The nature and application of feeding standard

  (1) The scientificity, practicability and relative rationality of feeding standards

  Animal feeding standard is based on the theory of nutrition science, based on the results of production practice, its indicators and values are sufficient from a large number of scientific experiments, has been widely verified by intermediate experiments and production practice, consulting and based on a large number of scientific literature at home and abroad, it reflects the scientific side of nutrition needs, but also has a practical side, theory combined with practice, with a high degree of scientific and practical. For example, in recent years, China has adopted its own pig breeding standards, which have been tested through intermediate tests and small batch production. Compared with 10101 pigs without feeding standard, the average feeding period of 11667 pigs was shortened by 25 days (125:150), and the daily gain of each pig was increased by 19. 9% (560: 467g), lean meat percentage increased by 21.7% (56%: 46% ), feed utilization efficiency increased by 22.7% (0.27: 0.22), net income increased by 5.44 yuan per head of commercial pig. Therefore, the feeding standard has high scientificity and practicability, and has great guiding effect on production practice. However, due to the complexity and diversity of actual production conditions, the correct application of feeding standards and the nutritional needs of animals are affected by many factors, such as animal species, breed type, age, sex, physiological state, production level, production purpose, region, climate, feed conditions, feeding methods, environmental conditions and social economy, etc. Therefore, the scientific nature of feeding standards has certain limitations relative to the blind nature of production. It can not be too detailed, too specific, reflecting the average number of groups, and therefore has a general nature.

  (2) Universality, Regionality and Speciality of Feeding Standards

  Nutritional requirements and nutritional standards of animals are the reflection of observable events and laws under certain historical conditions, and the reflection of the scientific and technological development level of the local (same family) at that time (period). Because of the stability of germplasm characteristics of the same kind of animals, as well as the accumulation of scientific and technological knowledge and the improvement of production conditions, it is gradual and continuous in a certain period of time. Therefore, there are many similarities between the basic original and many indicators of breeding standards in different periods, and there is a certain inheritance between the previous and subsequent editions, which has relative stability. Since the world's feeding standards are based on common nutrition, feeding science theory and experimental means, so the basic principles and basic content of feeding standards have many similarities, a feeding standard of the same family is often adopted by other countries, or as a reference to develop their own national feeding standards, so feeding standards have universality.

  It should be noted that in feeding standards applied to the diet configuration should be adjusted according to the actual situation, here only vitamins as an example. Vitamins are essential trace substances for livestock and poultry. However, due to the neglect or even one-sided understanding of vitamin nutrition in breeding, there are frequent cases of livestock and poultry productivity decline and death due to vitamin deficiency. At present, no matter domestic or foreign vitamin nutrition standards, most of them are measured in the form of demand, and some include safety factors. Therefore, in the trial of vitamin feeding standards, attention should be paid to understanding and distinguishing the difference between demand and supply. Demand generally refers to the minimum dosage that can maintain the health and production performance of livestock and poultry under normal circumstances, while supply is in addition to considering the above factors. In addition, the total demand of livestock and poultry in different physiological states for vitamin utilization and certain factors affecting vitamin utilization should be considered. Practice has proved that the vitamin supply is about 1 time as much as it needs. Therefore, if there is no correct understanding of vitamin feeding standards, such as long-term measurement according to the required amount, it will inevitably lead to vitamin deficiency. Especially the high production performance of livestock and poultry in a short period of time and some external factors affecting vitamin utilization will make the vitamin deficiency of the body more obvious, thus causing greater losses. How to master the vitamin supply of livestock and poultry on the basis of demand is restricted by many factors, and certain flexibility is needed in practical application. Generally speaking, there are several aspects as follows:

  1, the impact of production performance: the higher the production performance, the greater the demand.

  2. Effect of dietary properties: When feeding high-energy and high-protein diets, the demand for vitamins increases.

  3, environmental conditions: such as under high temperature conditions or restricted feeding, due to the reduction of its intake and the corresponding increase in vitamin demand. In addition, intensive feeding, cage breeding and so on will reduce the contact between livestock and soil manure, will lead to a corresponding increase in vitamin demand

  4, the impact of disease or stress: because it affects the normal absorption of nutrients or increases consumption, vitamin requirements increase.

  5, the impact of restrictions between nutrients: such as vitamins and vitamins will produce some antagonistic relationship, vitamins and certain trace elements will also have a restrictive effect, which will affect the actual supply.

  6, the impact of vitamin efficiency: vitamin additives generally with the extension of time gradually reduce their effectiveness, such as the use of green feed to supplement vitamins also exist under the influence of production methods. Another example is that water-soluble vitamins are easily excreted with urine and are not stored in the body, while fat-soluble vitamins are not excreted with urine and can be stored in the body. Some vitamins themselves are oxidized too much. Therefore, in the actual application of vitamin feeding standards, we should fully consider various influencing factors, flexibly use feeding standards to determine the supply of vitamins, in order to make animal husbandry production obtain better benefits.