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.
2017 has been a challenging year in many parts of the country with excess rain and some widespread flooding. Several of the potential impacts of flooding are forage issue that may remain long after the water has receded.
Potential Forage Hazards:
Flood waters may deposit detrimental contaminants on pastures, fields and stored forage. Some of these hazards might include pesticides, dead animals, industrial waste, untreated sewage and silt.
Forage harvested after being flooded may still have some of the contaminants present on the lower portion of the forage. Any debris washed into the field, if not removed prior to harvest, may be accidentally baled up in either round bales or square bales. Even clean silt clinging to the forage may increase the ash content of the forage.
Stored forage, particularly round bales or the lower level of hay stacks may become saturated with moisture, leading to mold issues and potential organic matter decay.
Organic matter that is baled into forage, particularly round bales, may create an opportunity for clostridium botulinum bacteria to multiply anaerobically as the organic matter decays. This bacteria produces the deadly botulism toxin, one of the most potent toxins produced in nature.
Clean and disinfect flooded facilities as soon as possible. Make certain structures are sound before entering to work on them.
Remove debris from barnyards, pastures and fields. Unfortunately, no easy solution!
Make certain the ground has dried enough to support vehicles before driving in flooded areas.
If stacked hay or round bales have been soaked, do not feed the affected bales. If bales must be fed (i.e. emergency forage needs), monitor consumption closely and avoid spoiled areas. If in doubt, throw it out!
If harvesting forage from fields that have been flooded and dried out, be very vigilant when mowing and conditioning the forage. You may have to wait a few extra days to allow plants to recover. If there is silt on the lower stem areas, consider leaving longer stubble. Local Agricultural Extension Educators may have specific recommendations for specific locations and for types of rakes that do a better job of reducing ash content.
Be extra vigilant when feeding baled forages that have been harvested off of ground that has been flooded.
You may want to soil test fields and pastures to see if lime or fertilization will be useful.
If rainfall patterns change, flooding may become more common. Extra vigilance and management may be required to keep horses healthy in these challenging conditions.
Useful Reference: Barnhart, Stephen K. “Summer Flooding of Hay Fields” Integrated Crop Management News, Iowa State University Extension and Outreach, June 2008.
Question: My two horses tested high in their fecal egg counts; I dewormed them regularly. We had a mild winter and they were still foraging on the pasture. I am wondering if I am managing their manure badly? We drag the manure piles in the pasture, but are we spreading out the parasite eggs and making it worse?
Answer: Good pasture management can help reduce parasites, especially stronglyes. Strongyle larvae develop within the manure pile, migrate onto pasture forages during wet weather and wait to be ingested by horses. Rotational grazing, avoiding overgrazing and ideal stocking rate can help to reduce strongyles. We recommend initiating grazing when pasture grasses are between 6 to 8” tall and rotating horses to a new pasture (or a drylot) when most of the forage has been grazed down to 3 to 4” tall. A pasture where most of the forage is below 3” tall is considered over‐grazed. This is especially important when managing strongyles as larvae tend to inhabit the lower part of forage plants. Allowing your horses to graze a pasture during the winter months (when forage re‐growth is not possible) may have resulted in over‐grazing and ingestion of parasite eggs. We recommend a stocking rate of 2 acres of pasture per adult horse. If the pasture is well managed, this should result in not needing to supplement hay during the grazing season. Parasite populations tend to be greater if the pasture stocking rates are higher (less than 2 acres per horse), especially in over‐grazed pastures. Since you have two horses, ideally you would have at least 4 acres of pasture.
Dragging is a recommend pasture management activity. Dragging is necessary to disperse manure piles since horses will rarely graze near these areas. However, to help reduce the parasite load, dragging should be reserved for hot and dry periods of the summer. A few weeks of high temperatures and limited rainfall after dragging will help kill strongyle larvae. During this time, it’s important to remove the horses from the pasture. During wet periods, horse owners should remove the manure from the pasture weekly, if possible. This may not be practical in all situations, but may be necessary in high‐risk scenarios.
We suggest you continue to work with your veterinarian and use your fecal egg count results to strategically deworm your horses. Implementing a rotational grazing program, avoiding overgrazing, dragging manure piles during hot and dry periods and confining your horses to the drylot during the winter months should also help reduce the parasite load in your pasture and horses.
Question: I’ve heard conflicting recommendations on when to start grazing my horses. Is April 1st too early to start grazing? Answer: Spring grazing should be introduced slowly and delayed until grasses reach 6 to 8″ to optimize both the health of the horse and pasture. Calendar date is not important as weather conditions and grass growth can very greatly from year to year.
When pastures reach 6 to 8″, begin grazing for 15 minutes, increasing the grazing time each day by 15 minutes until 4 to 5 hours of consecutive grazing is reached. After that, unrestricted or continuous grazing can resume.
We also recommend feeding horses their normal hay diet before turning them out to pasture during the first several grazing events of the year. This strategy should help avoid rapid intake of pasture grasses.
Even though hay and pasture are both forms of forages, there are significant differences. A gradual change from one feedstuff to another provides enough time for the microbial populations to adjust, reducing the chance of colic and laminitis.
Managing pasture can be a very important tool in controlling feeding cost for all livestock, particularly 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 1100 pound adult horse.
There are a number of key steps in managing pastures, particularly small acreages
Do not turn the animals out on pasture too early in the spring. Forages need some growth to recover from the winter and allow root systems to develop.
Do not turn animals out on tall cool season grasses such as brome grass and orchard grass until the plants are 8-10 inches tall.
If pastures are short cool season grasses such as Kentucky blue grass or rye grass, the plants should be 6-8 inches tall before grazing.
If you do not know your pasture composition, err on the side of allowing adequate growth before grazing.
Remove animals from the pasture when plants are grazed down to 3-4 inches in height. Grazing too early or 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, requiring expensive renovation.
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 section to allow the first section to recover, total pasture yield can be increased substantially, helping to control total feed costs.
Clip and drag the pastures after you pull the animals off to control weeds and control parasites and flies.
A small investment in supplies to allow pasture to be managed and rotated can pay for itself in higher pasture yields. Managing the pastures and selecting the right feeds can help manage total yearly costs as well as improve animal health and condition.