Plan now for the summer slump


What are you going to do this summer when growth in your cool-season pastures slows down? What will you do if they stop growing altogether sometime this summer?

You must be thinking, “Aw come on man, why are you asking me that when spring has barely gotten into gear?”

The answer is simply that a little advance planning in the next few weeks may solve some huge headaches later this summer.

Weather records indicate that moderate droughts occur more frequently than we care to admit. Even in summers with average rainfall, cool-season grass growth slows. So why do we often seem surprised when pasture growth is insufficient in the summer?

What to do?

There are some very basic, but extremely important management practices that keep pastures healthy and more tolerant of summer stresses. These include: adequate soil fertility, proper rest periods, and not applying nitrogen in dry weather.

But one of the most important is to not overgraze. If you leave plenty of leaf area after grazing, the pasture will recover faster and roots will keep growing. Removing 50 percent of the shoots stops root growth.

So don’t overgraze your pastures even when soil moisture is adequate, but especially under dry conditions.

Overgrazing will surely limit recovery after a dry spell, which just prolongs the agony. Have a plan to avoid grazing your cool-season pastures too short during dry weather. This may involve sacrifice paddocks where you can feed hay or other feeds.

Your plan should also include establishing species that handle dry weather better than cool-season grasses.

Using alternative species

Cool-season grasses will have slower summer growth even with good management and average rainfall. They will stop growing altogether if rainfall is too short.

I suggest a good strategy is to have a small portion of your pasture acreage in species that are known to be more productive in the summer.

In the rest of this article I will discuss several good options for improving summer forage supply. I will begin describing some annual species, because you can plant and use them this year. Then, I will discuss a few perennial species to consider for longer-laid plans.

Warm-season grasses

Sudangrass, sorghum-sudangrass, and pearl millet grow very well during the summer. When managed properly, they provide high-quality forage within 35 to 50 days after planting.

The best of these is sudangrass, because it is fine-stemmed, leafy, and will regrow well after grazing.

The summer annual grasses should be planted only after soil temperatures reach 60 to 60 degrees, which usually happens in late May in Ohio. They can be planted until the end of June in northern Ohio and mid-July in the southern half of Ohio.

This makes them a good double-crop option when planted no-till immediately after wheat grain harvest.

Brown-midrib sorghum-sudangrass and sudangrass varieties are newer types that are higher in digestibility than standard varieties. These varieties are preferred by sheep and can give better cattle and calf gains than normal varieties.


Field peas and soybeans are sometimes included in summer pasture mixes with annual warm-season grasses to improve protein content. The legumes usually increase the seed cost, so evaluate the cost to benefit ratio of including annual legumes vs. supplementing livestock with other protein sources.

Prussic acid (hydrogen cyanide) poisoning can occur when feeding the sorghum species that are under severe stress. This poison can kill animals quickly if present in high concentrations, which happens when tissue is damaged.

An advantage of pearl millet is that it does not cause prussic acid poisoning. The most common time for prussic acid poisoning is right after a frost. But drought, bruising, trampling, or wilting of leaves can also result in high prussic acid in the plant.

Nitrate poisoning is also a concern during drought or anytime the plants are growing slowly.

Don’t feed the horses

Poisoning of horses fed sudangrass, sorghum-sudangrass hybrids, and forage sorghum has been reported. The exact cause of poisoning is not known. Do not feed horses any of these summer annual grasses.

Teff is a relatively new summer annual forage grass for our region. Compared to the millets, sorghums, and sudangrasses we normally use, teff is much leafier and finer stemmed, and it often contains more crude protein and TDN. However, it usually doesn’t produce quite as much total tonnage.

Teff plants can be pulled out by the roots by grazing livestock, so it is probably a better choice for hay than for grazing. It makes a very palatable hay and is well accepted by horses, llamas, alpacas, and similar livestock.

Recently weaned calves also adapt to teff hay quite quickly. These may be the kind of uses where teff is better suited than most of our other summer annual grasses. Stock cows, replacement heifers, and other cattle also like it.

Late summer grazing

Forage brassicas like turnips, rape, and stemless kale can be planted in May to early June to provide late summer grazing. These crops require well-drained soils. They do not tolerate competition, so control weeds and existing vegetation by tillage or herbicides during establishment.

Rotational grazing or strip grazing management should be practiced for all the annual species mentioned in this article.

A sufficient number of animals should be placed on these pastures to graze them down in less than 10 days.

These often come to mind for improving summer productivity in grazing systems. Examples include switchgrass, Indiangrass, big bluestem, and eastern gamagrass. These species grow best during the warm summer months.


The primary complaint about the perennial warm-season grasses is that they are very slow to establish, usually requiring two to three years before full production is achieved. They also require specialized management to maintain productive stands. But with patience and good management, they can be a viable option.

Alfalfa is a perennial legume with deep roots that keep it productive through the summer months. It requires high fertility, soil pH at 6.5 or above, careful grazing management, and the use of bloat prevention tactics. For these reasons, many shy away from alfalfa in grazing systems.

In my opinion, alfalfa provides a great opportunity to improve productivity in grazing systems, but high management is required. Using alfalfa in grass mixtures on small, well-managed areas can dramatically improve animal performance and gain per acre.

In a University of Kentucky study, cattle gained 1.3 to 2.1 pounds per head per day, and 477 to 732 pounds gain/acre for 103 to 152 days on alfalfa.

In addition, grazing tolerant varieties are now available that have improved persistence under rotational grazing.

Forage chicory

This is a deep-rooted perennial forb that like alfalfa is more productive during the summer than cool-season grasses. It is readily grazed by livestock and is high in minerals. Grass-based dairy operations in southern Ohio have found chicory in the stand improves their milk yields.

Forage chicory usually persists for about three years, so reseeding must occur fairly frequently. Grazing must be managed aggressively in the spring to control bolting of the stems.

Learn more

I encourage you to consider using some of the species mentioned in this article within your grazing system, particularly if you often run short of forage for summer grazing.

Learn more about these species and their management by getting a copy of the Ohio Agronomy Guide, which is available at Ohio county extension offices or online at

(The author is a professor in the Department of Horticulture and Crop Science at Ohio State University. Questions and comments can be sent in care of Farm and Dairy, P.O. Box 38, Salem, OH 44460.)


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