Presented by: W. Davind Wilson, MRCVS
What can your Veterinarian do for Parasite Control?
With a myriad of choices, designing a worming program for
your horse can prove quite cumbersome. Unfortunately,
the increased availability of commercial parasite control
has reduced the role for veterinarians in the planning
and implementation of comprehensive programs.
Beware! Parasite control is complex and entails much more
than deciding which of many available anthelmintics to
select from the feed store or through the latest horse supply
catalogue. Your equine practitioner is the one most qualified
to address and oversee a program that best protects the
health of your horse and your individual needs.
The following steps reveal how your veterinarian can work
with you in managing parasites for your horse.
Step 1--Initial consultation and assessment
You and your veterinarian should establish and evaluate the
financial capabilities of the owner
compliance capabilities of the barn
geographic location and climate
housing and management practices (number of horses, feeding
documented problems from the past
Step 2--Evaluation of the current parasite status
To more specifically evaluate the current parasite situation,
your veterinarian will likely collect, or ask you to collect,
two or three fresh fecal balls from at least 20% of the horses
on the farm. The horses chosen should represent the
spectrum age and management practices employed on the farm.
The results from the fecal exam will provide a very useful
guide to overall status of the herd and degree of pasture
contamination and transmission potential.
Step 3 - Evaluation and correction
Did you know that you can eliminate most parasite species
from the environment through several management strategies,
without the use of dewormers? For example, the regular
(at least twice weekly) removal of feces from paddocks
and pastures, either manually or using tractor-powered
vacuum units, has been shown to greatly reduce the number
of infective eggs and larvae.
Other strategies include:
regular mowing and harrowing of pastures (particularly
during hot, dry weather and cold weather) can break up
manure piles and expose eggs and larvae to the elements
frequent rotation of horses to fresh pastures,
avoidance of overgrazing and overcrowding (more than
one horse per two acres)
grazing horses with cattle and sheep,
making sure that supplemental feed is fed off the ground,
keeping visiting horses separate from resident horses and
deworming before joining the herd,
constructing feeders so that horses cannot pull feed onto
cleaning both feeders and waterers regularly to minimize
deworming mares one month prior to foaling,
thoroughly washing mares before foaling unless precluded
by weather conditions,
keeping mares and foals separate from other horses,
reserving the cleanest, least-grazed pastures for foals and
other young stock.
W. David Wilson, MRCVS, of the University of California,
Davis, is chairman of the Biologic and Therapeutic Agents
Committee of AAEP, and Edward W. Kanara, DVM,
of the University of Pennsylvania, is the AAEP board
liaison to that committee.