| Table of Contents | Preface | Background | Definitions | Implementation Guidelines |
| MDS I Calculation Form | MDS II Calculation Form | Factor Tables | Appendix & Additional Information |

Separation siting of Ontario livestock barns originated in 1970, with the introduction of the document "A Suggested Code of Practice". Ontario was experiencing what at the time seemed like a proliferation of new, large livestock and poultry barns. 'Large' at that time was 600 feeder hogs, 60 dairy cows, or 15,000 chicken broilers. These seem small by today's standards. Today, large barns are commonly triple the size of those of the past, accommodating 2,000 feeder hogs, 250 dairy cows, or 50,000 chicken broilers at one time. To address nuisance effects associated with odour, A Suggested Code of Practice recommended fixed minimum separation distances between livestock or poultry barns and neighbouring houses, residential zones, lot lines and roads.

A Suggested Code of Practice encouraged farmers to apply for a Certificate of Approval from the government. The Certificate outlined the minimum amount of land required based on the avoidance of risk to ground water pollution by compounds of nitrogen, and the number of animal units on the farm. A Suggested Code of Practice rationalized that the effect of objectionable odours in a neighbourhood could be reduced if livestock and poultry facilities were located as far as practically possible from nearby dwellings. It recommended simple, fixed minimum separation distances for both the proposed barn and manure storages.

Revisions were made in a subsequent edition of A Suggested Code of Practice in 1973. While it contained a framework for the establishment and expansion of livestock enterprises, it provided little protection from encroachment by other land uses. In 1976, the Agricultural Code of Practice was published which incorporated a number of changes and provided a two-way approach to separating livestock and poultry barns from non-compatible uses and vice-versa. It introduced the concept of a sliding scale for separation distances, since fixed distances were too restrictive, or too lenient, depending on the size and type of farm.

In 1976, the Minimum Distance Separation I (MDS I) formula was established to determine the minimum separation distances between proposed new development and existing livestock facilities and/or permanent manure storages. The Minimum Distance Separation II (MDS II) formula was developed to determine the minimum separation distances between proposed new, enlarged or remodeled livestock facilities and/or permanent manure storages and other existing or approved development.

Both formulae were updated slightly in 1995 in two documents entitled, Minimum Distance Separation I (MDS I) and Minimum Distance Separation II (MDS II) but the basic principles of the formulae remained the same.

This document replaces all earlier versions of the MDS Formulae.

A review of this document will be undertaken by OMAFRA every five years to ensure the document reflects current land use planning practices and technological innovation within the livestock industry, and continues to meet the needs of agriculture and rural communities.

Note to the User Regarding CD Software

To assist municipalities, farmers, consultants and the general public, as a public service, OMAFRA has developed a software program for distribution and use with the MDS Formulae. The 2006 version distributed by OMAFRA will be considered to be the official version for purposes of calculating MDS. OMAFRA is not responsible for errors due to inaccurate or incorrect data or information; mistakes in calculation; errors arising out of modification of the software, or errors arising out of incorrect inputting of data. All data and calculations should be verified before acting on them.

Figure 1. New urban development meets an existing livestock facility.

| Table of Contents | Preface | Background | Definitions | Implementation Guidelines |
| MDS I Calculation Form | MDS II Calculation Form | Factor Tables | Appendix & Additional Information |