WildRoseBeef
Range nerd & bovine enthusiast
...that anyone wishes to share! 
Grazing Systems (from Forages: An Introduction to Grassland Agriculture, 6th ed. Vol.1)
Grazing System: integrate the components of animal, plant, soil, environment, management and other factors with the intent of accomplishing specific goals or outcomes.
Grazing systems are site specific, so they need to be described in terms of:
- Land: soil type, salinity, erosion potential and history, and fertility status
- Plants: species, varities, weeds, stage of growth relative to periods of use, percentage ground cover, forage mass
- Animals: number, kind, sex, size, production status, and age
- Management: intensity, grazing methods, number and size of paddocks, irrigation, fertilization, pesticide use, harvest events
- Location: latitude, longitude, elevation
- Climate: temperature, precipitation, humidity, season of the year.
Animals' and plants' responses and behaviours are different from that observed when managed alone. This is because each piece of a system behaves as a consequence of its relationships with other parts of the system. When that piece is managed in isolation away from the influence of the other system components, it is no longer under the same influences and may behave differently.
Grazing is usually the least expensive means of feeding livestock because costs of buildings, equipment, and labour associated with stored forages or purchased feeds are reduced or eliminated. It is almost always more profitable when livestock harvest their own feed. However, designing grazing systems that can ensure an adequate daily supply of forage for each animal on a year-round basis is challenging. Forage species differ in their season of growth and use. Livestock differ in their nutritional needs depending on their age, production status, or use for work. Matching the seasonal potential for quality and quantity of forage growth to the livestock's need for nutritional quality and feed quantity is one of the major challenges in grazing-system design. When successfully achieved, needs for harvesting or purchasing feeds are minimized or eliminated and profitability is generally improved.
Grazing systems must address many objectives:
- Provide the appropriate quality and quantity of forage for the livestock present.
- Ensure survival of the forage stands, promoting healthy, vigorous plant growth, and maintaining the desired botanical composition.
- Obtain the desired quality of life for the manager
- Protect the environment while conserving natural and nonrenewable resources.
Increasingly, other objectives also must be considered:
- Develop and protect wildlife habitat
- Sequester carbon from the atmosphere
- Reduce soil loss from wind and water erosion
- Protect water quality and quantity, animal health and welfare, animal product quality and safety.
- Protect aesthetic value and open space
- Offer hunting, eco-tourism, or recreational opportunities
In the future, integrating grazing systems with cropping systems may offer one of our best opportunities to manage and protect our natural resources while providing an economic return and maintaining needed levels of food and fibre production to meet the needs of an increasing global population. (Why, this is already happening, particularly with what is called crop-residue grazing or aftermath grazing.)
Grazing Management
Grazing management involves manipulation of the soil-plant-animal complex to achieve the desired results.
Grazing management can be made more intensive or more extensive. Intensive grazing management uses additional inputs of resources, labour, or capital to increase livestock production per acre or per head or to improve forage production and utilization. Extensive grazing management uses lower optimum inputs of labour, resources and capital to achieve profitable and sustainable plant and animal production.
More or less intensive systems are not "good" or "bad." In fact, managers do not simply choose between extensive and intensive systems, they select from a continuum of possible inputs that might include more managerial time, more fertilizer nutrients, more fencing, or other inputs. Choices are influenced by assessment of input costs in relation to the value of the anticipated productivity increases and economic return. The inputs chosen first are often those judged to be most limiting, i.e., those with the greatest likelihood of increasing productivity or efficiency of production. Many weather, soil, plant, animal, and environmental impact considerations must enter into the decision.
Management strategies and intensity of management must also fit the lifestyle goals and abilities of the manager. Systems that demand intense management will not work well in situations where circumstances compete for time and energy required to manage such systems no matter how well suited the system may be in other respects.
