Calf Scour Slides
The following are versions the text slides I
presented in VMS 261 Accidents and Disease lectures. At student request, these are
presented here for their use and do not constitute veterinary advice.
Calf Scours Objectives:
What is it and how it "works"
What I as a veterinarian will recommend to:
Treat a calf with the problem
Prevent the problem from occurring
What is it?
The discharge of more fluid than normal fecal matter from
the bowel, often more frequently than normal.
With this is lost more water and important electrolytes (salts) than are taken in.
Normal Fluid Balance
Physiology of Diarrhea
Normal cycling of body water into and out of intestinal tract is
Normally considerably more fluid is secreted into the intestine and reabsorbed than is
Two main forms:
Excess secretion (hypersecretion) into intestine, normal reabsorption back out
Ex: E. coli K99
Normal secretion into intestine, reduced (malabsorption) back out
Ex: Most other infectious diarrheal agents
Diarrhea Imbalance - Hypersecretion
Diarrhea Imbalance - Malabsorption
Results of Diarrhea
Body fluid loss => Dehydration
Signs: Skin "tents", mouth isnt slick, limbs and ears are cold, eyes
sink and a gap appears between the eyeball and inner lid.
Urine output drops or stops
Body electrolyte (salts) loss and imbalance
Heart and skeletal muscle function affected
If shifts are severe enough, heart stops
Early Fluid Loss (<5% BW
Detect scouring calf before fluid loss becomes profound so oral replacement is
Replace lost body fluid and electrolytes in large enough quantity often enough that
loss does not become profound.
Moderate Fluid Loss (7% BW)
Calf is standing, skin "tents" for 4 seconds or less, eyes are bright, oral
membranes are moist.
To eveluate skin tenting, twist a large fold of loose skin in the neck area or gently
pinch an upper eyelid
Calf will suck electrolyte solution from a bottle
Leave calf on milk and add several 2 quart electrolyte feedings per day until scouring
Even though nutrient absorption is incomplete, the calf needs what it can get from the
Old recommendation to take calf off of milk is wrong.
Severe Fluid Loss (>9% BW)
Calf is dull and lying down but upright, skin "tents" for 5 seconds, eyes are
sunken slightly with a slight gap, limbs are cold, oral membranes are warm but sticky.
Calf needs 1/2 gallon of warm high energy electrolyte solution (e.g. Entrolyte HE) by
stomach tube (esophageal feeder) twice several hours apart to survive.
These solutions contain high levels of glucose to provide energy and other components
to promote absorption.
Calf needs to be moved to a warm area where it can be monitored.
Calf is lying flat in a coma, skin stays "tented", eyes are deeply sunken
with a big gap, limbs are cold, oral membranes are cold, pale and dry to touch.
Only 1 gallon of special fluids by IV drip soon will save the calf; SQ and oral fluids
wont be absorbed because circulation is too poor.
Take calf to veterinary clinic immediately.
Enough balanced electrolyte fluids must be given to:
Replace % of body weight (BW) lost
Meet maintenance requirements (50 ml / kg BW per day)
Keep up with ongoing loss of 1 to 4 Liter per day in the diarrhea.
For a 7% dehydrated 80 lb calf, this is 6 to 9 quarts of electrolyte solution the first
Commonest Infectious Diarrheal Agents in Young
The most common mistake is to give too little; if too much is given, the
calf will urinate it away.
One of the signs that enough is being given is that more normal large
volume urination resumes.
Escherichia coli (E.coli) strains
Salmonella serotypes dublin, typhimurium, and others
Key E. coli Characteristics
Normal gut flora of all mammals so E. coli is ubiquitous (everywhere).
Three disease forms:
Colisepticemia - any strain:
Enterotoxigenic - specific strains (K99 and others).
Enteropathogenic - specific strains.
A most common cause of calf death.
Because the organisms involved in calf scours are usually highly antibiotic resistant,
OTC antibiotics are usually not effective.
E. coli spreads from the gut through calfs body and causes
abscesses in the brain, eyes, kidneys, and joints.
Occurs when newborn calf ingests it in manure, mud or other material before or along
with getting colostrum.
Virtually impossible to treat successfully.
Prevented by calving in clean, dry areas, cows having clean udders, and keeping
colostrum clean and refrigerated or frozen.
