Thursday, September 13, 2012

How do fecal egg counts compare?

This was a difficult year for internal parasites, as only seven goats officially qualified for the sale. As the test and summer progressed, fecal egg counts and FAMACHA© scores continued to increase. This trend was not reversed until some of the wormier goats were dewormed.

How does this year compare to previous test years?
Last year, fecal egg counts got significantly higher, but not until mid-September, when moisture returned. 2009 and 2010 were both dry years, so egg counts never really got that high and few goats required deworming

There were some problems early in the test in 2010, due to the ineffectiveness of the initial deworming (levamisole was off the market). In 2009, the last "wet" year, egg counts peaked at d-70 and declined rapidly after a significant number of goats were dewormed.

In 2012, the goats started the test with the highest level of worm infection. Fortunately, the triple deworming was very effective at reducing egg counts and eliminating the worm load.  The test goats were then given a low dose of worm larvae (L3), in hopes of "seeding" the pastures with worm eggs.

In a "normal" summer, egg counts will climb through the summer until a significant number of goats become clinically parasitized. After the susceptible animals are dewormed with an effective anthelmintic, egg counts will go down. The resistant goats will maintain low egg counts throughout the summer. This is what occurred in 2012.