Guest Blog that is a guidance not a science article - if you have any additional questions, we recommend speaking with your trusted vet
The winter is coming to an end, so it's almost time for horses to start being more outside again. This is an ideal time to consider a good strategy for deworming. The worming schedule and choice of the appropriate product depends on many factors - this means that the strategy of fighting off parasites in a stable should be considered individually.
The idea of deworming may not be entirely clear for everyone, so we shall start with a few facts about parasites and their dangerous influence on a horse's body.
The main visible symptom is that the owner sees a visible weight loss in the horse, despite increasing the amount of feed. This can be one of the symptoms of parasitic diseases, however, in many cases the weight does not change.
(Horrible, I know) pictures 1 and 2 show an adult roundworm (Parascaris equorum) that has been found in a horse. The owners claim that it was "the fittest and most nourished horse in the whole stable".
The symptoms caused by a parasite can be very different, it all depends on its species. The most frequent signs include: progressive destruction, cough, diarrhoea, cyclic colics (which often damage the intestine wall or stomach where the parasites live and eat). Intense colics are from a result of the blocking of the intestine or in the place it ends/meets other intestine.
To be more aware of it, try to imagine a pipe 8 cm in diameter and strings round it thick like pencils. Around 20-30 strings is enough to more or less block off the pipe. The population of the worms grows at an appalling pace, i.e. every adult can produce as many as 200,000 eggs, which will give offspring.
Another fact of high importance is that most parasites, during their life cycle stages, are travelling through different organs like: lungs, blood vessels, liver. During these movements, the structure of organs is being damage. It has a great influence on the workings of the organ as well as on the general condition of the horse.
Choosing the worming schedule, some rules should be taken into a consideration.
Regular worming, ie. 2-3 times a year limits the spread of parasites and avoids the infection of other horses in the stable.
It is important to change the medicine in the paste. For example, the most popular ivermectin should be used interchangeably with pastes that have fenbenzadole or moxidectin. It avoids the immunization of the parasites on the used medication. Only substances designed especially for horses should be used, and only in an oral administration form.
It is worth remembering that, before the spring, horses should be wormed with praziquantel containing pastes. It avoids the potential tapeworm infestation.
If there are foals in the stable, they can be wormed from 60 days old. The best recommended substance for the first time is fenbendazole. Further worming should take place every 2-3 months. Warning, a foal under 6 months can not take any preparations with moxidectin.
For complete protection of little horses, you should also take good care of the mothers. During pregnancy they should have been provided with a dose appropriate for their weight (last one two weeks before the delivery) and one time on the day of the delivery. Giving the medicine in the day of delivery prevents the strongyloides from passing to the foal's organism with the mother's milk. The strongyloides are able to last all the pregnancy in mammany gland and to activate during lactation, in the body of a new parasitifier. Strongyloidasis causes many dysfunctions in the health of foals, because of its ability to travel between different organs.
To be familiar with the level and kind of infestation, an egg count should have been done 2-3 times a year. The procedure is just to collect specimen of a fresh stool, put it in a bag and sign it. When prepared in this way, the material should be given to a nearest veterinary clinic or to a doctor in the stable. The most effective result can be achieved if the specimen is taken from all of the horses and doing an egg count. According to research around 30 % of infestinated horses will give a positive outcome. Therefore, the bigger group of animals will be examined, you'll get a far more accurate picture of the level and kind of infestation.
Encysted Strongyles will not show up in faecal counts. These must be treated at this time of the year and is only effectively treated by with Moxidectin or 5-day Panacur Guard.
It will allow you to chose a proper treatment. If the results are positive, we recommend that you repeat the test after around 3 weeks in order to control the effectiveness of the medicine.
Finally, I advise you to weigh your horses from time to time. You can use zoometric tapes or ask your veterinary doctor to estimate the weight of your horse, because the most frequent mistake during worming is an incorrect dose of paste.