Watching cattle graze and asking why they eat what they do, can be considered a waste of valuable time for some, but not when the manger is seeking to accomplish the goal of rangeland improvement and understanding why certain things are happening to the rangeland resource, the study can be quite interesting.
At first glance, what the cow, sheep or goat eats appears to be somewhat indiscriminate, as she has her head down and does not appear to be focusing on certain plants. However, when she bites into a plant that seems to have a better flavor-more succulent-easier to chew- more nutritious??-contain a particular nutrient that she is craving??, she will concentrate on that plant for a few moments then move to the next area. (One thing of note: The higher the density of grazing animals in a given area the less discriminant they are. Competition for grazing space can be an interesting aspect of how the grassland manager manipulates his livestock.)
What plants do they prefer? Why are some grazed shorter than others at first bite? (Switchgrass, Indiangrass, Kline grass, Sideoats and many others will have the top 1/3 to ½ of the plant grazed the first round. Other plants will be grazed to a noticeably short level up to 90% the first grazing even in good growing conditions, but then totally avoided during other times. (Old World Bluestems, Rough Tridens and Sand Drop Seed)
‘Take half leave half’ I wonder. Each plant appears to have developed growth characteristics that promote survival and adaptation to the grazing animal’s preferences. Grassland management is not an exact science. The many variables cause for numerous undeterminable equations.
THE BETTER IT GETS THE FASTER IT GETS BETTER.
Pictures depict Switchgrass prior to and after one day of grazing. It is a highly preferred grazing plant.