritation results in tearing and can lead to corneal ulceration, scarring, and
blindness. It may affect one or both eyes. Mild cases of entropion can be treated by
injecting a long acting antibiotic under the skin of the affected eyelid. Sometimes,
staples, sutures, or clips will need to be applied to the skin surface of the affected eyelid.
Rams carrying this trait should not be used for
Epididymitis (Brucella Ovis)
Epididymitis is a venereal disease of rams caused by Brucella ovis. Epididymitis means
inflammation of the epididymitis, the tubular portion of the testical that collects the
sperm produced by the testes and stores it until it is ready to transport. Severely affected
rams will often have at least one enlarged epididymis and may show pain when the
testicle is manipulated. Epididymitis causes varying degrees of damage. It may cause
infertility by affecting the ram's ability to produce viable sperm. It is the number one
ram fertility problem seen in the sheep industry. Epididymitis is contagious and is
transmitted during homosexual activity or during the breeding season via the ewe. Only
about half of the rams affected by epididymitis respond to antibiotic treatment. Damage
is usually permanent. Prevention is to buy virgin or disease-free rams, to subject rams to
diagnostic testing, and to cull affected rams
External Parasites
Also called ectoparasites
External parasites affecting sheep include keds, ticks, lice, mites, and nasal bots. Mange
(sheep scab) in sheep is rare and a reportable disease in the U.S. 8
Fly Strike
Also called blowflies, wool maggots, fleece worms, and myiasis
Fly strike is the infestation of the flesh of living sheep by blowfly maggots. Of all
domestic animals, sheep are most often affected because wool, particularly dirty wool
attracts blowflies. Blowfly populations are greatest during the summer months.
Docking, shearing, and removal of dags (wool contaminated with feces) will help to
prevent flystrike. Insecticides are another control measure. Hair sheep are less
susceptible to fly strike due to their absence of wool. Blowflies are also attracted to
wounds, foot rot, weeping eyes, or sweat around the base of the horns of rams.
Sheep Keds (or ticks) - Sheep keds are wingless, reddish brown biting flies that
resemble, and are sometimes called, ticks. They use piercing- sucking mouthparts to
feed on blood. High ked populations cause unthriftiness and emaciation and make
animals more susceptible to diseases and other stresses. Sheep keds are readily
controlled with insecticides. Treatment is recommended immediately after shearing.
Keds can only survive off the animal for about a week. Keds do not thrive well on the
short hair of hair sheep.
Lice - Lice are quite small, ranging from 1/20-inch to 1/10-inch long. They spend most
of their time next to the skin, and are difficult to see within dense wool or hair. Three
species of lice are found on sheep. The primary animal reaction to lice is itching. Severe
infestations can cause anemia. Various insecticides can be used to control lice on sheep.
Nasal bots
Also called sheep bot fly and head bot
The sheep bot fly is a fuzzy, yellowish-gray or brown fly that deposits tiny larvae on the
muzzles or nostrils of sheep. The larvae migrate into the nostrils and head sinuses and
develop. A snotty nose is the symptom. Animals will hold their heads down or in a
corner to escape the flies. Weight reductions of up to 4 percent have been attributed to
bot infestations in some studies. The highest bot levels are seen in November and
December. A systemic insecticide formulation containing ivermectin is effective against
larval stages of the nasal bot.
Scabies
Also called sheep scab, psoroptic mange, and wet mange
Sheep scab is a very contagious disease, caused by mites feeding on the surface layers of
the sheep's skin. Severe itching occurs, wool or hair falls out in patches, and the skin
becomes reddened, crusted with scabs and sore. Positive diagnosis can be made only by
scraping lesions and examining the scrapings microscopically for mites. The preferred
method of treatment is dipping with insecticides. Scabies has been declared eradicated
from the United States.
Facial eczema
Facial eczema is a condition of severe dermatitis in cattle, sheep, and goats caused by a
toxin in spores of the saprophytic fungus Pithomyces chartarum, which lives in dead
vegetative material in pastures, especially perennial ryegrass. Facial eczema is an
example of "secondary photosensitization," in which the skin lesions are really the 9
secondary result of liver damage, rather than the direct result of a plant toxin. The liver
damage in facial eczema is caused by the toxin sporidesmin in the fungus spores. Facial
eczema is relatively common in areas of New Zealand and has also been observed in
Australia, South Africa, and in irrigated perennial ryegrass fields in the United States
(Oregon). Perennial ryegrass is the grass species most associated with facial eczema. P.
chartarum as does not grow well in legumes. The occurrence of facial eczema is also
influenced by livestock genetics. Performance testing programs in New Zealand have
identified genetic lines of sheep that can tolerate relatively high toxin situations.
Animals suffering from facial eczema should be removed from the contaminated pasture
and provided with shade, cool water, and a good diet. Feeding high levels of zinc may
help prevent facial eczema.
Fescue Toxicosis
Most Tall Fescue (Festuca arundinacea) is infected with a fungal endophyte. The toxins
that result from the endophyte create a number of problems for the grazing animal,
although sheep appear to be less affected by the endophyte than cattle and horses.
However, sheep are prone to "fescue foot," hyperthermia, poor wool production, and
reproductive problems, as well as lowered feed intake and the resulting poor weight
gains. Diluting Kentucky 31 tall fescue with legumes and supplementing with other feeds
will reduce the toxic effects of fescue on livestock. Alternative tall fescue cultivars are
also available.
