What species of forages are highest in nutrition? A producer and expert panel.
STUART GARDNER
Nutritional value varies more with stage of maturity than it does with species in most cases, especially with warm season plants. This also goes for cool season forages at the end of their growing season, when length of day / photoperiod length causes them to mature.
Warm season perennial grasses such as bermudagrass, bahiagrass, and dallisgrass, are best suited for the warm season based humid subtropical region, which covers all of Louisiana.
Another factor is is warm season annuals vs cool season. These warm season forages, are categorized as C4 forages (warm season plants). Cool season forages are categorized as C3 plants. Their quality is generally much better than warm season C4 forages. Warm season forage quality is generally lower than cool season annuals (annual ryegrass / clovers, etc). We have virtually no cool season perennials in the south 2/3 of the state. There is a bit of fescue in a limited area of extreme north LA.
Location of the grazing operation and specific soil types dictates which species are suitable for the site. Next, comes the management regime of the pasture / hayland manager.
All forage plants have 3 basic phases of growth.
Phase 1 - immature, seedling growth stage, high in quality, high in moisture, low in dry matter. (Not recommended for grazing or haying use)
Phase 2 - still in vegetative growth stage, quality is good, quantity is good, moisture is usually in the 25 to 50% range, and dry matter content is moderate (TDN= 50 - 70%). Grazing and haying use is recommended in Phase 2 to get good quality and volume.
Phase 3 - plants have entered into reproductive stage, plants are producing seed, and maturing. Quality has declined and is marginal for livestock, quantity is at a maximum volume, dry matter content is high, usually at 60 -80%. Quality is low, TDN is usually 30 to 45%, or even less in some cases.
Good grazers and hay producers, manage to graze and hay forages in Phase 2. Great grazers manipulate forage plants with grazing management to keep them in phase 2 when possible.
As usual, this topic is dynamic and complicated.
Stuart Gardner, Area 2 Range (Grazingland) Conservationist, USDA Natural Resources Conservation Service, Lafayette, Louisiana
Justin Fuselier, Eunice, LA
Grass nutrition is owed too many factors. Some factors include species type, stage of growth, warm season types (c4) vs cool season types (c3). One consideration often overlooked could be soil health and fertility.
Dr. Willian Albrecht back in the 1940’s and 50’s focused much of his work on soil fertility and the resultant plant and animal nutrition and health. Albrecht described that as you went east of the 95th meridian and south, you entered the soil deconstruction zone. This is because of lack of parent material degradation, coupled with high precipitation that exceeds evaporation, and increased heat and humidity, results in net soil weathering processes. These prevalent forces of nature favor soil fertility removal.
One signature trait of a deconstructed soil is a increase in soil acidity. Albrecht explained that acidity is nothing more than a lack in fertility. When the basic cations (Ca, Mg, K, Na, and some minors) are stripped off the clay colloid, they get replaced by Hydrogen. This gives a rise in acidity or a lower pH. He explained it is a fallacy to lime the soil to correct pH.
More appropriately, one should consider the basic cation balance of those mentioned above. Ideally, the best balance observed was 68% Ca, 12% Mg, 5% K, 1%Na, the rest micronutrients. Whenever Albrecht observed this balance in nature, he would find the highest levels of plant and animal health. He actually linked US soils maps and WW1 draft data and could correlate draft rejects to areas of deficient and unbalanced soil fertility. He explains that fertility is held in a available manner exclusively by the clay and organic faction of the soil profile. The organic faction being superior because it can hold both positive and negative components of nutrition. In soils without parent material degradation, the soil the fertility of the clay colloids is replenished by organic matter decomposition. Trouble can develop when our modern practices of soil disturbance and highly soluble fertilizers burn out the organic matter and nothing is left to reload the clay colloid. Quick acidification can result as the loss of fertility hastens. At this point soil systems loose structure, biology, water-holding capacity as the whole system is diminished. Perhaps worst of all, our forage base becomes a dumbed down version of nutrition and incomplete feed stuffs for our cattle.
Another major focus of Albrecht's studies showed that as the fertility of soil decreased, so did its protein production potential. Both lack of protein production and more specifically the lack of complex proteins plague the fertility poor regions. It is this complex protein profile that supports the performance and reproduction in higher organisms like cattle, bison, and deer. It's why our deer are smaller, also why the bison usually didn't come so far east. He also proved that when plants grow in low fertility they shift to a more carbohydrate rich state. It’s why traditionally you find pig production in the East, cattle production in the West.
He explained it was a fallacy to raise protein levels in plants for feeding higher organisms with just nitrogen fertilizers. The resultant increase in protein content is result of simple protein increases, not the more complex ones suited for higher organisms. He attributes the increase in simple proteins as being a reason for increased insect, disease, and weed pressure that often accompanies nitrogen applications. The higher level proteins could only be synthesized from microbial delivery mechanisms ins the presence of balanced soil fertility in healthy soil with good structure. One might refer to this as virgin soil. It is the effort of regenerative pastoralist to create that virgin soil.
Albrecht harped on the fact that the protein content of animal feeds is based only a measurement of nitrogen percentage present in the sample. This is because all protein contains nitrogen, but all proteins are far from equal. The type and quality of the protein is not quantified on feed tags because it is both cumbersome and expensive to test. Nitrogen fertilization to increase protein percentage is still common practice today in both animal and human foods.
In order to get real food value and increase the food value of the forages you already have you might consider the state of your soil. How close are you to virgin soil? What is your ranch lands last 50-100 yr history? How degraded is your resource? Soil testing using Albrecht's methods can at least show you where your fertility levels are. Strategies can then be applied to remediate some of these deficiencies. Excitingly, with regenerative agriculture in the focus, it is being demonstrated that with soil heath principles applied to our grazing systems we can improve the state and function of our soils.
To learn more about Dr. William Albrecht and his work look for his book series at www.acresusa.com . To soil test using his methods send soil samples to www.LoganLabs.com .
ED TWIDWELL
You asked me last week about coming up with a listing of nutritional value of various forages. To me, it is very difficult to put a numerical list together as management practices have such a dramatic effect on forage quality. Maturity is by far the major component affecting forage quality. Fertilization, especially with nitrogen, can affect the crude protein content of the forages. I guess I prefer to just offer ranges in quality, primarily based on maturity. I found an excellent table in the Southern Forages book, and that information is in the attached file below.
Bermudagrass is probably the highest quality forage for Louisiana. However, it is very difficult to produce bermudagrass in low fertility soils, such as in the northwest and southeast regions of the state. Producers in those areas are better off planting bahiagrass, as it can tolerate poor fertility conditions much better than bermudagrass. So even though bermudagrass is a better quality grass, producers in those areas would be much better off planting bahiagrass. I think the key for most producers is to utilize the forages that best fit their soil types, climate, soil fertility, stocking rate, etc.
