The profit brought by the increase of milk production by one ton is far more than the increase of milk price by ten cents -- Zhen Yuguo

"Not making money" can be said to be one of the key words in the discussion of dairy farms. Some cattle farms say that the reason why cattle farms do not make money is because the price of milk is too low. For this, dairy farms should examine their own pastures. If the problem of China's dairy industry is only the problem of milk price, then the problem is not so difficult to solve! The problem is not that simple. I believe that the profit brought by an increase in milk production by one ton is far more than a dime increase in milk prices. Direction is more important than effort. Now the production level is relatively low, the problem of more pastures, dairy production must deviate from the normal track.

The feeding and management of dairy cows cannot be separated from these three lines. The normal lactation curve is shown in the figure below. You can use the milk production records of the pasture to draw the curve and see the difference from the normal curve. If the difference is not big, your pasture is well managed. The blue dotted line in the figure is an abnormal lactation curve.

Fig.1 Comparison of ideal milk production cycle and abnormal milk production cycle

The solid purple line represents the normal feed intake curve, which is not the case for many pastures. There are also body condition change curves. These are the normal rhythms that cows should have. Whether it is changes in yield, changes in feed intake, changes in body condition, it is normal to follow such rhythms.

In the early stage of lactation, the nutrition required by the cow's production does not match the nutrition of the food. The cow is in a state of energy imbalance, and its body condition will definitely decline, because a certain amount of body fat is used to produce milk.

After the peak period of lactation, feed intake gradually catch up, then the nutrition will be excessive, the body condition will gradually recover, forming a cycle.

The blue dotted line in the figure is the abnormal lactation curve of dairy cows with lactation days of about 500 days. Many dairy cows are in the intermediate state between the normal lactation curve and the abnormal lactation curve, and the difference in milk yield is more than one ton.

About two months after delivery, cows will face three major obstacles at the same time: peak lactation, maintenance of body condition and resolution of reproduction: many cows in pastures cannot go up to peak, cannot maintain peak (poor body condition) and prolonged lactation (reproduction obstacle) are all manifestations of these three major obstacles. These three obstacles can be solved by management.

Two months after delivery, the normal body condition of the cow is about 2.75. If the body condition has dropped below 2 at this time, it will definitely affect the normal reproduction. The time of estrus and mating will be delayed until the body condition is restored before mating. In addition, the peak of milk production is moving forward, and there are some birth canal diseases such as placenta failure and endometritis. The whole production rhythm of dairy cows will be very different from the normal rhythm. It is impossible for such pastures to make money.

A normal cow will have a negative energy balance 2 months after delivery. At this time, she needs to take more food to provide more nutrition to maintain a normal body condition. Therefore, the root of the rapid decline in body condition lies in the failure to increase the feed intake before and after delivery, but the cow has the maternal ability to feed its offspring. At this time, she can only use body fat to produce milk. As a result, the body condition declines rapidly. After the decline to a certain extent, the cow can only reduce milk production in order to save its own life, and the peak period cannot be maintained, while the milk volume of one kilogram during the peak period is equivalent to 250 kilograms, it is also difficult to increase milk production throughout the lactation period.

If this kind of problem occurs in the pasture, it means that the perinatal period is not well managed. If the management is good and the pre-and post-natal feed intake is normal, the body condition will drop to 2.5 points at most. For cows with a yield of more than 10 tons, it may be slightly worse, and it is normal for some cows to drop to 2.25.

◆ One Center-Rumen Function

◆ Two basic points-perinatal management calf management

From the perspective of nutrition, the basic idea of raising cattle can be simply summarized as a center and two basic points. One center is centered on the stability of rumen function. Every feeding and management measure in the pasture cannot be separated from the control of rumen function. The first basic point is to do a good job in the perinatal period, which is not only the foundation of ensuring output, but also the most fundamental problem of making money. The second basic point is the management of calves, which is very important because it is related to the future development of the pasture. In the past, the traditional feeding mode led to many pastures not paying attention to the cultivation of calves and reserve cattle. We often see many pastures with short and large stomachs. This phenomenon is very typical, which shows that the calves are not well cultivated at the stage, so the yield of cattle cannot be high.

