ovine caprine_board_review by z1UXeXh9


									                                                                 OVINE/CAPRINE BOARD REVIEW

Internal parasites of sheep

    Tapeworms – Moneizia expansa infects lambs
    Liver fluke – Fasciola hepatica only seen in autumn; wet areas, snail
    Nematodes – causes gastroenteritis; lambs and goats of any age are most vunerable
     a.   Ostertagia circumcincta most important
     b. Haemonchus controtus is most pathogenic (anemia and death)
     c.   Trichostrogylus axei – infects cattle and horses as well as sheep
    Control:
     a.   Benzimidazoles – act by affecting tubulin polymerization; only one to kill nematode eggs
     b. Levamisole and morantel – act on acetylcholine receptors
     c.   Ivermectin and moxidectin – affect Cl ion movement in the gamma aminobutyric acid receptors

     Strategic worm Deworming
     1. Before and after parturtion have  egss. Move to pasture that is clean for newborn babies. Deworm every 3-4 weeks w/ effective wormer for
          a.    largest animal in the group (not average)
          b. Injectable (Levamasol) for sheeps only
          c.    All other wormers should be given orally
          d. Annual rotation only
          e.    Sheep should never be kept on same paddocks as goats or follow goats on a grazing rotation
          f.    Use clean pastures – a single tx when ewes are taken inside or before turn out shoul suffice for worm control
          g. Tx lambs at the end of June and move to a clean pastue
          h. Spring suppression – it takes about 3 weeks for ingested larvae to develop into egg-laying adults, lambs and ewes can be used to ‘clean’ contaminated
                pastrue by tx them every 3 weeks from turn out; the last dose is in June to ensure that pasture infectivity has reached a low level
     2. After birth, fast female for 12 hours if bendemedazoles -  rumen juice and enhances drug
     3. Keep in paddock for 72 hours. Larvae are killed but eggs are expelled
     4. The put on safe pasture. Do at 3 week intervals w/ the same dewormer for one year. Don’t rotate. Change to a completely different class.

     Tactful deworming
     Don’t deworm on conenience (shearing, foot care). Worm 7-14 days after a rain. Based on weather.

     Measure eggs/gram (> 500 eggs/gram w/ McMasters in spring or > 1000 eggs in fall

    Blowfly – Lucilia sericata, caesar; lay eggs in response to fleece rot
    Nasal bot fly – Oestrus ovis; deposit larvae on nose of sheep; characteristic nose rubbing and nasal discharge that may look like scrapie
    Head fly – Hydrotaea irritans; causes ‘broken head,’ lesions, especially in horned Scottish Blackface; injuries are self-inflicted by avoiding the fly; blood feeder
    Sheep scab – Psoroptes ovis; wool loss, highly infectious allergic dermatits caused by excretory products of this mite; can cause epileptic seizures
    Psoroptic ear mites – subpopulation of the scab mite (above); non specific signs
    Lice – Bovicola/Damalinia ovis, Linognathus ovillus; wool biting and fleece staining
    Sheep Ked – Melophagus ovinus

Dicrocoelium dendriticum
    ‘the lancet fluke
    Bile ducts of sheep in NE US, sheep farming countries
    Land snail
    Ants via slime balls, work way to brain of ant
    Sheep eat ants on top of grass after crazy episode in AM
    Biliary hyperplasia, cirrhosis, scarring of liver surface, distension of bile ducts, anemia, edema, emaciation

Fasciola hepatica, ‘the liver fluke
    Bile ducts of cattle, sheep, goats and other ruminants
    Leaf-shaped & cone-shaped projection, egg has yellow shell
    Skin covered with tiny spines (can barely see)
    Tip of cone has oral sucker
    Ventral sucker at level of shoulders
    Water snail
    Vegetation below water level
    Metacercariae are swallowed by the cow when eaten or when stirred up and drank, Excyst and become juvenile flukes in the duodenum
    Acute fascioliasis- sheep, ‘traumatic hepatitis’ caused by migrationof large #s of juvenile flukes ‘Black Dx’ DEATH
    Chronic fascioliasis – sheep & cattle, migratory tracts cause hepatic fibrosis, thrombus
    Hyperplastic cholangitis – biliary mucosa becomes permeable to albumin
    Pipestem Liver – Calcification of bibrotic lesions develop
    Most pathogenic fluke of cattle in US, major cause of liver condemnation, causes ‘Fascioliasis’, ‘Liver Rot, or Liver Fluke Dx,’
    Best known fluke

Taenia ovis
Cysticercus ovis
    Mutton tapeworm
    Measly mutton
    Adult: Small intestine of dogs
    Metacestode: musculature of sheep and goats
    Armed, TTT egg, metacestode is a Cysticercus
    Sheep and goats
    Same as above only eggs are ingested by sheep. Cysticercus within ovine musculature is called ‘measly mutton’ Dogs are infected by ingestion of raw, poorly
     cooked measly mutton.Cysticercus evaginates, scolex attaches and tapeworm begins growth

