Roughage is a kind of low energy and high fiber feed. Staying in the rumen of dairy cows for a long time will stimulate rumination, which is conducive to the normal development of rumen function. Diseases can be caused when concentrate accounts for 60% to 70% of the diet of dairy cows. Roughage plays an important role in guaranteeing the normal function of the rumen and improving the milk fat rate of dairy cows. Roughage is an indispensable component of dairy cows' diet. High-quality roughage can account for 2/3 of the dry matter in the diet, which is equivalent to 2.5%~3.0% of the weight of dairy cows. Therefore, high-quality roughage plays an important role in dairy cow production.
Corn straw is the most common roughage for dairy cattle breeding. It is characterized by extensive sources, abundant resources, low prices, and the most popular use, but its low nutritional value limits the use of ration.
Leymus Chinensis, also known as Alkali grass, is a perennial herb of the genus Leymus of Gramineae. Its stem and leaf are lush, nutritious and palatable. It is good forage for feeding dairy cows. Leymus Chinensis has a long nutritional growth period and can maintain a high nutritional content, which has a good effect on the growth and production of dairy cows.
The silage feed is to fill green feed into silage cellar or silage tower and other equipment. Undersealed conditions, through microbial fermentation, the feed is acidified to achieve the purpose of long-term preservation of green feed nutrition. There are many raw materials for silage. At present, corn straw is the main raw material. Silage has the advantages of long shelf life, keeping the nutrition of forage to the maximum, good digestibility and palatability, and improving the yield of dairy cows. It is a good feed for dairy cows throughout the year, especially in winter and spring.
⑴. Lack of high-quality roughage
Corn straw, Leymus Chinensis and corn silage are the main forages, but lack of high-quality leguminous forage. Corn straw has low nutritional value. It should be pretreated before feeding, such as ammoniation, alkalization, etc. However, we only crush corn straw with simple hydrazine or machine, and feed it directly to cattle, without more effective chemical or microbial treatment, so that its utilization rate has not been further improved.
Silage is very popular, but silage technology is uneven. Among the silage made by cattle farmers, only 30% of the total silage is of good quality, while 40% to 50% of the silage is of poor quality. Feeding capacity is also inadequate, with an average of 10-15 kg/day per cow per household. To ensure a high yield of dairy cows, daily silage supply per cow should not be less than 20 kg per day.
⑵. Backward feeding mode
When breeding dairy cows, the feeding methods of breeders are too extensive. Feeds are not stirred and mixed. Even stirring is not uniform. Feeds are directly put into the trough. Using the method of classified feeding, and the feeding time is long, usually, straw in the morning and evening, silage at noon, and the feeding amount of all kinds of feeds are seldom calculated, so that cattle feed at will.
All these have seriously affected the appetite and normal digestion and absorption of dairy cows, resulting in the phenomenon of selective feeding, incomplete nutrition, inadequate nutritional value, and waste of feed. For high-yielding dairy cows, it is easy to suffer from insufficient dry matter intake and milk production decline, which will also cause postpartum weight loss, reproductive disorders, and metabolic diseases. Therefore, improving the processing and feeding methods of dairy cattle feed and feed conversion rate have become an urgent problem to be solved.
⑶. The unbalanced proportion of concentrate and roughage in feed
Dairy cows are ruminants of herbivorous livestock. The feeding principle is based on roughage and supplemented by concentrate. The nutrition of corn straw, Leymus Chinensis and corn silage can not meet the need for high yield of dairy cows. To improve milk production, farmers blindly increase the proportion of concentrate in feed to make up for the shortage of nutrients in roughage, resulting in the imbalance between concentrate and roughage.
Because of the important role of roughage for dairy cows, the proportion of concentrate in the diet of dairy cows should not be too high. If the proportion of concentrate in feed is high, the nutrient supply will be high, the milk yield will increase, but the milk fat rate will decrease. If the proportion of roughage is high, the nutrient supply is low, the milk fat rate is high, and the milk yield is decreased. Considering the proportion relationship and the production efficiency of dairy cows, the ratio of concentrate to roughage is about 50:50. Imbalance will lead to less crude fiber in the diet, increased rumen acidity, adverse rumination of dairy cows, decreased milk production and milk fat, occurrence of rumen acidosis, ketosis, postpartum paralysis and other metabolic diseases, which will further lead to the short service life of dairy cows and the decline of economic benefits.
⑷. Dispersed feeding and low level of feeding management
In the countryside, as well as the interior of the countryside, cattle raising is scattered, failing to form an effective cooperative mechanism, and the poor information, which seriously restricts the raising management level of cattle farmers and the improvement of the per-unit yield of dairy cows, and limits the further development of the cattle industry. The shortcomings of small-scale feeding are poor quality of milk, excessive bacteria, difficult to control environmental pollution, low scientific and technological content, weak awareness of epidemic prevention of dairy cows in farmers, which is not conducive to technical promotion and professional services.