In addition to this, any new horse entering a yard should have a worm egg count performed prior to turnout, to prevent contamination of pastures.
An important part of an effective worming program is to ensure that drug treatments and faecal sample testing are combined with good pasture management (avoidance of overstocking, poo picking and harrowing during dry periods) and to minimise infection levels and reliance on wormers.
It is important to note that pregnant mares & young foals are more susceptible to a worm burden than other categories of horses and that wormers administered to the mare will not be passed to the foal via her milk. While any worm can affect foals, the most significant parasites are ascarids, also known as roundworms.
Ascarids take advantage of the naïve immune systems of young or debilitated horses. The more traditional interval dosing will be more appropriate for a young foal from 1 month of age although heavy roundworm burden can cause problems if a sudden and massive kill of the roundworm occurs following the worming dose. Mares should be wormed during pregnancy, particularly one month before their ‘due date’ with 5 Day Panacur Guard.
When administering a wormer, it is important to estimate the horse`s weight as accurately as possible to avoid underdosing (or overdosing in case of Equest, as it has not got a large safety margin). A weight tape could be helpful to monitor weight, especially when dealing with a growing foal.
When administering an Ivermectin or Moxidectin based wormer, it is important to dispose of any leftover product safely and contaminated faecal output as these wormers are very toxic to dogs, especially Collies.