The most important condition for maintaining the health of farm animals and increasing their productivity is the organization of proper feeding on the farm. The diet for cattle, small cattle, pigs, rabbits and others should be developed as balanced as possible. The nutritional value of the feeds offered to agricultural animals can be determined by different methods.
Classification
Fodders can be used on farms specializing in the cultivation of agricultural animals:
The first variety includes mainly root crops and silage. Coarse feed is grass, hay and straw. Concentrates are the most nutritious and expensive food for animals - whole or rolled grain, crushed, bran. Compound feeds can also be used on farms. They are usually a mixture of concentrates and roughage. Such formulations are also characterized by a high degree of nutrition and relative high cost.
Quality assessment should be carried out on farms for all types of feed used. In this case, the ration is developed depending on which animals are raised on the farm.
How is the assessment made?
Judge the quality of the proposed productive animal feed, taking into account the following factors:
- organoleptic properties;
- energy concentration;
- nutrient content;
- quality class;
- eatability.
By organoleptic properties are meant primarily:
- taste, color, structure, smell of feed;
- degree of its pollution;
- the presence of various kinds of undesirable impurities or poisonous plants in it.
Taste and smell are very important properties of the feed. To a large extent, the eatability of the food offered by animals depends on them. Cows, pigs, sheep, horses, etc. are able to distinguish between sour, sweet, bitter and salty tastes.
The concentration of energy refers to the number of feed units (k. Units) in 1 kg of food offered to animals. When evaluating the nutritional value of the feed, the percentage of its protein, carbohydrate, fiber, biologically active substances and trace elements content is determined.
A bit of history
Scientists began to develop methods for evaluating feed in the XVIII century. Over time, these technologies have improved. Initially, food for animals was mainly evaluated only by chemical composition. Nutrition of feeds was first proposed to be determined by Eingof and Davy.
Later, feed began to be divided into water and solids, isolating soluble and insoluble, nutritious and useless from the latter. After some time, hay and nitrogen equivalents were taken. Then came the concept of digestible nutrient.
In the middle of the XIX century. The German scientist Geneberg laid the foundations of a modern zootechnical analysis of feed. This researcher divided nutrients into five main groups.
Modern assessment methods
Currently, when determining the quality of feed, all nutrients are divided into:
- crude fat;
- IDA;
- crude protein;
- biologically active substances;
- crude fiber.
For the convenience of determining the quality, special tables have been created by which you can find out the percentage ratio of these components in one form or another of the feed. For example, clover contains 17% protein, 3% fat, 25% fiber, etc.
Complicating the determination of the nutritional value of a feed can be that the balance of nutrients in its various forms often changes depending on the timing of harvesting, growing technology and some other factors. So, with overexposure of plants in the fields in their tissues, the content of fat, protein and carotene decreases. At the same time, their taste does not change for the better either, which, in turn, affects eatability.
The ratio of water to dry matter
The chemical composition of animal feed can be different. The characteristics of dry matter have a significant impact on the quality of food used on farms. However, the water of animal feed must contain a sufficient amount. With its lack in sheep, cows, rabbits, blood thickening is observed, the process of absorption of food is disrupted, chewing is difficult.
The amount of water in the feed is determined by drying its sample at a temperature of 105 ° C. Repeat this procedure until the mass of the sample ceases to change. Most of the water is contained in such feeds as silage, root crops, green grass, bard. Although such food is inferior in nutrition to concentrates, animals on farms must receive it.
What can be expressed nutritional value
Different methods can be used to determine the value of a particular type of food for animals. In Russia, the nutritional value of feed is customary to express:
- in oat units;
- energy units;
- exchange energy.
In the last century, the quality of feed in our country was assessed mainly only by the first method. Quite often it is used today. But in 2003, a transition from oatmeal to an energy feed unit began in Russia. In metabolic energy, the nutritional value of animal feed is determined in poultry farming and fur farming. In other industries, the last two methods on the list can be used simultaneously.
Oat unit
In this case, to calculate the nutritional value of the feed you need to know:
- chemical composition;
- digestibility factors.
In addition, fat deposition constants for pure nutrients are taken into account. These values were determined back in the 19th century by Geneberg. Fat in animals is delayed by eating:
- 100 g of pure protein - 23.5 g;
- 100 g of fiber - 24.8 g;
- 100 g of fat from cereals - 52.6 g, etc.
The expected fat deposition, of course, may differ from the actual one. The calculation of the latter is carried out depending on the type of feed. To determine the content of oatmeal in 1 kg of food for animals, the actual fat deposition rate is divided by 150.
Validity Ratios
Determining the actual fat deposition for roughage, among other things, make a discount on fiber. For its digestion, animals spend a lot of energy. In this case, take into account primarily the percentage of fiber in a particular type of food.
For concentrates and root crops, the actual fat deposition is found by multiplying the expected by the coefficients of usefulness. The latter are determined by a simple technique developed by specialists. Utility ratios are the percentage of the amount of fat actually gained by animals to expected. Composes this indicator:
- for potatoes and milk - 100%;
- wheat bran - 84%;
- carrots - 87%;
- beets - 76%;
- most types of cereals - 97%.
Exchange energy
The quality and nutritional value of feeds may vary. In addition, not all food is digested when animals eat it. Thus, the value of food can be determined by the exact proportion of its energy used by the body of cows, pigs and other animals to make up for its own costs. This part of the energy is called exchange. It is by its quantity that the quality of the food offered by the animal can be estimated.
The nutritional value of feeds can be determined using two methods:
- by conducting balance experiments on different types of animals;
- by calculation using equations based on the content of digestible nutrients.
For each particular animal species, there are different equations for determining such an indicator of feed nutrition as the content of metabolic energy. Calculations in this case have to be made quite simple.
Energy Feed Unit
In accordance with the international SI EKE expressed in joules. One j is equal to 0.2388 cal. In this case, one calorie is equivalent to 4.1868 J. To determine one energy unit, the indicator of the exchange energy of the feed is divided by 10.
EKE, among other things, is differentiated for poultry, cattle and pigs:
- ECE s = 3,500 kcal of pure energy;
- ECE cattle = 2,500 kcal;
- ECE p = 3,500 kcal.
This approach is primarily due to the fact that different types of animals unequally effectively use the nutrients of the feed.