According to the different stages of milk production and the growth and development of dairy cows, to meet the nutritional needs of dairy cows and achieve the goal of high yield, the nutritional standards of feed in different stages are also different.
1.Dry period (from stopping milking to 15 days before delivery).
The main diet should be high-quality hay and be fed with an appropriate amount of green, root feed and concentrate. Concentrate feeding should not be excessive. Generally, concentrate mixtures are about 2.5 kg. In the later stage of dry milk, it is necessary to increase dietary nutrition and reduce the amount of calcium in mixed concentrate to meet the postpartum needs of dairy cows. At this stage, the feed ratio of concentrate to roughage should be about 3:7.
2.Perinatal period (within 15 days before and after delivery).
Cows should gradually increase concentrate feeding, but the maximum feeding should not exceed 1% of the cow's body weight (for cows with severe prenatal breast edema, it is not appropriate to feed more concentrate) while reducing salt to prevent constipation of cows. Drink hot bran and salt-calcium soup 10-20 kg (500 g of bran, 50 g of salt and 50 g of calcium carbonate) after delivery to help cows recover their physical strength and expel the placenta as soon as possible. The ratio of calcium to phosphorus was adjusted to 3:1 within one week after delivery.
3.Peak lactation period (within 16-100 days after delivery).
At this stage, part of the nutritional needs is to restore physical fitness, and more importantly, to meet the needs of milk production. Dairy cows reach the peak lactation at 4-6 weeks postpartum. Guided feeding methods can be adopted at this time. From 5-7 days postpartum, cows are fed with high-quality hay and adequate drinking water. The concentrate is increased by 0.5 kg per day. The feeding level is 1.2 times of the feeding standard until the lactation is no longer increased, and then normal feeding begins. At this time, concentrate feed should be 2.5 kg of base material, 1 kg concentrate per 2.5 kg milk production, and concentrate to roughage ratio is 5:5.
4.Mid-lactation (101-200 days postpartum).
At this stage, the feed intake of dairy cows increased, and the feed concentrate should be reduced compared with the earlier stage. The ratio of concentrate to roughage was 4:6, and the dry matter intake could reach 3.5%-4.5% of the body weight. During this period, the milk production of dairy cows is flat to down, with a monthly decrease of 5%-7%. Therefore, effective measures should be taken to slow down milk production as much as possible.
5.Late lactation (201 days postpartum to before dry milk).
In this stage, the milk yield of dairy cows has decreased significantly (8%-12% per month). Concentrate feed should be reduced appropriately, and the ratio of concentrate to roughage should be about 35:65. However, concentrate feeding should be increased by about 1 kg one month before dry milk to ensure that the nutrition needed for fetal development is met.
6.The calf feeding period (1-6 months after delivery).
Calves should be fed colostrum within 1 to 2 hours after birth. The amount of colostrum should be no less than 1 kg, and the daily amount of milk should be 10 to 15 kg during lactation. After 7 days of birth, calves can be trained to eat special concentrates and soft hay and silage, and weaning can be considered when calves can eat about 1 kg of starter every day. Generally, calves can be weaned in about three months.
7.The breeding period of bred cattle (7-18 months after delivery).
At this stage, the rumen capacity of the bred cattle is greatly increased, and the ability to utilize green feed and roughage is improved. Therefore, the breeder should take advantage of this favorable opportunity to strengthen the feeding to gain greater daily gain. The daily concentrate feed is about 2.5 kg, and the roughage is free to eat.