04/24/2026
F***l worm egg counts are very important to animal owners and producers, but unfortunately, many of the worm egg count techniques used across the country are not the same and often provide unreliable results. Techniques used for dogs and cats seldom work for cattle, sheep, goats and horses. We also believe that shortcut techniques such as “pooling samples” in order to save time and reduce costs also creates inaccuracies!
The most common technique used for sheep and goats is a McMaster’s test which uses a dilution test (one drop of f***l solution on a glass slide) to estimate worm burdens by using a single drop but lacks sufficient sensitivity to find low egg laying parasite species such as Nematodirus or Trichuris (whipworm) and because this test uses a 50X multiplication factor it greatly over estimates high worm egg counts for stomach worms like Ostertagia and Haemonchus.
There is also a newly emerged technique being promoted by several national labs for “the pooling of samples” from a large group of animals or a herd obtaining a single overall average estimated count. Since sample size (1-3 grams of manure) is too small to pool, these labs are providing misleading results. The results of blending 1-3 grams of manure in the lab from cows producing 60-70 lbs. of manure daily will not produce the same results as individually sampling 18-20 cows in a herd with statistically proven results. Finding an average count in cows showing 20 eggs/3 grams, for example, equals 3,000 eggs per pound of manure or 200,000 eggs shed per day per cow. These results will not be found in one drop of liquid manure no matter how many other drops of manure they are combined with.
At MidAmerica Ag Research, we use the “Modified Wisconsin Sugar Flotation Method” and have been conducting f***l worm egg counts for producers since 1985. Our records show that we have conducted over 1.5 million samples from all major livestock and wildlife species from all 50 states during this period of time. The Modified Wisconsin Sugar Flotation Method is very sensitive, very accurate and the kind of specific laboratory test simple enough to apply to mass screening of parasitisms. This test has the ability to precisely detect the presence or absence of parasitism. The “Sheather’s solution” used for the test is neither hypotonic nor hypertonic so the eggs retain their original size and shape and can then be identified to genus or species found. Egg enumeration is also conducted at the same time on each sample which then determines egg shedding levels for each animal tested. Altogether, the Modified Wisconsin Sugar Flotation Method provides the necessary science needed to determine best treatment options to prevent physical harm and production losses from occurring to all animals being tested.
