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Guest Expert:
Martin K.
Nielsen, DVM, PhD
At Horsemen's Laboratory,
helping horse owners understand the most effective way to use fecal egg counts (FECs) is part of
our mission; as such, we're constantly on the lookout for new information and
research we can share with our customers.
In the January issue of Worm Control News, we reported on
a recent study investigating ideal methods of collection and storage of fecal
samples, an important consideration for our customers.
We're pleased to share the following insights from the study's principal researching veterinarian, Martin K. Nielsen, DVM, PhD, regarding Factors affecting equine strongyle fecal egg counts
during collection and storage of fecal samples, just published in the January 2010 issue of Veterinary Parasitology.
Dr. Nielsen is assistant professor in the Department of
Large Animal Sciences, Faculty of Life Sciences, at Denmark's University of
Copenhagen. Dr. Nielsen has also spoken on the topic of equine parasite
resistance, and was a visiting scientist at the University of Kentucky's
Maxwell H. Gluck Equine Research Center.
A summary of the study results was featured in the
January, 2010 issue of Worm Control News. The study abstract can be read
on the PubMed Web site.
Horsemen's Laboratory (H-Lab): How & why did the
study idea originate?
Dr. Nielsen: This study originates back to my time as a
veterinary student in Denmark, when restrictions on anthelmintic usage were
being introduced. By law, anthelmintics would only be available through
prescription, and we were predicting that more emphasis would be put on regular
parasite testing using fecal samples to reduce the need for anthelmintic
dewormers.
Since no one was able to give clear-cut advice on how to
best collect and store fecal samples, we first performed a preliminary version
of the study. Based on the outcome from this pilot study, we revised the
protocols and performed the same study at two geographically different
locations to add more strength to the conclusions.
H-Lab: What factors caused the differences in the U.S.
and Denmark results?
Dr. Nielsen: Generally, there was very good agreement
between the two locations, underlining that the results are reliable.
The only major difference was in the part of the study
where we left fecal samples for up to 24 hours on the stall floor before
analysis. Here, the Danish barn was substantially colder than the U.S.
counterpart, so the Danish egg counts were unaffected while the U.S. counts
declined after 12 hours. This finding shows that samples can be collected from
stall floors, provided it is within the 12 hour window.
H-Lab: Horsemen's Lab provides fecal egg count testing by
mail - based on your study results, are there any particular recommendations
you would give for the process of collection and shipping?
Dr. Nielsen: I find it useful to know that as long as
samples are less than 12 hours old, they can be collected from the stall floor
and analyzed. This was even in a warm Georgian barn, where the temperature was
around 27 C (about 80 F).
We also learned that fecal samples tolerate room
temperature for up to 5 days when kept airtight. Our results suggest that if
samples are only a few days underway in the mail, the results will be reliable.
It is important that samples are packed as airtight as possible to prevent egg
hatching. Altogether these are simple recommendations for the horse owner to
use when collecting and submitting samples for analysis.
H-Lab: Are you or your colleagues planning additional
study in this area? If yes, can you give a general sense of direction/topic?
Dr. Nielsen: Yes, we are currently designing a study evaluating
the reliability of the McMaster method for generating egg counts. We frequently
encounter horses with 0 egg counts, and usually say that they may not be
exactly 0 and should be interpreted as a very low egg count. With this new
study, our overall aim will be to understand and even increase the accuracy of
fecal egg count testing, particularly important when we are testing for
parasite drug resistance on the farms.
Coming
next month: Highlights from the presentation Are The Worms Winning? The
Lowdown on Rising Parasite Resistance.
Click here to return to the February issue of Worm Control News.
Click here to visit the Horsemen's Laboratory Web site.
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