Livestock farming has emerged as one of the major sources of income in rural areas. The drier and the more underdeveloped an area, the more is the contribution of livestock towards income of the rural people. In livestock farming, the main expenditure is on feeding animals. I account for about 70 percent or more of the cost of production and maintenance of animals. This is particularly true in rural areas where livestock production is more of a family business and labor, and other inputs are minimal. Thus, a proper understanding of the nutritional requirements of the animals, the value of various feeds and fodders, and their optimum utilization can result in saving on production expenses. Moreover, the development of livestock, with the introduction of improved breeds, will not produce desired results unless animals are properly fed, giving opportunity to express their potential.
The animals need feed for maintaining themselves, i.e. for basic physiological processes, as well as restoring wear and tear of various body tissues. This is their maintenance requirement. The other requirements are for growth and production which include reproduction. production of milk, meat, egg, wool etc.
Unveiling the Soil-Plant-Animal Connection
There exists a close relationship between soil, plants, and animals.
The important constituents of animals and plants are water, carbohydrates, protein, fat, minerals, and vitamins, and each of these has specific functions to perform.
In plants, the percentage of water, protein, fat, and minerals varies with the species, as also to a considerable extent with the soil and agro climatic conditions and stage of growth or harvest. In animals, the percentage of the constituents varies with age and nutritional status.
In nature, a definite cycle of nutrient transfer from soil to plant to animals and back to soil is maintained. There is a very significant effect of soil condition on plants and animals. The major soil factors which affect the nutrient uptake by plants and particularly that of minerals are soil pH, moisture, temperature, fertilizer application, and plant species or variety. Some human-induced factors like excessive use of fertilizer particularly nitrogen and heavy irrigation upset the balance and impair absorption of nutrients from soil. Deficiency of minerals, particularly trace minerals, is more often encountered in crops grown in alkaline soils. However, in soil where some minerals, such as molybdenum or selenium, are in excess, introduction of grass would avoid toxicity. Excessive nitrogen fertilizer generally reduces uptake of calcium and magnesium, and there can be excessive nitrogen accumulation in plants.
Soil ingestion contributes substantially to trace minerals obtained by animals. Absorption from such soil may be good, but in some cases its excessive intake may be injurious.
A very direct relation exists between nutritional status of the animals with the type of plants consumed. The nutrients available to the animals depend upon the species and variety of the plant used.
However, with regard to the minerals, the relationship is peculiar. The relative requirement of plants and animals differ, e.g. the requirement of potassium, magnesium, and zinc in plants is higher than that of animals; it is reversed with regard to iodine, cobalt, and sodium. The phosphorus requirement is the same. Thus in some cases, the mineral status of soil may not have the same effect on plants and animals. Herbs and weeds generally have higher concentration of minerals, followed by legumes and lastly the grasses. In ruminants, most of the ingested nutrients are recycled through excreta thus maintaining a balance.
The animals when allowed to graze freely are selective, and by seeking a combination of weeds, legumes, and grass balance the intake. However, with considerable reduction in grazing land and increase in the number as also the production capacity of the animals an entirely different approach to feeding has to be taken. Moreover, in India natural good-quality pasture is very scarce and the availability of green fodder is limited. Most of the farmers have to adopt a straw plus concentrate feeding system. This situation demands a thorough understanding of the types of feed available, possibility of using byproducts and non-conventional feeds as well as improving utilization of crop residues like straw to make the best use of existing resources and also maintain production.