Sarah Flack, Sarah Flack Consulting
Adapted with permission from: Mendenhall, K. (ed.) 2009. The organic dairy handbook: a comprehensive guide for the transition and beyond. Northeast Organic Farming Association of New York, Inc., Cobleskill, NY. (Available online at: http://www.nofany.org/organic-farming/technical-assistance/organic-dairy, verified 18 July 2012).
The methods of pasture management on organic dairy farms vary from large extensively grazed pastures to simple rotational systems to management intensive grazing (MIG) where cows are moved to fresh pasture twice or more every 24 hours (see Table 1).
The information in this article will emphasize the MIG system of grazing management. It is also possible, however, to use this information to set up a less intensive system that still provides enough pasture to meet farm goals. If a less intensive grazing system is the choice, additional acres per cow will be needed since the productivity of the pasture will be lower. Additional land will need to be added to the grazing rotation as plant growth rates slow in summer. The type of pasture system used should be determined by the farm’s overall goal and the production objective for the livestock.
When compared to MIG, the extensive grazing or large pasture system requires less daily management in moving the cows, fence, and water tubs. However, extensive systems require more acreage of pasture, more clipping and may require occasional pasture renovation over time due to overgrazing damage. Extensive grazing systems, particularly systems where cows continuously graze the same pasture for most of the summer, provide lower total dry matter intake and more variable feed quality. These types of systems generally result in lower milk yields and profitability, but require less day-to-day management.
A rotational grazing system is NOT the same as a Management Intensive Grazing (MIG) system. The major different is that in a MIG system, close attention is paid to how fast plants are growing. The number of days pastures rest after each grazing increases significantly as growth rates slow. One of the key guidelines of a successful grazing system is variable recovery periods.
A few organic dairy farmers use a type of grazing called “Holistic Planned Grazing.” This system will also produce high quality pastures and may be particularly useful to farmers who experience extended drought conditions. This method of grazing requires specific planning, mapping, and recordkeeping to monitor the grazing season.
Good grazing management such as MIG will favor the better pasture plant species, reduce weed problems, and increase the quantity of pasture dry matter produced while improving the nutritional quality of the feed. A high quality pasture, particularly with good soil management, will produce feed with the highest nutritional value and vitality so that animals are healthy and the meat, milk, and manure produced is of the highest possible benefit to the farm.
A good quality MIG pasture will contain a mix of many plant species, no bare soil, and will have uniformly distributed cow pies from the most recent grazing. The pasture will have patches that were not closely grazed during the last grazing, since cows do not like to eat the grass right next to their manure.
In a continuously grazed or simple rotation system where plants are not allowed to recover fully between grazings, there are more likely to be patches of bare soil, less desirable grass and clover plants, and increasing weeds. Patches will appear that never grow very tall, and clover and other legumes may be completely absent. These are all symptoms of overgrazing damage. There may also be a buildup of dead plant material or thatch on the soil surface and cow pies that have not decomposed quickly.
|Continuous Grazing||Rotational Grazing||Management Intensive Grazing (MIG)|
|Cows are in the same paddock for the whole grazing season.||Cows are rotated around several pastures, usually on a set rotation. Recovery periods are not varied as plant growth rates slow.||Cows are moved to a new paddock only when it has fully regrown. They are moved at least every 3 days. Recovery periods are variable.|
|Cows will graze selectively, making it difficult to balance the ration. Pastures will generally provide enough feed in spring, but later in the summer pasture will be too short, or too over-mature to provide enough dairy quality feed.||Cows may have adequate DMI and pasture quality in the spring, but as plant growth rates slow the pastures will be too short or plants will over-mature and provide less dairy quality feed.||Cows will have adequate DMI and pasture quality throughout the grazing season.|
|Pasture quality and quantity will significantly decline as the season progresses.||As cows rotate back into pastures that are not fully regrown the quantity and quality of feed will decline.||Cows only rotate back into pastures that are fully recovered. Additional acres will be added into the grazing rotation as growth rates slow.|
|Pasture quality will decrease each year due to overgrazing damage, increased weeds, and rejected forage. Clipping and reseeding may be needed.||Pasture quality will decrease each year due to overgrazing damage, increased weeds, and rejected forage. Clipping and reseeding may be needed.||Pasture quality will improve over time.|
This article is part of a series discussing pasture management on organic dairy farms. For more information, see the following articles.
This is an eOrganic article and was reviewed for compliance with National Organic Program regulations by members of the eOrganic community. Always check with your organic certification agency before adopting new practices or using new materials. For more information, refer to eOrganic's articles on organic certification.