Northeast Organic Dairy Producers Alliance




Grazing is Good for the Environment, Right?

By John M. Thurgood, NYC Watershed Agriculture Program

Grazing has many environmental benefits. However, not all grazing practices are good ones. Some can lead to substantial degradation of natural resources. Let's start our discussion with why grazing does makes environmental sense.

Environmental benefits of grazing
Grazing livestock on high quality pasture reduces the amount of purchased grain being imported to the farm. The decreased import of nutrients reduces the phosphorus and potassium build-up on the land over time. Land that has excessive levels of phosphorus and potassium is prone to leaching and run-off into streams.

Grazing can allow you to distribute manure where a manure spreader can't reach. Most dairy farms in New York have more nutrients in manure than they need for crop production, so distributing manure on pastures utilizes these excess nutrients and reduces nutrient accumulation on cropland.

Grazing farmers tend to have grass based forage systems, which reduce the amount of erosion they experience compared to farms growing crops in rotation. Since they don't grow much if any corn, they tend not to use pesticides for crop production.

Having livestock harvest feed themselves reduces the need for mechanically harvested forage. This reduces the use on non-renewable fossil fuels, and decreases the wear and tear on equipment and human resources devoted to crop production. Farmers tell me that it takes less time to build and move fence than it takes to harvest, store and feed forages.

Grazing farmers also tend to use less electricity. When animals are out on pasture, they are not in mechanically ventilated and artificially lighted barns that may use a considerable amount of electricity.

Grazing dairy farmers report that they have lower culling rates compared to when they continuously housed their cattle in the barn. The lower culling rate means that fewer resources need to be devoted to raising dairy replacements. If we assume that $1,500 is the value of a good dairy replacement, then economics would say that just about $1,500 worth of resources have been devoted to raise the animal. Grazing conserves these resources.

Finally, when animals graze they manure on the countryside and only limited odors are generated. This is in contrast to the odors made when a spreader load of manure is applied to the land. Manure odors are attracting more attention as a form of air pollution. In addition to reducing odors, people that live in and visit rural areas say that they love to see cattle on the land. Cows on the land help to enhance neighbor relations and in a broader context, may lead to greater tourism and the economic benefits from the tourism industry. This tourism then leads to a more economically vibrant rural community.

Grazing pitfalls
OK, so that's the positive side of grazing. How can this very positive animal husbandry practice go wrong? As you might expect, problems usually involve manure.

Manure from poorly engineered laneways can flow off into streamcorridors. This is especially true since laneways are commonly placed on the edge of pastures, and these borders often have a stream, or drainage ditch associated with them.

This same type of run-off can occur when waterers are place on the edge of pastures, or in laneways. Manure from grazing animals can be concentrated in small areas if there are limited watering sites, or if livestock are not rotated in relatively small paddocks where they are then forced to eat all of the plants, and in-turn, manure over the whole area of the paddock.

Over-grazing of pastures can lead to areas of bare ground that run-off with significant rainfall, or snowmelt. With this run-off goes manure nutrients and sediment, possibly polluting nearby streams.

Finally, livestock that are allowed unlimited access to streams, lakes and ponds, make significantly "deposits" of manure directly into the water. So, grazing can, in fact, lead to very severe environmental degradation. The good news is that these potential environmental concerns can be at least reduced and at best eliminated.

Constructing laneways away from the edges of pastures will reduce run-off to streams and ditches. On slopes, make use of broad-based-dips to divert water from the laneway at regular intervals. These dips will also reduce your longer-term maintenance on the laneway, since you will be protecting the lane surface from erosion.

Building the laneways on an angle up the slope will improve drainage and reduce the erosive power of water moving down the laneway. Moving livestock through alternate traffic routes can, in some cases, eliminate the need for an improved laneway. This may be less feasible with dairy cattle that move to and from the barn twice each day.

A farmer gave me a really interesting idea on how to keep manure out of your laneways and in your pastures. When bringing his cattle off pasture, he allows them time to stand up and loaf for about five minutes before leaving the paddock. When cattle stand after having been resting, they almost always& well you know. Here's his point, he would rather have the manure nutrients in his pasture, feeding plants, than in the laneway. Is it worth the extra five minutes? He thought it was.

