1 Production characteristics of high-yielding dairy cows

In the field of livestock and poultry, the conversion efficiency of dairy cows to other energy elements such as protein in feed can reach about 5 times that of beef cattle breeds. The amount of milk produced by high-yield dairy cows in China is as high as 8000 kg per year, and the products produced are far more than beef cattle breeds with the same self-weight. The economic and social benefits brought by the breeding industry are also higher than those of beef cattle. Compared with ordinary dairy cow breeds, the formation time of lactation peak of high-yielding dairy cows is longer, and the lactation peak will occur about 40 days after the birth of calves, and a few dairy cows will delay 10~20 days backward on this basis. The lactation curve of high-yielding cows showed a large parabolic shape, the overall inclination was relatively small, and the maintenance time of high milk yield was relatively long. However, if you want to get a good amount of lactation, you need to provide certain nutrients and ingredients. Therefore, compared with general dairy cow breeds, high-yielding dairy cows have higher requirements for nutrients in the feed. If they are not provided with sufficient nutrients, it will affect the energy conversion of high-yielding dairy cows.

2 Key points of high yield dairy farming technology

Selection of 2.1 varieties

Different breeds of cows exhibit different dairy quality and productivity. At present, the larger breed in China is Holstein, which is a relatively high lactation type of dairy cow. Under normal feeding management, it can produce about 7,000kg of milk per year. However, the milk index of Holstein cattle is relatively lower than that of Juan Shan cattle. For example, the production level of brown cattle raised in Xinjiang is far lower than the overall level of Chinese Holstein cows, but Xinjiang brown cattle can live in harsh environmental conditions such as hot summer and cold, and are more suitable for breeding in pastoral areas. In addition to the differentiation of dairy cow breeds, in the individual aspect, scientific screening can be carried out in combination with the appearance of the system, the parity, the production performance measurement system of dairy cows and the age of the first match. According to the cow appearance characteristics, body quality and other effective screening, high-yield dairy cows generally show the characteristics of tall, strong udder, strong hind limbs, high-yield dairy cows body appearance is triangular state. Dairy cows usually enter the sexual maturity period at the age of 8~12 months, but the overall development degree is insufficient. If the cow is bred in advance, the lactation amount of the cow will be greatly reduced. The best suitable breeding period is 16~18 months old, during which the cow's self-weight accounts for about 70% of the adult cow and reaches the sexual maturity state completely. Compared with 3-5 cows, the lactation of 1-2 cows will be reduced by about 15%.

2.2 science planning cattle shed

The location for the construction of the cattle house requires scientific planning, such as selecting a location with high terrain, wide direct sunlight and far away from straight winds. During the construction of the cattle house, it is necessary to adhere to the basic principle of "sitting north and facing south" to ensure that each cow can obtain a certain range of activity space, and scientifically use the idle space in the farm to effectively reduce the consumption of cattle house construction and site selection. funds. Combined with the number of breeding, a large range of dairy cow activity area is built, and a large number of feed tanks and drinking water tanks are provided in the area to ensure that high-yield dairy cows will not be affected and disturbed in the process of eating and drinking water.

Environment Construction of 2.3 Cattle House

During the breeding period of high-yield dairy cows, it is necessary to provide sufficient activity space for them, and lay fine sand in the external lying pen position, and lay rubber mats inside to remove the excrement of dairy cows in time, so as to create a healthy, comfortable and easy-to-produce breeding environment for them, and effectively improve the milk quality of high-yield dairy cows. High-yielding dairy cows are more sensitive to high temperature, and hot weather conditions will cause serious damage and impact on the heat balance of dairy cows, and reduce the reproductive performance and productivity of dairy cows. According to relevant statistics, high-yield dairy cows need to ensure that the temperature of the barn is maintained at 12 ℃ ~ 15 ℃ during the breeding process. If the ambient temperature is too high, the effective flow of air inside the barn can be promoted by opening doors and windows and other methods, and the temperature of the barn can be effectively reduced. In addition, a sprayer can be set up at an appropriate position in the diet passage. When the ambient temperature rises to about 30 ℃, a sprayer with a water pressure of 0.2 MPa can be used to carry out physical cooling to ensure that the spraying time is about 10 min/time. In addition, shading devices are added in the exercise area to reduce excessive sunlight exposure and affect the growth and development of dairy cows.

2.4 feeding points

2.4.1 Ordinary feeding

The daily food needs of high-yield dairy cows fully meet the diversified characteristics, mainly green roughage, supplemented by appropriate amount of concentrate, to provide scientific feed feeding methods. Breeders need to focus on the overall quality of roughage and provide it with a balanced green and juicy feed. In the hot summer, it is necessary to properly improve the nutritional composition of the daily feed of dairy cows, provide sufficient water for them, and add an appropriate amount of energy-based feed in the daily feeding process. The temperature of drinking water needs to be maintained at 12 ℃ ~ 16 ℃. The feeding period of high-yielding cows should be strictly in accordance with the basic principles of giving less and adding more, quantitative timing.

