Extension column: Grazing alfalfa regrowth
September 17, 2013
An important principle of adaptive grazing management includes identifying unique or unusual circumstances and "adapting" to take advantage of the opportunity presented. Climatic variation in the Northern Plains is likely to present unusual circumstances with regularity – the challenge is to see the opportunity and have sufficient flexibility to respond.
Growing season conditions this year were not typical. We generally expect our most reliable rainfall during spring and early summer. While May and June provided improved moisture from a year ago, July and early August were generally very favorable. Cool temperatures also extended later in the growing season than typical. These conditions created very favorable conditions for regrowth of alfalfa in hayfields that were harvested by early July. As I looked around portions of the Tri-State region I've traveled, I was very impressed by the quantity of alfalfa recovery in alfalfa-grass hayfields. While alfalfa is a cool-season plant, it was certainly able to respond to favorable moisture where it occurred.
Alfalfa regrowth may provide an opportunity for an unanticipated autumn feed supply. Grazing fall residue is not unusual, but the quantity available this year may provide an opportunity to benefit by carefully allocating this resource. An abundant feed supply might also provide a chance for careful managers to gain experience with more intensive grazing patterns than they have previously used. Hayfields are generally level or gently rolling and perhaps more uniform than typical pasture areas. This could simplify the process of allocating pasture for brief occupation periods, such as daily moves.
A number of items should be considered; some related to more intensive grazing management and others related minimizing risks associated with grazing alfalfa.
Most area hayfields have a secure perimeter fence. This should be double-checked and a plan for erecting temporary subdivision fencing should also be developed. Simplicity and ease will contribute to success. If temporary electric fence is unfamiliar, visit with neighbors or friends who have experience. Adequate chargers and grounding are essential, particularly in the fall when the soil is drier.
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Adequate water supply is also essential. Many area hayfields have wells or water lines nearby, but evaluate the effort required and potential benefit if you are considering a new procedure. Water facilities that are not reliable will doom the experiment to failure. Planning a fencing pattern around accessible water will also improve success.
Hayfields may appear to be uniform in the springtime, but variation in alfalfa stand density may dramatically influence the feed available in a unit of land area. Anticipating this variation might influence plans about the direction of subdivision fences and the shape employed. If there are obvious patterns in alfalfa density, including thick and thin areas within subdivisions, may simplify allocating adequate feed for each move. Clipping and weighing standing forage will provide the most reliable guidance to what is available. Fall growth is likely to be negligible, so repeated clipping may not be required. Growing season grazing often requires a "back fence" to avoid regrazing growing forage. This may be unnecessary if livestock distribution can be controlled and feed available is adequate.
Deciding which animals are most likely to benefit from the nutrition available from alfalfa regrowth should be considered. Knowing which animals are likely to be easiest to manage should also influence selection.
If higher stock density, temporary electric fence and more frequent animal moves are a new experience for the manager and the livestock a high degree of patience will be essential. If fences are managed to remain "hot" animals will learn, but this is likely to require several days. Adequate perimeter fencing should be planned.
Having a "plan B" to fall back on if unanticipated problems emerge will bolster confidence in implementing a new strategy. For example, recognizing the possibility of bloat and providing for an alfalfa-free "escape pasture" would be prudent.
Alfalfa can be an extremely nutritious feed, but the nature of those nutrients confers some risk of bloat. Ruminant livestock digest the fibrous portion of forages with the help of microbes. Part of that digestion process is the production of large quantities of gas, primarily carbon dioxide and methane. Normally that gas escapes easily when the animal belches. Soluble proteins, characteristic of legumes, especially alfalfa, increase the surface tension of the fluid in the rumen. This stabilizes the gas bubbles and traps gases that would normally escape. Severe bloat can occur rapidly and result in death.
No management procedure guarantees bloat prevention, but several precautions greatly reduce the hazard. Bloat risk is highest when alfalfa forage is lush and immature. Most hayfield regrowth has bloomed and is more mature and therefore less bloat prone.
• Never move hungry cattle onto alfalfa, especially for the first time.
• Avoid moves when foliage is wet or damp. Moving livestock in the afternoon generally reduces this likelihood.
• Avoid changes in diet. Provide adequate forage every day and avoid excessive defoliation. The more frequently animals are moved, the more uniform the diet is likely to be.
• Feed a bloat reducing compound and monitor intake to ensure it is adequate.
• Anticipate freeze events and do not graze alfalfa immediately after a freeze.
A check with a number of local feed suppliers indicated that supplement blocks containing poloxalene are available. Check ahead, compare prices based on daily intake required for adequate protection. Plan to have blocks on hand before you start grazing alfalfa and start livestock on the blocks for several days before they are turned onto alfalfa. Product labels should provide precise recommendations.
Perhaps the biggest risk associated with grazing alfalfa in the fall occurs immediately after a freeze. Freezing temperatures rupture cell walls in the plant and further increase the accessibility of the culprit proteins in the rumen. Be alert to predicted freezes and avoid grazing alfalfa for three days following a freeze. This is why an "escape" pasture may be so important. Use adequate caution when returning animals to alfalfa. An alternative plan would be to wait until after a hard freeze to begin grazing alfalfa.
If you have alfalfa regrowth this year, spend some time considering how your operation can most benefit from its careful use and consider developing some novel approaches!
The intake of Poloxalene should be monitored, as intake will vary among animals and days.