Intestinal parasites, or Helminths, are a widespread concern in equine populations and can represent a major challenge in maintaining the health and welfare of horses. These parasitic worms can cause significant risks when they infest horses in large numbers, leading to a range of issues and while various species of intestinal parasites exist, certain types are more commonly seen and pose the greatest health threats. Understanding the complexities of modern parasite management is crucial for anyone involved with horses to ensure effective treatment and prevention strategies. In this context, it’s important to explore the challenges, considerations, and best practices for managing intestinal parasites in horses.
The most common helminths which affect the horse include:
- Large Strongyles (Strongylus spp.)
These parasites damage the blood vessels that supply the intestinal walls, potentially leading to life-threatening complications such as blood clots and colic. - Small Strongyles (Cyathostomins spp.)
Cyathostomins are the most common intestinal parasites in horses. Their larvae encyst within the intestinal wall, and when they emerge in large numbers, they can cause “Larval Cyathostominosis”, leading to severe mucosal damage and inflammation. This condition has a fatality rate of up to 50%. - Tapeworms (Anoplocephala perfoliata)
Tapeworms tend to gather at the ileocecal junction, where they can cause blockages, leading to discomfort and colic. - Ascarids (Parascaris spp.)
Roundworm infections are particularly dangerous for foals and young horses, which can quickly develop heavy worm burdens. This can result in intestinal obstructions, severe inflammation, and even pulmonary hemorrhages as larvae migrate through the lungs.
Identifying the Signs and Symptoms of Intestinal Parasite Infestations
The clinical manifestations of intestinal parasite infestations in horses can range from mild and subclinical to severe, life-threatening conditions and can vary greatly depending on the species involved, the severity of the infestation, and the horse’s overall health and immune response.
Common clinical signs associated with intestinal parasites include acute weight loss, a noticeable decline in condition, and reduced appetite. Horses may also exhibit lethargy, colic, and diarrhea, all of which can significantly affect their performance and overall well-being. In more severe cases, abdominal distension may occur, and abnormal blood panel results may be found. These clinical manifestations underscore the importance of regular monitoring and early detection, as well as the need for effective parasite management strategies to mitigate the risks posed by these common yet potentially dangerous pathogens.
Anthelmintic Resistance: An Emerging Challenge
Whilst various practices in pasture management can help reduce the impact of parasitism, deworming using anthelmintic drugs for both treatment and prophylaxis has long been a cornerstone of equine management. However, the emergence of drug-resistant parasite populations presents a growing challenge. Anthelmintic drugs, introduced in the 1960s, were initially administered on a schedule dictated by the drug manufacturer across large equine populations. While this approach was initially effective in reducing worm burdens, it has inadvertently promoted significant drug resistance due to over-reliance on these routine treatment regimens. Compounding the issue has been the absence of new drug classes in the past 40 years, leading to today’s significant challenge in parasite control.
Rethinking Parasite Management
Modern equine medicine has been compelled to reassess traditional deworming protocols with a pivotal development in Targeted Strategic Dosing. This involves the assessment of parasite status in the horse prior to the use of any anthelmintic treatment and is also vital in taking into consideration environmental, geographical and epidemiological factors which may influence the lifecycle of intestinal parasites.
Fecal worm egg counts (FWECs) provide a count of the number of strongyle eggs per gram, including ascarid eggs. Low shedders (under 200 eggs/g) who are otherwise healthy, are not considered to pose a significant risk to themselves or the herd so treatment is targeted for those returning FEWC’s higher than this threshold. Blood or saliva antibody testing can be effectively used to measure tapeworm antibody levels, and more recently serum antibodies from blood testing can identify a burden of encysted small strongyles.
By identifying which horses are shedding the most parasite eggs and thus contributing the most to the herds infection risk, it is possible to tailor treatment for specific parasite species and avoid unnecessary treatment for those that don’t need it, slowing drug resistance, saving costs and reducing unnecessary exposure to the potential negative side effects of deworming itself, such as gastrointestinal irritation, colic and even neurological symptoms. Research has also shown that anthelmintics can negatively affect the intestinal microbiota, potentially leading to dysbiosis and its associated health conditions.
Although the ultimate goal may seem to be the eradication of all intestinal parasites, it is crucial to recognize that host-parasite relationships are a natural occurrence. Horses have coexisted with these parasites for millennia without anthelmintics, and research has shown that an innocuous parasite burden may actually be beneficial in stimulating natural immunity.
Enhancing Digestive Tract Health and Parasite Management with SUCCEED®
There are several factors that contribute to a horse’s ability to manage normal parasite loads, with the health of the gastrointestinal tract playing a central role in this process. By incorporating SUCCEED® Digestive Conditioning Program® into a horse’s daily routine, the gastrointestinal tract, particularly the large intestine, can receive vital support. This includes the essential population of beneficial bacteria, fungi, and protozoa that help maintain a balanced hindgut environment. Optimizing total digestive health in this way provides a strong foundation, enabling the horse to better handle the potentially negative effects of anthelmintic treatments. Moreover, supporting digestive tract health with SUCCEED® could help low shedders to maintain optimal health both internally and externally. This approach not only minimizes the need for unnecessary treatments but also reduces the risk of further development of drug resistance, ultimately contributing to more sustainable and effective parasite management practices.
In conclusion, ensuring the health of the gastrointestinal system is a crucial component in managing intestinal parasites. By supporting complete digestive health with SUCCEED®, we can support a horse’s natural ability to cope with parasite control practices, reducing reliance on overly frequent treatment protocols, and promote long-term well-being.
