Spring is the time when pastures in the upper Midwest experience a renewal after a cold winter—its arrival does not necessarily follow the calendar date but more of the soil temperatures needed to re-activate the perennial pasture plants. Spring also brings with it challenges related to grazing. Since plants are waking up after a long winter period some of the spring grazing questions relate to timing; how soon can I move my cattle into pastures? how long should I allow the animals to graze the same pasture? how long should I the rest the pasture in between grazings? There are other challenges that may need to be addressed before we even think about grazing such as presence of winter injury or the need for reseeding or renovation. Other considerations relate to the logistic side of grazing and pasture management such as fence condition, degree of weed control and fertilization needs.
As soon as possible evaluate your pastures for winter kill
The combination of lack of snow cover, and extreme cold in the Upper Midwest brought by the polar vortex may have a negative impact on pasture vegetation and be responsible for winter injury in some fields. The impact of frigid temperatures will not be evident until later in spring, but an evaluation of live plants is a critical first step. Different locations set all-time record low; as soon as the weather permits check your field for winterkill, sample different locations by digging plant material. Usually less than around 10 plants per square foot are not deem economical.
How soon can I move animals into pasture?
Caution is advised when deciding to initiate spring grazing. During this time, daylength and temperature are on the increase, which favors higher growing rates of forages leading to less fiber in the forage compared to other seasons of the year. Allow sufficient time for the forage to have initiated the spring regrowth where full leaves are grown. Have and have a plan in place to deal with excess forage later in the spring. Part of that plan may be to hay the excess forage or to graze the pastures using two or more groups; have a grazing group with higher needs such as your milking herd graze first, and immediately followed by a second group with less nutritional requirements such as dry cows. If deciding on early grazing, try to use a different paddock each spring.
Spring forage is usually very high in protein and low in fiber resulting in diarrhea or depending on pasture botanical composition bloat can be present if animals are brought into pastures with immature clovers or alfalfa. Also, allow for a gradual transition from stored forage into pastures over a two-week period.
Another consideration for when to start grazing has to do with how wet your pastures are. Moving cattle in when the paddocks are too wet may cause unnecessary compaction of the soil due to hoof action.
How long should animals graze and rest the pasture?
Grazing is a compromise between quantity of forage available and quality of that forage. The longer animals remain in a paddock the higher the chances that they will go back to the same spot that they had grazed when they first entered the paddock not allowing for that plant to build reserves for regrowth of grazed leaves. If pastures are adequately stocked, the grazing will be uniform, and they should be ready to move into the next paddock after two or three days of grazing, but this could extend to a week depending on pasture condition. The height of the canopy should be an indicator of when to move into the next paddock. Half of the canopy should be grazed and about half should remain in order for the plants to make new leaves and build reserves before next grazing.
Grazing rotations vary depending on the operation. For example, grazing of dairy cattle is usually intense and consist of short utilization periods (half a day) with rest periods that are shorter (three weeks). Beef cattle operations may have grazing rotations consisting of 3-4 days of grazing and four weeks of pasture rest period.
- Check pasture fences. Following winter your fences may have debris, fallen trees, or may be damaged from previous grazing season. Walk and check your permanent and temporary fences. During spring the soil is soft and makes it simpler If needing to replace posts, grounding system, wires and/or braces.
- Needs for weed control and fertilizer. Scout your pasture for weeds, and if needed, do the control early in the spring when actively growing but before you fertilize the pastures. Control weeds first then apply fertilizer or manure as needed. If your pastures are too wet to graze, take advantage of the situation and control your pasture weeds.