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Choose different levels of high-yielding dairy cows
According to the "High Yield Cow Management Regulations": ZBB43002.85 stipulates that high-yielding dairy cows refer to a herd that has a milk yield of more than 6,000 kg for 305 days and a milk fat percentage of 3.4%. According to the statistics of 695,154 cattle registered in China in 1994, the average milk yield was 75 if kilograms. In the US Holstein registered cattle, there were 256,945 cows recorded in milk production, with an average milk yield of 8,730 kg and a milk fat percentage of 3.66%. It can be seen that the milk production levels of high-yielding dairy cows in different years and different countries are different. How to choose high-yield cows? 1. According to the current dairy breeds of dairy cows, there are mainly Holstein cows, Julian cows, more racing cows, Altai cattle and Swiss brown cows. More than 95% of dairy cow breeds in China are Chinese Holstein cows. Holstein is a large-scale dairy cow with the highest milk yield. The herd with an annual output of more than 10,000 kilograms is more common. The highest herd in China has reached 8773.2 kg. The highest milk production in the United States, Lisda, reached 30,833 kg in 365 days and the milk fat percentage was 3.3%. Therefore, in order to obtain a high yield of cows, Holstein should be selected first. In areas with poor feeding conditions, other varieties can also be selected. 2. It is the most important basis for the selection of high-yield cattle to determine the milk production and milk fat percentage of cattle based on milk production performance. The producer shall measure the milk production rate for one cow per month and one milk fat rate for the milk collection unit. The interval between two measurements shall be no less than 26 days and no longer than 35 days. Under normal circumstances, dairy cows produce calves 1 time in 1 year and stop milking 2 months before birth. Therefore, the milk production time in 1 lactation period is 305 days, and the high-yield cattle can also be 365 days. From a genetic perspective, there is a negative correlation between milk production and milk fat percentage. The higher the milk yield, the lower the milk fat percentage. Therefore, the selection of high-yielding cattle, in addition to the amount of milk produced, should pay more attention to the rate of milk fat. For low-fat rate bulls, don't choose to use them. 3. According to the appearance of the body, the appearance of the cow's body shape is closely related to its milk production. Choosing a good body shape, especially good breasts and limbs, is important for improving milk production. High-yield cattle must have such characteristics: high physique, medium volume, milk with obvious body shape, strong breast attachment, strong limbs, moderate nipple size. The requirements are: 1 body weight: US Holstein adult bull weight 1100 kg, body height 160 cm, adult cows were 650 kg and 140 cm; 2 overall triangle, that is, from the front, along both sides of the shoulders down The two straight lines are drawn, and the two lines are wider and wider, showing a triangle. From the side, the hindquarters are deep, the forequarters are shallow, and the top and the ventral lines extend forward and intersect to form a triangle; from the top to the bottom, the front The body is narrow, the hindquarters are wide, and the lateral lines of the two bodies intersect in the front and also form a triangle. 3 The breast, which is the most important functional body feature, the base of the breast should be extended and extended and attached well. Four milk areas were evenly weighed, and the rear area was high and wide. The nipples are vertically cylindrical and well-spaced. 4 Legs and feet, especially the hind legs are more important. Cow genital organs and breasts are in the hindquarters and require strong hind limbs. In short, any dairy cow with a large body shape, obvious characteristics of milk, and developed digestive, reproductive, and lactating organs must be able to eat, drink, and prolific milk. 4. According to the genealogical lineage, the content includes: dairy cow breed, cow number, date of birth, birth weight, adult body size, weight, appearance score, grade, and cow's milk production scores. In the pedigree, there should also be parental and grandparents' body weights, appearance ratings, grades, cow milk production, milk fat percentage, and grades. In addition, disease and quarantine, breeding, and health of cows should also be recorded in detail. It is important to select high-yielding dairy cows based on the above information. If dairy cows are purchased, preventive measures must be taken to avoid afferent diseases, especially tuberculosis, contagious abortion, leptospirosis, trichomoniasis, and mastitis. 5. According to age and parity age and parity have a great impact on milk production. Under normal circumstances, the initial distribution age is 16 to 18 months, and the body weight should reach 70% of the annual cattle. Cows born at the first and 2th cows have 15% to 20% lower milk production than cows with 3 or more births; cows born from 3 to 5 cows have increased their milk production step by step, and cows born after 6 to 7 months have descended. According to the study, the milk fat percentage and milk protein ratio decreased slightly with the increase in the age and parity of dairy cows. Therefore, in order to make cows or dairy herds more productive, producers must pay attention to the choice of age and parity. Most people think that a high-yielding herd, if the average parity is 4 children, the reasonable parity structure is: 1 to 3 tires account for 49%, 4 to 6 tires account for 33%, and more than 7 children account for 18%. 6. Estimating feed remuneration based on feed remuneration is an indicator for selecting high-yielding cattle and is also the basis for assessing milk costs. For this purpose, the producer should collect the amount of feed and raw feed for each cow and calculate the feed remuneration and total milk production during the whole lactation period. Total feed dry matter. High-yielding dairy cows should have a maximum intake of at least 4% of dry matter. Every kilogram of milk produced should eat at least 1 kilogram of dry matter. Below this standard, it can cause weight loss or cause diseases such as metabolism. 7. Determining milking speed based on milking speed is an important indicator for selecting high-yielding cattle. It has been determined that US Holstein milk 3.61 kilograms per minute and Shanghai black and white flowers 2.28 grams. Therefore, high-yielding dairy cows should select individuals with fast milk discharge. The above are several methods commonly used to select high-yield cows. In order to achieve both high productivity and high efficiency, it is recommended that the 6th and the 7th should be measured repeatedly to seek ways to increase the production efficiency of high-yielding cattle, and to prevent high yields from being inefficient.