Let’s look at the facts. Grain commodity prices are the highest in recent memory. Marginally producing hay plots could quickly be plowed to grow corn this year rather than alfalfa or grass hay. If this occurs, can you guess where the price of hay is headed? The solution may be not just pastures but ‘well-managed’ pastures. Well-managed, irrigated perennial pasture may provide an overlooked alternative to producing high-quality forage to help balance feed requirements. Our purpose is to provide you with a few ideas to achieve the goal of well-managed pastures for dairy cows.

Regardless of the perennial grass and legume species in your current pasture or if you’re planning to plant new pastures this year, do not allow overgrazing. We can’t stress this enough. Irrigated pastures will no longer be a less expensive feedstuff for your lactating or dry cows or growing heifers, because just like growing hay, time (days) is required for regrowth to occur.

Hopefully, you’re planning on using a type of rotational grazing system where dairy animals are moved from one paddock to another. (There are several systems available.) As dairy livestock graze one paddock, the others paddocks are resting and regrowing forage for the next grazing event. The other option we too often see is continuous, season-long grazing, when dairymen leave livestock on the pasture so long without any management, the pasture has no time for regrowth. Now, you may be thinking, “If I just use rotational grazing, then I’ll never overgraze my pastures.” Wrong! Overgrazed pasture plants can occur in the same pasture within a few feet of well-managed or even overgrown (rank and mature) pasture plants. Here are a few ideas to avoid overgrazing.

Most dairymen are checking fields more closely with soil tests than years ago. However, you may not have tested the soils in currently used pastures or where new pastures will be planted. Imbalances of nutrients and soils with either too high or too low a pH increase stress on the growing forage plants which can impact pasture production. Balanced soil nutrition results in more uniform plant growth and quality, reducing overgrazing. By using a combination of soil test results and walking each pasture, you’ll observe nutrient deficiencies, providing a more comprehensive view of each pasture’s nutritional status.

Nitrogen (N) deficiency in perennial, cool-season grasses is visible by a yellow color, just like sulfur (S) deficiency. However, N deficiency will appear on the oldest plant tissue while S deficiency appears yellow on the newest growth. Sometimes you’ll see yellow on both parts of the plant. Phosphorus (P)-deficient grasses and legumes will be stunted; often purple hues can be found on the leaf tips, leaf margins or even the stems. Potassium (K) deficiency starts with a burnt look on the leaf tip then migrating down both margins (sides) of the leaf. The center portion of K-deficient leaves will finally turn brown in color.

Unless you’re practicing management intensive grazing, recycled nutrients from the grazing dairy animal are often not uniformly spread on pasture. Harrowing is another tool to use in manure or nutrient management of pasture. An alternative to skyrocketing nitrogen prices or organic pasture include adding legumes into the pastures. Legumes have the ability to fix N during the growing season, supplementing N coming from the urine. Both N sources will stabilize grass and legume yield and quality potential. Be proactive in your soil and plant nutritional approach and you’ll go a long way in developing a well-managed pasture.

Drinking water must be available in each paddock. Lactating dairy cows can drink 35 to 45 gallons of water per day; but this can increase in the summer when pastures are not as lush as in the spring or fall. Dry cows and heifers need about 20 to 30 and 10 to 15 gallons per day, respectively.

The system delivering drinking water to your paddocks should be of adequate size to provide at least these daily amounts while animals are grazing. Quality of the drinking water is important.

The NRC 2001 set safe drinking water standards for nitrate concentrations at less than 44 parts per million (ppm) or 45 to 132 ppm as safe, if the animal’s diet was low in nitrates. When nitrates in the drinking water ranged between 133 and 220 ppm, harm could come to your grazing dairy animals, if exposed to the nitrates for a long time. This becomes a concern with overgrazed pastures.

Grasses grow by taking up large quantities of nitrate during regrowth then move them to the new growth as it occurs. Depending upon the soil fertilization program, new or old pasture growth can be high in nitrates. A combination of high-nitrate drinking water, along with high-nitrate pasture due to overgrazing, may be just explanation for lower milk production or sudden deaths occurring while dairy animals are grazing on pasture.

Placement and number of cross fences is one more key ingredient to a well-managed, irrigated pasture. Many more irrigated pastures are presently under center pivots. New innovations in electric fencing make pivots safe and efficient for grazing. We encourage you to work with both fencing and pivot contractors when setting up new pastures under center pivots.

One thought to keep in mind, depending on the class and number of dairy animals to be grazed: You’ll likely have more than one forage species to be grazed. Match the best pasture species to individual fields (recognize each field has limitations) in order to meet the yield and quality goals you have for your dairy cows. Try to keep at least eight paddocks per pasture mix, either within or between pivots, so each mix can be grazed and rested appropriate to the growth patterns and month of the season.

Finally, stubble height or the height of the pasture after grazing is completed should not be less than three to five inches tall for most irrigated, cool-season pastures.

We view the bottom three inches of plant stubble and crown as the plants’ bank account. The bank account in this case is for sugar and non-structural carbohydrate storage. By overgrazing to less than three inches, the bank account is robbed, resulting in slower regrowth, with more days wasted before the pasture is ready for the next grazing cycle. This creates greater stress on the plants, greater variation in pasture quality, greater chance for weed invasion (especially in the fall), increased chance of nutrient losses, quicker stand decline and more.

The only good thing about overgrazing is that if you’re practicing your tee shots you can easily see the white balls in the field! Well-managed irrigated pastures can make a major contribution in the dairy operation, if you’re willing to manage it as well as you mange the rest of the dairy. PD