Calf Scours

Causes, Prevention, & Treatment

Brendan Kraus, DVM

Thanks Dr. Larson

Calf Scours Complex

Multifactorial Disease

Host

Agent

Environment

Host Factors

Level of Immunity

Passive Transfer

Calves are born without antibodies

Calves should ingest at least 1 gallon of colostrum

in the first 12 hours of life (recommendations have changed)

Many calves ingest inadequate levels

Host: Level of ImmunityPassive Transfer

Host: Level of ImmunityPrevention Tips

1) Ensure Adequate Passive Transfer

2) Prevent Dystocia

3) Bull Selection Based on EPD for birth weight and calving ease

Select for Calving Ease

Host: Level of ImmunityPrevention Tips

4) Proper Development of Dam

Dam should calve at BCS 5.5-6.0

Avoid over-condition or rapid weight gain in late gestation (fat in pelvic canal)

BCS 6

Environment FactorsOvercrowding

Poor Sanitation

Damp or wet ground

Age of Dam

Poor Quality Milk/milk replacers

Environment: Overcrowding/SanitationPrevention Tips

1) Optimize Environment/Sanitation

Calving areas should be as clean and dry as possible

Calves should be dispersed as much as possible (intensive vs. extensive)

Intensive vs. Extensive Concentration

Intensive Permits Ready

Intervention

Extensive Favors Hygiene

Environment: Overcrowding/SanitationPrevention Tips

1) Optimize Environment/Sanitation (cont.)

Separate calving pasture from winter feeding pastures (more uncommon for spring calvers)

Feeding strategy considerations

Feeding Strategy Considerations

Bale feedersSpread balesFeed bunk movementWater sourcesStockpiled forage

Environment: Overcrowding/SanitationPrevention Tips

1) Optimize Environment/Sanitation

(cont.)

Calving areas should have adequate drainage

Provide protection from the wind

2) Control Exposure

Which calves are at risk?

Environment: Overcrowding/SanitationPrevention Tips

Calves are not Equally at Risk!

Most calves are 1 to 2 weeks of age at time of death Calves older than 3 weeks are at low risk of death

From David Smith et al, 2004

0%

10%

20%

30%

40%

50%

0-5 6-10 11-15 16-20 21-25 26-30

Calf Age (days) at Time of Death Due to Scours1 to 3 week-old calves are also

shedding the most scours pathogens

Calves are not Equally at Risk!

0%

5%

10%

15%

20%

25%

30%

Attack Rate by Week(From Start of Calving Season)

Calves born early in the calving season are at low risk Calves born late in the calving season are at high risk

From David Smith et al, 2004

Calves are not Equally at Risk!

From David Smith et al, 2004

0%

5%

10%

15%

20%

25%

30%

Attack Rate by Week(From Start of Calving Season)

The risk of scours and the severity of disease in each affected calf increases as the calving season progresses The age at disease onset decreases as the calving season progresses

2) Control Exposure (cont.)

Pasture RotationKeep young calves away from older calves

Environment: Overcrowding/SanitationPrevention Tips

Control Exposure: Keep Young Calves away from Older Calves

Pasture Rotation

1) Mid-late gestation pasture (minimum)Can be sorted at preg check OR

2) Move heavies every 1-3 weeksNew calves being born on clean

pastureOlder calves staying behind in

contaminationHerd reassembled for breeding

Youngest calf around 3 weeks old

Environment: Overcrowding/SanitationPrevention Tips

2) Control Exposure (cont.)

Calve Heifers Early

Be Wary of Outside Calves

Agent

Escherichia coli (1-6 days)

Clostridium perfringens (1-14 days)

Rota Virus (5-21 days)

Corona Virus (5-36 days)

Cryptosporidium (6-21 days)

Salmonella (6-36 days)

E. Coli

2 types: Septicemia & Enterotoxogenic

Usually within 3-5 days of life

Severe, watery diarrhea (secretory, ETEC)

Depression

Hypothermia

Distant Infections (joints, brain navel, septicemia)

Enterotoxogenic E-coli

Clostridium perfringens

< 2 weeks oldLow morbidity : High mortalityHealthy, fast growing calvesHeavy milking damsSudden DeathDiarrhea/Abdominal PainNecrosis of small intestineEnlargement of intestinal lymph

nodes

Rotavirus

Most CommonOften found in mixed infections 5 days to 3 weeks of ageAffects small intestineVoluminous (Malabsorptive)

Lactose washout with osmotic diarrheaDehydrationAt least 7 days to repair intestinal

damage

Coronavirus

More Severe than Rota5 days to 30 days of ageLarge and small intestineDehydrationAnorexiaInfects intestinal cells more

severely Malabsorption/maldigestionRespiratory Infections

Cryptosporidium

Zoonotic Potential7 days to 30 days of ageProtracted, non-responsive

diarrheaIntracellular but

extracytoplasmicDrugs difficult to kill Off Label

Salmonella

> 10 days of ageFoul smelling diarrheaFibrin and mucosa may be

present in stoolDistant infections

Treatment Challenges

HypothermiaHypoglycemiaAcidosisLow ProteinElectrolyte ImbalancesHypovolemia/Dehydration

Treatment

Cornerstone of Treatment is

Fluid Therapy

Calculate Dehydration % and Replacement Amount

Fluid Therapy

Fluid Therapy

Correct DehydrationCorrect Electrolyte

ImbalancesCombat ShockSupport Internal Organ

FunctionSupplement Energy

Fluid Therapy

Routes of Administration

Oral

Intravenous

Oral Fluids

Must have GI motility (body temp)

Must have GI perfusion (dehydration)

Must have absorptive function (damage)

Benefits-Inexpensive

Intravenous Fluids

Rapid Replacement of fluid deficits

Replacement of Electrolytes (bicarbonate)

Base Deficit CorrectionReplacement of Ongoing

Losses

Treatment, Other

Nutritional SupportBody Temperature

MaintenanceMaintain Oral

Fluids/ElectrolytesAntibiotics +/-

Scours Outbreak

Short Term Intervention StrategiesTreat affected calvesCalving site selection and management

Change location of calvesCalving season

Move pregnant cows away from nursing cows

Dystocia managementMonitor calving closely

Good husbandry and nutrition of dam

Scours Outbreak

Long Term Prevention StrategiesCare and Nutrition of DamDystocia

Sire selection and heifer developmentCalving site selection and management

Plan ahead, get site readyPasture Rotation

Be as aggressive as you need for your operation

Vaccination (last for a reason)

Scours Vaccination

Dam vaccinated/antibodies in colostrum

To be used as a tool in the arsenalUsage determined by riskVaccination of younger stockMust have two rounds prior to

calving the first yearVaccinations available for the calfWill not work as sole prevention

measure

A Too Common Scenario?

It’s March 3, a cold drizzle is coming down as you slide across the pasture in 4WD. Vet and client are surveying a pasture of 40 cow/calf pairs. Calves range in age from 1 day to 2 months. The mud is ankle deep. Approximately 50% of the calves have fluid stools. Four calves have died in the last 2 days, and at present, 4 calves are weak and unable to stand. The client turns and asks, “What do you think we should we do?”

Questions?