Reducing the Use of Herbicides through Target Grazing
Wednesday, October 7, 2009 at 11:43AM 
Targeted grazing is defined as “the application of a specific kind of livestock at a determined season, duration, and intensity to accomplish defined vegetation or landscape goals” (Target Grazing Book, pg 11). Recent research is showing that the use of targeted grazing is an effective means of controlling weed growth in grazing lands. This seems like an excellent way to diminish the use of harmful chemicals in herbicides, while simultaneously providing food for livestock on the farm. By training livestock to eat weeds as well as conventional vegetation, the land ends up more fertile.
When utilizing livestock as a means to control weed population, there are numerous factors to be considered. Timing is one issue. When weeds are in their early stages, their nutritional content is high, and their toxin content is low. However, in later stages, this reverses, with nutritional content decreased, and toxin content increased. Another consideration is the type of livestock to be used. Cows, goats, and sheep all have different preferences in land type, as well as vegetation type. By choosing the correct livestock (or an optimal mix of livestock), it could be ensured that the maximum amount of weeds would be consumed.
The process of training livestock to eat weeds is not incredibly difficult. Exposing livestock to the target weed at a young age (considering the animal’s natural preference of vegetation type, i.e.: grass, shrub, etc.) in the presence of other familiar foods is one way to begin the training process.
Whether or not this practice could be stretched from grazing lands to vegetables is not yet determined. It would seem that after several generations of training livestock to eat specific foods, they would be more likely to “prefer” eating weeds; however, it seems likely that if they got even one taste of a “sweeter” vegetable, that that training would be quickly forgotten.
Ryan Town
There is an entire book on this subject available for free online.
Reader Comments (4)
This is very interesting. I hadn't known before about how goats can be trained to eat certain plants; I had thought they just ate everything. I am wondering what else these animals can do for the farm. Could we use them to produce milk, or would the flavor be tainted due to the weed-diet?
Could we do this as a joint effort with the another department at WSU? ie. could we just bring in the goats or other animals when we needed the weeds eaten and then return them and have them housed elsewhere?
This is really cool...I never knew goats could be trained to eat certain things. It was mentioned that their training may be lost if they tasted one "sweeter" plant. Has this ever been tried before at different farms? What did they do to reinforce the training?
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