As snow turns to rain, and as previously frozen ground reverts to mud, we shed our long underwear and other arctic attire while watching the landscape transform from brown to a lush green. We do this with the knowledge that in a few months the same landscape may turn brown again from the no longer abundant moisture.
A flush of spring grass is always a welcomed sight, but inherent in that grass growth are potential hidden dangers if not handled properly. Truth be told, we still see a lot of mistakes made with the initial flush of grass.
Don’t be too early
Early spring grass growth initiates from plant energy that’s been stored over the winter. Once enough leaf area develops, photosynthesis begins to drive growth. If too much initial grass growth is removed, or grazed repeatedly, subsequent growth will be slowed, root systems will be compromised, and stands will be less productive for the remainder of the growing season.
Research has shown grazing grass species prior to the four-leaf stage will reduce season-long yields as much as 30%. Over the long term, the benefit of feeding cows to keep them off grass until it is ready will outweigh the cost of reduced grazing capacity. When cattle do begin to graze, don’t allow them to take over 50% of the available forage; in other words, take half and leave half. This allows for faster recovery.
Frequent movement of cattle will also be beneficial to both cattle and grass. Giving grass some time to rest, especially as summer approaches, will enhance long-term pasture productivity.
Weakening pasture stands that will cost you throughout the summer are one thing, but there are also nutritional factors to consider with early spring grass.
Laden with water
Jeff Lehmkuhler, an extension beef specialist with the University of Kentucky, likes to point out that early spring growth is mostly water — as much as 85% to 90%. This means a cow requiring 30 pounds of dry matter intake would have to consume 250 to 300 pounds of actual grass due to the extremely high water content. Pastures that are still short and thin require cattle to expend a lot of energy just walking fields to find enough green grass to fill their rumens.
Grazing is a high-energy activity, and that’s especially true for spring grazing. It requires twice the energy as summer grazing because of lower forage availability and less forage consumed per bite.
Cows may need to be supplemented with energy and/or dry matter in early spring. This decision needs to be based on cow condition in relation to the breeding season, according to Lehmkuhler. Nutritionally balanced cows, in good condition, can go into the grazing season and have no problem maintaining condition and cycling during the breeding season. Unfortunately, that is not always the situation.
Thin cows will have trouble gaining enough weight on spring grass to cycle normally during the breeding season. It is not always guaranteed that cows will gain weight rapidly on lush spring grass.
In one University of Minnesota study, thin cows turned out on spring grass and supplemented with 3 pounds per head per day of dry distillers grains had similar conception rates to adequately conditioned cows not supplemented. Conversely, thin cows turned out on grass and not supplemented had conception rates 12% lower than adequately conditioned cows on grass.
Hay fills a need
The high moisture content of the spring grass will limit a cow’s dry matter intake. For this reason, many extension beef specialists recommend supplementing high-quality hay to add more dry matter to the spring-grazing diet and improve nutritional status.
Lehmkuhler says that cows will not eat much hay, but 5 pounds of dry-hay intake is equivalent to approximately 40 pounds of lush pasture. Allowing access to hay can provide cows an opportunity to boost their daily dry matter intake.
The Gerrish approach
Although an early entry into spring pastures has consequences, so does a late one.
Most experts agree that waiting too long will quickly put you behind from the start. It’s often recommended to begin grazing early but with two big caveats — offer larger areas and keep the animals moving. Both are needed to prevent overgrazing that will be detrimental to subsequent production.
Grazing consultant Jim Gerrish likes to turn out earlier than most — at the two- to three-leaf stage of grass development.
The grazing strategy that Gerrish recommends for minimizing the effect of an explosive spring flush is to get cattle across all the pastures twice in the first 45 to 60 days of the growing season. He moves cattle every day and offers large areas, expecting to complete the first cycle in just 20 to 25 days.
The second cycle is slower and takes 25 to 35 days to get around the paddocks. The objective is to make cattle take a little deeper bite to remove elongating stems. Gerrish explains that when undeveloped seedheads are being elevated from the base of the plant, they are highly nutritious and palatable. As the paddocks are made progressively smaller and stock density increases, there is more likelihood that grazing stock will remove the undeveloped seedheads.
By having the developing seedheads within the stem removed, new tillers are initiated, and these will result in vegetative growth for later in the season. Using this approach, Gerrish reports he has been able to keep seedhead production to just 10% to 20% of the tillers that were vernalized over winter — but the system only works if you’re willing to make frequent moves.
Once grass growth begins to get ahead of consumption, start skipping paddocks that can be used for hay production. This hay can then be used for supplementing summer pastures or fed during the winter.
Correctly managing spring grass growth isn’t easy, but having an effective plan in place will optimize both cattle and grass production for the remainder of the season.
