Food Ani. Med- Bovine- Musculoskeletal Disorders (Lameness) 5

drraythe's version from 2016-04-29 15:29


Question Answer
etiological agents of tetanus? (describe it a little)Etiology is Clostridium tetani, an anaerobic spore-forming bacteria commonly found in the environment
what is the thing that actually causes the tetanus dz?The TOXIN! Disease is caused by the elaboration of a neurotoxin (TeNT)
explain the pathogensis of tetanusC. tetani spores contaminate a wound site (The uterus of adult cows can be a site of contamination.)--> Commonly associated with castration or tail docking & less commonly with a navel infection. Especially a problem with banding (avascular necrosis). TeNT (neurotoxin) attaches & is taken into nerve cells, where it is transported and taken to the spinal cord, where it Wipes out inhibitory neurons --> Tetanic spasms of muscles. Incubation period is quite variable but seldom less than 1 week.
CSs of tetanus? Difficulty in rising, Hyperesthesia, Tonic muscle contractions (sawhorse stance, Pump handle tail, sardonic grin, lockjaw), prolapsed 3rd eyelid, Loss of ability to swallow (so cannot suckle), Recumbency, respiratory failure and death
how do you tx tetanus?unrewarding tx. You can use antitoxin to Neutralize circulating, but unattached toxin. Can also Open the wound to expose to oxygen & debride necrotic tissue.. Procaine Penicillin G or Gram positive antibiotic.Use sedatives to control hyperesthesia & supply muscle relaxation ( Diazepam @0.088 mg/kg q 6 h, Acepromazine @ 0.088 mg/kg q 8-12 h).
what do you use for PREVENTION of tetanus? Vaccination with tetanus toxoid early in life (toxoid not antitoxin!) (i.e. CD/T at 6 and 10 weeks of age should produce immunity lasting more than a year.). Also Practice aseptic techniques for docking & castration.( and you can Administer tetanus antitoxin at the time of surgical procedure.)
when/who do you wanna booster?Booster vaccination to pregnant does & ewes with CD&T during the last 4-6 weeks of gestation --> booster of colostral immunity.
what is the science name for the meningeal worm? what kinda worm is it? DH/IHParelaphostrongylus tenuis. Nematode that uses snails/slugs as the intermediate host & deer as the definitive host.
how are rumis infected by P. tenuis?Camelids & small ruminants eat the snail or slug becoming an aberrant host. Infection is dependent on ingestion of snail or slug carrying the infective L3 larvae. Evidence that infection can occur from ingestion of slime trail.
What are clinical signs of meningeal worm/ what are the CSs related to?Lameness , Incoordination, Difficulty rising, Neurological Signs typically affect the hind end 1 st. Advanced Disease= Vestibular signs. **Signs relate to larval migration within the spinal chord
*explain how the CSF varies between listeriosis, meningitis, and meningeal wormlisteria= monocytosis. Meningitis= neutrophilia. Meningeal worm= eosionphilia
DDxs for meningeal worm?Listeria, meningitis, Vertebral fractures or subluxations
how do you tx meningeal worm? Treatment is empirical based on history and clinical signs. Fenbendazole, banamine, Vit E, oxytet, supportive care
what are diff signs which might indicate prog of meningeal worm?Respond well if presented early. Inappetence & recumbency= Prognosis is guarded at best. Neurologic deficits that remain > 6 mos will be lifelong.
how do you tx vs how to you prevent meningeal worm?prevent= ivermectin. Tx= fenbendazole.
how can you prevent meningeal worm?Ivermectin SQ at 3 – 4 week intervals (resistance?), Pyrantel pamoate fed daily, Doramectin SQ q 60 days, Prevent access of deer and snails.