Foot Rot
Foot rot is one of the most economically devastating diseases in the sheep industry. It is
caused by the interaction between two anaerobic bacteria: Bacteroides nodosus, which
can only live in the animal's hoof; and Fusobacterium necrophorum, which is a normal
inhabitant of soil and sheep manure. Lameness in one or more feet is the most common
symptom of foot rot, though not all lame sheep have foot rot. Foot rot has a
characteristic foul odor. Foot rot can be controlled and/or eradicated by a combination
of hoof trimming, vaccination, foot bathing and soaking and culling. Zinc sulfate is
considered to be the most effective foot rot treatment. Foot rot is highly contagious.
Foot Scald
Foot scald causes the tissues between the sheep's toes become blanched or white, or red
and swelled. It is caused by a soil bacteria that is present in most environments and
manifests itself during wet conditions. It is easier to treat than foot rot. Placing sheep in
a dry area away from mud may clear the condition. Individual animals can be treated
with Koppertox. Groups of animals may be treated with a zinc sulfate foot bath.
Goiter
Goiter is an enlargement or swelling of the thyroid gland. Affected lambs have a swollen
throat. They are often born with little or no wool. They are weak and often die of
starvation. Treatment is usually unrewarding. But if the condition is not advanced, the
lamb may survive. Goiter in newborn lambs is due to a deficieny of iodine in the 10
pregnant ewe's diet. It can be prevented by providing iodized salt in the diet of gestating
ewes. The salt mixture should contain 0.007 percent of available iodine. An iodine
deficiency may also result in reduced yield of wool and reduced conception rate in the
flock.
Internal Parasites
Coccidiosis (Eimeria sp.)
Coccidia are single-cell protozoa that are a natural inhabitant of the sheep's gut. Young
lambs are particularly susceptible to coccidia especially during periods of stress (e.g.
weaning). Coccidia damage the lining of the small intestine, affecting absorption of
nutrients. The most common symptom of coccidiosis is diarrhea. The diarrhea may be
bloody or smeared with mucous. The diagnosis of coccidiosis cannot be confirmed by
identification of oocysts in fecal samples. Coccidosis is mostly a management-related
disease, caused by overstocking and poor hygiene. Coccidiosis can be prevented by
including Lasolocid (Bovatec®), Monensin (Rumensin®), or Decoquinate (Deccox®)
in the feed or mineral. Coccidiosis should be treated with Amprolium or sulfa
medications.
Stomach worms
(Haemonchus, Trichostrongylus, and Ostertagia sp.)
Also called roundworms, nematodes, and gastro-intestinal parasites
The internal parasites of primary concern in sheep are the stomach worms, with the
Barber Pole worm (Haemonchus Contortis) being of primary concern and the small
brown stomach worm being of secondary concern. The barber pole worm is a bloodsucking parasite that pierces the mucosa of the abomasum, causing blood and protein
loss. The primary symptom of barber pole infection is anemia (blood loss). Anemia can
be observed in the sheep by examining its lower eyelid, which will become paler (whiter)
with increasing infestation. An accumulation of fluid under the jaw, called "bottle jaw" is
also a tell-tale of barber pole infection. The small brown stomach worm also burrows
into the lining of the abomasum, but it causes typical digestive symptoms, especially
diarrhea. Microscopically, it is difficult to differentiate between the barber pole worm
and the brown stomach worm. The eggs only differ in size not appearance.
Nematodirus spp.
The life cycle and transmission of Nematodirus differs from that of other sheep worms.
Infective N. battus larvae generally don't survive for long on pasture when weather
conditions are warm and dry, but can survive for several months during cool and damp
weather. The symptoms of nematodirus are scours, weight loss, and sudden death.
Tape worms (Moniezia sp.)
There is disagreement as to whether tapeworms cause serious problems in sheep. They
are generally considered to be non-pathogenic, though they can cause weight loss,
diarrhea, and even death in extreme cases. The only anthelmintics that are effective
against tape worms are the benzamidizoles (fenbendazole and albendazole).
Lung worms
Lung worm larvae are passed in the feces, but travel to the respiratory system once they 11
enter the sheep system. The symptoms of lung worm infection are not obvious unless
the problem is severe. The same anthelmintics that are effective against stomach worms
are also effective against lung worms.
Liver flukes (Fasciola hepatica)
Liver flukes are generally not considered to be a problem in the Mid-Atlantic states.
Liver flukes require snails and open water to complete their life cycle. The only
anthelmintic that is effective against liver flukes (the adult form) is albendazole
(Valbazan®).
Meningeal worm (Paralaphostrongylus tenius)
Also called deer worm and brain worm
The meningeal worm is a parasite of the White Tail deer. Sheep, goats, llamas, alpacas,
and horses are abnormal hosts for the parasite. After they ingest the larvae, the larvae
travel to the spinal cord causing gait abnormalities and eventually paralysis. When the
parasite reaches the sheep's brain, it will kill them. Meningeal worm infection cannot be
detected in the live animal. When meningeal worm is suspected, high doses of
anthelmintics and anti-inflammatory drugs are recommended. Infections can be
prevented by limiting exposure to deer or by controlling snail populations, since the
parasite requires snails to complete its life cycle.
(Ovine) Johne's Disease (OJD)
Also called paratuberculosis
Johne's Disease (pronounced "Yo nees") is a disease that affects the intestines of mostly
ruminants. It is caused by a hardy bacteria called Mycobacterium paratuberculosis.
