Calf Diarrhea Flashcards
T or F, the specific agent causing scours in calves is very important to determine to solve the problem
False! specific agent is less important than risk factor triggers
what are the 3 aspects of the epidemiology of neonatal calf diarrhea?
pathogen, host, environment
true or false: calf scours is NEVER an individual animal problem
true! treating an individual and not asking about the rest of the herd is malpractice
list some causes of diarrhea in calves (there are a ton of these bestie just do your best)
ETEC (K99) or other E coli
salmonella
clostridium perfringens type C
campylobacter jejuni
rotavirus
coronavirus
totavirus
cryptosporidium
eimeria
giardia
yeast
nutritional
what exactly is nutritional scours?
- when the calf receives poor quality milk replacer or inappropriate replacer mixing
- if there’s sudden dietary changes
- over feeding
true or false: calves with nutritional scours have systemic signs
false, they should not be systemic, should be bright and alert, and should resolve in a few days
the most important pathogen causing diarrhea in calves less than 5 days old is ______
enterotoxigenic E coli (ETEC)
most common strain is F5/K99
why is it important to find virulence factors to confirm a diagnosis of ETEC?
because E coli is prevalent in fecal culture, but we don’t know if its specifically F5/K99, so we need to make sure! If a test comes back positive for E coli but we dont know the specific E coli, it may not actually be what is causing the diarrhea
how does a calf usually get ETEC? pathogenesis?
ingested from the environment, attaches to the intestinal epithelium and really likes the ileum, then spreads to the duodenum and produces toxins causing a secretory diarrhea. EPITHELIUM REMAINS IN TACT
_____ typically infects 5-15 day old calves, but can infect younger and older ones too
rotavirus
pathogenesis of rotavirus infection causing diarrhea
adult cattle and older calves excrete the virus into the environment, the calf ingests the virus from the environment, virus kills the villous enterocytes and reduces absorptive surface area causing a malabsorptive diarrhea. also toxin induced secretory diarrhea
rotavirus targets the ________ , which means ____
mature villar cells
the developing/immature cells quickly replace and there is minimal epithelial damage and it quikcly resolves
true or false: rotavirus often results in coinfection
true
clinical signs of rotavirus
profuse watery diarrhea, dehydration, depression, weakness, hypoglycemia
high morbidity and low mortality
which virus is similar to rotavirus but infects slightly older calves and causes more severe disease?
coronavirus
which virus causes winter dysentery in adults associated with BRD?
coronavirus
coronavirus typically infects calves that are how old
5-21 days old
coronavirus targets what cells?
crypt AND villous enterocytes, which means worse maldigestive and malabsorptive diarrhea
crypt loss=prolonged illness and more severe acidosis and dehydration
which has higher mortality, coronavirus or rotavirus? why?
coronavirus because it infects the crypt and villous enterocytes. rotavirus just infects the villous cells
which bacteria causing diarrhea in calves is provincially reportable?
salmonella enterica subsp enterica
which salmonella serovar causes systemic disease in young and adult cows, and which serovar causes acute diarrhea and outbreaks in calves less than 2 months old?
S. dublin: systemic disease, young and adults
S. typhimurium: acute diarrhea, outbreaks less than 2 months of age
which diarrhea pathogen infects calves usually before 28 days of age, and can cause a chronic carrier state?
salmonella enterica
You go see a set of calves that are 20 days old, all with a transient fever, dullness, anorexia, malodourous diarrhea with some mucus and blood, and are a little cold. When talking with the farmer, you also found one calf dead on the ground. What pathogen are you worried about
salmonella
how does salmonella cause disease? why does diarrhea develop?
it invades the intestinal mucosa and multiplies in lymphoid tissue and can evade host immune systems leading to systemic disease
diarrhea develops due to inflammatory response to an infection
a farmer has had a few calves with diarrhea suddenly die, and you do a necropsy and find intestines with fibrin deposits, blood everywhere, and lots of liquid. the mesenteric lymph nodes are also enlarged. what pathogen do you think caused this?
salmonella
which diarrhea pathogen is characterized by the following:
- very zoonotic and very common
- lots of subclinical infection
- infect calves 8-14 days old
cryptosporidium parvum
pathogenesis of crypto diarrhea
causes villous atrophy and disruption of the epithelial barrier causing inflammation–>malabsorptive diarrhea
which diarrhea pathogen is characterized by the following:
- high infection rate with low case fatality
- infects calves older than 21 days old
coccidosis/eimera
clinical signs of coccidiosis in calves
diarrhea, dysentery (mucus and blood), tenesmus, painful abdomen
pathogenesis of coccidosis diarrhea
exfoliation of intestinal mucosa causing diarrhea and possible hemorrhage
list the diarrhea pathogens from infecting youngest cows to infecting oldest cows using your pneumonic: “every cat runs, climbs, & catches silly grey antelopes, crikey!”