2.4.2 Feeding of periparturient cows

High-yielding dairy cows in the perinatal period need careful care and scientific feeding, mainly with high-quality green hay. Appropriate concentrate was provided about 15 d before delivery. After the production, the cattle should provide clean and suitable warm water, and add 2 kg brown sugar and a little edible salt to it. Feed easily digested and absorbed feed 1~2 d after delivery, and add a certain amount of concentrate 3 d after delivery to ensure that high-yield dairy cows are provided with an incremental amount of 0. 5~0. 8kg /d, and strictly control the feeding amount of root tuber and silage.

2.4.3 Feeding during lactation

Breeders need to provide high-energy and high-protein feed for high-yield dairy cows, and encourage dairy cows to maintain a good appetite for a long time, so that they can eat forage as much as possible. Green hay and other similar feeds can be eaten by themselves. Concentrated nutrition needs to be fed according to the milk ratio of 3:1.

2.5 Intensive Cleaning Care of Dairy Cows

In the actual breeding process, for the cows that produce milk for the first pregnancy, the breeding personnel need to carry out comprehensive breast massage within 300 d of the cow's pregnancy, and massage according to the standards of 1/d and 3 min/time, and stop breast massage about 15 d before the cow gives birth. In the management of high-yield dairy cows, it is necessary to brush the body surface of the cow regularly, and the high-yield dairy cows that are about to produce milk need to be brushed about 1 h before milk production. Within the specified time range, the cattle house should be cleaned and disinfected to prevent insects, so as to ensure the cleanliness of the overall environment of the cattle house and the hygiene and health of high-yield dairy cows, and provide more protection for the healthy development of high-yield dairy cows.

2.6 science milking

2.6.1 Pre-milking operation

1) Before milking, dry and sterile towels should be used to dry wipe the teats of high-yield cows to clean up the residual stains or impurities on the surface.

2) To conduct a comprehensive test on the quality of milk production of high-yield dairy cows. Before the formal milking operation, it is necessary to squeeze out 3 pieces of milk in advance, and carry out in-depth inspection on the quality of the squeezed milk. If there are any symptoms such as mastitis, it can be concluded that the high-yield dairy cow suffers from mastitis, and the milking operation is stopped to carry out drug treatment, the milking operation will not be performed until there is no milk clot. During the inspection of milk quality, it is necessary to check whether there is damage to the udder and nipple of the cow at all times. In particular, the cow with mastitis symptoms should not be ignored in the inspection stage.

3) Comprehensive disinfection. Using iodine glycerin solution to clean the nipple position of dairy cows, effectively remove the pathogenic bacteria remaining on the surface of the nipple, prevent the subsequent milking work to produce serious cross infection, in addition to the nipple to carry out effective disinfection after spraying disinfection of the nearby epidermis.

4) Wipe. After disinfection, the nipples of high-yield cows are wiped with sterile dry towels from far to near. After wiping for the first time, the towels should be turned over in time and wiped for the second time. Normally, a high-yield cow is wiped with a towel alone, and cross-use is not allowed.

2.6.3 Post-milking operation

Disinfect the nipples of high-yield dairy cows and dry them in time. The cup is soaked by medicated bath and other methods to reduce serious cross-contamination. High-yield cows need to disinfect the cup at the first time after milking. The cup can be washed with clear water and then put into 0.3 sodium chlorate solution for medicated bath disinfection.

2.7 strengthen night management

At present, many high-yield dairy farming enterprises pay more attention to the management of the day and ignore the important role of night management, which leads to the gradual decline of high-yield dairy cows. Through the relevant investigation and research, it is shown that the quality of night management of high-yield dairy cows is closely related to milk production. Breeders can provide the right amount of forage and water to the cows at about 10:00 p.m., which can effectively improve the resilience of high-yield cows and maximize the benefits of milk production. In addition, fluorescent lighting can also be added at night, combined with the growth of high-yielding cows to provide a fixed time of light effect, accelerate the metabolism of high-yielding cows, effectively improve the digestion of feed, and continuously improve the milk yield of high-yielding cows. In addition, it is necessary to avoid the delay of the empty cup period of high-yield dairy cows due to improper inspection work, which will affect the milk quality of high-yield dairy cows.

[1] Yang Hongwei. Analysis on the Key Points of High-yield Dairy Cattle Breeding Technology [J]. Livestock and Poultry Industry, 2022,33(05):62-64.DOI:10.19567/j.cn ki.1008-0414.2022.05.021.