The rumen of dairy cows is actually a biological fermentation tank. Among the known natural individuals, the rumen contains the largest number of microbial species, including 200 bacteria and 20 protozoa, with 10 billion bacteria per gram of rumen fluid. Rumen fermentation will produce a large number of volatile fatty acids (acetic acid, propionic acid and butyric acid). Milk fat in milk mainly comes from acetic acid produced by fiber fermentation in rumen roughage, lactose mainly comes from propionic acid produced by starch and sugar fermentation in rumen concentrate, and milk protein mainly comes from microbial protein formed in rumen. Therefore, milk is actually a product of rumen fermentation in dairy cows. Rumen microorganisms can ferment feed to produce volatile fatty acids. If rumen cannot be absorbed, milk cannot be transported to mammary glands and body fat cannot be converted. Therefore, how much concentrate is fed is wasted.

The rumen of dairy cows is a biological fermentation tank, and milk is the product of rumen feed fermentation. Managing dairy cows is equivalent to managing a fermentation tank. The three elements of fermentation include: substrate (roughage, concentrate), strain (fiber decomposition bacteria, starch decomposition bacteria) and fermentation conditions (temperature, pH value). Just like making beer, you need a fermentation tank, fermentation substrates-wort, yeast and fermentation conditions, but rumen fermentation is more complicated. If the milk index produced by the cow is not up to standard, it must be a problem in one of the three fermentation elements. Among them, maintaining the stability of rumen pH value is the key to managing the rumen of dairy cows. Rumen has a complete mechanism to maintain the stability of rumen pH value, which mainly includes: ◆ effective and complete buffer system-rumination and saliva; ◆ effective absorption system of VFA-absorption of rumen papilla; ◆ lactic acid scavenger-lactic acid using bacteria to remove lactic acid. The following are a few examples to illustrate that managing cows is actually managing rumen fermenters.

◆ Dietary effective fiber (saliva secretion, guarantee buffer system)

A cattle farm in Tianjin once called me and said: There is something wrong with the cattle farm. The milk yield is only over 5 tons. When a little more concentrate is fed, the cows will have diarrhea and the yield cannot be increased. Later I checked the diet formula of the cattle farm and there was no problem. It was not until one visit to the scene that I understood the problem. All roughage including silage in the cattle site are finely ground with a pulverizer, and the amount of effective fiber in the diet is insufficient.

If the amount of effective fiber is not enough, the rumination and chewing of dairy cows cannot be promoted, so the amount of saliva produced by dairy cows will also be reduced, thus affecting the function of rumen buffer system. Therefore, in order to maintain the stability of pH value of cattle stomach, there must be a stable amount of effective fiber in the diet, and NDF provided by roughage in the diet of dairy cows must be paid attention to at least 25%, for high-yielding cows below 21% is dangerous.

The total amount of fiber material in dairy cow's diet is not enough, but it is also necessary to maintain a certain appropriate length. Binzhou screen is often used to check TMR diet to ensure sufficient particle size in the diet. The purpose is to maintain a perfect buffer system in the rumen, stabilize the pH value of the rumen, and thus ensure stable rumen fermentation. One may ask whether adding baking soda to the diet can replace the lack of effective fiber, and the answer is no. The addition of baking soda is only a necessary but very limited supplement to the lack of saliva secretion.

◆ Dietary non-fibrous carbohydrate NFC (control acid production and maintain acid-base balance)

Many people in the cattle farm have asked me the same question, whether they should not feed too much corn silage to the cows, otherwise it will cause rumen acidosis in the cows. In fact, corn silage belongs to the physiological alkaline feed, which provides effective fiber which is advantageous for balancing the pH of the rumen. The main cause of rumen acidosis caused by increasing the feeding amount of corn silage in many pastures is not due to excessive silage feeding, but actually due to the NFC in the diet caused by increasing the feeding amount of corn silage, which is mainly caused by excessive starch. If we use a lot of whole plant corn silage in the dairy cow diet, because the silage contains a lot of corn seeds, we should reduce the corn in the concentrate supplement accordingly. As long as the starch content in the whole diet is controlled at a certain level, there is no problem to appropriately increase the feeding amount of corn silage. We used to feed cows simply considering the fine-coarse ratio, which is too coarse. In fact, as long as we control the content of effective fiber and NFC in the diet, we can effectively control the rumen acidosis of dairy cows.

