By Jeff Lehmkuhler
When should I start feeding hay to my beef cows? This seems like a simple question with a simple answer. However, as with many questions, there often is not a single perfect answer. Being an academic, I have to justify my existence by taking a simple question and making it complex, right? The simple answer is to start offering hay when there is insufficient pasture forage to meet the herds’ needs. The difficult question then becomes when is there not enough pasture forage to meet the herds’ nutritional needs?
You can search the internet for this and find pages of discussions on forums. If you take some time to read through the forum responses, you can quickly begin to learn many factors can trigger when managers begin offering hay. Location impacts growing season and forage species. Drought and precipitation enters the discussion as it relates to forage availability in the pastures. Frost and the cessation of forage growth pops into the responses. Flooded pastures in our coastal regions which lowers access to forage submerged by water has to be considered. Weather forecast such as an extreme cold or snow that covers up grass triggers some to put out hay. Calving season is a consideration by some. Deer season comes into play when cattle are on leased land and the desire to bring cattle home before Bessy is mistaken for a large whitetail. Mud and the impact of grazing stockpiled forage is also a factor. Availability of crop residues like corn stalks is also a factor added into the discussion. There are other factors that could be added, but this list illustrates that there is not a single factor triggering a manager to start feeding hay.
From the animal perspective, forage availability is the major factor that would trigger when to start feeding hay. Many factors can impact forage availability. Factors can include drought, flooding, deep snow or ice, timing of planting, soil fertility and stocking density. Forage availability directly influencesvintake levels of grazing animals. A summarization of research has demonstrated that intake for sheepvand cattle is maximized when forage availability is near 2,000 lbs of dry matter per acre. When foragevavailability declines to approximately 1,000 lbs of dry matter per acre, only 90% of maximum intake canvbe achieved resulting in nutritional restriction. Grazing activity greatly increases energy expended byvthe animal. Sheep, for instance, were found to have 170% greater energy expenditure when grazingvcompared to sheep that were not grazing. Much of this increased energy expenditure was explained by a 134% increase in walking. Additional research has demonstrated that grazing activity increases energy cost to the animal 15 to 16 fold over just walking. I guess this supports the saying there is no free lunch.
Production efficiency will be reduced as energy needs increase to compensate for greater distances traveled as forage availability becomes limited. At some point, energy expended for grazing activity will exceed energy consumed. Offering hay should ideally be initiated at the point that maximal intake cannot be achieved. If one were to estimate 90% ground coverage for a cool‐season forage and assume 250 to 300 pounds of dry matter per inch of height per acre were present, one could monitor forage height as an indicator of when hay feeding should begin. For example, at a 3 to 4 inch height, the forage availability would be estimated to be 750 to 1,200 lbs/acre. Based on the aforementioned research, maximal intake expected would be 75 to 90%. This intake limitation will impact performance.
When deciding on late season grazing management, one also should consider the potential impact on forage growth the following spring. Research has demonstrated that grazing stockpiled tall fescue can lead to a decrease in forage production the following spring. This may be viewed as a negative, yet, it can be incorporated into part of the forage management. Setting aside separate pastures or paddocks for stockpiling and grazing can help you plan the spring grazing movements of livestock. Areas not grazed in the fall would be expected to have faster spring forage accumulation, allowing earlier spring grazing on these pastures and provide time for fall stockpiled grazed areas to recover. Grazing stockpiled fescue fields short will promote increased seed‐to‐soil contact when frost‐seeding legumes, enhancing establishment while reducing fescue competition in the spring. Consider your management objectives for areas of the farm can help plan late season and winter grazing.
When should you start feeding hay? I would suggest hay feeding be initiated earlier than later. A potential trigger point may be when forage height reaches about 4 inches for tall fescue‐based pastures. As forage availability declines hay intake will increase. Access to hay will allow for a greater opportunity for livestock to achieve maximal intakes and in turn performance. We took a relatively easy question and complicated it while perhaps not giving a bullet‐proof answer. As is the case with many of these questions, the answer depends on your management objectives. Hopefully you have something to chew on this winter with respect to grazing management and factors that can trigger the initiation of hay feeding.