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Parasite Control Calendar for Beef Cattle

A month-by-month planning calendar for timing internal and external parasite control activities in beef cattle operations.

RanchSafety Team January 20, 2026 5 min read

Annual Parasite Control Planning Calendar

This calendar provides a framework for timing parasite control activities throughout the year. Adjust specific dates based on your location, climate, and veterinary recommendations.

January

Internal Parasites

WeekActivityNotes
1-2Monitor body conditionParasites burden may be impacting winter performance
3-4Plan spring deworming strategyReview last year's FECRT results

External Parasites

WeekActivityNotes
1-4Monitor for liceCheck cattle showing rubbing, hair loss
1-4Retreat for lice if neededEspecially if fall treatment efficacy was poor

Records & Planning

  • Review previous year's parasite control costs and outcomes
  • Order deworming products for spring
  • Schedule FECRT if planning resistance testing

February

Internal Parasites

WeekActivityNotes
1-2Continue body condition monitoring
3-4Prepare for spring turnoutPlan which pastures are "clean"

External Parasites

WeekActivityNotes
1-4Continue lice monitoringPeak lice populations often late winter
3-4Treat for lice if populations highBefore spring shedding

Records & Planning

  • Identify most susceptible animals for targeted treatment
  • Plan pasture rotation for parasite management
  • Check dewormer inventory and expiration dates

March

Internal Parasites

WeekActivityNotes
1-2Collect fecal samplesPre-turnout baseline FEC
3-4Strategic dewormingBased on FEC results, not calendar

External Parasites

WeekActivityNotes
1-2Final lice treatment if needed
3-4Begin watching for first fliesVaries by region/weather

Records & Planning

  • Record pre-turnout FEC results
  • Set up back rubbers and dust bags
  • Prepare fly control equipment

April

Internal Parasites

WeekActivityNotes
1-4Begin clean pasture rotationPut young stock on cleanest pastures

External Parasites

WeekActivityNotes
1-2Monitor fly emergenceWatch for first horn flies
3-4Begin fly countingWeekly counts to track buildup

Feed-Through Products

WeekActivityNotes
1-2Start IGR mineralBegin 30 days before anticipated fly season

Records & Planning

  • Record date of first fly observation
  • Note pastures grazed and rotation sequence
  • Ensure back rubbers/dust bags are charged and positioned

May

Internal Parasites

WeekActivityNotes
1-4Continue rotation strategyDon't overgraze; keeps cattle from grazing low where larvae are

External Parasites

WeekActivityNotes
1-2Continue fly monitoringCount flies weekly
3-4Apply ear tags when threshold reached200+ flies per animal

Actions When Tags Applied

  • Record tag application date
  • Record tag product/lot numbers
  • Calculate anticipated tag removal date

June

Internal Parasites

WeekActivityNotes
1-4Mid-season FEC checkSample young stock

External Parasites

WeekActivityNotes
1-4Peak fly season beginsMonitor tag effectiveness
1-4Check tick burdenTreat if heavy infestation

Summer Heat Considerations

  • Ensure adequate water (parasites + heat = increased water needs)
  • Monitor for face fly/pinkeye issues
  • Watch for anaplasmosis signs in tick-heavy areas

July

Internal Parasites

WeekActivityNotes
1-4Hot/dry conditions favor youLarvae die quickly on hot, dry pastures

External Parasites

WeekActivityNotes
1-4Maintain fly controlRecharge back rubbers/dust bags
1-4Monitor tag effectivenessEarly failure = resistance

Summer Management

  • Clean up stable fly breeding areas (old hay, manure accumulation)
  • Maintain dust bag/back rubber supplies
  • Check animals under trees for tick accumulation

August

Internal Parasites

WeekActivityNotes
1-2Monitor for mid-summer buildupIf moisture returns
3-4FEC check if concerned

External Parasites

WeekActivityNotes
1-4Continue fly controlMay need pour-on supplement if tags weakening
1-4Watch for late-season tick activity