Johne's most commonly occurs in dairy cows, but may also affect beef cattle, sheep, and
goats. The strain that affects sheep is different than the one that affects cows, though
there is an intermediate strain that sheep are susceptible to. While cattle experience
diarrhea, in sheep, Johne's tends to be a wasting disease. There is a theoretical link
between Johne's Disease and Crohn's disease in people.
Joint Ill
Also called navel ill and polyarthritis
Joint ill occurs in lambs up to one month of age. Affected lambs are often lame in
several joints, usually limb joints, including fetlocks, knees, hocks and stifles. Affected
joints are hot and painful. The lambs are dull, feverish and clearly unthrifty. Some may
have swollen, infected navels, while others may have symptoms of pneumonia or
meningitis. The infection is usually caused by strains of streptococci, though coliforms
and occasionally Actinomyces pyogenes may be isolated. Affected lambs should be
treated with a long-acting penicillin. Joint ill is prevented by good hygiene and using a
navel dip, such as betadine or gentle iodine.
Lactic Acidosis
Also called ruminal acidosis, grain overload, and grain poisoning
Lactic acidosis is caused by excess consumption of concentrates (grain) which results in 12
high levels of acid being produced in the rumen. Affected sheep appear depressed and
listless and may have abdominal pain. They should be drenched with an antacid such as
carmalax, bicarbonate of soda, or products containing magnesium carbonate or
magnesium hydroxide. Acidosis is prevented by proper feeding management.
Concentrates (grain) should be introduced to the diet slowly and increased
incrementally to give time for the rumen to adjust.
Lameness
It has been estimated that 80 percent of the flocks in Great Britain have lame sheep.
Lameness is a sign of several foot conditions – some of which are very serious – as well
as some other problems. They include foot rot and foot scald, strawberry foot, foot
abscess, foot-and-mouth disease, bluetongue, ovine interdigital dermatitis (looks like
scald), sore mouth, arthritis, nutritional deficiencies, mineral excesses, and physical
injuries. The more common foot problems can be avoided or minimized if good
husbandry practices are followed. Regular hoof inspection and foot paring will prevent
many problems.
Laminitis
Also called founder
The lameness related to laminitis is caused by inadequate blood flow in the foot. Signs
are heat in the feet. It is normally associated with digestive problems resulting from
excessive intake of grain (grain overload/acidosis), which usually masks the effects on
the feet. Such animals usually die before the feet become involved. Recovered animals
may exhibit foot growth and/or permanent lameness. Feeding management is key to the
prevention of laminitis/founder.
Listeriosis
Also called circling disease
Listeria monocytogenes, the bacteria that causes listeriosis is widely distributed in
nature and is found in soil, feedstuffs, and feces from healthy animals. It is most
commonly associated with the feeding of moldy silage or spoiled hay, but because the
organism lives naturally in the environment, listeriosis may occur sporadically.
Listeriosis usually presents itself as encephalitis, but may also cause abortion in ewes.
Sheep with the neurological form of the disease become depressed and disoriented.
They may walk in circles with a head tilt and facial paralysis. Mortality is high and
treatment (high doses of antibiotics) is generally not effective.
Mastitis
Also called hard bag and blue bag
Mastitis is an inflammation of the mammary gland (udder) which is usually caused by a
bacterial infection. The bacteria causing mastitis in ewes are Staphylococcus aureus and
Pasteurella hemolytica. There are two types of mastitis: acute and chronic. The glands
of ewes with acute mastitis may be discolored and dark, swollen and very warm. The
affected ewe may be reluctant to walk, may hold up one rear foot, and may not permit 13
her lambs to nurse. Ewes with chronic mastitis often go undetected. Mastitis is treated
with intramammary infusions of antibiotics and systemic antibiotics. There is no vaccine
for mastitis.
Milk fever
Also called hypocalcemia and parturient paresis
Milk fever is a metabolic disease affecting mostly pregnant ewes near term when
calcium requirements are highest. It is most commonly caused by an inadequate intake
of calcium, but can also be caused by a ewe's inability to mobilize calcium reserves prior
to or after lambing. Milk fever presents similar symptoms as pregnancy toxemia but can
be differentiated by the affected ewe's response to calcium therapy. Ewes in the early
stages of milk fever can be administered calcium gluconate subcutaneously. More
seriously affected ewes will require intravenous calcium and other supportive therapies.
Milk fever can be prevented by providing proper levels of calcium in ewe diets,
especially during late gestation.
Ovine progressive pneumonia (OPP)
Also called lunger disease and Maedi-Visna
Ovine progressive pneumonia is a slow developing viral disease that is characterized by
progressive weight loss, difficulty in breathing and development of lameness, paralysis
and mastitis. It is very closely related to caprine arthritis-encephalitis virus (CAE) and is
caused by a retrovirus. The OPP virus closely resembles Maedi-Visna which is a similar
slow or retrovirus found in other parts of the world. OPP is transmitted laterally to other
susceptible animals or to offspring through ingestion of infected milk and colostrum.
Veterinary diagnostic laboratory assistance is required for diagnosis. There is no
treatment, but OPP can be eliminated from the herd using annual blood testing and
removal of positive animals and removal of the lambs from the ewes prior to suckling. It
is estimated that over 50% of the flocks in the U.S. are infected with OPP with the
number of sheep infected within a positive flock anywhere between 1% to 70%.
However, the vast majority of infected sheep will never show respiratory disease or a
wasting syndrome.
