Apr 08, 2011
Understanding Cattle & Women?
Understanding why cattle select certain forage species or certain plants/weeds within a given species is about as well understood as why women need so many shoes when they only have two feet and why they need company to go to the ladies room when out with friends?!
Cattle and forage interactions are complex. Just like women! And I’m sure there are plenty of Cattlewomen that are puzzled about us Cattlemen and why we do what we do on a daily basis! Defoliation or grazing patterns are dependent on factors such as the amount of time cattle are allowed in a specific area to graze, the time of season the forages are grazed, species of forages and length of the growing season in your area.
When pastures are grazed two or more times, initially un-grazed grasses or weeds are less likely to begrazed in following rotational grazing periods. Preferred forage species are consistently consumed more intensively and frequently than less preferred species regardless of the grazing schedule or stocking rate.
Grazing schedules and stocking rates may have little effect on the height at which forages are grazed. Intensity and frequency of grazing tend to be greatest when plant growth is most rapid. An example would be Alfalfa (a cool season legume), in the spring and fall. The intensity and frequency of grazing increase linearly as forage allowance decreases in the fall after a "Killing Frost".
PLANT RESPONSE TO GRAZING
Plant response to grazing is dependent upon the degree and frequency of grazing, and the stage of plant maturity. Recovery of the forages will depend upon the amount of green leaf and stem area that remains after grazing, growing conditions, and competition from adjacent plants/weeds. If soil moisture and air temperatures are not favorable for plant growth, little or no recovery will occur like what happened here in the North-East last season. If the forages become dormant before stems and leaves are replenished, late season overgrazing reduces plant vigor more than early season over use. When favorable growing conditions occur, rate of recovery increases as the amount of remaining plant increases. Competition from un-grazed adjacent plants and/or weeds may reduce recovery even if favorable growing conditions do occur, especially when grazed plants have been over-grazed. While uniformly heavy grazing (MOB Grazing), across all species will reduce competition, the desirable effects of MOB grazing must be balanced against undesirable effects on your cattle, pasture/paddock stability, watershed protection, and aesthetic values (the way the pastures look).
Proper utilization of most forages is removal of 50% or less of the present, current year leaf and stem tissue by weight. A simple procedure can be used to develop a visual perception of percentage forage utilization. Clip the current year growth from random bunches of your forages at the ground level. Wrap the samples with string or tape. Balance each sample on your finger. The point of balance is the height at which 50% of the leaf and stem tissue would be removed. Clip the sample at this point and balance each half to estimate heights for 25 and 75% utilization. Proper utilization will cause little reduction in root growth and plant vigor. Grazing in excess of 60% will cause dramatic reduction in amount and depth of root growth.
MOB grazing is very detrimental under drought conditions. During the drought that occurred in our area last season, drought-induced death losses of grasses in pastures were extreme under heavy grazing and moderate to not different when moderately grazed, compared to un-grazed pastures. So far this season it doesn't appear that moisture is going to be a problem. We've otten so much snow and rain in the last 2 months that getting into the fields to plant or getting out cattle on pasture may be delayed due to too much moisture. Our friends in Montana wish they had a moisture over abundance! Is there a happy medium between drought and drowning?! Add that question to the list of things we may never figure out. Like our women.