Who decides on the horse's deworming?

The vet in coordination with the owner. Frequency, active ingredient and approach depend on age, keeping, pasture and parasite risk. The sharer doesn't decide and doesn't administer.

What is selective deworming?

Instead of fixed dates, a fecal sample is analyzed first. Deworming is given only if the test shows relevant parasite load. Advantage: less resistance development, less stress for the horse. GST recommends in many cases.

What can the sharer observe regarding parasites?

Behavior changes, coat state, weight, manure (visible segments, unusual consistency). Also tail rubbing on posts. All observations to the owner.

How is deworming documented?

In horse passport, in vet practice software and in own overview. Fields: date, active ingredient or preparation, vet, reason, next check, notes.

Can parasites transfer to humans?

Most horse parasites are host-specific and not transmissible. Some (e.g. certain fungi) can rarely affect humans. On suspicion, discuss with vet and physician.

Guide

Horse deworming: overview and structure without medical recommendation

2 min read

Deworming has become more complex than it seemed. Instead of routine four times yearly, Swiss practice shifts toward selective deworming. This guide shows the structural aspects and the sharer's role without recommending schemes.

Why structural only

Which active ingredient, what frequency, what strategy for a specific horse depends on many factors: age, keeping (box, pasture, open), number of horses, parasite situation, history, individual risks.

The vet is the only person who can assess these together and set a concrete program. GST and SVPM publish updated recommendations regularly.

Selective deworming as growing Swiss standard

Classic routine deworming: Fixed dates yearly, regardless of actual status. Simple but resistance risk.
Selective deworming: Fecal sample analyzed first. Wormer only if test shows relevant load. More planning but more effective against resistance.

On SVPM pages and GST continuing education, selective is recommended in many constellations.

Structure of a deworming document

Horse. Name, TVD number.
Date. Day, month, year.
Reason. Routine, positive fecal, acute symptoms.
Prior fecal sample. Yes or no, date and result.
Active ingredient or preparation. Determined by vet.
Vet. Name and practice.
Reaction. Anomalies observed in following days.
Next check. Planned date for next fecal or routine.

What the sharer observes

Coat state. Dull, poor food intake.
Weight and BCS. Unintended loss despite adequate feeding.
Manure consistency. Visible segments, unusual consistency, diarrhea.
Behavior. Tail rubbing on posts is classic.
Vitality. Apathy, reduced performance.

To owner without diagnostic attempts.

Pasture management as prevention

Pick up droppings. Weekly, summer more.
Pasture rotation. Don't keep horses permanently on same field.
Mixed grazing with other species. Sheep or cattle eat horse parasites without being hosts.
Respect grazing adaptation. Too early and intensive in spring stresses and raises sensitivity.

FSVO and Swiss Equestrian integrate these measures into compliant keeping.

What the sharer doesn't do

No deworming administration. Not even mild or OTC. Vet-only.
No diagnosis attempts. Report, don't interpret.
No frequency change. Vet and owner decide.

Frequently asked questions

Who decides on deworming? Vet with owner.

Selective deworming? Fecal first, wormer only if relevant load.

Sharer observation? Coat, weight, manure, tail rubbing. To owner.

Document deworming? Passport, vet software, own overview.

Parasites to humans? Mostly not. On suspicion, vet and physician.

Sources

Deworming overview in HorseCompanion

Dewormings and fecal samples documented per horse. 12-month overview ready. Start for free

Updated: June 2026