Pink eye
Also called infectious keratoconjunctivitis
Pinkeye is a highly contagious disease affecting the eyes of sheep. Pinkeye may result
from many different infective agents: Chlamydia, certain viruses, and mycoplasma. The
disease will usually complete its course in three weeks in individual sheep. The use of
eye medications containing antibiotics may be helpful in individual cases. There are no
effective vaccines available. The agent that causes pinkeye in sheep and goats is different
from the one that causes it in cattle.
Pizzle Rot
Also called sheath rot
Pizzle (or sheath) rot is an infection in the sheath area of the ram. It is caused by the 14
bacteria, Corynebacterium renale or one from that group. The other factor is high
protein diets (>16 percent). Ammonia, produced by the excess urea in the ram's urine
can cause severe irritation and ulceration of the skin around the preputial opening. The
debris from the ulcer form a crust which may block the opening to the prepuce. Pizzle
rot can affect a ram's desire and ability to breed.
Pneumonia
Also called respiratory disease complex
Pneumonia is second in importance to diseases of the digestive tract. Pneumonia is a
respiratory complex with no single agent being solely responsible for the disease. The
most common bacteria isolated from respiratory infections is Pasteurella haemolytica
or Pasteurella multocida or both. Affected animals become depressed and go off feed.
They may cough and show some respiratory distress. Temperatures are usually over
104°F. The disease may be acute with sudden deaths or take a course of several days.
Pneumonia is treated with antibiotics.
Polioencephalomalacia (PEM, CCN)
Also called polio and cerebrocortical necrosis
Polioencephalomalacia is a disease of the central nervous system, caused by a vitamin
B1 (thiamine) deficiency. Since the rumen manufactures B vitamins, polio is not caused
by insufficient thiamine, but rather the inability to utilize it. The most common
symptom of polio is blindness and star gazing. It most commonly occurs in lambs that
are consuming high concentrate diets. Polio can also occur in sheep that consume plants
that contain a thiamase inhibitor. Polio symptoms mimic other neurological disease
conditions, but a differential diagnosis can be made based on the animals' response to
injections of vitamin B1.
Pregnancy Toxemia
Also called ketosis, twin lamb disease, lambing paralysis, and hypoglycemia
Pregnancy toxemia is a metabolic disease affecting ewes during late gestation. It most
commonly afflicts thin ewes, overfat ewes, and/or older ewes carrying multiple fetuses.
It is caused by an inadequate intake of energy during late pregnancy, when the majority
of fetal growth occurs. Treatment is to increase the blood sugar supply to the body by
administering glucose intravenously or propylene glycol or molasses orally. In extreme
cases, removal of the fetuses is the only recourse to save the ewe. Pregnancy toxemia can
be prevented by providing adequate energy to ewes during late gestation, usually ½ to 1
lb. of grain per head per day, more for high producing ewes. Adequate feeder space is
necessary so that all ewes are able to consume enough feed.
Rabies
Rabies is a viral disease of the central nervous system of mammals, spread by contact
with saliva from an infected animal, usually through bites or scratches, abrasions, or
open wounds in the skin. Domestic animals may become exposed during normal grazing
or roaming. Sheep have symptoms similar to cattle, and sometimes vigorously pull their 15
wool. Livestock and horse owners may decide to vaccinate their animals if they are often
exposed to potentially rabid wild or domestic animals. Generally, production animals,
such as dairy cow herds and sheep flocks, are not vaccinated because the potential risks
are usually lower than the annual costs of vaccination and because human contact with
individual animals is low. Small groups of valuable purebred animals may be an
exception.In recent years, a few states have required vaccination for rabies before an
animal (including some livestock) is exhibited.
Rectal Prolapse
A rectal prolpase is protrusion of the rectal tissue through the exterior of the body. It
usually begins as a small round area sticks out when the lamb lays down or coughs. In
extreme cases, the intestines can pass through the opening and the disease can be fatal.
There are many predisposing factors to rectal prolapses, including genetics, short tail
docks, coughing, weather, stress, and feeding concentrate diets. Rectal prolapses tend to
occur more in ewe lambs than wether lambs and more in black-faced sheep than whitefaced sheep. It is primarily a disease of feed lot lambs. Usually, lambs with prolapsed
rectums are prematurely slaughtered or sent to market. It is possible to repair a rectal
prolapse by amputating the prolapsed part of the rectum.
Ringwomb
Ringwomb is failure of the cervix to dilate sufficiently to allow delivery of lamb(s). While
sometimes the cervix of affected ewes can be opened with gentle pressure or the
injection of hormones, usually such efforts prove futile and a c-section to remove the
lambs is the only viable course of action. Unfortunately, little is known about the cause
of ringworm and how to prevent it.
Ringworm
Also called club lamb fungus, wool rot, and lumpy wool
Club lamb fungus is a highly contagious fungal infection of the skin of sheep. It is
especially a problem with show lambs. Club Lamb Fungus is caused by fungus of the
genus Trichophyton. Infection occurs when the fungus invades the skin and hair (wool)
follicles. Fungal spores are transmitted by contaminated clippers, blankets, combs,
bedding, bunks, and pens. Lesions can appear anywhere, however, most are found on
the head, neck, and back. The infection is susceptible to anti-fungal agents. Club lamb
fungus causes a nasty ringworm infection in people.
Scrapie
Scrapie is a fatal disease affecting the central nervous system of sheep and goats. It is
spread during lambing season when lambs come into contact with infected placentas.