ECRCCSGAC
E coli, C perfingens, rotavirus, coronavirus, crypto, salmonella, giardia, attaching and effacing e coli, coccidia
best diagnosgtic for calf diarrhea is
a fresh carcass (acute and untreated) and/or feces from live (acute and untreated)
important things to remember when collecting necropsy samples for investigating diarrhea in calves? are there special considerations for culture vs viral isolation?
collect various samples of the gut, cut lengthwise and put in formalin, also collect from major organs and an ear notch to check for BVDV
for culture: tie off loops of each section of bowel and mesenteric LN and submit fresh in separate labelled bags
for virology: fresh feces OR tires off loops of bowel in separate bags
for parasites: feces for float and FAT for crypto/giardia
for mineral/toxicology: liver fresh or frozen
what is septicemia?
inflammatory response to bacteremia or endotoxemia resulting in systemic signs, usually E coli. high fatality rate and requires aggressive therapy.
what are clinical signs of septicemia?
severe depression, tachypnea, anorexia, hyperemia of mms, injected sclera. as it progresses, weak pulses and cold extremities
calves usually get septicemia in 2 ways, what are they?
calves less than 2 weeks old with failure transfer of passive immunity
calves with neonatal calf diarrhea involving bacterial translocation of the gut
septicemia can be mistaken for pneumonia because…
it causes metabolic acidosis (which also happens in pneumonia)
describe mild, moderate, and severe dehydration findings for calves
mild (6-8% dehydrated): slightly depressed, 2-4mm of eyeball recession, and 1-2 sec skin tent
moderate (8-10% dehydrated): depressed, 4-6mm eyeball recession, 2-5 second skin tent
severe (10-12% dehydrated): comatose, 6-8mm eyeball recession, 5-10 second skin tent
based on the dehydration table we have to memorize @%^##&@&#@#^@&^# >:( , which calves need IV fluids and which ones dont?
for mild dehydration, they don’t need it, but moderate and severe dehydration calves need it
mentation is relative to the level of ____
acidemia
what kinds of things are associated with acidemia?
inability to stand, weakness, ataxia, poor suckle reflex, and a slow palpebral reflex
what acid base derrangement do scouring calves get?
metabolic acidosis
loss of bicarb in the feces, decreased renal excretion of H+ ions, poor perfusion=lactate
why is D-lactate is produced by bacteria?
as a result of maldigestion and malabsorption of carbohydrates in the gut
what are the components of individual calf treatment for diarrhea? use “remember, cats prefer tuna my wanker”
replace fluids/electrolytes
correct acid base imbalances
provide energy support
treat the bacteremia/septicemia
mitigate pain
warm body to ideal temp
we should give IV fluids when the calf is ____% dehydrated
8 or more
when are oral electrolyte solutions a good option for calves with diarrhea?
in calves with normal mentation, <6% dehydrated, and HAS a suckle reflex
you are treating a calf with diarrhea and you decide to go with OES. The owner asks what you should do about giving the calf milk. you say…
alternate milk feedings with OES and spread it out thru the day. DO NOT withhold milk! they need the energy!
when are IV fluids indicated for calves?
if >8% dehydrated, if the calf cannot stand, or if the calf has a weak or absent suckle reflex
how do you calculate how much IV fluids to give to the calf?
replacement fluids: % dehydrated x body weight
ongoing losses: usually 2-4 L a day
maintenance requirements: 50ml/kg/day
what are the IV fluid options?
isotonic saline: slightly acidifying (probs not)
isotonic sodium bicarb: alkalinisation effect
LRS: most scouring calves have lactic acidosis so some say to avoid this
P-LYTE: affordable and closest to physiologic values :)
how do you correct for acid base imbalances by adding bicarb to IV fluids?
add bicarb to IV fluids using this equation:
bicarb requirement=body weight kg x base deficit in mEq/L x 0.6
besides adding bicarb to IV fluids, what other options are there for correcting acid base imbalances?
there is isotonic saline with bicarb in it 1.3% solution: can give 10% of isotonic bicarb over 3-4 hours
hypertonic saline (doesn’t correct acidemia)
hypertonic bicarb 8.4%: 5-10ml/kg over 10 minutes
if you are using hypertonic solutions to correct acid base derrangement, what do you need to remember?
allows follow up with additional fluids like OES or IV
how do you provide energy support in a calf with neonatal diarrhea?
can give dextrose IV. it is non alkalinizing and it is not sufficient on its own due to lack of sodium
add 5-10% to other solutions
true or false: popular oral sulfa boluses are not recommended for bacteremia/septicemia for calves with diarrhea
true, dont use them!
which calves should you be giving antibiotics to and what are your options?
calves that exhibit systemic signs of illness AND/OR have blood or mucus in the feces
ceftiofur, ampicillin
for salmonella: amoxocillin, TMS, cefitofur, but usually need culture and sensitivity
what is the drug Halofuginone for?
an anti-protozoal solution that can reduce clinical signs of crypto
what NSAIDs should you use for these calves with diarrhea?
meloxicam or flunixin
