Positive Effects (Rare):
* Increased plant growth: Some endophytes can promote plant growth, leading to increased forage availability for horses.
* Resistance to pests: Endophytes can protect plants from certain insects and diseases, leading to healthier forage.
Negative Effects (Common with N. coenophialum):
* Fescue toxicosis: This is the most common problem associated with endophyte-infected grasses, particularly tall fescue. The toxins produced by N. coenophialum can cause a range of symptoms, including:
* Reproductive problems: Infertility, abortion, prolonged gestation, and dystocia (difficult birth) are common in mares.
* Reduced milk production: Foals may be weak and have reduced growth rates.
* Heat stress: Horses are more sensitive to hot temperatures and humidity, and may experience panting, sweating, and lethargy.
* Lameness: Affected horses may develop hoof problems and circulatory issues.
* Reduced performance: Horses may experience decreased athletic ability and stamina.
* Other health issues: These can include muscle tremors, weight loss, and coat changes.
How to Manage Endophyte-Infected Grasses:
* Identify the problem: Have your pasture grasses tested for endophyte presence and levels.
* Switch to endophyte-free pastures: If possible, replace infected grasses with endophyte-free varieties.
* Manage grazing: Rotate pastures to reduce the amount of time horses spend on infected areas.
* Use a grazing management system: This can include techniques like stockpiling (allowing grasses to grow tall and then grazing later) or rotational grazing.
* Supplementation: Provide additional feed, such as hay, to help horses meet their nutritional needs.
* Consult with a veterinarian: Discuss specific management strategies for your horse, and be aware of potential health risks associated with endophyte-infected grasses.
It's important to note that not all endophytes are harmful. Some strains of N. coenophialum have lower toxin levels and may not cause significant problems. However, it's always best to be cautious and manage pastures to minimize the risk of fescue toxicosis.