While the occurrence of scrapie in the U.S. sheep flock is low, only one in 500 animals
and scrapie, it is a disease of regulatory concern. This is because scrapie is a member of
a family of diseases called "transmissible spongiform encephalopathies (TGE's), which
also includes chronic wasting disease (in mule deer and elk), mad cow disease (bovine
spongiform encephalopathy) and classic and new variant Creutzfeldt-Jacob's Disease (in 16
humans). Producers of breeding stock are encouraged to enrolled in the voluntary
scrapie flock certification program, which after five years of scrapie-free monitoring,
enables a flock to be certified "scrapie-free." Furthermore, while scrapie is not a genetic
disease, a sheep's genetic make-up influences its susceptibility to scrapie if exposed to
the infective agent. Therefore, sheep can be tested for scrapie resistance.
Sore mouth
Also called contagious ecthyma, scabby mouth, pustular dermatitis, and orf
Sore mouth is the most common skin disease affecting sheep. It is a highly contagious
viral infection that can also produce painful human infections. The virus causes scab
formation on the skin, usually around the mouth, nostrils, eyes, mammary gland and
vulva. It first appears as tiny red nodules, usually at the junction of the lips. Effective
vaccines are available. The vaccine is applied to a woolless area in the inside of the ear or
under a leg where it cannot spread to the mouths of other animals. Once the vaccine is
used on the premises, it should be continued yearly. Flocks that have not experienced
soremouth should probably not vaccinate for soremouth, since the vaccine introduces
the virus to the farm.
Spider Syndrome
Also called hereditary chondrodysplasia
Spider syndrome is a genetic condition that results in lambs with severe malformations
of the skeletal system. These animals have very fine bone , crooked legs and a crooked
spinal column , distinct lack of muscular development and usually do not survive to full
maturity . The cause of the condition appears to be genetic alteration due to selection for
extreme length and height in show sheep. The disease is found predominantly in blackfaced lambs: 75% Suffolk and 25% Hampshire. In order to have this disease, lambs
inherit a recessive gene from each parent.
Urinary calculi
Also called water belly, urolithiasis, and calculosis
Urinary calculi is a metabolic disease of wethers and rams characterized by the
formation of calculi (stones) within the urinary tract. Blockage of the urethra by calculi
causes retention of urine, abdominal pain, distention and rupture of the urethra or
bladder. The most common cause of urinary calculi is feeding rations with high
phosphorus levels. Grain products tend to be very high in phosphorus relative to
calcium, whereas forages have a better ratio. The ratio of calcium to phosphorus in the
ration should be at least 2:1. Providing the proper balance of minerals in the ration is
preferred to offering minerals free choice, since there is no guarantee animals will
consume adequate amounts of free choice mineral. The addition of ammonium chloride
to the ration will aid in preventing urinary calculi. It is also important that animals have
an ample supply of clean, potable water. The addition of salt to the ration will increase
water intake and decrease stone formation. 17
Uterine prolapse
A uterine prolapse is when the womb is turned inside out and pushed through the birth
canal by the abdominal strainings of the ewe. It occurs immediately after lambing and is
a life-threatening situation. A prolapsed uterus must be manually forced back into the
ewe. The uterus should be cleaned with a warm, soapy, disinfectant solution prior to
replacement and should be replaced before the tissues become dry or chilled. Deep
sutures are necessary to keep the uterus in place. Affected ewes should be removed from
the flock. Older ewes are more commonly affected than younger ewes.
Vaginal Prolapse
Vaginal prolapses (protrusion of the vagina) are most commonly observed during the
last month of pregnancy or shortly after lambing. Many factors have been implicated in
the cause of vaginal prolapse, such as hormonal/metabolic imbalances, overfat/overthin
body condition, bulky feeds, lack of exercise, dystocia in previous pregnancies, increased
abdominal pressure and fetal burden. Prolapses often recur in subsequent pregnancies.
The exposed vagina of affected ewes should be washed with soapy disinfectant solution
and forced back into the ewe. A bearing retainer or "spoon" can be inserted and secured
in the ewe to prevent further prolapsing. In a ewe that has lambed, sutures are used to
secure the prolapse. Affected ewes and their offspring should probably not be kept in the
flock for breeding animals due to the possibly hereditary nature of the problem.
White muscle disease (WMD)
Also called nutritional muscular dystrophy and stiff lamb disease
White muscle disease is a degeneration of the skeletal and cardiac muscles of lambs. It is
caused by a deficiency of selenium, vitamin E, or both and can be a problem wherever
selenium levels in the soil are low. Symptoms are stiffness of the hind legs with an
arched back and tucked in flanks. Treatment is the administration of selenium and
vitamin E by injection. Feed rations should be evaluated to determine if they are
providing adequate levels of selenium and vitamin E. When feed supplementation is
adequate, preferred, lambs can be given an injection of selenium and vitamin E shortly
at birth. Dietary supplementation of selenium is preferred to selenium injections.
Flock vaccinations
Vaccinations are an important part of a flock health management program. They provide inexpensive "insurance" against diseases that can commonly affect sheep and lambs.
Clostridial Diseases
In most cases, the only universally-recommended vaccine for sheep and lambs is CD-T. The CD-T toxoid provides three-way protection against enterotoxemia caused byClostridium perfringins types C and D and tetanus (lockjaw) caused by Clostridium tetani. Seven and 8-way combination vaccines that include additional clostridial diseases, such as blackleg and malignant edema are also available, but the extra protection may not be necessary.
