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Managing a large organic dairy herd on pasture

Sarah Flack Published on 11 September 2015

Dairy cows grazingAt the Horizon Organic Dairy Farm outside Kennedyville, Maryland, 480 lactating cows are grazed in a carefully designed and managed pasture system. Providing this many cows with high-quality pasture requires good herd and pasture management skills.

To effectively manage these needs and details, the farm has also carefully invested in and constructed cow lanes, miles of electric fencing and a pasture drinking water system, as well as improved pasture plant species, pasture irrigation and fertile soils.

The farm’s successful grazing system comes down to four key factors that can be considered by other organic dairy farmers managing larger herds: grazing and paddock management, herd and farm investment, well-designed infrastructure and efficient farm management.

Grazing and paddock management

During the grazing season, cows are fed a portion of their daily ration in the freestall as a mixed ration of forages and grain. They get the rest of their daily dry matter intake requirements from pasture. The lactating herd is milked and grazed in four separate groups of about 120 cows, allowing farmers to manage cows with different needs separately. It also ensures that each smaller group doesn’t spend too much time walking back and forth to pastures or waiting around to be milked.

During the non-grazing season, cows are milked three times a day. However, this changes during the grazing season, when part of the herd is milked just twice a day, allowing them to spend more time on pasture to reduce the distances they need to walk.

For example, some pastures on the farm require the herd to walk more than a mile-and-a-half round-trip. During hot, humid summer weather, cows graze only at night and stay inside during the day with fans and sprinklers to prevent heat stress and maintain feed intake.

In an effort to provide better options for the herd, over time the grazing system has been refined so pasture quality is higher. Pastures include annuals such as sorghum-sudangrass and triticale as well as perennial pastures with a high legume content.

Legumes in the perennial pastures provide nitrogen, a particularly important nutrient for an organic farm since synthetic nitrogen fertilizer is prohibited. The high-legume pastures also provide a significant amount of the dairy cows’ protein needs during the grazing season.

The goal of the farm’s grazing system is to provide high-quality pasture to the herd while also using cows to improve the pastures. This requires moving the grazing groups frequently into new pasture. Each new area is then grazed for a short period of occupation, often two days or less in each area.

This lets cows eat about one-third of the pasture and leave the rest behind, meaning the herd can eat the highest-quality forages without damaging the plants by grazing them too short or too often. This is a win-win management system for both plants and cows.

Herd and farm investments

After each grazing, the paddock may be clipped if needed to control weeds or excess plant residue. After each grazing/clipping cycle, the paddock is then left to regrow for three to five weeks.

The length of the regrowth period is varied depending on how fast the pasture plants are growing and is managed carefully so animals don’t return to the paddock too soon. This long recovery period, combined with short-duration grazing, provides high-quality forage to the cows while also using the cows to improve the health of the pasture plants and soils.

Moving four groups of cows to a new pasture daily and then letting each area regrow for more than three weeks can quickly add up to a large amount of paddocks and fence in use on the farm. This system also requires drinking water in each paddock and lanes that can handle a lot of hoof traffic. In addition, during dry periods it is necessary to run irrigation, and when there is excess forage or weeds, mowing is required.

Fencing for the many paddocks is done with high-tensile permanent fence along the lanes and around the perimeter of large fields. Portable poly wire and posts are used to create interior paddock subdivisions. Portable fence allows flexibility on paddock sizing as the grazing group sizes change throughout the grazing season.

Lanes and piped drinking water are also needed to make the system work. Multiple groups of cows use the same lane, so once each group is grazing, the gate is closed so they stay in the paddock while other groups can use the lane.

Well-designed infrastructure

While in the paddock, cows need a good supply of drinking water. This is provided by two large portable tubs with float valves in each paddock. Water lines are buried under the lanes so these portable tubs can be connected to a high flow rate of water anywhere on the farm.

Lanes require good design and solid construction to withstand four groups of cows walking back and forth to the barn multiple times each day. To limit these impacts, most lanes have road-building fabric under a solid layer of fine gravel.

The majority of pasture on the farm can be irrigated when necessary using two center pivots. Without irrigation, the farm would have to allow much longer regrowth periods for pasture plants during dry weather. This would make it much more challenging to provide enough high-quality pasture to 480 cows.

However, the logistics of irrigating a pasture that has been subdivided into many small paddocks is not always an easy task. Taking down the fence each time the irrigation is run isn’t practical. To solve this, several modifications to the fences were made that allow the wheels of the center pivots to run over the fences instead of having to move fence out of the way.

Efficient farm management

In order to keep track of all the animal groups, feeding, milking and herd movement, there is an extensive record-keeping system on the farm. Farm maps, which also include names for all the paddocks, are posted in several locations on walls in farm offices. This makes it easier for farm staff to communicate with each other about which paddock each group grazes in, as well as which areas are being clipped, irrigated or allowed to regrow.

The farm keeps extensive records of just about everything as part of its management system. These include details about which pasture is grazed and by which group, along with milk production and feeding records.

By closely monitoring pasture quality and cow performance, farm managers are able to adjust the supplemental ration fed to each group every day. For example, when cows are getting more protein from a high-legume paddock, protein in the ration will be reduced and more energy will be added.

These records are kept primarily as a helpful tool for the farm staff to manage cow performance and well-being. However, these records also play an important role in maintaining the farm’s organic certification, which includes regular inspection by an organic certifier.

For both organic and conventional farms, a well-designed and managed dairy grazing system can provide a myriad of important, positive results for the health of a herd, the health of a farm and the bottom line of costs and farm management.  PD

Sarah Flack is a consultant specializing in providing practical information on grass-based and organic livestock production. She has a diverse background in sustainable agriculture, which includes both on-farm and academic experience. She is currently writing a book on the subject of grazing methods, which will be published later this year.

PHOTO: Photo courtesy Horizon Organic Dairy Farm.

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