Comparison of FEC Methods

Measurement of fecal egg counts (FEC) is the standard approach for assessing strongyle-type parasite egg shedding in livestock and is the primary means for assessing dewormer efficacy. There are several fecal egg counting methods. They vary in sensitivity, accuracy, precision, and technical difficulty. Scientists compared three methods (modified Wisconsin 3-chamber, 3 chamber McMaster, and Mini-Flotac) in cattle, sheep, horses, and llamas.

In both an egg-spiking study and clinical samples, the Mini-Flotac system recovered the most eggs and yielded the highest EPG (closest to the true value). For horses and llamas, both the Mini-Flotac and McMaster yielded significantly higher EPG than the Wisconsin method. Mini-Flotac was most accurate and precise test for both species of ruminants. The Wisconsin method was the most precise for horses and the McMaster was more precise for llama samples.

Researchers suggested that the Mini-Flotac be used routinely in all species, but especially when high accuracy is needed, such as when performing fecal egg count reductions. They also determined that the straining step is a potential source of egg loss for McMaster and Wisconsin. Samples should be strained through cheesecloth.

The study did not examine the more traditional 2-chamber McMaster procedure or evaluate different flotation solutions.

Source: Veterinary Parasitology June 2018. Read Abstract