Detailed Explanation of Key Technical Points for Velvet Deer Breeding and Reproduction

Physiological Characteristics of Velvet Deer

Sexual Maturity and Suitable Age for First Mating

Sexual maturity is the maturity of reproductive physiology, at which point deer can produce mature sperm and eggs and exhibit sexual behavior. The sexual maturity of velvet deer is related to factors such as breed, type, sex, genetic status, nutritional conditions and individual development. Sika deer mature earlier than red deer, females earlier than males, and deer of the same breed with good nutritional status and rapid individual development also mature earlier. General sexual maturity period: female sika deer at about 16 months of age; well-developed deer reach sexual maturity at 7 months of age; male deer at about 20 months of age; red deer at about 28 months, but some deer reach sexual maturity at 16 months of age.

The suitable age for first mating is 16 months for female sika deer and 40 months for male sika deer (three-saw males); 28 months for female red deer and 40 months for male red deer (three-saw).

Estrus Patterns

Estrus Period Velvet deer are seasonally estrous animals. In northern China (areas north of 40 degrees north latitude), the estrus season for velvet deer is from September to December, with some individuals continuing until February to March of the following year. The entire estrus and mating period may include 2 to 3 estrous cycles. However, the normal estrus period for sika deer is from September 15 to November 15, with the peak estrus period from September 25 to October 20; while the mating period for red deer can be about 10 days earlier, specifically from September 5 to November 10, with the peak period from September 15 to October 10. About 80% of velvet deer can conceive during the first estrous cycle.

Estrus Cycle The interval between two consecutive ovulations is called the estrus cycle, which is 12 to 16 days for sika deer and 16 to 20 days for red deer. The estrus cycle is also related to factors such as age, health status and external environment. Mature, healthy deer have slightly shorter cycles, and vice versa.

Estrus Duration This refers to the duration of each estrus. For sika deer it is generally 24 to 36 hours, with the peak estrus period occurring 11 to 24 hours after the onset of estrus; for red deer it is about 24 hours, with the peak estrus period occurring 6 to 7 hours after the onset of estrus.

Estrus Manifestations include three aspects: behavior, reproductive tract changes and ovarian changes. Male deer in estrus exhibit fighting, antler rubbing, lip curling, ground pawing, thickened neck circumference, pushing against people or objects, long loud roars, reduced appetite, and urine dripping while the penis twitches. Female deer in early estrus exhibit excitement and restlessness, wandering, lip smacking, occasional mooing, willingness to approach males but refusing mating; during peak estrus they stand still, raise the tail and arch the back, accept mounting, often show opening of the infraorbital glands, tail swishing and frequent urination, swelling of the vulva with egg-white-like mucus discharge, low grunting, or nuzzling the male's head, assuming a mating posture to accept copulation; in late estrus, the female becomes calm, refuses mating, and the vulvar mucus changes from egg-white-like to orange-yellow, finally reddish-brown, and dries on the vulvar hair.

Whether a deer is in estrus can be judged based on its behavior. In recent years, for red deer, the method of palpating the ovaries as done with cattle and horses has been used to determine estrus status; the teasing method can also be used to determine estrus in female deer, that is, using one male deer of the same breed with its penis surgically altered or fitted with a teasing cloth, then placing it into the female herd. If a female stands still and accepts mounting, it indicates that she is close to ovulation. At this point, the teaser male is removed and a breeding male is introduced or artificial insemination is performed, which can basically ensure conception.

Mating of Velvet Deer

Preparation for Mating

First, breeding males should be selected based on velvet production history, breeding capability and breeding direction. Males aged 3 to 7 saw, full of energy, with strong libido, good semen quality and high velvet yield should be selected as breeding males. Required velvet yield: sika deer saw-standard three-branch velvet fresh weight per unit of 3.5 kg or more; red deer 5.5 kg (three-branch) or 7.5 kg (four-branch) or more. Feeding of breeding males should be intensified from mid-July.