Nomenclature of Grazing Systems
The term animal unit(AU) was developed to facilitate comparison of different kinds of livestock. An animal unit is defined as an 1100 lb (500 kg) nonlactating mature cow (Bos taurus) fed at maintenance or its equivalent in other kinds and classes of livestock. Defining the equivalent presents challenges and has been the subject of much debate. An often used general rule of thumb suggests that five ewes (Ovis aries) are equivalent to on mature cow or one horse (Equus cabalus).
Forage mass is the amount of forage dry matter per unit land area at a single point in time. Forage yeild is the total mass of forage produced per unit of land area over a period of time. Forage allowance is a relationship between forage mass per unit area and the number of animal units at any given point in time. At high allowance levels, each animal as a large amount of forage available from which to choose its diet. Performance per animal generally increases as forage allowance is increased up to some point, after which it will level off.
Stocking rate is an animal-to-land relationship measured over a defined time period. Stocking density refers to the animal-to-land relationship at a single point in time. Grazing pressure is a ratio of animal units to forage mass. When grazing pressure is low (i.e., few animal units per unit of forage mass) forage supply exceeds animal needs. Individual animal performance may be high due to selective grazing and/or optimum bite size, but output per unit of land area is decreased because forage is wasted. In this case, increasing grazing pressure may increase output per unit area. However, as grazing pressure continues to increase, performance per animal and per acre will begin to decline.
Grazing Methods
Grazing methods are grazing management procedures designed to achieve specific objectives.They are used to achieve specific defoliation strategies for plants or to allocate nutrition to different classes of livestock. They may influence nutrient recycling or be used to discourage trailing, a social behaviour in which cattle move in single file, forming paths of bare soil that can lead to soil erosion or streambank degradation. There are many grazing methods: rotational and continuous stocking, creep grazing, first-last grazing, sequence grazing, strip grazing, buffer grazing, frontal grazing, and others. No one grazing method is the best. Each is designed to accomplish specific objectives; thus, choosing the correctt method is critical to success. Indeed, several different grazing methods are usually included within a grazing system.
[These methods and more I will cover later.]
Grazing Systems (from Forages: An Introduction to Grassland Agriculture, 6th ed. Vol.1)
Grazing System: integrate the components of animal, plant, soil, environment, management and other factors with the intent of accomplishing specific goals or outcomes.
Grazing systems are site specific, so they need to be described in terms of:
- Land: soil type, salinity, erosion potential and history, and fertility status
- Plants: species, varities, weeds, stage of growth relative to periods of use, percentage ground cover, forage mass
- Animals: number, kind, sex, size, production status, and age
- Management: intensity, grazing methods, number and size of paddocks, irrigation, fertilization, pesticide use, harvest events
- Location: latitude, longitude, elevation
- Climate: temperature, precipitation, humidity, season of the year.
Animals' and plants' responses and behaviours are different from that observed when managed alone. This is because each piece of a system behaves as a consequence of its relationships with other parts of the system. When that piece is managed in isolation away from the influence of the other system components, it is no longer under the same influences and may behave differently.
Grazing is usually the least expensive means of feeding livestock because costs of buildings, equipment, and labour associated with stored forages or purchased feeds are reduced or eliminated. It is almost always more profitable when livestock harvest their own feed. However, designing grazing systems that can ensure an adequate daily supply of forage for each animal on a year-round basis is challenging. Forage species differ in their season of growth and use. Livestock differ in their nutritional needs depending on their age, production status, or use for work. Matching the seasonal potential for quality and quantity of forage growth to the livestock's need for nutritional quality and feed quantity is one of the major challenges in grazing-system design. When successfully achieved, needs for harvesting or purchasing feeds are minimized or eliminated and profitability is generally improved.
Grazing systems must address many objectives:
- Provide the appropriate quality and quantity of forage for the livestock present.
- Ensure survival of the forage stands, promoting healthy, vigorous plant growth, and maintaining the desired botanical composition.
