UT Beef and Forage Center

Native Warm-Season Grasses- Article

Pat Keyser

Dr. Pat Keyser, Professor and Director, Center for Native Grasslands Management

(865) 974-0644

pkeyser@utk.edu

Although having as much as 30% of a forage base in warm-season grasses is a great target for fescue belt cattle farms, trying to get there all at once is not a good idea. A much better approach is to convert a few acres at a time, working towards that goal incrementally. Once that threshold has been reached, you could graze much of your herd on the warm-season grasses all summer. But what should you do while working towards that goal, or for any other reason, you only have a few acres of native warm-season grasses?  Is there a way to take better advantage of that forage?  In a word, yes!
Let me start by addressing one approach that I would encourage you to avoid: simply building those few acres into your normal rotation. In that scenario, cattle will be going onto the natives, adjusting rumen microbes to a new forage, and just when they have made that adjustment, switching them to a different forage, requiring some level of adjustment all over again. Moving from one grass type to another is not as big a deal as switching from grass to a grain-heavy diet, for instance, but there can still be an adjustment period. When the forage they are going back to is an endophyte-infected tall fescue (like KY 31), that return trip can be rough. Such switching back and forth can wash-out the forage quality advantage of native grasses.

A better alternative would be to use the higher quality native grasses to optimize performance on a sub-set of your herd. Using the natives for heifer development might be the first priority. These animals are typically more sensitive to fescue toxicosis, require adequate rates of gain, and are important to get – and keep bred.  Assuming you are holding back enough heifers to replace 20% of your brood cows, maybe 8-10 animals for a 50-cow herd, you could carry them all summer on as many acres – or less, depending on the species of grass in question. And all that time, away from toxic forages. A similar approach would be to put second-calf heifers on the native grasses. Re-breeding these animals can be an issue and having a high quality, non-toxic, low-cost forage would help minimize rebreeding problems.
Another good option, for fall-calving herds anyway, is to use the limited acres of native grass pasture for backgrounding calves. If you are weaning fall calves in May, that is perfect timing for moving these calves onto a forage that can produce as much as 200 pounds of gain for as little as $0.25-$0.30 per lb over a 90 or so day summer grazing season. Studies at UT have shown that this approach provides consistently positive rates of return, despite softening in markets over those months and the larger size classes (8 vs. 6 cwt) that sell for lower per pound prices. For heifer calves, these same forages can provide a good leg-up on development and attaining puberty in a timely and cost-effective way.

During drought periods, taking advantage of the more reliable summer production of the natives is also a benefit a few acres of these grasses can provide. During such droughts, heifers should still be a priority for using the natives, but in fall herds, third-trimester cows may also be a consideration.
Strategic use of small acreages of native grasses under one of the approaches described above can assure you get the best return on the investment in the short run.