ATHEN, Ohio -- For livestock producers wanting the most out of their pastures, measuring forage dry matter content before and after livestock grazing is the most effective way of managing an intensive grazing system.
Pasture measurement allows a grazier to determine how much forage dry matter is available in a pasture paddock, and once that is estimated, the producer can figure out how many animals should be grazed for a given period of time.
"Pasture measurement will help the grazier to make decisions about how to best use pasture paddocks and over time will provide a trend of how much forage dry matter is being produced per week," said Rory Lewandowski, an Ohio State University Extension educator in agriculture and natural resources. "Using this type of information can help a grazier plan the livestock rotation for periods of rapid growth as well as periods of slow growth. The trend can provide an early warning system in a drought year and help the grazier plan accordingly."
Lewandowski offers some strategies for taking pasture measurements. One strategy is to measure a paddock due to be grazed on a weekly basis.
"This will help to give you an idea about your rotation speed. If you are consistently measuring 2,400 to 3,000 pounds of forage dry matter per acre in paddocks about to be grazed, this indicates the rest period has been long enough," said Lewandowski. "If forage dry matter is less than 2,200 pounds per acre, then rotation speed should be slowed down to allow the pasture more time to recover and grow."
Another strategy is to measure the paddock before and after animals are turned out.
"These additional measurements will give you information about how you are managing plant residual, an important part of how quickly a plant recovers from a grazing pass. Most pastures should be managed so there is 1,200 to 1,400 pounds of forage dry matter after animals have grazed," said Lewandowski. "The other advantage of this strategy is that you will get a good idea of pasture growth rate in terms of how much dry matter is being added per acre each week."
To take pasture measurements, the most economical option is to use a pasture stick. The current pasture stick model being used in Ohio has a scale to measure forage height, a scale to estimate forage density, a table of pounds of dry matter per inch for various pasture forage types, information about length of grazing rotations, and information about calculating the pounds of dry matter available for grazing.
The basic steps involved in using the grazing stick are:
Another option to measure pastures is the rising plate meter, which has a built-in counter.
To use the rising plate meter, record the beginning number on the counter, make 30 measurements, and record the end number. Then subtract the end number from the beginning number and divide that result by the number of measurements to get an average. Multiply this average by a conversion factor (currently 107.04) for cool season grass pastures. Use this number as the total forage dry matter acre and follow the steps outlined for the pasture stick to make the remaining animal use calculations.
"The plate meter is quicker, but the cost of this instrument is about $450, compared to $5 to $7 for the pasture stick," said Lewandowski. "It is important for graziers to put some effort into pasture measurement if they want to increase their pasture management skills. Pasture measurement can help to take some of the guesswork out of allocating pasture forage and it can help to reduce the slope of the learning curve associated with management intensive grazing."
SOURCE: Ohio State.