Measures to Improve Reproductive Capacity in Meat Donkey Breeding

I. Strengthen Selection of Breeding Stock

Reproductive capacity is greatly influenced by genetic factors, and the reproductive performance of different breeds and different individuals also varies. In particular, the male donkey has a great influence on offspring, so selecting male and female donkeys with high reproductive capacity is the prerequisite for improving the donkey reproductive rate. In selecting female donkeys, attention should be paid to a comprehensive assessment under normal feeding conditions of their age at sexual maturity, estrus and ovulation, foaling interval, conception capacity and nursing performance, etc. In selecting male donkeys, attention should be paid to the male donkey's genetic performance, body shape and appearance, reproductive history and reproductive results, and importance should be attached to examinations of the male donkey's general physiological state, reproductive organs (the texture and size of the testes and epididymides, sperm output ducts, and the function of the accessory sex glands), semen quality (sperm motility, density, and sperm morphology) and reproductive diseases, etc.

II. Increase the Number of Female Donkeys

Female donkeys are the basis for the multiplication of the donkey herd. The greater the number of female donkeys in the herd, the faster the herd multiplies. Therefore, rapidly developing large-scale donkey farming is the most effective way to improve the donkey reproductive rate.

III. Scientific Feeding and Management

Strengthening feeding and management, especially ensuring that female donkeys have appropriate body condition during the estrus and breeding season, is the material basis for ensuring normal estrus and ovulation in female donkeys. Nutritional deficiency will make female donkeys thin and weak, affect endocrine activity, reduce sexual function, and disrupt reproductive function, often resulting in absence of estrus, silent estrus, estrus without ovulation, and reduced ovulation number, etc.; breeding male donkeys show poor semen quality and decreased libido, etc.

IV. Do a Good Job in Estrus Identification and Timely Breeding

Under normal circumstances, newly released eggs have relatively strong vitality, and their fertilizing ability is also high. Generally speaking, the closer the time of insemination or natural mating is to ovulation, the higher the conception rate. This requires that the estrus identification of female donkeys be as accurate as possible so that insemination can be carried out at the right time. The estrus identification of female donkeys is usually based on external observation, with emphasis on rectal examination. Rectal examination, based on changes in the presence, size, and texture of follicles, grasps the degree of follicular development and the time of ovulation to determine the most appropriate time for insemination. In recent years, while promoting the rectal palpation insemination method, insemination combined with touching the degree of follicular development has reached a conception rate of about 60% per estrous cycle.

V. Follow Operating Procedures and Adopt and Promote New Breeding Technologies

The promotion of artificial insemination technology, especially the application of frozen semen, has greatly improved the utilization value of breeding male animals and the production level of the donkey herd. In the process of promoting artificial insemination technology, operating procedures must be followed. From estrus identification, cleaning and disinfection of instruments, semen collection, semen processing, freezing, preservation and insemination, it is a whole set of very detailed and strict operations, and all links are closely connected. If any link is not handled well, it can cause failure to conceive and infertility. In order to improve the reproductive capacity of donkeys, suitable and mature new breeding technologies should be gradually applied, such as synchronized estrus, embryo transfer, superovulation, controlled parturition, induced estrus, sex control, gene introduction, artificial insemination, embryo freezing and preservation, and other technologies. The correct use of reproductive hormones can restore normal reproductive function in female donkeys with reproductive disorders, thereby maintaining and improving their reproductive capacity.

VI. Carry Out Early Pregnancy Diagnosis to Prevent Failure to Conceive and Empty Pregnancy

Through early pregnancy diagnosis, it is possible to determine as early as possible whether a female donkey is pregnant and to treat them differently. For female donkeys confirmed pregnant, pregnancy protection should be strengthened so that the fetus develops normally, which can prevent mis-mating due to estrus after conception. For non-pregnant female donkeys, the causes should be carefully and promptly identified, corresponding measures taken, and supplementary mating carried out without delay to reduce the empty pregnancy time.

VII. Reduce Embryonic Death and Abortion

This issue involves a relatively broad scope, is also relatively complex, and has many influencing factors. If early embryos that have not yet formed fetuses stop developing and die in the female donkey's uterus, they are generally absorbed by the uterus, and some are expelled from the body with estrus or urination. Because embryonic disappearance and expulsion are not easily discovered by people, this is called silent abortion. The average abortion rate of donkeys is about 10%, and abortion mostly occurs around the 5th month of pregnancy. During this period, avoiding sudden changes in feeding conditions and maintaining reasonable work or exercise intensity are effective preventive measures. Some suggest that subcutaneous implantation of 300 mg progesterone after 120 days of pregnancy may also be effective in preventing abortion.