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Building a horse barn is a significant undertaking and there are many aspects to consider. An important consideration is the management of manure and runoff. A nutrient management strategy (NMS), in addition to being a legal requirement for most barns, will help you manage your manure and runoff according to the regulations and the needs of your operation in the future.

Nutrient management strategies

A nutrient management strategy (NMS) identifies:

  • how much manure is produced and stored on the farm
  • contact information for the owner and operator of the farm
  • siting of new barns and manure storage facilities in relation to sensitive features such as wells and surface water
  • how runoff is managed
  • an overview of the landbase that the manure is applied to or other locations
  • a contingency plan for unforeseen circumstances or emergencies

Farms with greater than 5 nutrient units (NU) require an NMS before submitting an application for a building permit for a building or structure used to house horses or store manure. Figure 1 shows one type of manure storage. An approved NMS is also required for these types of building projects in unorganized townships even though a building permit is not required.

Approval of the NMS by the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) is required for any building project involving livestock housing (barn) or a manure storage facility.

This photo shows a 3-walled cement pad, located close to the bar. Reinforced concrete walls make it easy to push against with a front end loader, and the concrete floor provides for trouble free entry and exit.
Figure 1. A 3-walled manure storage with reinforced concrete walls, located close to the barn.

For horses, nutrient unit calculations are shown in Table 1. Small framed animals such as Shetland ponies are 2 ponies equals 1 nutrient unit (NU). Medium framed horses such as riding and pleasure horses are 1 horse equals 1 NU. Large framed horses such as Clydesdale or Belgians are 0.7 horses equals 1 NU.

If you are building a barn for 8 Belgian horses, this is 11.4 NU (8 horses divided by 0.7 NU factor for large frame horses = 11.4 NU).

Table 1. Nutrient units
Type of horse
(unweaned foals are included with the mares)
NU factorNumber of animals needed to exceed 5 NU
Small framed
(i.e., Shetland pony)
Medium framed
(i.e., typical riding or pleasure horse)
Large framed
(i.e., Clydesdale or Belgian)

For farms with other livestock species and/or mixed livestock operations, call the Agricultural Information Contact Centre at 1-877-424-1300 for further information.

There are a few situations where a Nutrient Management Plan (NMP) is also required. The NMP details how manure, fertilizer and other nutrients are applied to a given land base. It is a five-year plan that lists the characteristics of the land, crop rotation, and cropping and nutrient application practices. It enhances the use of nutrients by crops in the field and reduces environmental impacts. An NMP is required:

  • on farms with 300 NU or greater
  • if an NMS is required and the farm is located within 100 m (328 ft) of a municipal well

Because there are relatively few equine farms that are required to have NMPs in Ontario, this factsheet will focus on the requirements for an NMS.

NMS preparation and approval

Nutrient management strategies must be prepared by an individual certified under the regulations of the Nutrient Management Act, 2002. There are two choices for certification for a farmer:

  • Take the necessary courses to prepare the NMS.
  • Hire a certified consultant to prepare the NMS.

See for a list of certified consultants. Once the NMS has been prepared, send it to OMAFRA in Guelph for approval.

Farmers preparing their own NMS can use the Agrisuite software available from OMAFRA. A two-day training course is offered on how to use Agrisuite. Another option is to use the OMAFRA Nutrient Management Strategy Preparation Workbook to work through the NMS on paper. To order a copy, contact the Ridgetown Campus of the University of Guelph at 519-674-1619, or toll free 1-877-480-9992.

For more information on consultants, nutrient management courses or who to contact for information on nutrient management, call the toll-free Agricultural Information Contact Centre 1-877-424-1300 or see the Nutrient Management section at

Implementing the NMS

The NMS is a legally binding document. Once the building permit has been applied for, the manure must be managed in accordance with the NMS.

For example, if the NMS indicates that manure is going to be picked up regularly by a certified broker, the farmer is under a legal obligation to have the manure picked up by a broker. If the situation has changed and the broker is not able to pick up the manure, the farmer is still legally obliged to manage the manure according to the approved NMS. The farmer could make alternate arrangements for the manure to be picked by another broker or neighbouring farmer or apply the manure on the horse farm fields if available. These options should be part of the contingency plan for the NMS and help the farmer adjust and change over time while still meeting regulatory obligations.

By February 15 of each year, the farmer is required to review the NMS, summarize the activities of the previous year, keep a written record of this summary and note any updates to the NMS for the upcoming year and keep this annual record with your NMS documentation on the farm for future reference.

An NMS can be valid for a long period of time. For example, an NMS remains valid until there is a change in ownership or when expansion of a livestock barn or manure storage is planned, and a newly approved NMS is required showing details of the expansion.

At any time, farmers planning a change on the farm that would require an NMS — for example, adding livestock housing or manure storage facilities — must submit a revised NMS, prepared by a certified person, for approval before making any changes to the farm.


Prepared prior to obtaining the building permit, a nutrient management strategy proactively addresses manure management for horse barn facilities. It takes into consideration nearby water resources, manure storage capacity, runoff management, land application and other destinations for the manure from your farm, along with a contingency plan. The benefits of a well-thought-out NMS can be realized for years after construction is completed. Integrating manure storage and runoff management at the start of the project reduces risk to nearby water resources, reduces the potential for complaints from neighbours and improves the ease with which daily chores are completed.

For more information on the NMA, contact the Agricultural Information Contact Centre toll-free at 1-877-424-1300 or e-mail

Nutrient management disclaimer

The information in this factsheet is provided for informational purposes only and should not be relied upon to determine legal obligations. To determine your legal obligations, consult the relevant law, If legal advice is required, consult a lawyer. In the event of a conflict between the information in this factsheet and any applicable law, the law prevails.

This factsheet was written by Peter Doris, Environmental Specialist, OMAFRA, Brighton, and reviewed by Dale McComb, Environmental Specialist, OMAFRA, Guelph.