Question Answer
Scrapie is the common name for what problem?Transmissible Spongiform Encephalopathy (TSE), which is a Afebrile, progressive, degenerative disorder of the CNS
3 theories about what causes scrapie are?(1) Filamentous Virus (2) Prion= Self replicating protein (3) Small nucleic acid with a protective protein coat that is encoded in the host DNA
what is PrPC^SC?Rod shaped protein that has 100% correlation with infection. Protein is not autolyzed. Has been recovered from frozen and formalin fixed tissues
how is scrapie transmitted?horizontal and vertical
explain the pathogenesis (how are the infected, age infected most commonly, how does it cause problems)Most commonly affects animals ~ 3 ½ yoa or greater. Oral infection occurs at birth. Remains latent for > 8 mos, where it is Replicating in the lymphoreticular system. Lasts b/t 2 & 5 years. PrPC^SC protein is toxic to cells, so the accumulation leads to neurodegenerative lesions
which genetic factors inc susceptibility to scrapie?Codon positions of the PrP gene at 136 & 171 are associated with increased susceptibility & decreased survival time
1* scrapie occurs in which breeds?Suffolk, Cheviot, Southdown, and Hampshire sheep
suffolks with what genetics are most suseptible? AA136, RR154, or QQ171
which gene makes all breeds more suseptible, and which gene confers resistance? QQ171makes all breeds more susceptible, RR171confers resistance
*if you suspect scrapie, what should you know?REPORTABLE DZ
(not sure if need to know dx) dx of scrapie? Histopathology of brain tissue is the standard (Highly Sn & Sp). Antemortem testing is being developed using lymphoid tissue from the 3 rd eyelid
tx for scrapie?no tx- fatal dz
how do you prevent scrapie?Flock certification program: 5 yr assessment with 4 levels, Final level allows sale and export w/o restriction
which two bact of the resp passages/oropharynx can cause acute inflammation of the inner & middle ear resulting in vestibular signs (i.e. neurologic)?Mannheimia haemolytica & Histophilus somni (In young calves, Mycoplasma has also been associated with otitis & neurologic signs.)
clinical signs of otitis can mimic what other dz?The clinical signs can mimic Listeriosis: Febrile, Circling in one direction, Loss of equilibrium to the extent of not being able to rise, Ear droop (often with exudation from the ear canal present)
(not sure if need to know dx) dx otitis?CSF can be normal but there can be extension to the brain = ↑ neutrophils / CT
what might CSF/hemogram be like with otitis?CSF normal, hemogram will show systemic resp dz
Very difficult to get good antimicrobial penetration into the middle and inner ear. Antibiotic commonly used in BRD(bovine resp dz is my guess)? (3) and how long? Florfenicol, Ceftiofur, tilmicosin. Treatments are of long duration. Can also use antiinflamatories (NSAIDs) an antihistamines
what risk is there from dehorning?Thermal Meningitis from dehorning
MAJOR SIGN OF... TEME? CCN? Listeriosis? otitis media? sinusitis?TEME: stupor. CCN: blindness. LISTERIOSIS: CN deficits. Otitis media: vestibular problems. Sinusitis: head pressing/depression
postmortem finding for... TEME? CCN? Listeriosis? otitis media? sinusitis? TEME: cortical infarcts (causes thrombosis- H. somni.). CCN: flattened gyri, autofluorescence. (thiamine deficiency). Listeriosis: +/- meningitis, microabscesses in brainstem (L. monocytogenes, think circling/CN probs!), otitis media: brain normal, exudate in ear canals. Sinusitis: doming of front bone, exudate in sinuses.
Vitamin A deficiency--> causes? common in who? signs?Encephalopathy- common in feedlot cattle (see Convulsions, Blindness)
Vitamin E deficiency--> causes? common in who? signs?common in equine: There is Demyelination, so you will see Ataxia, Recumbency
Ca++ or Phos deficiency--> causes? common in who? signs?common in Rapidly growing weaned calves &Dairy cows. Cause Vertebral fractures, Tetany, Milk fever. And see Weakness, Ataxia, Recumbency, Tetany
Ca++ Excess--> causes? common in who? signs?Common in equine. causes Cervical instability. Will see Wobblers, Weakness, Ataxia
K+ deficiency--> causes? common in who? signs?common in cattle. You will get weakness. You will see post-partum recumbency.
Vit. E / SE deficiency--> causes? common in who? signs?Can see in anyone. Get nutritional myodegeneration. see Weakness, Ataxia, Recumbency, Death
Mg++ deficiency--> causes? common in who? signs?see in Ruminants. Get Grass tetany(this is name for Mg deficiency), Milk tremors. See Convulsions, Tremors, Ataxia
Cattle foot-carrying lame in the rear. “3 legged lame” Problems seems to be spreading. Started with recent purchase of 2 new cows. What is it?My theory is hairy heel wart. Thought to be caused by treponema bact. highly correlated to herds with new members. It has hair-like projections too. (spray oxytet on it) suggest footbaths

The things he skipped but then kinda went over anyway- hit a few high points

Question Answer
where (dairy or beef) do you see hygromas? what are they? why do they happen? where are they seen most commonly?happens on daires a lot- its a fluid filled sac caused by trauma (think small stalls). seen most commonly on the carpi and the hocks.
Tibial Hemimelia-- what is this, what breeds do you see it in most often?autosomal recessive gene most commonly seen in shorthorns (said in class inc rates in angus) It is a really short tibia congenitally
fescue foot can cause?necrosis
DDx for calf with head tilt and droopy ear?he said mycoplasma mastitis and histophilus somni
when does ascending myelitis usually happen?happens from infected tail docking site which ascends- he said "its basically an abscess which goes up the spinal cord"