2. Animal Nutrition on the Rangeland
Isfahan University of Technology, Isfahan, Iran
Animal Nutrition
on the Rangeland
(Part 1)
By: A. Riasi
(PhD in Animal Nutrition & Physiology)

3. The topics
Role of ruminant livestock in sustainable agricultural systems
Introducing the grazing animals
Principles of ruminant nutrition
Anatomy and physiology of ruminants digestive system
Advantages of pregastric fermentation
The options for increasing intake on a high quality pasture
Role of energy and protein in ruminant nutrition

4. The topics (continue) Matching nutritional requirements of livestock
Forage sampling and production estimates, plant toxicity and grazing- related disorders.

5. Introduction
Grazing animals are very important for agricultural and natural resources systems.
Introduction
Grazing animals are very important for agricultural and natural resources systems. Of course, they provide meat, milk, and fiber. But grazing animals also can be incorporated into a crop rotation to take advantage of nutrient cycling. Actually, when nutrient cycle efficiently in a pasture system, they move through various soil organisms and pasture plants, then through the grazing animals, and back to the soil again ad manure and urine. They can be utilized to control weeds or to harvest crop residues. Grazing animals can also be an added source of income, diversifying farm enterprises and thereby rendering a farm more sustainable from an economic point of view.
Much of what we understand about livestock nutrition has been developed from studies and experience with confinement feeding operations, where concentrated nutrients in the form of grain, oilseed products, and harvested forages are delivered to animals in a drylot. These types of practices leave out many of the biological and climatological variables that accompany grazing situations: plant species, forage stage of maturity, soil fertility and water holding capacity, annual and seasonal precipitation and mean temperature, etc. As they plan for the nutritional needs of their grazing animals, graziers need to take each of these variables into consideration.
Ranchers are in the business of converting sunlight, water, and carbon dioxide into a high-quality human food source.

6. Efficient nutrient cycle in a pasture system
Introduction
Efficient nutrient cycle in a pasture system

7. Introduction
Much of what we understand about livestock nutrition has been developed from studies and experience with confinement feeding operations.

8. Introduction
The intensive animal rearing systems leave out many of the biological and climatological variables that accompany grazing situations:
Plant species
Forage stage of maturity
Soil fertility and water holding capacity
Annual and seasonal precipitation and mean temperature, etc.

9. Introduction
Grasslands and rangelands occupy a large proportion of the world area.
Grasslands and rangelands occupy a large proportion of the world area. These ecosystems are naturally able to capture sunlight and convert it into food energy for plants. Humans have harvested plant energy for thousands of years since the beginnings of agriculture. Literally millions of tons of plant derived food energy is harvested off arable lands each year. But most of the land in most countries of the world, is not tillable and is considered rangeland, forest, or desert. These ecosystems can be very productive from a plant biomass perspective, but since they are generally non-farmable, the plants they produce (grasses, forbs, shrubs, trees) are not readily usable (from a digestive standpoint) by humans. However, grassland ecosystems (both rangeland and temperate grasslands) produce plant materials that are highly digestible to ruminant animals.

10. Introduction
Ruminant refers to grazing animals that have the ability to digest and metabolize cellulose, or plant fiber, and ferment it to form the volatile fatty acids and microbial proteins that the animal can then digest and use. This is of particular importance to the sustainability of agricultural production systems because grasslands and rangelands have the capacity to produce millions of tons of this energy source. Grazing of native and introduced forages on grasslands and rangeland thus is a very efficient way of converting otherwise non-digestible energy into forms available for human use: milk, meat, wool and other fibers, and hide. This is of particular importance to the sustainability of agricultural production systems because grasslands and rangelands have the capacity to produce millions of tons of this energy source. Camle, Cattle, sheep and goats have the ability to convert plant carbohydrates and proteins into available nutrients for human use, making otherwise unusable land productive. They can be utilized to control weeds or to harvest crop residues. Grazing animals can also be an added source of income (family, regional people and national) , diversifying farm enterprises and thereby rendering a farm more sustainable from an economic point of view. However, proper care of the land and its grazing animals requires a sound understanding of ruminant nutrition.