Place waterers away from streams and drainage areas to allow for buffering of run-off from these areas. We all know that when a cow drinks, the cow will generally manure. Avoid placing waterers in draws in the pasture. Finally, have many watering points. The more sites for water, the better will be your distribution of manure.

So, what causes overgrazing and bare ground on pastures? Is it having too many animals? Not really. It's not giving the plants in the pasture enough time to re-grow between grazings. This lack of rest leads to a shallower root system and less vigorous plant growth. Over-grazing tends to push plant species over years of grazing to those of shallower root systems, such as bluegrass and white clover. Bluegrass is less drought-tolerant than deep rooted species such as orchardgrass.

So, overgrazing leads to plant species that are more susceptible to environmental factors such as drought, and keeps these plants in poor condition with short root systems. Over a period of years, this leads to bare ground and unproductive pastures. The solution is to allow your pastures enough rest so that they will grow vigorously. If there isn't enough forage in the paddock to meet nutrient needs of your cattle, and "you have to move them," it is better to provide supplemental forage than to move them to a pasture that is not ready.

Access to streams and crossings
Cattle that have unlimited access to streams can create significant environmental havoc. The direct deposition of manure into the stream can be considerable. Penn State graduate student Erin James has researched cow manuring in streams. She relates that there are may factors that affect the direct amount of manure deposition including the size of pasture, width of the stream, location of shade, supplemental feed, alternative water supplies, etc.

This being said, her research on a farm in the NYC Watershed shows that a when a cow is on pasture with unlimited access to the stream an average of 3-5 percent of the cows flops are direct deposited into the stream. So, working the numbers of a 50 cow Holstein dairy herd, on pasture 18 hours a day with unlimited access to the stream, about 6 to 10 tons of manure can be deposited over a six month grazing season. Wow, that's two to four spreader loads!!!

Where cattle have access to streams it is common for stream banks to become unstable and slough off. The streambank is no match for the power of the hooves of a 1,500 pound cow. Stream banks are even more prone to eroding since they are covered in many cases by overgrazed grasses that have shallow root systems.

The most effective solution to direct deposition and unstable streambanks is, you guessed it, fencing. Financial assistance for cattle exclusion and establishment of riparian forest buffers is available from the Farm Service Agency through the Conservation Reserve Incentive Program (CREP). Cost sharing money is available for fencing, alternative water supplies, cattle crossings and tree planting. Total exclusion with alternative watering sites is far and away the best option to protect stream health and water quality. If total exclusion isn't feasible, providing limited access points is a big help. By only allowing 2-3 cattle to water at a time, the cows will tend to push each other on, so cows tend to drink and go, and not linger in the stream.

Cattle pressure on streams can be reduced somewhat without fencing. Providing alternative water in the pasture away from the stream corridor tends to draw cattle away from the stream. If your stream corridor is wooded, having shade areas away from the stream will give animals an attractive alternative to the stream. Still, these approaches are not nearly as effective as fencing.

Cattle crossings can be significant sources of pollution. If the crossing has stable banks, the only action needed may be to limit the width of the crossing, so that the cattle push each other across the stream. Unstable banks should be protected in some manner. Alternatives include shaping and applying some form of aggregate, use of cattle slats, or building a bridge. Your decision on which alternative is the best for you really depends on the specifics of the site, the number of cattle using the crossing, the frequency of use and what you have to spend.

Feeding Areas
Permanent supplemental feeding areas in pastures should be avoided because they tend to become denuded and nutrients tend to build up at these sites. The slickest solution I've seen is using a three-point hitch mounted bale unwrapper in the field. The bale is unwrapped in a different location each feeding. Moving large round bale feeders or feed wagons can generate similar results. If you have to use the same site on the longer-term, a concrete pad with buckwall at the feeding area will allow you to collect and spread the nutrients. Plan for a 300 foot natural filter area below the permanent feeding site.

So is grazing good for the environment?
With thorough planning and management, you bet!!! Avoiding the pitfalls will ensure that you are maximizing the environmental benefit of grazing.

John M. Thurgood is a Senior Whole Farm Planner with the NYC Watershed Agriculture Program. This article first appeared in the Winter, 2004 issueof Small Farm Quarterly and is reprinted by permission of Cornell Small Farms Program. For more information on a variety of small farm topics, visit or contact: John Thurgood, CE NYC Watershed Agriculture Program, 607-865-7090,



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