Forage and Floods – After the Water Recedes

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:

  1. 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.
  2. 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.
  3. 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.
  4. 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.

Recommendations:

  1. Clean and disinfect flooded facilities as soon as possible. Make certain structures are sound before entering to work on them.
  2. Remove debris from barnyards, pastures and fields. Unfortunately, no easy solution!
  3. Make certain the ground has dried enough to support vehicles before driving in flooded areas.
  4. 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!
  5. 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.
  6. Be extra vigilant when feeding baled forages that have been harvested off of ground that has been flooded.
  7. 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.

Additional pasture management resources can be found at the University of Minnesota Extension Horse Program website.

Ask the Expert: Parasites and Pasture Management

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.

This article is reprinted with permission from Krishona Martinson, PhD, University of Minnesota. This and other horse nutrition articles can be found at http://www.extension.umn.edu/agriculture/horse/nutrition/.