Multiceps multiceps sheep coernurus tapeworm of dogs
          Coenerus cerebralis ‘gid or staggers or sturdy bladderworm of sheep’             Adult: small intestine of dogs
          Metacestode: brain and spinal cord of sheep or goats Armed Taeniid, TTT eggs, 14-20 branches Coenurus found in nervous tissue of intermediate host.
          A large flid filled baldder contains several hundred invaginated scolices attached to the wall of the tissue capsule.          Sheep and goats
                      Adults in host. Gravid proglottids shed daily in feces or migrate to anus. Proglottids motile and rupture realeasing 1000s of eggs. Eggs ingested
          by sheep. Eggs hatch in intestine and oncosphere is released. Onco penetrates intestinal mucosa and enters circulation. Larval tapeworm migrates to brain
          and spinal tissue, leaving winding yellow-grey streaks. Coenurus develops in brain or spinal cord. Dogs eat.        Acute meningoencephalitis may develop in
          lambs. Development of 1 or 2 coenuri in the brain. Sheep will demo neurological signs AKA
               ‘gid’ or ‘sturdy’ or ‘staggers’
               Cyst in brain. Sheep holds head to one side and turns in a circle toward affected side
               be blind in one eye on opposite side lower head and step high.
               May have jerky or staggering gait
               Paralysis

Facultative myiasis
              Contaminated wounds on sheep, cattle, goats, dogs, cats & wild mammals
              House fly, blow fly or flesh fly        Females lay eggs in decomposing flesh (contaminated wounds)
              The anterior (pointed) end of the larva has a pair of oral hook.
              The posterior end have spiracles.
              Cutaneous myiasis is called Strike or fleece rot in sheep        Surgical maggots

Oestrus ovis
                Nasal bot fly
                Nose of sheep and goats
                Adults dark gray w/ small gray spots
                L have 2 large black oral hooks on anterior end
                Modified complex meta
                Females deposit L, not eggs
                Lay on nostrils of sheep
                L develop in nasal & frontal passages
                Sneezed out and begin again
                L and Adults are pathogenic
                You’ll find sheep w/ noses to the ground to prevent adults from laying larvae
                Produces ‘False GID’

Psoroptes ovis, Psoroptes bovis, Psoroptes equie
               Scabies mite, scab mite of large animals
               Skin surface of sheep, cattle and horses
               Long, jointed pedicels (stalks)          Non-tunneling mite/non-burrowing mite. Live entire life cycle on skin
               Causes SCABIES
               Reportable to USDA
               Highly contagious that spreads rapidly from sheep to sheep. Sheep will have patches of skin exposed.. Very pruritic.

Dystocia in sheep – see page 193
    Caused by:
     a.    Ring Womb – clover toxicity, need to lacerate cervix or do C-section if cervix does not dilate using lots of lube; pick up hind legs
     b. Overcondition can cause mal-P,P, P
     c.    Undercondition – pregancy toxemia in ewes get ketone body buildup, occurs before parturition
     d. Malpresentation, position and posture not as common except in excessively fat ewes
     e.    Uterine inertia can occur
    Dystocias cause:
     a.    Decrease in lamb survival
     b. Mess up thermoregulation in lambs, especially w/ hypoxia
     c.    Mothering ability decreases in ewe w/ dystocia
     d. More common in meat breeds (Merinos, Rambuleaux)
    Need to cull if dystocia
    Induce w/ Dexamethasone b/c no longer CL dependent – will give birth w/in 48-72 hours
    Remember to check for other lambs b/c multiple births

Dystocia in doe
    Can very easily rupture uterus – be very gentle and use lots of lube
    Incomplete cervical dilation is common
    Use same principles as in cow to remove
    Induce when >140 days w/ PGF2 b/c CL dependent
    Can also give Dexamethasone for kids

Determine whether acute or chronic:

           DDx for acute pneumonia in sheep:
                     a.    Bacterial – pasteurellosis; Pasteurella hemolytica; Mycoplasma ovipneumonia
                      b.   Parastic pneumonia – ‘Husk’; Dictyocaulus filaria and Muellerius cappillaris;
                      c.   Mechanical pneumonia – misuse of drenching gun

           DDx for chronic pneumonia in sheep:
                    a.    Ovine progressive pneumonia (Maedi, Maedi-visna)
                    b. Jaagsiekte – pulmonary adenomatosis; neoplasma or growth which is contagious and transmissible in sheep in Iceland
                    c.    Parasitic pneumonia – see above
                    d. Caseous lymphadenitis
                    e.    Post dipping pneumonia
                    f.    Enzootic pneumonia
                    g. Meliodosis
                    h. Johne’s dz – chronic wasting

