horse pasture has several maples trees. I was told they are toxic to horses,
but our horses seem fine. Are they toxic? If they are, do we have to remove
them from our pasture?
Answer: Wilted (not fresh) maple leaves are toxic to horses. However, horses must eat 1.5 to 3 pounds of wilted maple leaves per 1,000 pounds of bodyweight to become sick. Wilted maple leaves can remain toxic for four weeks, but they aren’t generally believed to retain toxicity the following spring. Thus, illness normally occurs in the fall when normal leaf fall occurs.
Illness from maple leaves has only been reported in horses. Common signs after the first day of eating leaves include depressed behavior, tiredness, not eating, and dark red/brown urine. Signs may progress to going down with labored breathing and increased heart rate before death. Don’t cut down maple trees in horse pastures. Instead, keep branches out of reach of horses (for example, trimmed above their reach) and fence horses out of areas with a lot of wilted maple leaves. However, horses will rarely choose to ingest wilted maple leave unless very hungry. For more information on wilted maple leave toxicity, click here.
can be a beautiful time of year for horseback riding. However, frost can
negatively impact horse health during fall grazing.
There are no reports of toxicity of
horses grazing frost damaged pastures (includes grass and legume species).
However, frost damaged pastures can have higher concentrations of nonstructural
carbohydrates, leading to an increase in potential for founder and colic,
especially in horses diagnosed with or prone to obesity, laminitis and Equine
Metabolic Syndrome. To help prevent these health issues, wait up to a week
before turning horses back onto a pasture after a killing frost. Subsequent
frosts are not a concern as the pasture plants were killed during the ﬁrst
Why do nonstructural carbohydrates increase during the fall? During
the day, plants carry out the process of photosynthesis. In this process, they
make carbohydrates as an energy source for the plant. A second process,
respiration, is carried out when the plants use up the carbohydrates they
produce during the night for energy. Plant respiration slows down when
temperatures are near freezing. As a result, the plants hold their
carbohydrates overnight. Freezing can stop respiration and lock the
carbohydrates in the plant for over a week. Thus, plants tend to contain more carbohydrates
in colder temperatures or after a frost. Often, horses will prefer forages
after a frost due to the higher carbohydrates levels.
For more information on fall health concerns for grazing horses, click here.
Managing pasture can be a very important tool in controlling feeding cost for all livestock, including horses being kept on small acreages. If pasture is going to provide a substantial amount of the required nutrition for a horse, it takes about 2-3 acres, per 1,100 pound adult horse.
Even with adequate acreage, weather conditions can limit pasture regrowth and decrease the amount of forage available. Avoiding over-grazing is important for both the pasture and for the animals. Keep the following in mind:
Remove animals from the pasture when plants are grazed down to 3-4 inches in height. Grazing too long and allowing animals to eat the grass off too close to the ground, will kill the grass and turn the pasture into a dirt lot where the only green plants are weeds, potentially requiring expensive renovation. Also, if animals eat the grass too close to the ground on sandy ground, the risk of sand colic may increase. Animals may also consume potentially toxic weeds if no other forage is available.
If you have limited acreage, consider purchasing some temporary fencing so that you can rotate the pasture. The outer fencing should be a safe, permanent fencing. You can cross fence the pastures with temporary fencing such as capped steel posts and appropriate electric wire. By allowing the animals to graze one section, then moving them to another, total pasture yield can be increased substantially, helping to control total feed costs and improve pasture health. Clip and drag the pastures after you pull the animals off to control weeds, parasites and flies.
As pasture declines, you will need to adjust the amount of forage that is offered to maintain dry matter intake and nutrient intake. If the forage available is lower protein and lower energy than the pasture has been, you may have to adjust the concentrate portion of the diet. If you are using a ration balancer, you may need to move to the higher feeding rates. If the higher feeding rates do not maintain Body Condition Score and Topline Score, you may need to switch to a different feed to allow higher feeding rates. It is essential to monitor both Body Condition Score and Topline Score.
Declining pasture quality can be a particularly serious issue for young growing horses, pregnant mares and senior horses.
Make certain that fresh clean water is available at all times and that salt is available at all times. If you are not feeding a balanced feed or ration balancer, offer appropriate mineral free choice as well.
If space is very limited, keep a dry lot area where animals can be fed and watered to prevent areas of pasture from being overgrazed.
Managing the pastures and selecting the right feeds as pastures change can help manage total yearly costs as well as improve animal health and condition.
Fall can be a beautiful time of year for horseback riding. However, falling leaves and frost can negatively impact horse health.
Ingestion of dried or wilted, but not fresh, maple leaves is associated with the toxicosis. Dried leaves are not generally believed to retain toxicity the following spring. Toxicosis normally occurs in the autumn when normal leaf fall occurs. Although studies indicate that leaves collected after September 15 are more toxic, cases of toxicosis in horses due to wilted leaves after summer storms have been observed.
Horses are the only species for which maple leaf toxicity has been reported. Horses are often depressed, lethargic, and anorexic with dark red or brown urine after the first day of ingestion. They may progress to going down with labored breathing and increased heart rate before death. Horses should be fenced out of areas where wilted maple leaves are plentiful.
Prunus species (species in the cherry family) contain cyanide and should be removed from horse pastures. Cyanide is released after chewing the plant or seed, or when the plant material wilts (after a frost). Animals are most commonly found dead within minutes to a few hours of ingestion of the plant.
There are no reports of toxicity of horses grazing frost damaged pastures (includes grass and legume species). Frost damaged pastures can have higher concentrations of nonstructural carbohydrates, leading to an increase in potential for founder and colic, especially in horses diagnosed with or prone to obesity, laminitis and Equine Metabolic Syndrome.
To reduce the chance of adverse health effects, it is recommended that horse owners wait up to a week before turning horses back onto a pasture after the first killing frost. Subsequent frosts are not a concern as the pasture plants were killed during the first frost.
Fall provides an ideal time of year to improve horse pastures. August 1st to September 15th is an ideal time of year to seed or overseed pastures and rid pastures of perennial weeds.
Fall is the best time to seed or re‐seed pastures due to the usually adequate moisture, less weed competition and cooler weather conditions.
Fall is also best for perennial weed control since perennial plants are storing carbohydrates in their roots allowing the herbicide to be translocated into the root for effective control.
Make sure to check fences; especially posts. Fix broken posts before they are frozen into the ground. Finally, make sure the pasture grasses have 3 to 4 inches of re‐growth going into winter. This will help with winter survival and a quicker spring growth.
Keeping horses on pastures over winter causes damage to plants and offers the horse little nutrition. Keeping the horses in a sacrifice paddock (dry lot) with access to hay, water and shelter is recommended.
Horse owners should use caution when grazing after the first killing frost of the fall. Frost damaged pasture forages can have higher concentrations of non‐structural carbohydrates following the first killing frost of the season.
This can lead to an increase in the potential for laminitis and colic, especially in obese horses or horses diagnosed with laminitis and equine metabolic syndrome. To reduce the chance of adverse health effects, it is recommended that horse owners wait one week before turning all horses, including healthy horses, back onto a pasture after the first killing frost.