One of the major bottlenecks restricting the development of China's dairy industry is to solve the problem of roughage for dairy cows. It is unrealistic to use alfalfa to solve the problem. Domestic high-quality alfalfa is limited, and the price of imported alfalfa is too high. However, the digestibility of inferior alfalfa and Leymus chinensis is too low to provide an appropriate amount of effective fiber. If you want to increase milk production and feed intake, you cannot use too much, otherwise it will become a bottleneck to limit feed intake. Therefore, for China, the most economical and effective way to solve the problem of roughage is to use whole plant corn silage scientifically, reasonably and as much as possible, which is also the most effective way to reduce the feeding cost. However, the premise is to balance the diet of dairy cows, that is, to regularly detect the content of water and NFC or starch in silage. When the NFC content in the combined diet exceeds 35%, attention should be paid. For Chinese diet types, it is not recommended to exceed 38% at most on the premise of using TMR. For retail investors and small pastures, the content of corn can be controlled, including the seeds in corn silage. If the content of corn in all diets exceeds 5-6kg per cow per day, attention should be paid to the risk of rumen acidosis.

◆ TMR diet (stable substrate supply system)

I have been to such a pasture. I feed silage in the morning, sheep grass at noon and alfalfa at night. It is different in the morning, middle and evening. So I told the farm manager: You are raising cows, not people! If fed in this way, the substrate in the rumen fermentation system will change three times a day, and the three substrates will be different in three time periods. Different substrates will lead to different rumen microbial cells, and the rumen environment will also change if the cells are different. The fermentation efficiency cannot be improved, and finally the milk yield will be affected. This is why TMR is used. TMR can mix various feeds together to ensure that every bite of the cow's diet is the same. Under the premise of TMR diet feeding, dairy cows have to feed 9-14 times a day, and the daily diet is the same, indicating that the substrate and thallus of the rumen system are the same every day. If the two fermentation conditions are normal, the rumen pH value will be in a normal stable state, thus effectively improving the rumen fermentation efficiency while maintaining the rumen health. Therefore, TMR feeding is actually to achieve a balanced supply of rumen fermentation substrate, but also to achieve the continuity of rumen fermentation, in the premise of maintaining rumen health also improve the efficiency of rumen fermentation, rumen management is one of the most effective measures.

◆ Prenatal 4 weeks to start perinatal management (promote rumen papilla development, ensure VFA absorption system)

Pathogenesis of rumen acidosis in the transitional period-VFA production exceeds the absorptive capacity of the rumen papilla

The perinatal period of dairy cows is the high incidence of rumen acidosis, the main reason is that the production of VFA in the rumen exceeds the absorption capacity of the rumen nipple, so in order to avoid the occurrence of acidosis, in addition to controlling the amount of dietary effective fiber to maintain the rumen buffer system, controlling the amount of rumen NFC to reduce acid production, it is essential to improve the absorption capacity of dairy cows to VFA.

The rumen microorganisms need to transition 4 weeks before delivery. To make the rumen lactic acid scavenger-lactic acid using bacteria active, it takes at least three weeks of incubation time, the most important of which is the development of the rumen mucosa, so that the volatile fatty acids (VFA) can be effectively absorbed, otherwise VFA will accumulate in the rumen and cause acidosis. So I tell you that subclinical ruminal acidosis is caused by volatile fatty acids, not lactic acid. Clinical acidosis is caused by lactic acid. If it is lactic acidosis, it shows that the situation of cattle is already very extreme and there will be problems soon.

The development of rumen mucosa in dairy cows is regular. During the peak lactation period, the feeding amount and energy of the diet are relatively high. Assuming that the VFA produced by the rumen is 100 at this time, the VFA produced during the dry milk period is only 30%, and only 30% of the rumen absorption surface is needed. Therefore, the rumen nipple begins to shrink gradually in the late lactation period. Therefore, in order to produce more milk after calving, it is necessary to start the transition before calving and develop the rumen papilla in advance. After calving, with the increase of feed intake (fermentation substrate),VFA production will increase, the absorption of rumen mucosa will also increase, and the milk produced will also increase. If the rumen papilla is not well developed at this time, the VFA produced by fermentation will accumulate in the rumen. Therefore, good perinatal management is very important.

To sum up, the management of rumen function is the core of dairy cattle feeding management. Many feeding management measures we have formulated are actually managing the function of rumen, maintaining the stability of rumen fermentation substrate (diet), bacteria (rumen microorganisms) and fermentation conditions (pH value). For example, controlling the limited amount of fiber in the diet is to improve the rumen buffer system; controlling the amount of NFC in the diet is to control the amount of acid production; strengthening the perinatal management is to improve the absorption capacity of the rumen nipple and effectively improve the absorption of rumen VFA; using TMR diet is to achieve a balanced supply of rumen substrate and to achieve the continuity of rumen fermentation. The above points are also the core nutritional measures to achieve healthy and efficient dairy cows.

Source: China Dairy News Network