Enterotoxigenic E. coli (ETEC)
Specific strain (K99) attaches to intestinal cells and causes a hypersecretory
Toxin turns on cells fluid pump which in turn pumps large amounts of fluid into
This process can pump so much fluid into the gut that the calf dies before the external
signs of diarrhea appear.
Almost the only diarrhea that occurs within first 3 days of life, often in first
Prevented by feeding colostrum containing K99 antibodies.
Cow vaccine available.
Enteropathogenic E. coli (EPEC)
Specific strains attach very tightly to gut wall and secrete various toxins,
causing both excess secretion and malabsorbtion as well as general systemic effects on the
Corona & Rotaviral Diarrhea
Virus kills cells of intestinal villi, leading to malabsorbtion diarrhea.
Infected calves begin shedding 1011 virus per gram of feces about 3 days
Carrier cows in the herd shed low numbers of virus.
Virus survives in the environment for weeks.
Vaccines are available although not always efficacious.
Antibiotics are ineffective (virus).
Infected calves can shed the organism in feces, urine, saliva, and nasal
secretions, contaminating everything they touch and everything that touches them
(hands, esophageal feeders, nipples, ...).
Salmonella survives in the environment for months. Only direct sunlight kills it
in the environment.
Because of antibiotic resistance, OTC antibiotics are usually not effective.
Depress the normal bacterial flora, making the animal more susceptible to infection and
perhaps prolonging the diarrhea.
Are required if infection is systemic.
Current commercial vaccines are of questionable effectiveness.
This is a zoonotic disease, meaning that humans can get it!
Ubiquitous organism that survives for months in the environment.
No antibiotics are effective.
Not killed by most disinfectants at practical concentrations.
Can be transmitted by dust in the air.
This is a zoonotic disease, particularly for the immunocompromised.
Most diarrheal agents:
Survive well in the environment.
Infections arent curable with drugs.
Establish carrier states in herdmates.
How do you reduce clinical disease?
Focus Areas for Prevention
Maximize the calfs natural resistance and acquired immunity
(colostrum) prior to exposure.
Minimize dystocia, maintain proper nutrition and body condition of dam in critical
third trimester of pregnancy.
Delay and minimize the infectious dose that the calf is exposed to.
As most of these agents are ubiquitous (in most herds), calf must eventually
acquire the infection and develop an active immunity.
Minimize exposure dose by minimizing density of susceptible calves.
Minimize environmental survival of infectious agents by maximizing drying and exposure
to sunlight of potential infectious material (feces)
Work with "Mother Nature" by exploiting the opportunities in the
Example: Viral Calf Scours
Facts about viral calf scours
Some cows are chronic carriers, intermittently shed low numbers of the
viral scour agents.
The agents survive very well in the environment.
The incubation period for these in baby calves is usually around three days.
Scouring baby calves infected with these shed them in very high numbers, contaminating
everything around them.
Heifers' calves are more susceptible than cows' calves.
Reducing Exposure - Beef
Move cows and heifers to separate calving area several weeks
Skin and hair of cows on winter feed and bed ground will have infectious agents shed by
Heifers have poorer colostrum.
Heifers need more supervision.
Reducing Exposure - Beef
1 Day after calving, move pair to large pasture area to spread
Exposed calf takes about 3 days to begin shedding agent in large numbers.
If scours develops in a group, leave all of that group in place but turn out new pairs
to a new pasture.
More infected calves are subclinical shedders than are clinical cases (The Iceberg
DO NOT bring in purchased calves to replace dead
They are often colostrum deprived and usually have been exposed to the
full gamut of infectious agents.
Reducing Exposure - Dairy
Within first day, move calf to a cleaned individual hutch that
isolates the calf from contact with and the air space of other calves.
Work has shown that the more air space each individual calf has and the more distance
away from other calves, the less disease that they will have.
Sanitize anything that contacts the mouth of a calf prior to that contact
(bottle nipples, esophageal feeders, pill guns, hands).
Reducing Exposure - Dairy
After weaning from milk, group by age in progressively larger
1 to 7 to 14 to 28
DO NOT hold back calves on the basis of small size; these are
often carrier animals that will infect younger groups.
Acquired Immunity (Colostral Antibodies)
Group poor doers separately if they aren't advanced with their own group.
Due to the nature of the bovine placenta, calves
are born without any antibodies.
They are needed to fight infection.
They are in the colostrum (first milk) produced by the dam.
