1. Harvesting and Storage of Roughage
Crude fibers are the main nutrients affecting the digestibility of roughage. The higher the content of crude fibers, the higher the degree of lignification, and the more difficult it is to digest. The main factor affecting the amount of crude fiber in roughage is harvest time. The content of crude fiber is different in the whole growth period of roughage. When harvesting, we should grasp the appropriate harvesting time and do a good job in the storage of roughage to ensure the quality of them.
The roughage commonly used in dairy cow production is whole-crop corn, maize straw, Gramineae and leguminous forage. The optimum harvesting time of whole-crop corn is the late milking stage when the moisture content is 70%-80%, the dry matter content is high, and the crude fiber content is relatively low. At this time, harvesting can improve the digestibility. The main storage method of whole-crop corn is to mix silage materials. Silage tanks and silage cellars can be used. In the process of silage, patrol work should be done to prevent leakage of water and air and to affect quality. Maize straw is harvested after ripening and breaking off the sticks. The moisture content of maize straw is generally 65%-75%. The main storage methods of maize straw are silage and ammonia storage.
Gramineae grasses mainly include Leymus Chinensis and Oatgrass. The best harvest period is the early heading stage. In this period, not only the forage yield is high, but also the lignin content is low, the digestibility is high, and the feeding value is good. Before storage, it is necessary to air-dry before harvesting, so it is better to do it on sunny days when harvesting. This can shorten the time of air-drying, reduce the moisture content of forage to 25% and then store in bundles. It can keep the freshness of forage grass and reduce the loss of nutrients. In the process of storage, we should pay attention to the proof of rain, moisture, and fire.
The best harvest time of leguminous forage, such as alfalfa, is the squaring stage when the lignin content is low, the dry matter content is high, and the feeding value is the highest. When storing, water should be controlled below 16% and packed under pressure. Because of the high nutrient content in the leaves of leguminous forage, it is necessary to avoid leaf falling off and reduce the quality of forage as far as possible. The storage method is the same as that of gramineous forage.
2. Processing of roughage
In order to improve the utilization rate of roughage, it needs to be processed before feeding. The most commonly used methods to treat roughage are chopping and crushing. It is not appropriate to cut the roughage too short during processing. Generally, the length of roughage should be 1-2 cm. Too short is not conducive to digestion, will affect ruminant activity, make it stay in the rumen for too long, but affect the utilization of roughage. Silage or ammonia silage can be used to treat the whole-crop corn and other green fodder. Its main purpose is to improve the nutritive structure of roughage, improve the nutritive value, quality and palatability of roughage by using biological fermentation or ammonia water treatment, to improve the utilization rate of roughage. The results show that the utilization rate of roughage can be increased by 30%-50% after silage and 20% after ammoniation.
At present, some large-scale dairy farms often feed cows with complete mixed diets. This technology is very effective for improving the utilization rate of cow roughage. This technology cuts or crushes various feed raw materials into suitable size, and then feeds cows after full and even mixing, which can increase the feed intake of cows to ensure the rumen health of dairy cows, thereby improving the utilization of roughage. Before using this technology, attention should be paid to selecting the appropriate mixer track, and the mixing sequence of raw materials should be reasonable, the particle size should be moderate, and the appropriate water content should be adjusted according to the actual situation.
3. Rational Rations
Rational ration can also effectively improve the utilization rate of roughage for dairy cows. The number of neutral detergent fibers provided by roughage should be 50%-75% in the preparation of dairy cow diets, and roughage should be reasonably matched according to different physiological conditions and growth stages of dairy cows. What kind of roughage is suitable for which stage of feeding should be allocated reasonably. Replacement cows are mainly the development of rumen and skeleton. The rational dietary structure should be adjusted according to actual growth and development speed, fatness, intake, and excretion. At this time, a roughage with a slower rumen evacuation rate can be selected to feed.
Dairy cows should be suitable for fatness and not over-fattening during the dry period. Therefore, to control their intake, we can choose roughage such as maize straw and Leymus Chinensis with a slower tumor evacuation rate according to the nutritional needs of dairy cows during the dry period. During the early perinatal period, the appetite and intake of dairy cows decreased, and silage with faster rumen emptying rate was suitable for feeding. The feeding goal of dairy cows during lactation was to obtain the maximum intake to meet the nutritional needs of milk production and fatness recovery, so the dietary structure at this time should be both nutritious and fast through the rumen. Besides, silage and alfalfa can be fed, especially in the late pregnancy and lactation peak period, more attention should be paid to the rumen speed of roughage.
