The importance of implementing an appropriate worming programme should not be underestimated. Eventing Worldwide provides an overview of how to achieve an effective worming programme.
The importance of implementing an appropriate worming programme should not be underestimated. Parasitic worms can adversely affect the health and wellbeing of horses and ponies of all ages doing irreversible damage to the gut and other organs.
Spring is an important time for horse worm control as whilst the breeding cycle is dormant during the cold winter months. The increase in temperature in the spring leads to recrudescence of larvae and recommencement of the worms breeding cycle. Larval emergence in the spring and the increase in a horse’s burden can be detected by testing the faeces to confirm the presence of eggs.
Worm egg counts have an important role in this, as they help to identify when your horse actually needs to be wormed. Generally treat horses with a worm egg count greater than 200 eggs/g. Those with lower worm egg counts do not require treatment, preventing the unnecessary and ineffective use of wormers. Performing worm egg counts regularly aids in your understanding of your horse’s worm burden through the seasons.
Effective worm control aims to prevent worms from completing their lifecycle and thus prevent further pasture contamination. Worming programmes have evolved over the years and there are now a number of strategies that horse owners can use to help maintain their horse’s health and performance.
Using the same class of wormer every season will increase the chance of resistance developing. It is therefore important to rotate the type of wormer used after each grazing season. Resistance is when a greater frequency of individuals in a parasite population, usually affected by a dose or concentration of compound, are no longer affected. Once resistance is present in a worm population, the health, welfare and performance of horses infested with resistant worms will be compromised.
For this reason, it is essential that your horse is dosed accurately according to bodyweight. Using too low a dose of wormer may speed up the development of resistance. On the other hand, frequent, unnecessary worming may also increase the potential for development of resistance.
A rigorous pasture management programme will make a major contribution to effective worm control.
· Remove droppings on a regular basis (preferably daily, but at least twice a week) and don’t use horse manure as fertiliser.
· Don’t overstock pastures: a maximum of two horses per hectare or 1-1.5 acres per horse is recommended.
· Graze horses of a similar age together – young horses are more susceptible to a higher worm burden.
· Sub-divide grazing areas into smaller paddocks and graze on a rotational basis.
· Harrow pasture during dry conditions to expose soil-borne larvae so that they dry out and die.
· Graze paddocks with other livestock too. This will dilute the horse worm burden on your pasture.