These antibodies provide "passive immunity".
Work has shown that the higher the amount of these colostral antibodies absorbed by the
calf, the less the disease severity and duration that they will experience.
Colostral Antibody Absorption
Colostral antibodies cross the calf's gut wall into the blood stream where they
are an important component of the calf's immune system.
Occurs best during for the first hours of the calfs life.
With the passage of time before feeding, less will be transfered.
Stops completely after the first day.
Note: Anything else in colostrum (bacteria!) is also
You must keep colostrum and colostrum feeding equipment clean.
Methods of Feeding Colostrum
Natural Suckling: (only practical option for must beef cattle)
Highly variable colostrum intake
No opportunity to select high concentration colostrum
Frequently delayed colostrum intake, which lowers amount absorbed
30% to 80% of calves will have insufficient passive antibody levels to fight infection
Management policy controls colostrum intake amount
Selection of high quality colostrum is possible
Managment policy controls time of ingestion
10% to 20% of calves will have insufficient passive antibody levels to fight infection
Tubing with an esophageal feeder is usually more efficient and effective
than bottle feeding if it is done carefully.
Selecting and Feeding Colostrum
State to employees Within 2 hrs. of birth to
give sense of urgency!
Volume enough: (Use esophageal feeder)
4 quarts (Holsteins)
The old recommendation of 2 quarts is too little for the modern Holstein
Select first feeding colostrums from those cows producing less
than 20 lbs. total (2 1/2 gallons) of colostrum at first milking.
The colostrums from cows producing more that 20 lbs are often too dilute
for the calf to get enough passive antibodies to fight disease well.
Select colostrums that are greater than 50 mg / ml on colostrometer
Handling Colostrum - Dairy
Colostrum must be handled like grade A milk.
Disease causing bacteria will grow just as well in it as they do in milk.
These bacteria are transferred with the colostrum into the blood stream.
Harvest it into sanitized containers and refrigerate or freeze it if not used
Dont pool - BLV, Salmonella, and Johnes are transferred by colostrum.
If the herd has a known Johnes or BLV problem, keep track of which calves are fed
colostrum from a dam.
Cleaning & Disinfection
Because colostrum fights disease, it can be handled with dirty equipment
and held at room temperature - FALSE!
Colostrum only fights infection when it is in the calf!
Bacterial contaminates multiply at least as rapidly in colostrum as in
When warm, they can double in number every 30 minutes.
Anything that must be done to preserve milk quality must be done to
preserve colostrum quality.
Thorough rinsing and cleaning is the first step, whether hutch, hands, or
Remove all organic matter (feces, blood, milk, milk stone, milk fat, saliva).
Organic matter protects infectious agents from the action of disinfectants (chemical or
Soap, water, and scrubbing are the most important; mechanically removing the agents.
Use a disinfectant with labeled effectiveness against target agents.
Many commonly sold as disinfectants are not effective.
Environmental surfaces - One Stroke, Environ.
Tissue contact - Nolvasan or tamed iodine.
Allow adequate contact time (temperature dependent) at sufficient strength.
Organic material (milk, manure) inactivates most disinfectants, especially
Chlorine begins evaporating when mixed.
Literature References - Calf Scours
Hunt, E (ed.). Symposium on Calf Diarrhea. The Veterinary Clinics of
North America: Food Animal Practice. 1(3), 1985. WB Saunders Co.
A volume of 13 papers reviewing calf diarrhea, its causes, treatment and prevention,
including one on milk replacers and their components.
Roy, JHB. The Calf, 5th ed. Vol. 1 Management of Health. 1990,
Butterworths. 258 pp.
Detailed description of calf immunity and post-natal disease, particularly diarrhea.
Internet References - Calf Scours
Keep Them Alive (Nova Scotia Newsletter 5(5) MacKay, RD)
Calfhood Scours (D Marcinknowski, U Maine)
Electrolytes Are The First Line Of Defense For Treating Scours (D Marcinknowski, U
For Additional Information:
Calf Management - Birth to Weaning (dairy calves - T Brown, Tarleton State Univ)
Calf Scours: Causes, Prevention and Treatment (NebGuide)
Disease Protection of Baby Calves (colostrum in beef calves - Oklahoma State)
Electrolyte Treatment for Scouring Dairy Calves (KG Bateman, Ontario)
Neonatal Calf Diarrhea (KG Bateman, Ontario)