4. Strengthen the feeding and management of dairy cows
The utilization rate of the roughage of dairy cows is also closely related to the level of feeding and management of dairy cows. Only scientific and reasonable feeding and management can keep dairy cows good appetite and improve feed intake and digestibility of roughage. First, we should provide a comfortable feeding environment for dairy cows, pay attention to the control of temperature, humidity, and air quality, maintain the environmental hygiene of the cowshed, clean up the dung in time, and change the cushion frequently. In hot summer, effective measures should be taken to avoid heat stress in dairy cows. Dairy cows should be brushed 1 to 2 times a day to provide comfortable rest and exercise places to ensure that the cows have a certain amount of exercise time every day, which can improve the health and appetite of the cows. Provide dairy cows with adequate and clean drinking water. Ensuring the quality of feed and forbidding feeding mildewed feed for dairy cows.
Measures to Improve the Utilization Rate of Coarse Feed for Dairy Cows
1.The nutritional function of roughage
In addition to providing conventional nutrients, roughage has the following functions:
⑴. Promote the development of the rumen digestive function of calves.
It is beneficial to the development of the rumen digestive function of calves by feeding roughage earlier and increasing the proportion of roughage step by step.
⑵. Promote the rumination of dairy cows.
A ruminant is a special physiological function in the digestive process of ruminants. Ruminant can swallow large amounts of saliva, which is alkaline and can neutralize the acid produced by rumen fermentation, thus maintaining the relative stability of rumen acidity (pH). Rumen pH value is relatively stable, which can reduce the occurrence of metabolic diseases such as acidosis, promote the growth of rumen microorganisms and improve the digestibility of roughage.
⑶. It can maintain a stable milk fat rate.
The degradation products of roughage in the rumen are mainly acetic acid, which is an important precursor of body fat and milk fat synthesis. Therefore, the supply of roughage can maintain a stable milk fat rate.
⑷. Filling up the gastrointestinal tract to increases satiety.
In some special physiological stages, such as dry period, the intake of dairy cows can be controlled.
⑴. Appropriate processing
Cutting and comminution are the most common methods in roughage processing. Generally, the shorter length of the roughage is 2-3 cm. Cutting too short reduces the rumination time of dairy cows, and too long reduces the feed intake of dairy cows. The kneading and cutting of whole-crop corn straw and other silages before silage can not only improve silage quality but also improve the silage utilization rate. Cutting hay before mixing can improve the mixing uniformity of TMR, reduce animal pickiness and increase utilization rate. Maize, wheat and rice straw, the effective degradation rate in the rumen can be increased by 20%, and the protein content can be increased by 1-1.5 times. Granulation of Alfalfa not only reduces the loss of nutrients but also improves the utilization rate of alfalfa. After the mixed storage of distiller grains with 0.3 ammonium, the degradation rate of cellulose in distiller's grains can be improved. Adding lactic acid bacteria preparation and cellulase preparation to silage raw materials can increase the utilization rate of silage by 30%~50%.
⑵. Optimizing dietary composition
According to the nutritional needs and feeding standards of dairy cows, the nutritional composition table of feed, and the actual production of dairy cattle, the diet formulas were designed scientifically. Dietary ingredients should be multi-varieties and low proportion (at present, there are even more than 40 kinds of dietary ingredients in large-scale pastures in China), to ensure the level and source of dietary fiber and improve the balance and full price of dietary nutrients. The selected forage is free from mycotoxin pollution, especially hay, corn silage and by-products of grain processing, to ensure the health of dairy cows. The ratio of concentrate to roughage is suitable. In general, dairy cows should eat roughage (dry matter basis) which accounts for 1.5%~2.0% and concentrate (dry matter basis) which accounts for 1.0%~1.5% of their body weight respectively. Dietary ADF content was above 20% and NDF content was above 25%, which was beneficial to improve the simultaneous release rate of soluble carbohydrates and rumen degradable proteins.
⑶. Optimizing TMR processing technology
The order of TMR mixing is reasonable. The order of raw material addition of a horizontal TMR mixer is a fine to supplement, hay, silage, and dregs. The order of raw material addition of vertical TMR mixer is hay, silage, dregs, and fine supplement. The mixing time of TMR should be 3 to 8 minutes after the last feed is added. The moisture content of TMR is suitable, generally 40%~50%. The size of the TMR diet components is appropriate. The grain size of the TMR diet will affect the digestibility of nutrients by affecting the rumen filling degree of dairy cows, the contact area between chyme and rumen microorganisms and the outflow rate of chyme in the rumen.
⑷. Strengthen feeding management
Improve the dairy cows' breeding environment, do a good job of summer heat prevention and cooling, winter cold prevention and warming, and ventilation, ensuring clean drinking water and preventing disease occurrence and transmission. Increase the number of TMR feeding times, add little in more times, to ensure that dairy cows can feed freely throughout the day. There is enough space for dairy cows to feed. Improve the comfort of ground in feeding and moving areas and increase the rest and rumination time of dairy cows. The rest time of dairy cows should be 12 hours, and the total rumination time should be more than 8 hours.
⑸. Consider rumen fermentation regulators
Rumen fermentation regulators were added to optimize the rumen environment and improve feed conversion efficiency.