Ovine chronic progressive pneumonia
   AKA Maedi or Maedi-Visna
   Visna – dz of the nervous system
   Non-oncogenic ovine retrovirus
   Signs:
    a.   Chronic pneumonia
    b. Arthritis
    c.   Mastitis
    d. Ill thrift

   Sheep and Goats both – Eimeria caprovina
   Goats – Eimera
   Sheep – Eimeria ovinoidalis and crandallis
   D+, dehydration, wt loss and weakness
   Sulphonamides, Amprolium, Monensin (narrow safety margin), Salinomycin, Decoquinate

ORF – Contagious Pustular Dermatitis; Contagious Ecthyma, Scabby mouth
   Contagous to humans
   Scabs around mouth, nostrils, eyes and udders
   Pox virus
   High morbitity, low mortality
   No specific tx

Nematode gastroenteritis
   Ewes pass large numbers of worm eggs onto the pasture over a period of several weeks around parturition – known as Periparturient egg rise (PPER) which is an
    important source of pasture contamination
   Goats do not build up an effective immune response against trichostrongylid worms so remain susceptible to dz throughout their lives
   Lambs are most susceptible – causes profuse watery D+
   Tx in sheep in ivermectins
   Tx in goats (metabolize some anthelmintincs more rapidly than do sheep and elevated dose rates are sometimes required to obtain a satisfactory level of control

Pregnancy toxemia
   Negative energy balance due to hypoglycemia and ketonemia causing an accumulation of acetoacetate, beta-hydroxylation and acetone in the blood
   Caused by a falling plane of nutrition especially in the last month of pregnancy in ewes bearing twins and triplets
   Sheep show encepthalopathy w/ blindiness, muscle tremor, convulsions, metabolic acidosis and clinical course of 2-8 days, usually terminating fatlly unless
    treated early
   Will see elevated BHBA in aqueous humor of sheep
   HIGHLY FATAL in sheep

Contagious foot rot
   Dichelobacter nodosus
   Source is lesion discharge from other infected sheep
   Merino breeds most susceptible
   Highly contagious w/ higher rate in warm, wet conditions
   Shows inflammation of the skin at the skin-horn junction in the interdigital area w/ underrunning of the soft horn, will progress to underrrunning of the hard horn
    and inflammation of the sensitive laminae
   Distinct foul smelling exudate (small in amount)
   Protease test for strain virulence
   Topical tx w/ bactericides, parenteral Abs, vaccination & culling
   In goats, there is severe interdigital dermatits, but rarely underrunning of horn of the sole

Enterotoxemia of suckling lambs
    Caused by Clostridium spp (most common is Type C in North America)

           Yellow lamb disease
               Clostridium perfringens Type A;
               reported in lambs in California;
               causes hemolytic dz of acute onset of severe depression, collapse, mucosal pallor, jaundice, Hburia, dyspnea & severe abdominal pain

           Lamb dysentery
             Clostridium perfringens Type B and in young lambs Type C
               Type C occurs mainly in North America
               Can involve goats – cold weather
               Tends to increase in incidence as the lambing progresses
               Case fatality can reach 100%
               Ingested from soil and fecal contamination -  &  toxin
               Can cause sudden death – abdominal pain, brown, fluid feces w/ blood, tenesmus
               Pine – older lambs have chronic abdominla apin and reluctance to suck but no D+
               Major lesions in all species is a hrmorrhagic enteritis w/ ulceration of mucosa
               Vaccine – there is cross protection between Type B & C
               Antiserume immediately after birth during outbreak
               Vaccinate dams for long term protection

           Overeating Dz or Pulpy kidney
              Acute toxemia from epsilon toxin produceing vascular and nervous tissue damage
              Affects lambs 3-10 weeks old and goats of all ages
              Affects animals in good condition and on a rising plane of nutrition
              Rapid course w/ D+, depression, convulsions – often found dead
              Adult goats show more chronic dz w/ abdominal pain and bloody D+
              Hyperglycemia and glycosuria in sheep

    E coli strains from D+ lambs and goats are not generally toxigenic

White Muscle Dz
   Subacute enzootic muscular dystrophy
   AKA Stiff lamb dz in young lambs
   Caused by Selenium or Vit E deficiency
   Found in sternal recumbancy and unable to stand or will show weakness
   Stiff, goose stepping gait
   Muscle tremors
   Dyspnea w/ labored and abdominal type respiration
   Flying scapula – upper borders of scapula protrude above the vertebral column and widely separated from the thorax

    Pasteurella hemolytica
    Two manifestations:
     a.   Pneumonic pasteurellosis – most common which occurs in all ages
     b. Septicemic – very young lambs
     c.   Mastitis
    Carried in oropharynx and tonsils of healthy sheep and goats; increased prevelance in stress (climate or management) or poor ventilation
    Rapid onset and short course
    Sudden death, fever, cough, resp distress

To top