Application of Crude Fiber in Dairy Cow Diets

Application of Crude Fiber in Dairy Cow Diets

Crude fiber is the most abundant renewable resource on the earth, but because of its special structure, it cannot be used by ordinary livestock, and dairy cows can effectively use crude fiber substances through their digestive microbes. Under the action of rumen microbes, crude fiber can produce a large amount of volatile fatty acids (VFAs), and VFAs, as the main energy source for dairy cows, provide 70 to 80% of their energy needs. VFA mainly includes three kinds of acetic acid, propionic acid and butyric acid, accounting for about 95% of the total. Maintaining a constant ratio of acetic acid and propionic acid facilitates the increase of milk production and milk fat percentage. In addition, crude fiber plays an important role in maintaining rumen environment stability, promoting saliva secretion, and ensuring cow health. This article reviews related literature and research results at home and abroad in order to provide basis for the rational use of crude fiber, scientific formulation of diets, and guaranteeing the safety, health and high yield of dairy cows.

Crude fiber composition

Crude fibers include cellulose, hemicellulose, lignin, pectin, and the like. Van Soest proposes neutral detergent fibers (NDF), acid detergent fibers (ADF) and acid detergent lignin (ADL) as indicators for the determination of fibrous substances in feeds (where NDF2ADF = hemicellulose; ADF2ADL = cellulose; ADL2 ash = Lignin). China's national standard "GB 6434-86 Feed Crude Fiber Determination Method" is based on the acid-base treatment method. Now a variety of crude fiber assays are: filter bag analysis, near-infrared diffuse reflectance spectroscopy crude fiber method, secondary extraction rapid determination method and nylon bag method.

The nutritional effect of crude fiber on cows

(1) Controlling Feed intake

(2) Promote the secretion of saliva and maintain normal rumen function and health

(3) Promote intestinal peristalsis and microecological balance

(4) Provide nutrients for cows to ensure the health of dairy cows: Crude fiber is conducive to the healthy development of dairy cows.

(5) To improve anti-stress ability: Increased feeding of crude fiber can play a mitigating role in regulating the heat stress of dairy cows, and can increase the intake of cows and the amount of drinking water and slow the decline of appetite at high temperatures.

Measures to increase crude fiber utilization

(1) Physical Processing

(2) Chemical treatment: It mainly includes alkalization and ammoniation.

(3) Microbiological treatment: including silage, fungal treatment, and microbial additives.

(4) Application of cellulase: stimulate the secretion of endogenous enzymes, speed up the fermentation of cell wall components, eliminate the effect of anti-nutritional factors, improve the structure of digestive tract flora, and significantly increase the utilization of crude fiber by herbivores.

(5) Application of cation-anion balance (DCAB): Stabilizes and increases rumen p H , accelerates the rate of liquid circulation in the rumen, and enhances the activity of cell-decomposing bacteria, thereby increasing feed intake and digestibility of ruminants for roughage.

(6) Application of mineral elements: Rumen microbes have special requirements for both macro and trace mineral elements and can be used as components of microbial cell structures or as components of enzymes and coenzymes.

(7) Application of Proteins: Dietary protein supplementation can increase the digestibility of feed fiber material.

(8) Application of fat: When 3% fat is added as butter in the diet, the digestibility of DM and non-structural carbohydrates in the diet increases, while the digestibility of NDF and ADF decreases.

(9) Influence of environmental factors and feeding management strategies: The digestibility of neutral detergent fibers, acid detergent fibers, and acid-washed lignin decreased with the duration of nutrient limitation, and the digestibility increased when free-feeding was resumed.

Crude fiber determination:

The crude fiber is generally determined by experimental and instrumental methods. The principle of the laboratory method is to remove non-cellulosic substances from substances by using acids, alkalis, alcohols and other reagents and burning at high temperature, and then to obtain the content of cellulose. The instrument rule is to determine the content of fiber in the material through a coarse fiber analyzer and a CXC-06 fiber analyzer. It is not difficult to find that it is more convenient and simple to determine the crude fiber content by instrumental methods, but the measured results may not be accurate with the laboratory method.

Crude fiber is the most abundant renewable resource in nature, and it is necessary for the growth and reproduction of herbivores. Reasonable development and utilization can save other feed resources. China is a big country in agriculture. Making full use of crop straws to transform and add value on the spot is an important measure to improve the overall economic efficiency of large agriculture. Due to the high content of crude fiber and low crude protein content of straw, its digestibility is low, and physical, chemical, biological, nutritional supplements, and other methods can usually be adopted to increase the palatability and nutrient digestibility of straw to meet the nutritional requirements of livestock. need. The rational use of crude fiber has great practical significance for solving the shortage of feed resources and is one of the effective ways to promote the sustainable development of animal husbandry in China.