Feed nutrition: quality indicators and energy value assessment

2024 Author: Howard Calhoun | [email protected]. Last modified: 2024-01-02 13:48

The most important condition for maintaining the he alth 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 feed offered to farm animals can be determined by various methods.

Classification

Food can be used on animal farms:

• juicy;
• rough;
• concentrated.

The first variety includes mainly root crops and silage. Roughage is grass, hay and straw. Concentrates are called the most nutritious and expensive food for animals - whole or flattened grains, crushed, bran. Also, compound feed can be used on farms. They are usually a mixture of concentrates and roughage. Such formulations are also highly nutritious and relatively expensive.

Quality assessment should be carried out on farms in relation toall types of feed used. At the same time, the diet is developed depending on which animals are raised on the farm.

How evaluation is done

The quality of feed offered to productive animals is judged based on the following factors:

• organoleptic properties;
• energy concentration;
• nutrient content;
• quality class;
• eatable.

By organoleptic properties are meant primarily:

• taste, color, structure, smell of feed;
• degree of contamination;
• the presence in it of various kinds of undesirable impurities or poisonous plants.

Taste and smell are very important properties of food. To a greater extent, the eatability of the offered food by animals depends on them. Cows, pigs, sheep, horses, etc. are able to distinguish between sour, sweet, bitter, and s alty tastes.

Energy concentration is the number of feed units (f. units) in 1 kg of food offered to animals. When assessing the nutritional value of the feed, the percentage of proteins, carbohydrates, fiber, biologically active substances and trace elements in it is determined.

A bit of history

Scientists began to develop methods for assessing feed back in the 18th century. Over time, these technologies have improved. Initially, animal food was judged mainly on the basis of its chemical composition. Eingof and Davy were the first to propose to determine the nutritional value of feed.

Later, feed began to be divided into water and drysubstances, separating from the latter soluble and insoluble, nutritious and useless. After some time, hay and nitrogen equivalents were adopted. Then came the notion of a digestible nutrient.

In the middle of the XIX century. The German scientist Geneberg laid the foundations for modern zootechnical analysis of feed. This researcher divided nutrients into five main groups.

Modern evaluation methods

Currently, when determining feed quality, all nutrients are divided into:

• raw fat;
• MAR;
• crude protein;
• biologically active substances;
• crude fibre.

For the convenience of determining the quality, special tables were created, according to which you can find out the percentage of these components in a particular type of feed. For example, clover contains 17% protein, 3% fat, 25% fiber, etc.

Determining the nutritional value of feed can be complicated by the fact that the balance of nutrients in its different types often changes depending on the timing of harvesting, growing technology and some other factors. So, when plants are kept in the fields, the content of fat, protein and carotene decreases in their tissues. At the same time, their taste does not change for the better, which, in turn, affects palatability.

Water to dry matter ratio

The chemical composition of pet food may vary. Dry matter characteristics have a significant impact on qualityfood used on farms. However, water for animal feed should also contain a sufficient amount. With its deficiency in sheep, cows, rabbits, blood clots are observed, the process of food absorption is disturbed, 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 does not change. Most of the water is found in feeds such as silage, root crops, green grass, bard. Although such food is inferior in nutritional value to concentrates, animals on farms must receive it.

What nutrition can be expressed in

Methods for determining the value of a particular type of food for animals can be used differently. In Russia, the nutritional value of feed is usually expressed:

• in oat units;
• energy units;
• energy exchange.

In the last century, the quality of feed in our country was assessed mainly only by the first method. It is still used quite often today. But in 2003, Russia began to switch from oatmeal to an energy feed unit. In exchangeable energy, the nutritional value of animal feed is determined in poultry and fur farming. In other industries, the last two methods in the list can be used simultaneously.

Oatmeal unit

In this case, to calculate the nutritional value of the feed, you need to know:

• chemical composition;
• digestibility ratios.

In addition, net nutrient fat constants are taken into account. These values were determined back in the 19th century by Geneberg. Fat in animals is deposited when eating:

• 100g pure protein - 23.5g;
• 100g fiber - 24.8g;
• 100g fat from grains – 52.6g etc.

Expected body fat, of course, may differ from the actual. The calculation of the latter is performed depending on the type of feed. To determine the content of oat to. units. in 1 kg of food for animals, the indicator of actual fat deposition is divided by 150.

Usefulness ratios

Determining the actual body fat for roughage, among other things, make allowances for fiber. For its digestion, animals spend a lot of energy. In this case, first of all, the percentage of fiber in a particular type of food is taken into account.

For concentrates and root crops, the actual fat deposition is found by multiplying the expected by the usefulness factors. The latter are determined by a simple technique developed by specialists. The usefulness coefficients are the percentage of the amount of fat actually gained by the animals to the expected. Composes this indicator:

• for potatoes and milk - 100%;
• wheat bran – 84%;
• carrots – 87%;
• beets – 76%;
• most types of cereals – 97%.

Exchange energy

Feed quality and nutritional value may vary. In addition, anddigested when eaten by animals, of course, not all food. The value of food, therefore, can also be determined by exactly what proportion of its energy is used by the body of cows, pigs and other animals to replenish their own costs. This part of the energy is called the exchange. It is by its quantity that one can assess the quality of the food offered to animals.

Energy nutritional value of feed can be determined using two methods:

• by conducting balance experiments on different animal species;
• calculated using equations based on digestible nutrient content.

For each specific type of animal, there are equations for determining such an indicator of the nutritional value of feed as the content of metabolic energy. The calculations in this case have to be made quite simple.

Energy feed unit

In accordance with the international SI, ECE is 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 exchange energy of the feed is divided by 10.

ECE, among other things, is differentiated for poultry, cattle and pigs:

• ECE c=3,500 kcal clean energy;
• ECE _{Cattle=2,500 kcal;}
• ECE n=3,500 kcal.

This approach is primarily due to the fact that different animal species use feed nutrients differently.