Ruminant farming | Plant unconventional feed materials
In ruminant diets, roughage usually accounts for 40%~70%, or even more, and is an important source of nutrition for rumen microorganisms and host animals. Coarse fodder plays an important role in maintaining the intestinal health of ruminants and improving productivity. At the moment when the breeding cost has risen sharply, the use of plant unconventional feed materials in ruminant breeding is particularly important.
The so-called "plant unconventional feed raw materials" refer to the plant raw materials that have not been put into production due to their low nutritional value, mainly from agricultural by-products and food industry by-products. Plant unconventional feed mainly includes: crop straw, chaff, plant cake, forestry by-products, grains and dregs, etc. Compared with the animal unconventional feed, the plant unconventional feed is safe and reliable and can account for a large proportion in the feed formula, so it has more development potential in alleviating the cost pressure. The following summarizes several types of unconventional feed materials commonly used for rumination and the precautions for their use.
1. Crop straw and chaff
This kind of feed mainly includes rice straw (chaff), wheat straw (chaff), sorghum straw (chaff), soybean straw (chaff), peanut seedling (chaff) and dried potato. Straws have the characteristics of low protein and high fiber. As a kind of low quality roughage, its feed quality is mainly determined by its nutrient content. In recent years, scholars at home and abroad have conducted a lot of research on eliminating the anti nutritional factors in straw, reducing the crystallinity of cellulose, and improving the utilization rate of straw. It is found that physical treatment, chemical treatment and biological treatment can be used to decompose the crude fiber in straw into monosaccharides or oligosaccharides, improving palatability and nutritional value. Physical and chemical treatment methods can improve digestibility and increase food intake, but both have certain limitations. However, the treatment method of transforming straw by using biological adaptability and multi-function has attracted researchers' attention. With the continuous development of biological treatment technology, crop straw has greatly improved its nutritional value and palatability. It has achieved good results in the use of cattle and sheep feed, and has become one of the indispensable sources of ruminant roughage.
2. Forestry by-product
It mainly includes leaves, seeds, twigs and leftovers from wood processing. The protein content of this kind of feed accounts for 25%~29% of the dry matter, and also contains a lot of vitamins, which can be used as a good protein supplement. The leaves and seeds can be directly fed to livestock and poultry; The leftovers from processing of twigs and wood after hydrolysis, expansion, silage and fermentation can also be used, such as poplar leaves, elm leaves and fermented mulberry leaves.
3. Plant Cake
Unconventional plant cake mainly includes sesame cake, palm cake, sunflower cake, sesame seed cake, rubber seed cake, coconut cake, etc. Compared with other feeds, the cake feed has the following characteristics: high protein content, high available energy, low crude fiber content, and high mineral content. However, the cake feed has high phytate phosphorus content, which limits the use of phosphorus and has many anti nutritional factors.
4. Lees
It mainly includes distiller's grains, soy sauce grains, vinegar grains, fruit dregs, citric acid filter dregs, waste molasses, beet dregs, bagasse, medicine dregs, fungus bran and leftovers from corn starch industry. Among ruminants, sugar beet residue, apple pomace, bagasse and alcohol lees are more mature.
Precautions for roughage in ruminant feeding:
1. Suitable ratio of concentrate to roughage
The proper ratio of concentrate to crude could improve the utilization rate of dietary fiber. The research shows that the ratio of concentrate to crude in the diet should not be higher than 60%, and 70% may be the limit.
2. Application of Leguminous Forage and Straw Coarse Feed
Leguminous forage is the best source of roughage for ruminants. When ruminants are fed with low-quality straw such as wheat straw and corn straw, they should also be fed with leguminous forage powder such as alfalfa. This can improve the digestibility of fibrous substances, provide isobutyric acid, valeric acid, small peptides and amino acids required for the growth of certain cellulolytic bacteria in the rumen environment, and alfalfa degradation in the rumen can provide these substances.
3. Coarse feed particle size
Studies have shown that the rumen pH value and milk fat rate will be reduced after the coarse fodder is finely chopped or milled. Some studies have shown that feed particles passing 1.18mm sieve can quickly pass through the rumen and rarely stimulate chewing. Increasing dietary fiber level and coarse fodder particles can effectively increase chewing frequency and saliva secretion, and improve rumen pH, acetic acid, propionic acid and milk fat rate.
4. Processing of roughage
Mechanical processing (cutting, crushing, etc.) is the most simple and commonly used method for the utilization of roughage. In particular, the straw feed is relatively coarse and hard, which is easy to chew after processing, reduces consumption, improves feed intake, and reduces waste in the feeding process. The use of chemical substances such as acid and alkali to treat inferior roughage can decompose some nutrients in cellulose and lignin, and improve the feeding value. Biological treatment methods such as microorganism and enzyme can fundamentally solve the problem of poor quality of roughage.
To sum up, coarse fodder is a kind of feed resource widely existing in nature. Understanding the function of coarse fodder in ruminant production, developing and effectively utilizing limited natural resources are of great practical significance for alleviating the cost pressure of ruminant breeding, improving the breeding efficiency and solving the food competition between humans and livestock.