Type C
Enterotoxemia type C, also called hemorrhagic enteritis or "bloody scours," affects lambs mostly during their first few weeks of life, causing a bloody infection in the small intestine. Type C enterotoxemia is often related to indigestion and is predisposed by a change in feed, such as beginning creep feeding or a sudden increase in milk supply, perhaps caused by the loss of a littermate. The only way to provide protection to lambs is through the colostrum by vaccinating their dams two to six weeks prior to lambing.
Clostridial Diseases
In most cases, the only universally-recommended vaccine for sheep and lambs is CD-T. The CD-T toxoid provides three-way protection against enterotoxemia caused byClostridium perfringins types C and D and tetanus (lockjaw) caused by Clostridium tetani. Seven and 8-way combination vaccines that include additional clostridial diseases, such as blackleg and malignant edema are also available, but the extra protection may not be necessary.
Type C
Enterotoxemia type C, also called hemorrhagic enteritis or "bloody scours," affects lambs mostly during their first few weeks of life, causing a bloody infection in the small intestine. Type C enterotoxemia is often related to indigestion and is predisposed by a change in feed, such as beginning creep feeding or a sudden increase in milk supply, perhaps caused by the loss of a littermate. The only way to provide protection to lambs is through the colostrum by vaccinating their dams two to six weeks prior to lambing.
Type D
Enterotoxemia type D, also called "classic" overeating disease or "pulpy kidney disease," usually affects lambs over one month of age. Usually it is the largest, fastest growing lamb(s) in the flock that are affected. Type D overeating disease is usually precipitated by a sudden change in feed that causes the bacteria, already present in the lamb's gut, to proliferate, resulting in a toxic, usually fatal reaction. Type D is most commonly observed in lambs that are consuming high concentrate diets, but can also occur in lambs nursing heavy milking dams.
Passive immunity
To confer passive immunity to lambs through the colostrum (first milk), ewes should be vaccinated for CD-T approximately 4 weeks prior to lambing. Ewes lambing for the first time should be vaccinated twice in late pregnancy, about four weeks apart. Maternal antibodies will protect lambs for six to eight weeks, provided lambs consume adequate amounts of colostrum.
Lambs
Lambs should receive their first CD-T vaccination when they are approximately 6 to 8 weeks of age, followed by a booster 2 to 4 weeks later. If pastured animals are later brought into confinement or dry lot for concentrate feeding, a third vaccination should be given.
Lambs whose dams were not vaccinated for C and D can be vaccinated with some success at two to three days of age and again in two weeks. However, later vaccinations will be more successful since colostral antibodies interfere with vaccinations at very young ages.
A better alternative may be to vaccinate offspring from non-vaccinated dams at 1 to 3 weeks of age, followed by a booster 3 to 4 weeks later. Anti-toxins can provide immediate short-term immunity if dams were not vaccinated or in the event of disease outbreak or vaccine failure.
Feeder lambs
Purchased feeder lambs should be vaccinated against type D at the time of purchase and 2 to 4 weeks later. Feeder lambs purchased as 4-H or FFA projects should receive two type D vaccinations, if they were not vaccinated at the farm of origin.
Tetanus
Lambs whose dams were not vaccinated for tetanus should be given the tetanus anti-toxin at the time of docking and castrating, especially if elastrator bands are used. An antitoxin provides immediate short-term immunity.
Rams and pet sheep should be boostered annually for CD-T.
Enterotoxemia type D, also called "classic" overeating disease or "pulpy kidney disease," usually affects lambs over one month of age. Usually it is the largest, fastest growing lamb(s) in the flock that are affected. Type D overeating disease is usually precipitated by a sudden change in feed that causes the bacteria, already present in the lamb's gut, to proliferate, resulting in a toxic, usually fatal reaction. Type D is most commonly observed in lambs that are consuming high concentrate diets, but can also occur in lambs nursing heavy milking dams.
Passive immunity
To confer passive immunity to lambs through the colostrum (first milk), ewes should be vaccinated for CD-T approximately 4 weeks prior to lambing. Ewes lambing for the first time should be vaccinated twice in late pregnancy, about four weeks apart. Maternal antibodies will protect lambs for six to eight weeks, provided lambs consume adequate amounts of colostrum.
Lambs
Lambs should receive their first CD-T vaccination when they are approximately 6 to 8 weeks of age, followed by a booster 2 to 4 weeks later. If pastured animals are later brought into confinement or dry lot for concentrate feeding, a third vaccination should be given.
Lambs whose dams were not vaccinated for C and D can be vaccinated with some success at two to three days of age and again in two weeks. However, later vaccinations will be more successful since colostral antibodies interfere with vaccinations at very young ages.
A better alternative may be to vaccinate offspring from non-vaccinated dams at 1 to 3 weeks of age, followed by a booster 3 to 4 weeks later. Anti-toxins can provide immediate short-term immunity if dams were not vaccinated or in the event of disease outbreak or vaccine failure.
Feeder lambs
Purchased feeder lambs should be vaccinated against type D at the time of purchase and 2 to 4 weeks later. Feeder lambs purchased as 4-H or FFA projects should receive two type D vaccinations, if they were not vaccinated at the farm of origin.
Tetanus
Lambs whose dams were not vaccinated for tetanus should be given the tetanus anti-toxin at the time of docking and castrating, especially if elastrator bands are used. An antitoxin provides immediate short-term immunity.
Rams and pet sheep should be boostered annually for CD-T.
Other diseases
In addition to CD-T, there are other vaccines that producers may wish to include in their flock vaccination program, depending upon the health status of their flock, disease risk, and the diseases prevalent in their geographic area. These include sore mouth, foot rot, caseous lymphadenitis, abortion, e. coli scours, parainfluenza-3 (PI-3), epididymitis, and rabies.
