I try to start grazing as early as possible in March. When the snow melts, I will try to feed stockpiled fescue which also provides a clean field for the cows to have calves. This year, when we moved cows to start grazing March 3, grass had already started to grow and some fescue never died.
Spring growth started early with the warm summer-like temperatures. An interesting result was the fast growth of legumes. Normally we have concerns with grass tetany because cool spring temperatures favor grass growth over legumes. The result may be low magnesium levels for grazing livestock, resulting in tetany.
Legumes are higher in magnesium reducing tetany problems. The fast warm up we had allowed legumes to grow as fast as the grasses reducing problems. In addition, the early growth allowed many to start grazing livestock early, cutting weeks off winter feeding.
Even if they tried to feed hay, if pasture was available, the livestock would not eat the hay. Pasture and hay growth was two to three weeks ahead of normal. I usually notice common orchard grass starting to head out in southeast Ohio the end of April, this year it was the first of April.
The past week or two we have had more normal temperatures and growth has slowed. But new questions such as will frosted alfalfa and clover cause problems for livestock and will the freezes damage the stand?
According to Mark Sulc, OSU forage specialist, there is no danger to grazing frosted alfalfa except immediately after a frost, when cattle are more likely to bloat on alfalfa or clover. But otherwise there is no toxicity. If they need to go out on frosted pastures, take anti bloat precautions — feed some dry hay before putting them out and don’t let them go out hung, introduce them slowly, etc. Control grazing so they graze it down, not just top graze lush leaves.
How will this affect the stand of clover or alfalfa? Should I cut it?
According to Bruce Anderson, University of Nebraska Forage Specialist, a “light” frost/freeze where temps don’t go below 28 degrees for very long is likely to singe alfalfa tops a bit and set back growth rates for a while, but plants will grow out of it. No need to cut, although some growers seeking very high quality might do so if standing yield is high enough to justify harvest with the understanding that plants will be weakened by early cutting and should be allowed extra time to recover before the next cutting.
An extreme freeze around 20 degrees or less, like in 2007, likely will freeze plants all the way to the ground and they will collapse soon afterwards. Harvest is warranted if yield is sufficient but must be done immediately; once plants collapse much of the biomass will be unattainable and leaves will shatter quickly from those stems that still can be cut.
Experience in 2007 showed little or no benefit to regrowth by cutting or shredding damaged tissue since the freeze was so thorough that plants reacted to the killed tops just as they would if tops were killed by cutting instead of freezing. A freeze that penetrates about halfway down into the alfalfa canopy makes decisions more difficult.
Cutting will weaken plants that weren’t nearly ready to cut anyhow. But uncut plants will be confused, some continuing to grow, others creating new shoots from aboveground stems, and others with new shoots coming from the crown. And much of that regrowth will be slow to initiate.
If yield is high enough to justify harvest, probably should be cut, knowing that extra time will be needed for recovery before the next cutting. If yield of standing crop is low, probably best to just wait out the delay in regrowth. It will be hard to justify the time and expense of cutting/shredding with no immediate harvestable crop.
After a freeze that causes visible damage to alfalfa tissue, be extra observant of how the plants respond. In 2007, some regions experienced significantly higher than usual damage from foliar diseases and sometimes, insects, on regrowth following the freeze.
It was speculated at the time that weakened plants may have been less able to resist these pests or that the abundant amount of dead alfalfa plant tissue on the ground or surrounding the regrowth provide a more desirable environment for pests to develop.
While we have had some good things happen as a result of the early warm weather, we have had some challenges. As we become more experienced with grazing and forage management, we learn to incorporate the science with the art and be more prepared for weather extremes.
As I wrote this article last Thursday, several experienced grazers were evaluating the changing weather pattern to prepare for the possibility of a dry summer. Successful producers learn to plan weeks and months in advance for abnormalities and are better prepared to “weather the storm.”