There are several technical aspects to improve the performance of cattle using frozen sperm, and ignoring any one of them will affect the final improvement effect. The main skills are as follows:
1, Qing Qun
In order to rule out the interference of the poor bulls in the herd with the freeze-thawed breeding stock, the herds must be thoroughly cleared. The specific approach is to combine spring and autumn secondary clearing with perennial Qingqun, and to timely cast off sexually mature bulls.
2, clusters, groups
In order to make effective use of precision tank equipment, cows should be properly concentrated. The size of the herd must be appropriate and the group is too large to be easily monitored. It is easy to cause missed matches. The group is too small to waste manpower. Generally 50 ~ 7O head is appropriate.
3, early spring robbing aphrodisiac
The main factor affecting the rate of mating is the cow's sensation. In winter, cows in our city are rarely supplemented, and most cattle farmers have very simple barnyards. In the spring, the situation is very poor, affecting the cow's normal estrus. Early spring can eat grass, although not enough, but vitamins, proteins, etc. can be added, it is meaningful to promote cows as early as heat and normal estrus. Therefore, catching the aphrodisiac in the early spring can improve the rate of acceptance, and it is also the key to improving the rate of acceptance.
4, monitoring situation, test situation
Cows should not be kept for long periods of time, but must ensure proper exercise. In free-range conditions, exposing the estrus cows mainly depends on the trial of bulls ligating the vas deferens and the mutual climbing between the cows. Therefore, the keeper must pay attention to the observation and establish a post responsibility system for the supervisors to prevent missed matches. The breeder should also pay attention to the supervision of the situation and observe the estrus performance of the cows so that the cows can be observed three times in the morning, evening and evening to prevent leakage. The proportion of bulls in the test should be 1:25, and it is best to yak the vas deferens from 3 to 5 years old. Yak and young bulls have certain shortcomings.
5, the correct use of frozen essence
It is often overlooked that freeze-thawing thaw, transport, and preservation of frozen essence thawing are correct or not. Off-site insemination must be on-the-go, and should not exceed 2 h after thawing.
6, timely infusion
In the past, we determined the timing of insemination from the beginning of estrus or stabilizing the bar. However, due to the difference in cow estrus and stabilizing time, the ovulation time of cows is usually 7 to 10 h after the end of estrus. Thus, estrus occurs. It is easy to determine the infusion time at the end of the day. Our current insemination time is insemination within 5 h after the end of estrus (refusal to climb). One or two inseminations are due to cattle.
7. Insemination method
Cervical grasping method insemination can achieve the purpose of deep insemination, and the mating staff must master this technique. According to the data, the stimulation of the cow and the cold hard opener during the breeding period can interrupt the uterine activity for 10 minutes, resulting in a decrease in the conception rate and an increase in embryonic mortality. According to a point of investigation, the cow hit 13 insemination frames and inseminated 6 heads. Later, it changed to 66 in situ and 45 quasi-fetus, which increased the rate of conception by 21.9%.
8, Baotai
When the cows estrus after 28 days after mating, they can be considered embryonic death. The causes of embryonic death are affected by many factors. Maternal factors, embryonic factors, maternal and fetal blood circulation, as well as heredity, nutrition, age, hormone imbalance, and high temperature can all cause embryonic death. Therefore, we must solve the problem from the aspects of strengthening the feeding and management of pregnant animals, shortening the interval between insemination and spermatozoa after thaw, and timely infusion.
9, consignments, midwifery
The use of large cattle to improve the local cattle, calves, a significant new birth, coupled with the calving of the cows during the calving season. There is no power to contract the baby during childbirth. If artificial confinement and midwifery are not implemented, calves and even cows may die. Based on this, we trained the breeders' production and midwifery techniques in a timely manner. At the same time, strengthen the winter management of pregnant cows. The annual survival rate of yak reached 89%.
10. Nurturing calves
Cultivating yaks is the last link to guarantee improvement. Although the improved yak inherits the excellent traits of the paternal ancestors, it must be scientifically bred to manage its potential production performance. To cultivate yaks, we mainly focus on weaning, feeding, grass-supplementing and feeding. The yak was weaned in November of that year and concentrated on half-shelf feeding. Each yak prepared 500 kg of roughage and 150 kg of concentrated feed, supplemented with salt, bone meal, and drinking water. The 18-month-old body weight could reach more than 300 kg. Cultivate good calves and speed up slaughter so that cattle farmers can benefit from them and use them to mobilize the enthusiasm of the improved cattle.
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