In addition to CD-T, there are other vaccines that producers may wish to include in their flock vaccination program, depending upon the health status of their flock, disease risk, and the diseases prevalent in their geographic area. These include sore mouth, foot rot, caseous lymphadenitis, abortion, e. coli scours, parainfluenza-3 (PI-3), epididymitis, and rabies.
Soremouth
There is a vaccine for soremouth (contagious ecthyma, orf), a viral skin disease commonly affecting sheep and goats. It is a live vaccine that causes sore mouth lesions at a location (on the animal) and time of the producer’s choosing. Ewes should be vaccinated well in advance of lambing. Show animals should be vaccinated well in advance of the first show.
To use the vaccine, a woolless area on the animal is scarified, and the re-hydrated vaccine is applied to the spot with a brush or similar applicator. Ewes can be vaccinated inside the ear or under the tail. Lambs can be vaccinated inside the thigh. Because the sore mouth vaccine is a live vaccine and sore mouth is highly contagious to humans, care must be taken when applying the vaccine. Gloves should be worn.
Flocks which are free from soremouth should probably not be vaccinated because the soremouth vaccine will introduce the virus to the flock/premises. Once soremouth vaccination is begun, it should be continued yearly.
There is a vaccine for soremouth (contagious ecthyma, orf), a viral skin disease commonly affecting sheep and goats. It is a live vaccine that causes sore mouth lesions at a location (on the animal) and time of the producer’s choosing. Ewes should be vaccinated well in advance of lambing. Show animals should be vaccinated well in advance of the first show.
To use the vaccine, a woolless area on the animal is scarified, and the re-hydrated vaccine is applied to the spot with a brush or similar applicator. Ewes can be vaccinated inside the ear or under the tail. Lambs can be vaccinated inside the thigh. Because the sore mouth vaccine is a live vaccine and sore mouth is highly contagious to humans, care must be taken when applying the vaccine. Gloves should be worn.
Flocks which are free from soremouth should probably not be vaccinated because the soremouth vaccine will introduce the virus to the flock/premises. Once soremouth vaccination is begun, it should be continued yearly.
Footrot
Footrot is one of the most ubiquitous and economically devastating diseases in the sheep industry. It causes considerable economic loss due to the costs associated with treating it and the premature culling of carrier animals. There are two vaccines for footrot and foot scald in sheep: Footvax® 10 Strain and Volar™ Footrot Bacterin.
Neither vaccine prevents the diseases from occurring, but when used in conjunction with other management practices such as selection/culling, regular foot trimming, foot soaking/bathing, etc., vaccinations can help reduce infection levels. Footrot vaccines should be administered every 3 to 6 months and especially prior to anticipated outbreaks of hoof problems (i.e. prior to the wet/rainy season).
Footrot is one of the most ubiquitous and economically devastating diseases in the sheep industry. It causes considerable economic loss due to the costs associated with treating it and the premature culling of carrier animals. There are two vaccines for footrot and foot scald in sheep: Footvax® 10 Strain and Volar™ Footrot Bacterin.
Neither vaccine prevents the diseases from occurring, but when used in conjunction with other management practices such as selection/culling, regular foot trimming, foot soaking/bathing, etc., vaccinations can help reduce infection levels. Footrot vaccines should be administered every 3 to 6 months and especially prior to anticipated outbreaks of hoof problems (i.e. prior to the wet/rainy season).
Abscesses (at the injection site) are not uncommon with the foot rot vaccines.
Caseous lymphadenitis (CL)
There is a vaccine for caseous lymphadenitis in sheep. CL affects primarily the lymphatic system and results in the formation of abscesses in the lymph nodes. It is highly contagious. When it affects the internal organs, it evolves into a chronic wasting disease.
The cost of CL to the sheep industry is probably grossly underestimated. The CLA vaccine is convenient to use because it is combined with CD-T. Vaccination will reduce the number of abscesses in the flock.
Caseous lymphadenitis (CL)
There is a vaccine for caseous lymphadenitis in sheep. CL affects primarily the lymphatic system and results in the formation of abscesses in the lymph nodes. It is highly contagious. When it affects the internal organs, it evolves into a chronic wasting disease.
The cost of CL to the sheep industry is probably grossly underestimated. The CLA vaccine is convenient to use because it is combined with CD-T. Vaccination will reduce the number of abscesses in the flock.
Abortion
Abortion is when a female loses her offspring during pregnancy or gives birth to stillborn, weak, or deformed lambs. There are vaccines (individual and combination) for several of the infectious causes of abortion in sheep: enzootic (EAE/Chlamydia sp.) and vibriosis (Campylobacter fetus).
Abortion vaccines should be administered prior to breeding. Ewes being vaccinated for the first time should receive a second vaccination (booster) in mid-pregnancy. Producers with problem flocks may consider giving a booster as well. Risk factors for abortion include an open flock and/or a history of abortions in the flock.
Unfortunately, there is no vaccine (available in the U.S.) for toxoplasmosis, another common cause of abortion in sheep. Since the disease-causing organism is carried by domestic cats, the best protection is to control the farm's cat population by spaying/neutering and keeping cats from contaminating feed sources.
Epididymitis
Epididymitis is a major cause of reduced fertility in rams from western range states. There are vaccines for epididymitis (Brucella ovis), but none are deemed fully effective. In addition, vaccination interferes with the ability to eliminate infected rams from the flock, as vaccinated rams will test positive for B. ovis.
