11 - winter dysentery, salmonella, peritonitis, fat necrosis
winter dystentery
bovine coronavirus
occurs in colder months
outbreak lasts < 2 weeks
1-2% mortality (rare)
fecal-oral route transmission
viral damage to colon/SI
clinical findings
sudden-onset explosive diarrhea, bubbly in puddles, thick mucus, melena
anorexia, depression
decreased milk production
decreased BCS
dehydration after 2 days
decreased rumen motility
PU/PD
afebrile
diagnosis
PCR
paired serology
treatment
spontaneous recovery
supportive care
control
biosecurity
no vaccine
salmonella
GNR
zoonotic
enteritis
GI infection → diarrhea, inflammation
typically occurs following exposure to large dose of virulent strain
significant reduction in milk production
common to shed w/o symptoms after infection
uncommon to persistently shed thorughout life
fecal-oral transmission
most common during cold months
mostly in lower ileum, cecum, spiral colon
watery to mucoid diarrhea, ± fibrin/blood
abortion may occur
diagnosis
culture
gold standard
repeated culture isolation of pathogen
single isolation may confirm acute infection
limitations: low sensitivity in chronically infected animals, may fail to detect subclinical carriers → intermittent shedding
PCR
highly sensitive
postive result not definitive for clinical disease
can use to serotype
serology
herd-level surveillance/monitoring
less reliable for dx individual clinical cases
treatment
abx, supportive care
fluid therapy
abx may cause endotoxin release
control
source animals from Salmonella-free herds
identify and cull chronically infected animals
good husbandry practices
biosecurity
Peritonitis
inflammation of serous membranes lining peritoneal cavity
infectious or noninfectious causes
generally non-contagious
may cause adhesions/impair organ function
peritoneum and omentum attempt to wall off areas of contamination
cr abdomen adhesions → no problem
cd abdomen adhesions → intestinal obstruction
etiology
primary
less common
infection spread hematogenously
immunocompromised animals
secondary peritonitis
more common
infectious or non-infectious, idiopathic
leakage or perforation of gastrointestinal organs
diagnosis
clincal signs
rectal palpation
abdominoparacentesis
peritoneal fluid analysis
cytology: inflammatory cells, bacteria
culture: infectious agents
management/treatment
generally poor prognosis
peritoneal lavage
fluid therapy/supportive care
aggressive systemic abx
surigcal intervention → repairs, necrotic tissue removal
fat necrosis
hard, necrotic fat masses within peritoneal cavity
cannel island breeds, japanese black cattle
beef cattle >2yo
can be mistake for fetus
etiology
associated with high-concentraiton diets, rich in long-chain saturated FAs
grazing tall fescue w/ enotyphodium coenophialum endyphyte
overconditioning, genetic predisposition, lack of exercise
diagnosis
firm, irregular masses on rectal palpation
hyperechoic masses, typically in omentum
r-flank exploartory may be necessary
rarely free-floating in abdomen
treatment/control
masses slowly increase in size
may have spontaneous resolution
remove animals from tall fescue pasture
legume-rich diet