To cut costs this winter, Sandy Smart, Professor & SDSU Extension Rangeland Management Specialist suggests cattle producers leave their balers in the machine shed and put their cattle to work.
“Swath grazing can be an effective strategy to extend the grazing season and reduce costs to livestock operations,” Smart said. “Think of the time and money cattle producers will save by having their cattle harvest the resource instead of spending the time and money it costs to bale and feed hay.”
Efficiency of grazing increases after a killing frost
Although grazing is an inefficient process (see Fig. 1), during the growing season, when residual leaf material is needed to maintain plant vigor – however after a plant sets seed or after a killing frost grazing becomes an efficient and effective tool.
“At this point in the growing season, less residual leaf material is needed to ensure plant vigor and therefore a greater grazing pressure can be applied to increase the harvest efficiency,” Smart said.
Smart suggested harvest efficiency may increase as much as 50 percent under very heavy stocking rates or grazing pressures that approach 50 animal unit days (AUD per Megagrams) (Fig. 1).
By contrast, Smart said haying could be as high as 80 percent efficient depending on the cutting height. Combining the advantages of these two techniques (high harvest efficiency of cutting and low labor costs of grazing) is the underlying principle behind swath grazing.
Harvest efficiency of swath grazing can be calculated by multiplying the efficiency at harvest time by the efficiency of grazing the swaths in the fall and winter.
If it is assumed 80 percent harvest efficiency at cutting and a 75 percent efficiency during the grazing of the swaths. Therefore we would realize a 60 percent overall harvest efficiency (80% x 75%).
In order to increase the grazing efficiency, Smart suggested strip grazing the swaths can help to lessen the wastage (Figs. 2 and 3).
How it works?
On the operation used for the example in Figures 2 and 3, Smart explained that the producer spends about half an hour per day moving the temporary electric fence to allocate new swaths.
“Feeding hay using round bales would take a similar amount of time but would also include the costs of running the tractor,” Smart explained. “Therefore, the producer is eliminating the costs associated with baling and bale moving portions of the haying enterprise.”
Before implementing swath grazing, Smart reminded cattle producers to consider and plan for water availability.
In addition, he added that cattle producers should test the nutrient content of the swaths prior to grazing so appropriate adjustments in supplements can be made.
“Most likely some level of protein supplement would be required,” Smart said.