Sheep and goats have been used for centuries by man to provide meat, fiber, and milk. But, just recently increasing interest has been shown in these small ruminants for various reasons and one being for their ability to manipulate forage to accomplish a variety of land management objectives, which benefit not only man but also the environment. I can remember about 50 years ago, when I was growing up, we would purchase a few sheep each summer to control weeds around the farmstead and especially in the cattle lots. It was not very long and we added a flock of sheep to our diversified farming operation.
Biological control is the deliberate introduction or manipulation of a pest’s natural enemies, with the goal of suppressing the pest population. This process has been used to manage insects, pathogens and weeds. Biological control is not intended to eradicate the target weed, but rather to put enough pressure on the pest to reduce its dominance to a more acceptable level. Biological weed control is environmentally safe, self-perpetuating and cost effective and is suited to an integrated weed management program. However, it does have one limitation. It is a long-term undertaking sometimes it is as long as three years before you see results.
Although slow in coming, biological weed control may have a major impact on managing weeds in pasture systems in the future. Sheep and goats are currently being used throughout the Great Plains to control noxious weeds. Many of these weeds could not be controlled by means of chemical, mechanical or cultural practices due to the high cost associated with these control methods or their relative ineffectiveness.
One such weed is leafy spurge which has consumed many acres in rangelands of Nebraska. These plants are very competitive and they quickly crowd out all other plants to form a monoculture. Cattle will not consume leafy spurge because of digestive distress caused by the latex-like sap it contains. Another pasture pest is the Western Red Cedar. This tree is infesting many pastures throughout the state and is causing large economic losses from decreased carrying capacities of these pastures.
Grazing management can be used to minimize the spread of certain weeds and to control large infestations. For grazing to be effective animals might have to be fenced into or off an area in order to adjust grazing pressure. The ability to concentrate stock on weed infestations at some stages of growth or certain times of the year and the ability to keep them off pasture or weeds at other times, is the key to weed control.
The livestock producer has to know the animals’ wants and nutritional needs and at the same time understand the desirable grasses growth patterns and also understand the weeds weak points and manage them in a way as to achieve your goals. This is called pasture management.
Source: Tom Drudik, UNL
