Mycotoxin Effects on Horses and Livestock
27 January, 2023 | Feedchar for Dairies Feedchar for Horses
How do mycotoxins affect horses and grazing animals? Here Agspand’s Consultants describe mycotoxins in certain pasture endophytes (fungi) that commonly appear on and in grasses and feeds, and some of their effects on animals.
Endophytes occur naturally in plants, which is why animal and pasture management along with Agspand’s FEEDCHAR® loose lick supplementation is recommended all year round.
FEEDCHAR® mineral plus charcoal recipe is a feed-grade, broad-spectrum digestive aid and toxin binder for horses and all grazing animals.
Suggestions to help animals with feed mycotoxin effects are given below.

FEEDCHAR® is a Registered Trademark product in Australia and a Certified Allowed Input for Organic Farming Number SXC 19091.
There are many different endophytes. Not all of them contain harmful mycotoxins, but it is worth being mindful of the main groups that do, as well as some potential mycotoxin symptoms in horses, cattle, sheep and livestock.
International research continues to identify different mycotoxins and which toxin binder supplements may assist, or not. To help cover the range of possible mycotoxins in feed, it is worthwhile using broad-spectrum toxin binders such Agspand’s FEEDCHAR® mineral plus charcoal combined. Animals seek these natural and organic ingredients themselves in the wild to help deal with seasonal plant potencies. Agspand tests them to ensure its FEEDCHAR® ingredients follow Australian regulations as safe to feed to animals.

Short-mown and stressed grass from animal overgrazing can still produce seed heads in its desire to reproduce.
SYMBIOTIC ERGOT feed mycotoxins such as Claviceps may exist in some of the wild wheats and sorghum as well as kikuyu, paspalum and older ryegrass and taller fescue grass varieties. Claviceps mainly appear at the base sheath and are hosted by the plants as self-protection to deter insects and animals eating new leaves as they emerge. Ergots show up later in the seed heads and are carried over to new plants. Short-mown and stressed, overgrazed grass can also produce seeds. Claviceps mycotoxins are most likely to have neurological or “drugged” types of effects on animals.
PRE-HARVEST FIELD-SOIL Fusarium feed mycotoxins derive from the soils in which pre-harvested plants grow. Fusarium invade and may take over the plant, such as the commonly described “blight” and “wilt”. These types of mycotoxins are related to many digestive and physical ailments in animals, including reproductive disorders.
POST-HARVEST MOULDY feed mycotoxins deriving from the natural breakdown of harvested feeds and hays, such as Aspergillus and Penicillin, are worldwide concerns for feed storage and transport, especially in wet seasons and humid climates. These types of mycotoxins can be highly carcinogenic to the liver, prompting the WHO to set safe limits for them in feeds. Digestive disruptions including severe colitis can be related to these types of mycotoxins in particular, depending on how much has been accidentally ingested.

Pasture mycotoxins may cause skin, coat and feet problems for horses and grazing animals. This picture shows the nose of a horse supplemented with Agspand’s FEEDCHAR® toxin binder for one week.
In general, pasture endophytes can be particularly strong in stressed grass struggling to grow from animal overgrazing, or from too much or too little moisture, or when the soil nitrogen is high.
Ag Departments warn these scenarios especially apply to grass emerging after dry seasons or droughts.
Mycotoxins can cause overheating in animals, and digestive inflammation, resulting in diarrhoea and weight loss, girth tension, and skin, coat and feet issues from extremity vasoconstriction (i.e. restricted blood flow at the face/nose, dock/rump, and feet). The worst effects of mycotoxicosis for females are possible late-term abortions, low birth weights, and an increase in still births. The Lolitrem B mycotoxin from ryegrass can also affect the nervous system and cause a lack of concentration, anxiety and hallucinogenic “staggers”.
Recent research on Finishing Steers by Matthew Reynolds and Kim Stanford et al. (2023) showed the effects on the cattle of Ergot mycotoxin in their feed was decreased DMI (dry matter intake) and ADG (average daily gain), decreased total shrunk body weight gain, final body weight and carcass weight, and decreased number of AAA graded carcasses (DOI:10.1093/jas/skad281.159).
Mycotoxin and animal and pasture management suggestions
To help manage animals and pastures with mycotoxin effects, Agspand Consultants suggest to:
- Avoid the close-grazing of pasture, because the base sheath of the plant potentially has the most concentrated amount of endophyte mycotoxins.
- Withhold hungry animals off grass that is just starting to shoot and regrow — wait to graze until the grass is higher, in Stage 2 of growth, showing two or more leaf branches.
- Maintain animals’ continuous access to fresh grass hay as part of their daily routine, which is essential digestive fibre that buffers rich, green grass. (Remember not to feed mouldy hay, grain, or maize as these can also contain mycotoxins.)
- Ensure animals regularly move and graze over different, small areas so that both the pasture and soils are rested, not stressed; for example, using Cell Grazing or Strip Grazing with temporary electric fencing (also ideal with Perimeter Tracks in Paddock Paradise set ups).
- Supplement animals’ daily diets with Agspand’s FEEDCHAR®, an Australian feed-grade and certified mineral–charcoal digestive aid and broad-spectrum toxin binder, to support animals’ Condition, Behaviour and Weight through all seasons.

A successfully managed small acreage with a Paddock Paradise layout for horses, along with Agspand’s Feedchar® daily supplementation.
After 8 Years, many clients who have maintained Agspand’s Feedchar continuously with their animals find it cost effective simply to mix small amounts through all feeds, or with vitamins and any extra minerals as may be needed for individual animal type, age, stage and season — your nutritionist or Agspand’s Animal Management Consultants are available to advise.
Agspand’s FEEDCHAR® website has further information on different animals’ supplementation.
Your local Agspand’s FEEDCHAR® Stockist may also assist.
Search Keywords in Agspand’s Feedchar Facebook page and private User Group for many users’ wonderful reviews and experiences.
Agspand’s FEEDCHAR® is a Registered Trademark and Certified Allowed Input for Organic Farming SXC 19091, proudly made in Australia. Using FEEDCHAR® long term with grazing animals supports carbon and regenerative farming for healthy, profitable agriculture.
Article by Steve Sullings and Karen Enkelaar
Animal and Land Management Consultants
Directors, Agspand Pty Ltd, Australia © January 2023