Pre-Weaning Planning

  • Schedule fall working for vaccines AND parasite control
  • Order fall deworming products
  • Plan pre-weaning calf treatments

September

Internal Parasites

WeekActivityNotes
1-2Pre-weaning FEC on calves
3-4Strategic deworming at weaningBased on FEC, not calendar

External Parasites

WeekActivityNotes
1-2Fly populations declining
3-4Remove ear tagsDon't leave in overwinter (resistance)

Fall Actions

  • Record ear tag removal date
  • Collect FEC samples at weaning
  • Evaluate fly control program effectiveness

October

Internal Parasites

WeekActivityNotes
1-2Fall strategic dewormingReduces overwintering larvae
3-4Monitor treatment responseFEC 14 days post-treatment

External Parasites

WeekActivityNotes
1-2End of fly seasonClean and store fly control equipment
3-4Watch for early lice

Fall Planning

  • Conduct FECRT if resistance suspected
  • Record fall deworming products and results
  • Plan winter parasite monitoring

November

Internal Parasites

WeekActivityNotes
1-4Minimal new infectionCold temps stop larval development

External Parasites

WeekActivityNotes
1-2Apply fall lice treatmentTreat before populations build
3-4Treat entire herd simultaneously

End of Season Review

  • Calculate year's parasite control costs
  • Evaluate control effectiveness
  • Note any resistance concerns

December

Internal Parasites

WeekActivityNotes
1-4Monitor body condition

External Parasites

WeekActivityNotes
1-4Monitor lice response to treatmentRetreat in 2-3 weeks if needed
1-4Watch for chorioptic mange

Annual Review

  • Complete annual parasite control assessment
  • Plan next year's program with veterinarian
  • Update control calendar for next year

Quick Reference: When to Act

Internal Parasites

IndicatorAction
FEC >200-300 EPGConsider treatment for that animal
Herd average FEC risingReview grazing management
Clinical signs (bottle jaw, poor condition)Immediate treatment needed
FECRT <90%Resistance, switch dewormer class

External Parasites

IndicatorAction
Horn flies >200/headTreat
Ear tags lasting <8 weeksResistance likely, rotate class next year
Lice visible/hair lossTreat entire group
Heavy tick burdenTreat and manage habitat

Regional Timing Adjustments

The Southeast tends to see flies emerge earlier (around April) and longer fly seasons overall. Year-round tick pressure is possible, and internal parasite loads tend to run higher than other parts of the country.

Dry Southwest

The shorter fly season and hot, dry summers work in your favor by reducing internal parasite pressure. Tick problems concentrate in riparian areas. Plan to adjust timing 2-4 weeks later than what this calendar shows.

Northern States

Flies emerge later, usually May or June, and the fly season wraps up sooner. Winter does kill off more parasites. Adjust timing 4-6 weeks later than calendar.

Texas (Varies by Region)

East Texas looks a lot like the Southeast. Hill Country falls somewhere in between. West Texas lines up closer to the Southwest pattern, while the Gulf Coast can see year-round parasite pressure.

Monthly Task Summary Checklist

MonthInternal ParasitesExternal ParasitesRecords
JanMonitor BCSLice check/treatReview year
FebPlan springContinue liceOrder products
MarPre-turnout FECSet up fly equipmentRecord FEC
AprStart rotationMonitor fliesNote fly emergence
MayContinue rotationTags when thresholdRecord tag date
JunMid-season FECMonitor tagsRecord FEC
JulHot weather helpsMaintain equipmentMonitor resistance
AugWatch for buildupSupplement if neededPlan fall
SepWeaning FECRemove tagsRecord removal
OctStrategic dewormClean equipmentFECRT if needed
NovMinimal concernFall lice treatmentCalculate costs
DecMonitor BCSMonitor liceAnnual review
Parasite Control Calendar | AnimalSafeRanch.com Print and post in barn or office for year-round reference Version 1.0 | January 2026