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What is arthogryposis?
"crooked joints", congenital articular rigidity, abnormal development of the nervous system
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Arthrogryposis may be caused by... (3 pathologic processes)
heritable defect of skeletal muscle, abnormal development of nervous system, consumption of toxins or viral infections during gestation
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Describe the presentation of arthrogryposis.
rigid joints (bilateral or unilateral), scoliosis, kyphosis, torticollis, limb rotation; sometimes stillborn, sometimes born alive
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What is the underlying pathogenesis of arthrogryposis?
failure of in utero limb movement
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What is dysraphism?
recognizable lesions caused by arrest or delay of neural tube closure (can see spinal cord exiting the spine, +/- exposed to environment), hypoplasia of spinal cord; sometimes associated with arthrogryposis
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How does dysraphism present?
cannot stand, unable to ambulate, extension of rear legs bilaterally at rest
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Why has there been an increased incidence f Bluetongue virus in northern europe?
increased ambient temps has lead to increased vector prevalence
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What are viral causes of arthrogryposis?
akabane virus, aino virus, cache valley virus, bluetongue virus, BVDv, border disease virus, schmallenberg virus
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What toxic plants are linked to arthrogryposis, scoliosis, cleft palate, limb rotations, osteoporosis, bone fragility, etc?
- Veratrum
- Lupinus
- Conium maculatum (hemlocks)
- Nicotiana tabacum
- Datura stramonium (jimsonweed)
- Locoweeds
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When ingested in the first trimester, __________ causes cleft palate, kyphosis, and arthrogryposis.
Nicotiana tabacum
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Describe Akabane.
infection of pregnant, naive ruminants--> hydrancephaly, arthogryposis
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Describe Aino virus.
infection of pregnant, naive ruminants--> hydrancephaly, arthogryposis
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Describe Cache valley virus.
arthogryposis, hydrancephaly in newborn lambs
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Describe Bluetongue virus.
- bovine fetus most susceptible ~125days--> hydrancephaly, arthrogryposis, brachygnathia, excessive gingival tissue
- infection later--> abortion
- calves may become PI and shed
- problem for wild bighorn sheep living around cattle herds
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Describe BVDv.
hydrancephaly, hydrocephalus, cerebellar hypoplasia when infected <150 days in gestation
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Describe Schmallenberg virus.
- transmitted by hematophagous insects
- arthogryposis, vertebral malformations, brachygnathia inferior, hydrancephaly, hydrocephalus, cerebellar hypoplasia, micromyelia
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What toxic plant is associated with cyclopian fetuses?
Veratrum
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Lupine infection during pregnancy is associated with ___________, and is especially prevalent in the ___________.
arthogryposis; Alpines
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When is it most likely that ingestion of a toxin plant will cause birth defects and why?
early on in gestation b/c later on, most of the "parts" are already fully formed and just getting bigger
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Describe double muscling genetics.
muscular hyperplasia and increased # of muscle fibers due to a mutation in the myostatin gene
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What are advantages and disadvantages to doubling muscling?
- Advantages: more meat, tender meat
- Disadvantages: almost all have dystocia, C- section necessary
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What is unique about the Piedmontese registry?
must have evidence of at least one mutant allele for myostatin (doubling muscling) in order to be registered
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What are "Bully Whippets"?
mutation of myostatin from a 2 nucleotide deletion, leading to increased muscularity and faster dogs
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What genetic mutation do Texel sheep have?
double muscling due to myostatin G to A mutation--> very tough meat
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Disorders of synthesis of bone matrix are known as _____________.
osteogenesis imperfecta
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Disorders of bone remodeling are known as ___________.
osteopetrosis
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What are the major types of dwarfism, and what causes them? (4)
- chondrodysplasia (defects in cartilage formation that affects growth/development on bones formed by endochondral ossification)
- bulldog type, telemark, snorter/ brachycephalic, long-headed
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Describe bulldog dwarfs in Dexters.
incompletely dominant gene, so homozygotes are bulldog dwarfs and heterozygotes just have short legs
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Describe bulldog dwarfism. (7)
short limbs, rotated, domed head, short maxilla, prognathic, ventral abdominal hernia, LETHAL dwarfism
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Bulldog dwarfism is associated with __________.
genetic defect in aggrecan gene
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Describe telemark lethal dwarfism.
autosomal recessive, calves are born alive but cannot stand, die of suffocation after birth, looks like milder form of bulldog
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Describe brachycephalic dwarfism.
short stature, pendulous abdomen, recurrent bloat, bulging forehead, short maxilla, shortened vertebral column, distal limb bones are shorter than proximal
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What causes proportionate dwarfism?
autosomal dominant, low growth factor levels?
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Ovine chondrodysplasia always occurs in __________ and is characterized by...
black-faced sheep (Suffolk or Hampshire); spider lamb syndrome, semi-lethal, autosomal recessive, descendants of "Walking Tall" (suffolk sire that disseminated his mutation)
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Describe spider lamb syndrome.
- heterozygotes- long-limbs, narrow trunk
- homozygotes- valgus deformity (knock kneed), axial skeleton deviation, roman nose
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Osteopetrosis is called _________ and occurs predominantly in _________.
marble bone disease; Red Angus
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What causes osteopetrosis/ marble bone disease?
accumulation of primary spongiosa in marrow cavities caused by an autosomal recessive gene
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Describe the presentation of osteopetrosis/ marble bone disease.
small premature calves, brachygnathia, stillbirth, protruding tongue, abnormal TMJ joint (can't open mouth), shorter bones, dense medullary cavities
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What is the genetic test for osteopetrosis/ marble bone disease?
test IDs mutant SLC4A2 anion exchanger
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What is tibial hemimelia?
bilaterally malformed or absent tibia and giant abdominal hernia, shaggy haircoat, retained testicles, meningocoele, pelvis does not fuse
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What causes tibial hemimelia?
recessive allele resulting in homozygous state (common in club calf circles- utilize genetic testing)
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Describe the pathogenesis and outcome of PHA.
lungs are small and not developed, don’t get rid of fluid as they should; lungs and kidneys are very important for circulation of amniotic fluid, without lungs they get very edematous; cow goes into labor even though the calf is dead, but the calf won’t come out; can try to put pvc pipe down calf’s throat to try and puncture a hole and release fluid, making it easier to pull; usually need C-section, cow usually still dies
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What does PHA look like on post-mortem?
hypoplastic lungs, normal CVS, no lymphatics, edematous/ anasarca
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Glycogen phosphorylase deficiency occurs in _________ and causes...
Charolais; exercise intolerance, myalgia, recurrent myoglobinuria, weak calves, elevated CPK and AST, azotemia; diagnosed by muscle biopsy
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