- Obtain the desired quality of life for the manager
- Protect the environment while conserving natural and nonrenewable resources.
Increasingly, other objectives also must be considered:
- Develop and protect wildlife habitat
- Sequester carbon from the atmosphere
- Reduce soil loss from wind and water erosion
- Protect water quality and quantity, animal health and welfare, animal product quality and safety.
- Protect aesthetic value and open space
- Offer hunting, eco-tourism, or recreational opportunities
In the future, integrating grazing systems with cropping systems may offer one of our best opportunities to manage and protect our natural resources while providing an economic return and maintaining needed levels of food and fibre production to meet the needs of an increasing global population. (Why, this is already happening, particularly with what is called crop-residue grazing or aftermath grazing.)
Grazing Management
Grazing management involves manipulation of the soil-plant-animal complex to achieve the desired results.
Grazing management can be made more intensive or more extensive. Intensive grazing management uses additional inputs of resources, labour, or capital to increase livestock production per acre or per head or to improve forage production and utilization. Extensive grazing management uses lower optimum inputs of labour, resources and capital to achieve profitable and sustainable plant and animal production.
More or less intensive systems are not "good" or "bad." In fact, managers do not simply choose between extensive and intensive systems, they select from a continuum of possible inputs that might include more managerial time, more fertilizer nutrients, more fencing, or other inputs. Choices are influenced by assessment of input costs in relation to the value of the anticipated productivity increases and economic return. The inputs chosen first are often those judged to be most limiting, i.e., those with the greatest likelihood of increasing productivity or efficiency of production. Many weather, soil, plant, animal, and environmental impact considerations must enter into the decision.
Management strategies and intensity of management must also fit the lifestyle goals and abilities of the manager. Systems that demand intense management will not work well in situations where circumstances compete for time and energy required to manage such systems no matter how well suited the system may be in other respects.
Nomenclature of Grazing Systems
The term animal unit(AU) was developed to facilitate comparison of different kinds of livestock. An animal unit is defined as an 1100 lb (500 kg) nonlactating mature cow (Bos taurus) fed at maintenance or its equivalent in other kinds and classes of livestock. Defining the equivalent presents challenges and has been the subject of much debate. An often used general rule of thumb suggests that five ewes (Ovis aries) are equivalent to on mature cow or one horse (Equus cabalus).
Forage mass is the amount of forage dry matter per unit land area at a single point in time. Forage yeild is the total mass of forage produced per unit of land area over a period of time. Forage allowance is a relationship between forage mass per unit area and the number of animal units at any given point in time. At high allowance levels, each animal as a large amount of forage available from which to choose its diet. Performance per animal generally increases as forage allowance is increased up to some point, after which it will level off.
Stocking rate is an animal-to-land relationship measured over a defined time period. Stocking density refers to the animal-to-land relationship at a single point in time. Grazing pressure is a ratio of animal units to forage mass. When grazing pressure is low (i.e., few animal units per unit of forage mass) forage supply exceeds animal needs. Individual animal performance may be high due to selective grazing and/or optimum bite size, but output per unit of land area is decreased because forage is wasted. In this case, increasing grazing pressure may increase output per unit area. However, as grazing pressure continues to increase, performance per animal and per acre will begin to decline.
Grazing Methods
Grazing methods are grazing management procedures designed to achieve specific objectives.They are used to achieve specific defoliation strategies for plants or to allocate nutrition to different classes of livestock. They may influence nutrient recycling or be used to discourage trailing, a social behaviour in which cattle move in single file, forming paths of bare soil that can lead to soil erosion or streambank degradation. There are many grazing methods: rotational and continuous stocking, creep grazing, first-last grazing, sequence grazing, strip grazing, buffer grazing, frontal grazing, and others. No one grazing method is the best. Each is designed to accomplish specific objectives; thus, choosing the correctt method is critical to success. Indeed, several different grazing methods are usually included within a grazing system.
[These methods and more I will cover later.]
