Ⅰ. Feeding of Dairy Cows in the High Lactation Period
The peak lactation period is the most difficult stage for raising cows, because the lactation is at its peak, and the feed intake of cows has not yet reached its peak. The feeding peak lagged behind the lactation peak for about one and a half months, so that the nutrient intake of dairy cows could not meet the needs of lactation, and had to use body reserves to support lactation. Therefore, at the beginning of the peak lactation period, the bodyweight still declined. The earliest body fat reserve is body fat. The body fat used by dairy cows during the whole lactation period and the middle lactation period can synthesize about 1000 kg of milk. If excessive use of body fat, in the case of insufficient glucose and impaired glucose metabolism, fat will be oxidized incompletely, resulting in an outbreak of ketosis in dairy cows, causing great damage to the body.
1. High-quality roughage
The roughage used in the diet of dairy cows in the peak lactation period must ensure good quality and palatability. Hay is dominated by high-quality forage, such as alfalfa and Leymus Chinensis. The best silage is whole corn silage. At the same time, certain beer grains, liquor grains or other green juicy feed are fed to keep a good appetite and increase dry matter intake of dairy cows. The feed should not be less than 1% of the bodyweight of dairy cows in terms of dry matter. In winter, carrot, beet and other juicy feed were added, and the daily feeding amount could reach 15 kg.
2. High-quality concentrate
An adequate supply of high quality and full price concentrates must be ensured. The feeding quantity should be increased gradually. It is appropriate to increase the feeding quantity by about 0.5 kg per day, but not the more the concentrate is, the better. Generally speaking, concentrate feeding should not exceed 15 kg, and concentrate should not exceed 60% of the total dry matter in the diet. When the proportion of concentrate is high, it is necessary to increase the number of concentrate feeding appropriately, adopt a few in many times, or use TMR diet, which can effectively improve the activity environment of rumen microorganisms, reduce the incidence of digestive disorders, ketonemia, postpartum paralysis and so on.
3. Satisfy energy needs
The key point of feeding is to provide high-energy feed with good palatability and increase the feeding amount appropriately, to minimize the momentum consumption of body fat reserve. However, because the high-energy feed is concentrate, and excessive concentrate feeding is harmful to the health of dairy cows, in this case, the energy concentration of diet can be increased by adding rumen fatty acid, vegetable oil, whole soybean, whole cottonseed, and other methods, without increasing concentrate feeding. However, the addition of oils, especially non-ruminal oils, will affect the intake of dairy cows, inhibit the activity of rumen microorganisms and reduce milk protein. Therefore, it is necessary to limit the amount of fat added to maintaining the maximum dry matter intake. The fat supply should be less than 0.5 kg per day. Animal fat should not be used.
4. Meeting protein requirements
Although fat is the earliest body reserve used by dairy cows, the most serious nutrient deficiency in the negative nutritional balance is body protein, which is not as efficient as body fat in milk synthesis and has less body reserve. Dairy cows can synthesize 6.56 kg milk per kg of weight loss, while the protein content can only synthesize 4.8 kg. The available body protein reserve of dairy cows synthesizes about 150 kg of milk, which is only one-seventh of the synthetic capacity of body fat reserve. Therefore, we must attach great importance to the supply of dietary protein. If the protein supply is insufficient, it will seriously affect the utilization rate and lactation of the whole diet. The dietary protein content is not the higher the better, too high will not only cause protein waste but also affect the health of dairy cows.
For example, the proportion of soybean cake in mixed concentrate is as high as 50%-60% in individual dairy farms, resulting in ketosis outbreak in cattle. The practice shows that the diet with high energy and protein requirements is the best for high-yielding dairy cows. The dietary protein of dairy cows must contain enough rumen non-degradable protein, namely rumen-passing protein and rumen-passing amino acid, to meet the needs of dairy cows for amino acids, especially lysine and methionine. Rumen-passing protein content in the diet should account for about 45% of the total protein in the diet. At present, the known feed with high rumen protein content is corn protein powder, wheat gluten flour, brewer's grains, and distiller's grains. These feeds have good effects on increasing the milk production of dairy cows.
5. Meet the needs of calcium and phosphorus and appropriate ratio of calcium to phosphorus
The requirement of calcium and phosphorus for dairy cows in the peak lactation period increased significantly. The contents of calcium and phosphorus in the diet must be increased in time to meet the needs of the lactation of dairy cows. Calcium content should generally account for 0.6%-0.8% of the dietary dry matter. The ratio of calcium to phosphorus should be (1.5-2.0):1.
Ⅱ.Management of Dairy Cows in High Lactation Period
The management of the peak lactation period involves the milk production and the health of dairy cows during the whole lactation period. Therefore, the management of the peak lactation period is very important. Lactation management aims to ensure not only the rapid increase of lactation but also the long and stable peak period of lactation, which are to maximize the potential of lactation of dairy cows and obtain the maximum lactation.
1. Breast care
The peak lactation period is the high incidence of mastitis. It is important to strengthen breast care. We can properly increase the number of milking, strengthen breast hot compress and massage. Medicinal bath on nipples after each milking can effectively reduce the chance of breast infection.
2. Extended feeding time
Dairy cows in the peak lactation stage have a large daily diet intake, so it is appropriate to prolong the feeding time. The empty time of the trough should be controlled within 2-3 hours every day. Feeds should be fed less frequently to keep them fresh.
3. Alternate feeding of roughage and concentrate feed
When feeding, if the TMR diet is not used, concentrate and roughage can be alternately fed to keep the dairy cows' appetite vigorous. In free-range feeding, adequate trough space should be ensured so that each cow can feed adequately. The number of leftovers per day should be controlled at about 5%.
4. Ensure adequate and clean drinking water
To strengthen the management of drinking water, we should always ensure that dairy cows have sufficient and clean drinking water during the feeding process. In winter, warm water should be drunk when conditions permit, and the temperature of the water should be above 16℃. In summer, it is better to drink cold water to prevent heat and cool down and keep the appetite of cows. Conditional farms can use automatic drinking water facilities to create better drinking water conditions for dairy cows.
5. Timely mating
We should pay close attention to the estrus of dairy cows after delivery. After estrus occurs, dairy cows should be mating in time. The suitable mating time for high-yielding dairy cows is 70-90 days after delivery.
6. Body condition maintenance
Raisers should strengthen the observation of dairy cows and make good records. If an abnormal situation is found, technical personnel should be invited to deal with it immediately. Observation mainly focused on body condition, feed intake, lactation, and reproductive performance. Before calving, the appropriate body condition score of dairy cows ranged from 3.5 to 3.75. At the peak of lactation, because the use of body reserves to maintain a higher amount of lactation, the body condition declined, but the worst condition should be more than 2.5 points, otherwise, cows will be extremely weak and susceptible to disease. If the cow is in poor condition, it should consider increasing concentrate feeding or prolonging feeding time and increasing feeding times.
7. Production record
Staff should record the estrus, mating, pregnancy, feeding methods, herbage consumption, milk production, milk composition, occurrence and treatment of diseases of dairy cows in detail, and make timely summary and analysis.