Yes, there is green grass.
Yes, both you and the livestock are more than eager to utilize it.
Yes, you both should wait before grazing it.
It is one of the hardest times of the season for some people, me included. We are tired of mud and tired of feeding hay. There is an increasing amount of fresh new lush green grass beckoning to be grazed. Why shouldn’t you allow the cows to partake in this new growth? When is the ideal time to start grazing?
Let’s think this over a little.
What is the real problem with grazing too early? Forages have just woken up from a long winter’s nap, and now they’re making new food. That early growth does not come from photosynthesis, but from from energy reserves stored in the roots and lower shoots.
You probably remember some past conversations we’ve had about not overgrazing last fall, especially before the forages went dormant. Why? You wanted your plants to build root reserves to sustain themselves over winter and provide energy for new growth in the spring. Whatever energy was stored in the roots is now expressed in the speed of new spring growth. If reserves were withdrawn last fall, then it will take longer for plants to jump start this spring. If you turn around and let livestock graze too early, especially if energy reserves were withdrawn last fall, then not only is spring production going to be reduced, total production for the whole year will be reduced.
If you either deferred grazing last fall until the plants were dormant or you stopped grazing once you reached appropriate stop grazing wintering heights (generally similar to stop grazing heights during the grazing season, four inches for cool-season forages), then energy reserves should be decent and spring growth normally will be good. Those reserves that were built in the roots and lower shoots last fall provide energy for quicker and more abundant growth in the spring. Overgrazing in the fall, preventing build up of reserves and then turning around and initiating grazing too early in the spring or never removing them the entire time. Energy reserves are grossly hampered in this situation and total yield potential for the season is quite often reduced by at least fifty percent.
I’ve heard people say, “The cows didn’t lose anything, they consumed it all.” Yes, they consumed all that was grown, but the amount that was grown didn’t come close to the potential of the field. It all boils down to:
“it takes grass to grow grass.”
So, when should I initiate grazing in the spring?
Fields that have good fast growth with reserves maintained over winter could be utilized for some grazing when forages are at least eight to ten inches tall. Try to remove no more than one third of the forage and then move them on to the next paddock/pasture. When forages are growing quickly, rotate quickly. Try to never remove more than half of the amount that was in the pasture when you arrived. We’re talking cool season forages this time of year, so you can’t go wrong with using four inches as the stop grazing height. Remember, stop grazing height is the shortest forages left standing, not the tallest. If the pasture is rotated correctly it will have a fair amount of forage, between four and six inches left standing.
Pastures that were grazed hard last fall, especially prior to dormancy, could use a longer deferment prior to grazing this spring. Those fields will need to grow some solar panel off the reserve left, and then spend valuable time rebuilding roots and root reserves before allocating energy and resources to growing forage. The plant is going to try and preserve itself and yield is the last thing on its mind; it’s thinking survival. Quite often you will find these stands initiating reproductive stages more quickly and earlier because of this survival mechanism. In some cases, some anti-quality factors in forages, such as alkaloids, may also be higher because of this.
In the long run, if you take care of the plant, the plant will help take care of you. Unless you have run out of hay or are calving in mud, wait until the grass is ready.