Calf diarrhea Flashcards
What is the agent that causes enteric colibacillosis?
Enterotoxigenic E. coli
What are the characteristics of enterotoxigenic e.coli
2 main virulence factors -> pilus formation, K99, K88 and f41 pilus or fibria which allows attachement to enterocytes
-heat stable enterotoxins, heat labile enterotoxins
What is the epidemiology of enteric colibacillosis?
a) most frequently isolated pathogen in diarrheic neonates
b) most commonly seen in calves, lambs, kids, and piglets from 1-4 days of age
c) associated with lack of colostrum and or contamined environment
d) often complicates viral or parasitic enteric diseases
What are the CS of enteric colibacillosis?
a) profuse watery diarrhea, no straining, dehydration, weakness
b) course is rapid - death may occur 6-12 hours after onset
c) temperature - normal to subnormal
d) heart rate -> may be elevated. normal or decreased
e) respiratory rate - may be elevated depending on degree of acidosis
What is the pathophysiology of secretory diarrhea
1) cell structure is not affected
2) Enterotoxins are secreted which increase intestinal secretion
3) the SI and LI absorptive cells remain capable of absorbing nutrients and fluid, the amount of fluid secreted, however, exceeds the absorptive capacity of these cells resulting in diarrhea
What can we see from lab results with enteric collibacilosis
-hypoglycemia, hyperkalemia, acidosis, prerenal azotemia, dehydration
How do we diagnose enteric collibacilosis?
Culture of E.coli with presence of pilus antigen, PCR isolates
ELISA or latex agglutination test on feces
Florescent antibody testing of intestinal tissues
What do we see on necropsy with enteric collibacilosis
no gross lesions
What do we see on histopath with enteric collibacilosis
minimal inflammatory reaction in the SI, some mild vilous atrophy. Sheets of gram negative bacilli adhere to the villous enterocytes of the SI mucosa
How do we treat enteric collibacilosis
-fluid therapy, colostrum feeding
-antimicrobials early in the disease : ceftiofur, spectinomycin, sulfas
How do we prevent enteric collibaclosis
a) proper colostrum managment
b) birth in a clean environment
c) vaccination of the dam with pili antigen
d) monoclonal antibody
What agent causes cryptosporidosis
Cryptosporidium parvum
What are the characteristics of cryptosporidiosis
a) zoonotic potential
b) oocysts sporulated at time of passage, infective immediately. Autoinfection
c) oocysts do not survive freezing but are hardy in the enviornmen. Build up in the environment over time
CS of crypto
a) disease occurs in calves 1-3 weeks of age
b) diarrhea, tensmus, anorexia, weight loss, depression
c) dehydration is ocassionaly present but usually occurs when other pathogesn complicate infection
Pathophysiology of crypto
a) does not invade the cytoplasm but attaches in the brush border at the cell surface resulting in malabsorption
b) distal SI is mostly affected
How do we diagnose crypto
a) fecal floation
b) histopath- organisms can be seen in the border. May see blunting and mild fusion of the vili
How do we treat crypto
a) fluids, vitamin A, supportive care
How do we prevent crypto
a) sanitation - clean with undiluted bleach
-5% ammonium
b) drying decreases infectivity
c) movement of calving and housing areas
How do they get salmonellosis
a) acquired from the environment- capable of surviving in the enviornment for long periods of time, sunlight kills it. Exposure to contaminated manure - rodent, birds, infected cattle
b) acquired from cattle- recrudencsce at times of stress
c) acquired through feed - contamination by feces
d) acquired through water- run off sources
Pathophysiology of salmonellosis
secretory and malabsorptive diarrhea
Secretory -> prostaglandin syntehsis from endotoxin effects
Malabsorptive -> destruction of microvillous and inflammaotry reaction in the bowel
What are the CS of salmonellosis
a) calves are usually between 10 days to 3 months of age but all ages are affected
b) enteritis, fever, inappetence, depression, and dehydration
c)intiially diarrhea is watery but as disease progresses, diarrhea may contain shreds of mucosa, fibrin, casts or frank blood. Putrid foul odor
d) signs of septicemia predominate
e) acute protein losing enteropathy and extreme weight loss
f) abortions
What do we see on necropsy with salmonellosis
a) fibrin tags on the intestine along with excessive peritoeal fluid
b) mesenteric lymph node are enlarged and often hemorrhagic
c) bowel contents may contain mucus, blood, fibrin
d) fibirin and mucosal casts are often found in the SI and LI
How do we treat salmonellosis
fluids, oral or IV
Antibiotics (ceftiofur, TMS)- parenteral treatment more effective than oral
NSAIDS- banamine
How do we prevent salmonellosis
Clean the environment, proper nutriton, reduce stress
What therapy do we do for the diarrheic patient?
Goals of fluid therapy
1 correct dehydration
2. electrolyte deficit
3. acid-base balance
4. energy supplementation
5. provide maintenace fluid
How can we assess dehydration?
6-7% -> sight enopthalmos, skin turgor slightly increased, mm moist
8-9%-> eyes obviously sunken, skin turgor obviously increased, mm tacky, 4 meg/k, bicarb deficity
10-12% -> eyes deeply sunken in orbits, skin tents and does not return, mm dry, depression or comatose 8meg/k bicarb deficit
How do we calcuate the amount of fluid needed to resotre volume deficit
percentage of dehyration x body weight in kg= volume of fluid in liters
How do we replace Na and CL deficit
-an isotonic saline solution is adequate to replace Na and Cl
-to replace K, can give 20 mE/i fluid if glucose and bicarb are in teh fluid
In diarrheic calves less than 1 week of age for acid base imblance?
In diarrheic calves older than 1 week
assume a 10-15 meg/l deficit
15-29 meq/l deficit
Energy supplementation in diarrheic animals
Most neonates with diarrhea are hypoglycemic
glucose will enhacne potassium resorption from the extracellular space to the intracellular space
supply by giving a 1-2% IV solution
How do we provide maintenace fluid
50-100 ml/kg, 40 ml /lb
When do we give IV fluids?
a) if calf has severe diarrhea
b) abscence or depression of suckle reflex
c) severe dehydartion of 8% or greater
d) unwillingness to stand
e) weak or absent pain reflex
What rate do we give IV fluids?
50-80 ml/kg/hr, can rehydrate over 4-8 hour period
When do we give oral fluids?
use when the neonate readily suckles electrolyte solution
Oral fluids rule of thumb?
- let animal nurse from bottle if it will
- provide calf with fluids as often as possible
- if using a stomach tube/ esophageal feeder in ruminants do not give more than 3-5% body weight at a time.
- if tubing, space feedings 2 hours apart
- leave electrolye solutions available for animals either in waterer or buckets between feedings
When do we give sq fluids
-when they suck but have a high fluid loss
when the suckle reponse is poor and the owner is delivering therapy
What are the sq fluids rule of thumb?
- 80 ml/kg total volume
- use isotonic solution
- no more than 10-20 ml/kg per site
- should be absorbed in 4 hours
When do we give antibiotics?
a) patient has fevers or bacteremias
b) patient has concurrent infections
-can alter the normal flora of the gut
-tetracycline and neomycin may interfere with healing of the gut linign
-better to give parenterally
How do we know how much buffer to give?
body weight x volume of distribution x deficit
how do we know how much potassium to give
.1 unit change in the pH
