Grazing Tolerant Alfalfa
Warren C. Thompson
In 1990, Alfagraze alfalfa, the first ever true grazing tolerant alfalfa by the University of Georgia Department of Crops and Soil Science. The researcher who developed the variety was Dr. Joe Bouton. The release of Alfagraze put an end to lack of persistence under grazing and held production level to match or exceed most hay type varieties when both were mechanically harvested.
Using animals as an integral part of the breeding program was a very unique and practical system to build-in persistence. To better explain the process, the following is a brief explanation of the system he used to develop Alfagraze, the first true grazing tolerant alfalfa variety.
1. The original selection nurseries were planted in grazing paddocks in the fall of 1978. The parental base consisted of 22 currently used alfalfa varieties as well as 1100 USDA plant introductions. This nursery was grazed continuously and intensively for the next three summers (May-September). The best surviving, high-yielding plants were selected and inter-mated. Their offspring were then planted into another grazing paddock where they were grazed for two years. At the end of the second selection cycle, 32 plants survived. Note: In these two cycles, Dr. Bouton started with an estimated 5½ million plants yet only 32 plants lived and became the germplasm base. Another way to look at the system: Alfagraze was made from one surviving plant for every 200,000 plants originally seeded. Is there any wonder that Alfagraze has done so well?
2. In the fall of 1986, Dr. Bouton established a series of five, small plot, grazing experiments where persistence under grazing and dry-matter yields were both evaluated against some of the most widely used and productive varieties on the market.
3. These studies, conducted at different locations, ran for a minimum of two years. All of the plots were continuously grazed by cattle for at least 140 days each year. The data was clear, intense grazing thinned stands and reduced productivity of all varieties except Alfagraze.
4. The final research evaluation phase was initiated in 1988 when large-scale animal performance trials (replicated two acre paddocks) were established. In these trials against popular used varieties, stocking rates and stand survival of Alfagraze was superior and its’ animal performance was outstanding (average daily gains of 2.2 pounds per day for four months and a total of 530 pounds of beef production per acre for the season). This beef performance was in addition to the 1.5 tons of hay harvested (per acre) in the spring each year before grazing.
Note: These procedures took time, patience, and careful analysis to prove the worth of Alfagraze. This same system has been used to develop the varieties, AmeriGraze 401+Z and AmeriStand 403T, AmeriGraze 201+Z, and AmeriGraze 702. Currently, other varieties are in various stages that mirror this system of development by our plant breeder Dr. Jim Moutray and his associates. I will deal with these later in this manuscript..
As far back as the early 1970’s farmers in much of the grazing belt had found that growing legumes with perennial grass increased beef cattle gains and milk flow at lower costs. Their problem was finding legumes that yielded well and survived with grass for three or more years. Alfagraze came on the market in 1992. With publicity based on field experiences and farmers hunger for a better legume to graze, Americas Alfalfa Inc sold out of seed the first planting season. Over a decade later, the Alfagraze is still being planted and has become one of the most popular alfalfa varieties that has ever been released and leads all other varieties when alfalfa is grown for grazing.
In an effort to get an on-farm evaluation of grazing alfalfa in the early 1990’s, we established 62 successful on-farm dairy, beef, sheep and wildlife grazing test demonstrations in 37 states with the assistance of forage extension specialists, county agents, and local seed dealers and distributor representatives. The basic objective was to test the grazing tolerance trait under real farming conditions. We also wanted to pass along these findings to farmers and professionals at the local, regional and national levels. Obviously, our objective was to find and develop an expanded alfalfa seed market. Grazing was without doubt, the best opening to do this. Since Alfagraze was the only valid grazing variety, hay producing varieties were all that we had to use at the time for comparison. We used the most prominent and highest yielding varieties grown on farms at that time. We were especially careful to use varieties that had been entered frequently in experimental grazing trials for comparison. In a few instances we were able to include varieties that were advertised as grazing varieties yet valid published data was or seemed to be lacking. After two and up to three years of production, ratings at each location were taken and released to the public.
RESULTS AND CONCLUSIONS
1. Grazing tolerance (GT) is a real and independent trait.
2. The GT trait has a higher endurance level than any tested variety whether grazed rotationally or continuously.
3. Once established, the ‘GT’ varieties live longer and are more durable whether harvested as grazing, hay or silage. Contrary to earlier professional assumptions, Alfagraze yielded with the best of hay varieties when harvested as hay. The newer varieties taken from this parentage rank in the top 10% of tested varieties in yield when mechanically harvested.
4. The ‘GT’ varieties produce higher meat and milk per acre and forage yields over a longer period of time than any other legume.
5. Compatible cool season grasses help to reduce treading and traffic damage during grazing seasons especially under wet soil conditions. Likewise, these same grasses are extremely helpful in diluting/reducing the incidence of bloat.
6. These GT varieties, when harvested mechanically have been proven to have higher resistance to mechanical traffic damage.
7. Wildlife enthusiasts have found that GT varieties are great forage for wild deer. Food plots of one to ten acres (sometimes larger) are being seeded every year, nationwide. The big advantages of alfalfa include better conception rate, increased summer grazing quality and increased carcass quality and weight as well as rack-quality are reported.
8. Restrictive (rotational) grazing produces more meat and milk per acre than continuous grazing. Also, stands remain more uniform with less weed intrusion.
THE BIGGEST PROBLEM TO DATE
The fear of bloat causes many farmers to shy away from grazing alfalfa. Even though alfalfa is about half as bloat-hazardous as white clover, it remains a concern. Here are some tips that I have used for years to help guide growers on dealing with bloat and keeping it to a minimum:
1. When animals are hungry, especially when they are emaciated, they are sure to over-eat. When you get ready to start the first round of grazing or interrupted grazing sequences, pre-fill them with free choice dry hay well ahead of field entry. (Many experienced grazers keep hay in front of cattle at all times).
2. Restrict the initial grazing entry to perhaps 30-45 minutes daily. Increase their field-time as they adjust.
3. Remain in the field with the animals while you are ‘breaking-them-in’.
4. Use Poloxolene (Bloat Guard is a familiar product) according to instructions prior to and during grazing.
5. Sell chronic bloaters while they are still among the living. There is conclusive evidence that bloat is heritable and can be passed on to the next generation(s).
When will bloat-free alfalfa varieties come on the market? Some Canadian researchers have already come up with some lines of alfalfa that have reduced bloating potentials (in the ballpark of 60-70%). In my judgment, it will be quite a while to get to the 95-100% level. Chances are it will come along with some form of biotechnological development that can take 10-20 years or more.
My advice: if you want the best possible meat and milk production per acre from grazing at the least possible costs, include grazing tolerant alfalfa in your pastures and follow the best management guidelines available. The basic guidelines are published in other sections of my lecture series.
It is my judgment the biggest breakthrough in alfalfa breeding in the past 50 years was the development and release of Alfagraze. The entire concept that brings in outside pressures and find durable and productive forage species at the same time, ‘weed-out’ weak traits that will not allow plants to persist under normal farm pressure. In recent years, insect and disease resistance has been added to this concept which has resulted in tougher, high yielding, more persistent series of varieties that also make alfalfa easier to grow and to use without fear of premature crop failures.
In recent years, we are beginning to see plant breeders use this same concept to improve the life span, yields and use in other legumes and even cool season grasses. We are in for some exciting times and the technology gained from the system to produce torture resistant Alfagraze will be recognized by farmers all across the USA and perhaps around the World as the cornerstone for persistence and yield of forages under pressure.