Roundworm eggs stick to many surfaces, including dust particles, making them highly transportable and able to stick to a dam’s nipples where a foal can ingest eggs while it nurses. Adult female round- worms can lay up to 170,000 eggs per day. Photo courtesy Dr. John Byrd


ROUNDWORMS— THE ARMADILLO OF WORM EGGS


T ough roundworms (Parascaris equorum)


Before You Deworm…. Horsemen’s Laboratory performs microscopic fecal egg counts that tell you how oſt en


have developed many survival mechanisms, they primarily aff ect only horses younger than two to three years of age. Younger horses have not yet developed immunity to this parasite infection. Under ideal conditions, the life cycle takes 79–110 days from egg to adult in the small intestine of the horse. It is believed that immunity occurs during a period of 14–17 days when fi ſt h-stage larvae migrate through the wall of the intestine into the blood stream, circulate to the liver and then to the lungs. Upon reaching the lungs, larvae are coughed up, swallowed and returned to the small intestine where they mature into egg-laying adults.


ROUNDWORMS ARE CHAMPIONS OF SURVIVAL


◗ Adult female roundworms lay as many as 170,000 eggs perday or 60,000,000 eggs per year.


you need to deworm your horse. Owner John Byrd, DVM, created Horsemen’s Laboratory in 1992 so horse owners could bet er evaluate their worm-control programs and make informed decisions about deworming their horses. Visit www.horsemenslab.com to learn more about Horsemen’s Laboratory and parasites,


to sign up for the monthly newslet er and to order testing kits. You can order kits by calling 800-544-0599 or emailing hlab@horsemenslab.com. If you have questions specifi c to your barn, pastures or testing program contact Dr. Byrd by email, phone or the contact form at hlab@horsemenslab.com


◗ Indestructible eggs are surrounded by a thick, strong protec- tive shell able to survive weather extremes of moisture and temperature.


◗ An embryo develops in the egg within a few days but can con- tinue to be infective for over 10 years, protected by the shell.


◗ Eggs stick to many surfaces, including dust particles, making them highly transportable and able to stick to a dam’s nipples where a foal can ingest eggs while it nurses.


◗ Recently, roundworms have been developing resistance to many of the deworming medications, including ivermectin,


“One drop of dew on a single blade of grass can contain 100 strongyle larvae, and some experts have stated there may be as many as 1,000. So at any given time, great numbers of larvae are developing in a pasture.”


36 | June 2012 • WWW.TRAILBLAZERMAGAZINE.US


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