11. Introduction Ruminants are grazing animals that have the ability to:
Digest and metabolize cellulose (plant fiber), and ferment it to form the volatile fatty acids (VFA)
Produce microbial proteins that the animal can then digest and use.

12. Introduction Ruminants are grazing animals that have the ability:
They can be utilized to control weeds or to harvest crop residues
Convert plant carbohydrates and proteins into available nutrients for human use
Grazing animals can also be an added source of income

13. Introduction Ruminants are grazing animals that have the ability to:
Making otherwise unusable land productive

14. Introduction
Proper care of the land and its grazing animals requires a sound understanding of ruminant nutrition

15. Introducing the grazing animals in Iran
There are nearly 150,000 dromedary camels living in the desert areas (South and Central) of Iran.
This is 0.56% of the world camel population and 3.8% of the Asian camel population (FAO, 2011).

16. Introducing the grazing animals in Iran
Number of sheep, goat and cattle (×1000 head) in Iran during different periods
Adapted from: R. Valizadeh, Ferdowsi University of Mashhad

17. Some important characteristics of sheep and goat rearing in Iran
Owned by small farmers
Based on extensive grazing
Highly influenced by the environmental variables (rain fall, weather, feed supply, drought etc.)
Economic variability due to uncertainty in feed availability, weather, rainfall, market, export and import animal products mainly food materials

18. Some important characteristics of sheep and goat rearing in Iran
Its number or increment rate is declining in comparison with the past decades because of urbanizations industrialization, low income, etc.
Genetic structure and physiological characters of the most Iranian sheep and goats are not clear
No comprehensive standard investigation had been carried out on distinguishing different breeds of these animals

19. Some important characteristics of sheep and goat rearing in Iran
What is known as breed of sheep or goat is based on the apparent physical conformation
All of the Iranian sheep breeds, except one (Zel breed) are fat-tail types
Although Iranian sheep and goats are grouped according to their main product, but generally they are kept for providing different products or sources of income including: meat, milk, fiber and hide

20. Some important characteristics of sheep and goat rearing in Iran
These small ruminants are resistant to high level of inorganic minerals in feeds and forages
Iranian sheep and goat live and produce over a remarkable wide range of environments from the desert type dry and warm climate to the mountainous cold zones
Iranian sheep and goats appear in different color from white to the completely black and many classes between

21. Some important characteristics of sheep and goat rearing in Iran
Iranian sheep produce mainly coarse fiber which is suitable for Iranian carpet industry
Most of Iranian breeds are high–set animals which is a suitable character for grazing over the rocky and mountainous areas

22. Importance of the nutrition of grazing animal
In grazing situations, ruminant nutrition affected by different biological and climatological variables:
Plant species
Forage stage of maturity
Soil fertility and water holding capacity
Annual and seasonal precipitation
Mean temperature and etc
Much of what we understand about livestock nutrition has been developed from studies and experience with confinement feeding operations, where concentrated nutrients in the form of grain, oilseed products, and harvested forages are delivered to animals in a dry-lot. These types of practices leave out many of the biological and climatological variables that accompany grazing situations:
plant species,
forage stage of maturity,
soil fertility and water holding capacity,
annual and seasonal precipitation,
mean temperature, etc.
As they plan for the nutritional needs of their grazing animals, graziers need to take each of these variables into consideration.

23. What are seven principles of ruminant nutrition?
1- Ruminants are adapted to use forage because of microbes in their rumen.
2- To maintain ruminant health and productivity, feed the rumen microbes, which in turn will feed the ruminant.
3- Ruminant nutrition needs change depending on age, stage of production, and weather.

24. 4- Adequate quantities of green forage can supply most- if not all- the energy and protein a ruminant needs.
5- Forage nutritional composition changes depending on plant maturity, species, season, moisture, and grazing system.

25. 6- Supplementation may be necessary when grass is short, too mature, dormant, or if animal needs require it (high-producing dairy animal).
7- Excessive supplementation may reduce the ability of the rumen microbes to use forage.