Therefore, it is necessary to create superior feeding conditions for high-yield dairy cows, continuously improve the composition and coordination of diets, and pay special attention to the balance of nitrogen and carbon, various minerals, trace elements and vitamins in the diet to meet the needs of high-yield dairy cows for energy and various nutrients after calving, which is an important material condition for improving the fertility of high-yield dairy cows.
Under normal circumstances, the uterus of dairy cows basically recovers about 30 days after calving, and the first estrus after delivery is mostly on the 50 th to 60 th day, which is also the peak of milk production.
During this period, if the cows are well nourished, they can maintain the normal activities of reproductive function, estrus and ovulation are also normal, so this period is the best period for postpartum mating.
The most suitable time for postpartum mating of high-yield dairy cows is 60-70 days after delivery, and the conception rate is the highest.
High-yield dairy cows often suffer from uterine diseases about 15 days after delivery. In view of this situation, it is generally necessary to check the uterus once after delivery 15 days for timely treatment, and check the uterus again 10 days before mating, and then mating, which can significantly improve the mating pregnancy rate.
Adjusting the calving season of cows and arranging breeding and calving in a planned way can make cows develop in a planned way according to human needs. Coordinate the needs of production and products, and use pens and equipment reasonably; Avoid uneven work and rest, coordinate feed and supply with the needs of cows, and properly handle the contradiction between reproduction and calving, so as to improve the reproductive efficiency of dairy cows.
Experience shows that calving accounts for 30% of the whole year in the first quarter, 20% in the second quarter, 10% in the third quarter and 40% in the fourth quarter, and calving should not exceed 5% in July and August.
In order to regularly meet the needs of people's fresh milk and dairy products processing plants in cities and industrial and mining areas, realize the planned supply throughout the year, make full use of cowsheds, and prevent workers from being too busy and idle all year round, such areas should calve evenly.
In dairy farms and individual cattle farmers with good equipment and high management level, the distribution density of calves should be arranged in late autumn and early winter, and it should be smaller in summer to solve the contradiction between supply and demand of fresh milk, give full play to the role of cows in high-yield period and obtain higher milk yield.
Calves can use rich forage after weaning, which is beneficial to the growth and development of calves.