BVD
When does embryonic death occur? what does it entail?
Defined as loss of pregnancy before 42 days of gestation
Conceptus is resorbed
Early embryonic period - from conception to maternal recognition at 17 days = cows retain normal 21 days estrus, may just appear as poor conception, usually unnoticed
Late embryonic period - up to day 42 = after maternal recognition of pregnancy, will appear as prolonged return to estrus
Herd may appear to have poor repro
What does fetal infection entail (>180 days) from BVD
Calfs immune system is completely developed
Produce antibodies
Born immune to the virus
Calf is normal and will not carry the virus
What are the ways of diarrhea without oral lesions vs with oral lesions
Without - Bacterial, viral, parasitic, nutritional/toxilogical
With = Viral - BVD and Malignant catarrhal fever
What is the pathology of Johnesq
MAP ingested orally or transferred via placenta
MAP taken up by peyers patches in lower SI
infects and reproduces in GIT and lymph nodes
Intestines become thickened -> decreased nutrient absorption
enlarged lymph nodes, thickened lymphatics
What are the four clinical syndromes of salmonellosis
Peracute septicemic form
Acute enteric form
Chronic enteric form
Carrier state
When does abortion/fetal mortality occur? what does it entail
After 42 days of gestation
abortion - fetal expelled
Mummification - aseptic fetal death, fetus not expelled, persistent Cl, usually 3 months plus (fetal bones, tissue not resorbed), can result in prolonged gestation
Can you see persistent infection in calves
Can cause immunosuppression - warts or ringworm
May lag behind others
Can look normal
Can still perform well in the feedlots in some cases
What is johnes disease
Mycobacterium avium ssp. paratuberculosis
Gram +, acid-fast bacillus
bacterial infection of the intestinal tract
long incubation period
What is the agent in salmonellosis
Genus salmonella - gram -, intestinal bacteria, S. Enterica most important for ruminants, provincially notifiable in most provinces
Host adapted vs non host adapted serovars
Host adapted - may be more invasive
What is salmonella dublin
Host adapted serotype
Highly prevalent in dairy cattle
Creates speticemic infections
Respiratory disease in calves 2-12 woa
What does persistent infection entail
Cow become infected by virus while pregnant between 40-120 days gestation
Immune system of calf is not developing
What is mucosal disease
PI calves infected with non-cytopathic BVD
Occurs between 6-18 months of age
Not all PI calves develop mucosal disease
What is the MAP of johnes disease
Bacterial infection
Waxy cell wall makes bacteria very resistant, resistant to most disinfectant, can survive fairly high temp
facultative intracellular pathogen
What is the host in salmonellosis epidemiology
Three main sources - Infected cattle
- Contaminated feed sources
- Rodents and birds
fecal oral transmission, aerosol, saliva and nasal secretions, milk and colostrum
How do you diagnose salmonellosis
Fresh fecal samples
PCR, ELISA
CBC, Biochemistry, Serology
Necropsy
What does fetal infection entail (120-180 days) from BVD
Calves may be born with congenital defects
Cerebellum may be underdeveloped
Eye problems - cataracts. blindness
Weak or stillborn, or abortions
Signs of mucosal disease
Off feed, depressed
Nasal discharge
Erosions and ulcers in mouth
Muzzle may have burnt or peeling appearance
fever
Dehydration
Diarrhea
What is the sources of infection for johnes? and Shedding
Feces, milk/colostrum, transplacental transmission
Shedding happens temp from 13-14 months of age, and then after 2 years
Clinical animals are heavy shedders
What are the host stressors and environmental exposure of salmonellosis epidemiology
Host - Temp extremes, transportation, crowding, ventilation, nutrition
Environmental exposure - cleanliness (manure management), calving pens next to sick pens
How do you treat salmonellosis
Fluid therapy - oral or IV
Antibiotics - controversial
NSAIDS - Ketoprofen or flunixin meglumine
What is cerebellar hypoplasia
Calf looks normal
Signs are unable to stand, ataxia, hypermetria, intention tremor, head tremor
Necropsy - cerebellum underdeveloped to nearly absent
How do you control BVD
Vaccination - pre breeding or prior to weaning and feedlot arrival
Eliminate carriers
Biosecurity
What are the clinical signs of johnes
Shows around 4-5 yoa
Weight loss despite good appetite, chronic diarrhea, emaciation, severe cases -> ascites
Clinical signs of salmonellosis
Often associated with stressors
outbreak - multiple animals
Hemorrhagic enteritis and anorexia
Fibrinous casts
Can just appear as enteritis with no blood or fibrin
Pneumonia in 2-12 week old calves
abortions
Sudden death
fevers of unknown origin
How do you prevent and control salmonellosis
Education
Biosecurity - cleaning and disinfection
Calves - reduce manure contamination