Pasture Species Selection by Animal Group

Nicole Santangelo and David Hartman, PennState Extension

Pasture renovation and reseeding decisions must be based on type of stock grazing. Matching forage species, varieties and growth to forage needs of livestock is critical to reducing use of stored or purchased feeds.

Cattle Grazing – PennState Extension

The Agronomy Highlight discussion is an opportunity to ask the author questions about the highlighted article, get updates from Penn State Extension Agronomy Educators around the commonwealth, share observations from your part of the state, and request content for the next issue of Field Crop News. Learn more about the weekly Agronomy Highlight discussion.

Spring is the best time of year to plan for pasture reseeding. If you are just fixing up a few bare spots, spring can be an ideal time to plant. However, most pastures are best renovated or reseeded in the late summer when competition from weeds is lowest. The good new is, we have plenty of time now to take soil tests, complete lime applications and choose a good seed mixture or pasture species to fit our farm needs. Read more on agronomics of pasture renovation in this Seeding Perennial Forages Article .

Choosing a Forage Species

There are several perennial cool season pasture forages we can choose from in Pennsylvania. Make sure to select forage species that will work well in your climate and with the soils on your farm. What works well in the mountains to the west, or the snowy plateau to the north, may not fare as well in the central valleys or southeast lowlands. Species that thrive on well-drained soils may not work well on heavy soils that are frequently water-logged.

The best strategy is to plant a diverse mixture of forage species to reseed a pasture. Diverse mixtures of grasses and legumes can typically withstand variabilities in soils, grazing management, and weather extremes. Many companies have commercially available mixtures that are formulated to meet the needs of various livestock species and classes, while considering climate and soils. More about selecting a forage species most conducive to your soils can be found in “ Selecting the Correct Forage Species” article.

Forage quality is mainly influenced by stage of maturity at the time of grazing. Forages in a vegetative stage are at their peak in nutritional quality. As forages mature, energy and protein levels decrease, while fiber levels increase. Livestock classes that have low energy demands, such as dry cows or dry/open ewes, can meet their nutritional requirements on these low-quality forages. However, a lactating dairy cow or a steer putting on weight will need higher levels of energy and protein to optimize performance. Understanding the nutritional needs of your livestock is important to knowing how to manage your pasture. To learn more, watch our ruminant nutrition video series.

In our travels, talking with farmer after farmer, we have concluded that grazing management surpasses all other agronomic struggles. Pasture management most of all depends on the livestock grazing, their stage of production and stocking rate. Attempting to answer these requests, we will review forage species selection by livestock type.



While most species of livestock can graze almost any forage type with a small amount of management, there are a few exceptions worth mentioning first.

  • Equine can be sensitive to clovers and alfalfa due to a fungus that can cause horses to ‘slobber’.
  • Pastures with a high percentage (>50%) of alfalfa and red clover may cause bloat in sensitive livestock under certain conditions.
  • Older tall fescues varieties such as Kentucky 31 can host a fungus (commonly referred to as an endophyte) that produces a toxin that will cause weight loss and reproductive issues for equine and livestock.
  • Clovers and alfalfa naturally produce estrogenic compounds that may under some conditions alter the estrus cycle and interfere with breeding in ewes (and possibly in cattle).



Some grasses and legumes are less ideal for certain species, however, may work with good management:

  • The growing point of timothy is well above the ground. Therefore, the grazing action of horses and sheep can reduce timothy in overgrazed pastures. Other grasses should be considered.
  • Kentucky bluegrass, reed canary and some varieties of orchardgrass can quickly get ahead of even a well-managed dairy grazing system, becoming less palatable and increasing selective grazing behavior. Great management of these paddocks and selecting newer varieties can overcome this.
  • Sheep typically select against reed canary grass and red clover. Smaller grazing paddocks may improve grazing action of these forage species.

Overall, there is a wide selection of forage species and even larger selection of varieties. It is important to choose new genetics to get the most production and quality out of your new forage seeding. Many of the newer varieties have overcome some of the issues those species have had in the past.

Also, you may think about your current pastures and how they may fit into your grazing system by season. This chart from the Penn State Agronomy Guide helps illustrate this:

This chart mentions a few grass species worth highlighting. Endophyte-free and novel-endophyte fescue varieties can be grazed without much concern for toxins, like those in Kentucky 31. Fescue is a great forage that has a long growing season and will stockpile into the fall and early winter. Perennial ryegrass is another species with slightly higher levels of non-structural carbohydrates (sugars, starch, pectin) than other grasses. In other words, higher energy levels, making it an ideal forage species for lactating dairy cattle, calves, stockers and lambs. Perennial ryegrass does prefer well-drained soils with good fertility.

The Penn State Agronomy Guide has great resources for helping choose the best forage species for your flock/herd, management style and soil conditions. For help choosing a forage species or mixture work with your seed dealer and Penn State Extension Educator.

Be the first to comment

Leave a Reply

Your email address will not be published.