| VOLUME 4 ISSUE 2 SUMMER 1994
NATIVE WARM SEASON GRASSES AS FORAGE
As I talk around and promote native warm season grasses for both wildlife and forage production I invariably get someone who makes a comment, something to the effect of, "Oh, that damned old wild grass. I fed that to my cattle one time and they turned away from it. Wouldn't eat it. ". If that is common enough that I hear it so often, there must be a lot of producers who have experienced the same thing. Knowing that, then how can I say that native grasses are so good and often preferred by cattle? I can simply explain the producers position because of his ignorance. Not to say that the producer is ignorant, the cattle producers I know are very sharp and have a lot on the ball. Ignorant, because they lack the specific knowledge in relation to native grasses and their proper application for quality forage. The first thing that concerns me is their so called "wild grass". Is it actually a native warm season grass? Could it be broom sage? Broom sage is a native warm
season grass but not a good forage grass, nor has it ever been promoted as one. Perhaps he's talking about purple top or grease grass, it is a warm season grass that develops a seed head about the same time as indiangrass and is commonly clumped in with the other productive, valuable forage grasses, but has little value. Without proper identification of what "wild grass" he's talking about it is difficult to make any statements about the reason his cattle wouldn't eat it. The other major reason cattle won't eat it is incorrect harvesting time, whether it be turning the cattle in too late for good forage or haying too late for best quality, though late harvested hay seems not to be as big a problem as turning cattle in too late. It also depends upon what other forage is available. The cattle may have a preference for new sprouts of green, cool season grass over mature, improperly harvested native warm season grass hay. Finally, it is not uncommon for cattle to be slow to accept a new forage with which they are not familiar. Several years ago I had a discussion with a producer who introduced his cattle to warm season grass, he stated that the cattle balled for days until they finally got hungry enough to try it. Once they ate it, when it came time to move them to another pasture the cattle nearly ran him down trying to get through the gate to the next warm season grass pasture.
Now we know why cattle won't eat it or may be slow to accept it but what do we do to correct the problem? First, learn to identify the productive native warm season grasses. The most common are: big bluestem, indiangrass, switchgrass and eastern gamagrass. The last issue of The Native Grass Manager provided identification tips so I will go on to the management recommendations. Number one, the rule to follow for grazing: Turn cattle in on native grasses when the grasses have reached between 12 and 18 inches growth. Regardless of how much cool season forage you have, always observe this rule. Don't let the warm season grass get ahead of you. If you wait until you have used up your cool season forage before turning cattle onto warm season grass, in many instances, and particularly true with switchgrass and eastern gamagrass, the native grass will have grown enough that many cattle will tend to turn their noses up to the warm season grass. The other rule to observe is to remove cattle when stubble height reaches 6 inches. This is important to maintain healthy, productive stands. The most efficient way to maintain stubble height is to have your native warm season grass pastures divided into 3 or 4 units or paddocks then rotationally graze them, remembering to not let the grass get ahead of you. It is better to leave forage in a unit and move on than to use all the forage in one unit before rotating onto the next pasture. If you are under utilizing your warm season forage there are two options. One, you can increase your stocking rates. Two, you can harvest rested pastures for hay. With proper stocking rates and combinations of warm season grasses, you will be able to fully utilize your forages. Additionally, by having pasture to rotate onto from the one being currently used you can allow adequate regrowth in previously grazed units before turning cattle back in.
In a grazing system stocking rate is one of the most important considerations. Stocking rates for native warm season grasses need to be adjusted based upon experience. Where do you start if you don't have any experience? Without getting into a full blown discussion about stocking rates I will offer a general rule, providing you at least a starting point. Assuming your native grass produces between two and four tons of forage per acre, it will support 1.5 to 3 animal units per acre, June through August. An animal unit is equal to 1000 lbs. live weight. I would be conservative the first time out, until I got a feel for grazing warm season grasses.
Regardless of grass, cool season or warm season, forage quality declines as grasses mature. Crude protein decreases and fiber increases. The maximum amount of forage being of highest quality is produced when the grasses are in the boot stage. Boot stage is when the seed heads are within a sheath of leaves (boot) before seed stem elongation. Boot stage is the best time to harvest for highest quantity and quality of hay. Once seed stem elongation occurs there is a tremendous reduction in the quality of hay. When seed matures fiber is nearly twice as high as protein in the forage.
In forage analysis warm season grasses consistently test lower than cool season grasses tested at the same growth stage. This has led most people to conclude that warm season forages aren't as good as cool season forages. Most people, being those who don't have any first hand experience with grazing or feeding high quality native warm season grass forage. The real proof is in the pudding. In animal performance trials warm season grasses do very well. The difference appears to be digestibility. In hay feeding trials at the University of Missouri, low quality tall fescue hay was compared to low quality big bluestem hay. (Low quality when compared on the same scale.) Tall fescue tested 7.19% crude protein and big bluestem tested 6%, but percent and rate of dry matter digestibility were better for big bluestem hay than fescue hay. This allowed the animals to process feed faster, allowing greater and faster forage intake, therefore faster weight gain. In another University of Missouri trial, at the Forage Systems Research Center at Linneus, MO, milk production of beef cows grazing big bluestem was equivalent to that of cows grazing high quality bromegrass-alfalfa pastures. During the summer '94 grazing season pregnant dairy heifers grazing eastern gamagrass at the Southwest Missouri Research Center produced 2.3 pounds per day average daily gain over a 70 day period. Managers at the Seat Demonstration Farm in Missouri compared average net income between native warm season grass and bluegrass pastures for the years 1983-85. Income was calculated as beef produced minus annual maintenance costs of the pastures. Net income per acre of native warm season grass was $107.88 versus $36.33 for the bluegrass. A difference of $71.55 per acre.
Relative feed value (RFV) is a an estimate of the energy value of forage. The RFV is calculated from the forage analysis. Hay grading systems are based in a large part on RFV. Comparisons of RFV are not valid when comparing native grasses to other forages. The calculations for RFV discriminate against the native grasses because, in general, they tend to have higher levels of fiber than other forages. Native grass are able to produce higher than expected gains from livestock for the levels of fiber present. Relative feed values can only be used to compare similar forages. Forage analysis should only be used to compare cool season grasses to cool season grasses and warm season to warm season.
I recently talked with a technician at a forage analysis lab, Livestock Nutrition Laboratory Services. I asked if there was any way we could make a fair comparison of cool season and warm season forages based upon the currently available test results. He said, and cautioned me that his statement had no scientific proof but was based upon his experience and observations, that a RFV of 70 in native grasses was approximately equal to a RFV of 100 for other forages.
Superficially, native warm season grasses don't appear to be very good forage - the hay looks coarse and stemmy compared to cool season grasses, forage analysis' don't measure up and cattle are slow to accept it when first introduced to it, but regardless of superficial appearances you can't argue with animal performance.
I'm not promoting native grasses as "the" forage for everyone. Proper use of native grass requires a willingness to learn about them and their management and the application of that knowledge. Some producers simply won't do it. In addition, native grasses are most productive in a forage system when used rotationally with cool season grasses or other forages. Native warm season grasses, in a forage system, work best as a compliment to cool season grasses, producing high yielding, high quality forage during the summer months when cool season grasses are at a disadvantage.
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