Pasture and paddock management

by Paul van Dam

Management of pastures and paddocks plays an important role in control over parasites, and time and effort spend on this will pay off handsomely in lowering the damage done by parasites and on reducing the money spent on remedies.

Horses are kept on pastures or in paddocks. For the purposes of this article, paddocks are defined as smallish enclosures in which horses are kept in small numbers. More often, they will have no grass cover and are often used to allow stabled horses some freedom during the day. Conversely, pastures are grasslands where horses graze.

General rules for both

• Make sure that there are no leaking pipes or water troughs. Worm larvae require humidity for survival and will be more prolific in wet or muddy areas. By the way, the same applies to fly larvae, so keeping paddocks dry will also reduce the number of flies.
• When you bring in a new horse, the ideal is to deworm and dip the horse at the previous premises 24 to 36 hours before you move it. If this is not possible, move it into a separate small paddock or quarantine area when it arrives at your place. Deworm and dip and keep it separate for 48 hours. Check for external parasites and, if at all possible, have a faecal examination done to check for worms. If clean on both counts, you can move the horse in with others.
• Do not mix young horses with mature ones. Young horses carry more parasites than older ones and will increase the worm load in the environment.

Simple rules for paddock hygiene

• Remove manure at least twice a week. Many horses will defecate in the same area every time, easing the cleaning process.
• Never feed your horse from the ground in these paddocks, as they will pick up worm larvae at the same time. Build hay racks and place these on concrete so that any spilt feed will drop onto concrete and not onto the infested soil.

Pastures

Some of the same rules apply to pastures, but there is a lot more that you should do and be aware of.

• In the previous article, we discussed the idea of not deworming all your horses at the same time. Should you however prefer to deworm them all at once, you should leave them in the same pasture camp where they were before the deworming. This will:
  • Ensure that they pick up some of the non-resistant worms from the old pasture, thereby preventing the resistant worms from taking full control; and
    Prevent a situation where a clean pasture camp (one that was rested) becomes infested with only resistant worms, which would happen if you move the dewormed horses (i.e. the horses in which you killed all the non-resistant worms) to such a clean camp.
  • Rest camps for three months to reduce the worm load and make them worm-safe. If you use cultivated pastures, it is a good idea to mow them (which will expose the infective worm larvae to the sun) at the same time. It is better not to irrigate the pastures when you rest them, as the moisture will allow the infective worm larvae to survive longer.
• Use a rotational grazing approach by changing the species on the pasture. Sheep or cattle will pick up many of the infective horse worm larvae while coming to no harm, as the larvae cannot develop to mature worms in these species. Cattle can also be used to pick up ticks from the pastures. There is a bigger selection of products available with which to dip cattle, and following a well-planned dipping programme for the cattle, one will not only reduce the total number of ticks, but will also get rid of ticks that might be resistant against the few products available with which to dip horses.
• Do not mow the pastures that were used by horses or put horses back in to graze on the short grass. The risk of infestation will be higher, as there will be more worm larvae in the short grass. It is fine to move horses into a camp that was used by cattle or sheep before and where the grass was grazed down short, even if horses were kept in this camp before. Horses can eat closer to the ground than cattle and will utilise the shorter grass. The cattle or sheep will have removed most of the horse worm larvae that were deposited there by the horses when they grazed the camp earlier.
• When you bring in new horses, after you have treated them against worms and external parasites, as explained above, do not put them on pastures that were rested and are worm-safe. If you do, they will infest the pasture with the resistant worms that were not affected by the dewormer, thereby increasing the risk for your other horses.
• Do not overgraze pastures. Usually horses will graze certain areas and defecate in others. If you leave them in the camp too long, you will force them to also eat the grass growing in the areas where they defecated, thereby increasing their worm burden.