E.Coli Scours
Scours in baby lambs can be caused by E. coli. There is a vaccine that can be administered to ewes at the same time as CD-T to pass immunity to lambs through the colostrum. An alternative to vaccination is to give newborn lambs oral E. coli antibody at birth.
Abortion is when a female loses her offspring during pregnancy or gives birth to stillborn, weak, or deformed lambs. There are vaccines (individual and combination) for several of the infectious causes of abortion in sheep: enzootic (EAE/Chlamydia sp.) and vibriosis (Campylobacter fetus).
Abortion vaccines should be administered prior to breeding. Ewes being vaccinated for the first time should receive a second vaccination (booster) in mid-pregnancy. Producers with problem flocks may consider giving a booster as well. Risk factors for abortion include an open flock and/or a history of abortions in the flock.
Unfortunately, there is no vaccine (available in the U.S.) for toxoplasmosis, another common cause of abortion in sheep. Since the disease-causing organism is carried by domestic cats, the best protection is to control the farm's cat population by spaying/neutering and keeping cats from contaminating feed sources.
Epididymitis
Epididymitis is a major cause of reduced fertility in rams from western range states. There are vaccines for epididymitis (Brucella ovis), but none are deemed fully effective. In addition, vaccination interferes with the ability to eliminate infected rams from the flock, as vaccinated rams will test positive for B. ovis.
E.Coli Scours
Scours in baby lambs can be caused by E. coli. There is a vaccine that can be administered to ewes at the same time as CD-T to pass immunity to lambs through the colostrum. An alternative to vaccination is to give newborn lambs oral E. coli antibody at birth.
Rabies
Though the risk to sheep is usually minimal, rabies vaccination may be advised if the flock is located in a rabies-infected area, the animals are valuable, and livestock have access to wooded areas or areas frequented by raccoons, skunks, foxes, or other known carriers of rabies. Frequent interaction with livestock may be another reason to consider vaccinating.
The cost of the rabies vaccine relative to the value of the animals should be considered. The large animal rabies vaccine is approved for use in sheep. Producers should consult their veterinarian regarding rabies vaccination. Some states require rabies vaccination for exhibition at fairs and shows. All dogs and cats on the farm should be vaccinated against rabies.
Though the risk to sheep is usually minimal, rabies vaccination may be advised if the flock is located in a rabies-infected area, the animals are valuable, and livestock have access to wooded areas or areas frequented by raccoons, skunks, foxes, or other known carriers of rabies. Frequent interaction with livestock may be another reason to consider vaccinating.
The cost of the rabies vaccine relative to the value of the animals should be considered. The large animal rabies vaccine is approved for use in sheep. Producers should consult their veterinarian regarding rabies vaccination. Some states require rabies vaccination for exhibition at fairs and shows. All dogs and cats on the farm should be vaccinated against rabies.
Autogenous vaccines
When no commercial vaccine is available, autogenous or custom vaccines can be made. They are usually made from bacteria or viruses that have been isolated on a farm in conjunction with a disease. Autogenous vaccines are usually not as effective as commercial vaccines.
When no commercial vaccine is available, autogenous or custom vaccines can be made. They are usually made from bacteria or viruses that have been isolated on a farm in conjunction with a disease. Autogenous vaccines are usually not as effective as commercial vaccines.
Giving Vaccines
Most vaccines are given subcutaneously (sub-Q), i.e. under the skin. Some vaccines are given intramuscularly (IM). Occasionally, some are given topically (e.g. sore mouth) or intranasally (e.g. Nasalgen®). For subcutaneous vaccines, use a 1/2 or 3/4 inch, 18- or 20-gauge needle. Subcutaneous vaccinations can be given over the ribs, behind the armpit, or high up on the neck. The needle used to withdraw vaccine from the bottle should not be the same needle used to inject the animal.
Most vaccines are given subcutaneously (sub-Q), i.e. under the skin. Some vaccines are given intramuscularly (IM). Occasionally, some are given topically (e.g. sore mouth) or intranasally (e.g. Nasalgen®). For subcutaneous vaccines, use a 1/2 or 3/4 inch, 18- or 20-gauge needle. Subcutaneous vaccinations can be given over the ribs, behind the armpit, or high up on the neck. The needle used to withdraw vaccine from the bottle should not be the same needle used to inject the animal.
In order for vaccination programs to be successful, label directions should be carefully followed. Vaccines should be stored, handled, and administered properly. Only healthy sheep and lambs should be vaccinated. It is also important to note that vaccines have limitations and that the immunity imparted by vaccines can sometimes by inadequate or overwhelmed by disease challenge.
Future vaccines
With the increasing role of small ruminants in small farms and sustainable farming systems, hopefully animal health companies will develop and license more vaccines for sheep.
Scientists are currently working to develop vaccines to protect small ruminants againstHaemonchus contortus and other gastro-intestinal and blood-sucking parasites. The research is promising. Thus far, the challenge has been developing effective vaccines using recombinant DNA technology, as other methods of vaccine generation are not economically feasible.
With the increasing role of small ruminants in small farms and sustainable farming systems, hopefully animal health companies will develop and license more vaccines for sheep.
Scientists are currently working to develop vaccines to protect small ruminants againstHaemonchus contortus and other gastro-intestinal and blood-sucking parasites. The research is promising. Thus far, the challenge has been developing effective vaccines using recombinant DNA technology, as other methods of vaccine generation are not economically feasible.
