Neurologic Diseases of Ruminants Flashcards
which cranial nerves are involved in the menace response?
cranial nerves II and VII
what causes cerebellar hypoplasia?
pestivirus
BVDV in cattle
border disease virus in small ruminants
what is the incubation period of rabies?
3 weeks to 6 months
what is polioencephalomalacia?
necrosis of the grey matter
what are the signs of polioencephalomalacia?
cerebral signs:
star-gazing
altered mentation
blindness with intact PLR
what are the risk factors for thiamine deficiency?
hypo/anorexia
poor roughage diet
ingestion of thiaminases
what does excess sulfur inhibit?
mitochondrial electron transport chain
what can be seen on a blood smear with lead toxicity?
anemia with RBC basophilic stippling
what are the common causes of salt toxicity?
inappropriate milk replacer without free choice water
high salinity well water/softeners
inaccessible water sources
what are the clinical signs of hypomagnesemia?
aggression
seizures
facial twitching
what are the three important mechanisms of bacterial meningoencephalitis?
general sepsis associated
Histophilus somni associated thromboembolic meningoencephalitis
Chlamydophila pecorum biotype 2
what is the pathophysiology of bacterial meningoencephalitis Histophilus somni?
part of bovine respiratory disease complex
thromboembolic vasculitis- polyserositis
what is mad cow/transmissible spongiform encephalopathies/prion?
bovine spongiform encephalopathy
is Listeriosis zoonotic?
yes
how is vitamin A derived?
from fresh green grass and stored in liver
how can you diagnose Parelaphostrongylus tenuis?
neurologic deficits localizing to spinal cord, can be anywhere
CSF show eosinophilic pleocytosis 50% of timee
what is radial nerve paralysis commonly due to?
prolonged recumbency, falls, or restraint injury
what is the most common peripheral nerve injury?
sciatic nerve
what is the brainstem involved in?
arousal
what is the thalamocortex involved in?
behavior: mental status, menace response, nasal septum tactile response
what is involved in the menace response?
cranial nerve II
cortex
cerebellum
cranial nerve VII
what is involved in the pupillary light reflex?
cranial nerve II
cranial nerve III
what is involved in position of the eye in the orbit and eye movement?
cranial nerve III, IV, VI
what is involved in physiologic nystagmus?
cranial nerves III, IV, VI, VIII
what is involved in palpebral reflexes?
cranial nerve V, VII
symmetry of the face: cranial nerve VII
what is involved in food prehension?
cranial nerve XII
masticatory movement: cranial nerve V
what is involved in dysphagia and laryngeal problems?
cranial nerve IX and X
how can you diagnose cerebellar hypoplasia?
cerebellar ataxia, nystagmus
pre-colostral antibody titers for BVDV
blood, skin, tissue antigen- false negatives possible
necropsy
how can you prevent cerebellar hypoplasia?
test and remove clinically affected neonates
BVDV vaccination of dams
biosecure management
what is cerebellar abiotrophy?
born normal and cerebellum atrophies at <1 year of age
what is cerebellar hypoplasia?
cerebellum incompletely developed from birth
how can you diagnose rabies?
identification of negri bodies or IFAT on CNS tissue
what are the four etiologies of polioencephalomalacia?
thiamine deficiency
sulfur toxicity
lead toxicity
salt toxicity
what supplies thiamine to ruminants?
rumen microbes
what is the prognosis of thiamine deficiency?
good if treatment initiated early
what are the sources of excess sulfur?
well contamination
feeding sugar by-products
how can you diagnose sulfur toxicity?
identify high sulfur source in feed
rumen gas cap hydrogen sulfide often low
post-mortem changes are identical to thiamine deficiency or polioencephalomalacia
how can you treat sulfur toxicity?
thiamine supplementation
supportive care
what is the pathophysiology of lead toxicity?
lead interferes with calcium signaling and multiple enzymes requires for ATP production
how can you diagnose lead toxicity?
whole blood levels reliable
radiographic lead lines
blood smear changes
how can you treat lead toxicity?
thiamine supplementation
supportive care
EDTA administration to chelate lead
how can you treat salt toxicity?
thiamine supplementation
supportive care
slow correction of hyponatremia
dextrose and isotonic sodium bicarbonate
what can cause metabolic cerebral disease?
nervous ketosis
hypomagnesemia
how can you prevent bacterial meningioencephilitis from Histophilus somni?
vaccine
oxytetracycline metaphylaxis on feedlot
how can you diagnose transmissible spongiform eencephalopathies- bovine?
histologic of immunohistochemical evaluation of the OBEX for abnormal protein aggregates and histologic changes
is transmissible spongiform encephalopathies- scrapie- associated with feeding practices?
no
is ante-mortem biopsy of peripheral lymphoid tissue diagnostic of scrapie?
yes- affected protein accumulates throughout lymphoid tissues of body
what are the parasitic cerebral diseases?
nervous coccidiosis
coenurus cerebralis
Parelaphostrongylus tenuis
what are the main brainstem/cranial nerve diseases?
listeriosis
otitis interna
vitamin A deficiency
is Listeriosis zoonotic?
yes
how can you diagnose Listeriosis?
CSF mononuclear pleocytosis and elevated protein
post-mortem: micro-abscesses
which antibiotics do not work on Listeriosis?
cephalosporins
how can you prevent otitis media/interna from M. bovis?
minimize respiratory disease in calves
milk/colostrum management: feed only commercial or pasteurized colostrum and milk
what is vitamin A important for?
bone, retinal, epithelial metabolism
why does blindness occur with vitamin A deficiency?
blindness due to retinal degeneration and compression of the optic chiasm due to boney hyperplasia
what is spinal lymphosarcoma often from?
BLV-associated
how can you treat Parelaphostrongylus tenuis?
high dose fenbendazole
supportive care
monthly ivermectin