Breeding females should be weaned in mid-August and organized into mating groups according to age, body condition and breeding plan (15 to 18 per group for sika deer, 10 to 12 per group for red deer). Feeding of females should also be intensified, and they should reach upper-medium body condition by the mating period, but should not be overly fat. Male and female deer pens should be reasonably arranged, and mating records should be prepared.

Mating Methods

Mating methods for velvet deer include the group-male group-female mating method, the single-male group-female mating method (which is further divided into one-male-throughout and mid-period replacement), the teasing mating method, the timed-pairing mating method and artificial insemination. However, the commonly used method is the single-male group-female one-male-throughout method. The specific method is: for sika deer on September 10, and for red deer around September 5, one breeding male is placed into the female herd. If the male has no special circumstances, it remains until the end of the mating period when it is separated out. However, if there are few superior breeding males, the teasing mating method or timed-pairing mating method can be used. That is, the breeding male and teaser male are kept separately in small pens. At 4:00 to 6:00 every morning and 16:00 to 18:00 every evening, the teaser male or breeding male is regularly placed into the female pen to seek estrous females, and then mating is conducted. After confirming each time that there are no more estrous females, the male is driven back to the small pen, ending the teasing and pairing. This method can maximize the breeding performance of superior breeding males. Each breeding male can mate with about 35 females in one mating period, and the pedigrees of offspring are clear, but the workload is greater.

Issues to note in velvet deer mating work: prevent inbreeding when selecting mating pairs, and prevent mating between breeding males and females with the same trait defects; first-time breeding males and females should not be mated together; breeding males removed during mid-period replacement should be kept separately, otherwise they may be attacked by other males due to carrying the scent of estrous females; at the end of the mating period, choose a clear day and remove the males before 8:00 in the morning, assigning dedicated personnel to watch over them to prevent intense fighting among them that could cause losses.

Causes and Countermeasures of Female Deer Infertility

The causes of infertility are relatively complex, but can be broadly attributed to the following:

Congenital infertility. Mainly caused by poor development of reproductive organs. Such deer should be culled as early as possible.

Nutritional infertility. Due to disease or poor feeding management, the female deer's body condition is too poor, causing embryos or even follicles to fail to develop normally, so conception cannot occur, or the embryonic vesicle disappears after conception. Such deer can be treated for disease and given improved feeding to reach above-medium nutritional levels, and they can definitely reproduce. However, those with certain infectious diseases that seriously threaten the herd should be culled.

Infertility caused by inbreeding, advanced age of female deer, or an excessively large female herd can be addressed with targeted measures to improve deer reproductive survival rates.

Pregnancy and Parturition of Velvet Deer

Pregnancy

After mating, if a female deer no longer comes into estrus, it can generally be considered pregnant. In addition, from external appearance, pregnant deer show increased appetite, increasingly better body condition, glossy coat, gentler temperament, and cautious and steady movement. By March to April of the following year, those showing obvious abdominal enlargement before eating are more than 90% pregnant. The gestation period of velvet deer is related to factors such as species, sex and number of fetuses, feeding method and nutritional level. For sika deer, the average is 229±6 days; 231±5 days for male fawns, 228±6 days for female fawns, and 224±6 days for twins, about 5 days shorter than single fetuses. The gestation period of various red deer is basically the same, such as 243±6 days for Northeast red deer and 244±7 days for Tianshan red deer, with 245±4 days for male fawns and 241±5 days for female fawns.

Parturition

The fawning periods of sika deer and red deer are basically the same, generally from early May to early July, with the peak fawning period from May 25 to June 15. However, the fawning period is also related to factors such as deer age, geographic region and feeding conditions. The formula for predicting the fawning date is mainly calculated based on the mating date and gestation days. Usually for sika deer, subtract 4 from the month and 13 from the day of mating; for red deer, subtract 4 from the month and add 1 to the day to calculate the fawning date.

Parturition Manifestations Before parturition, the udder enlarges. The time from the beginning of udder enlargement to parturition is generally 26±6 days. One to two days before parturition, the deer reduces food intake or fasts, paces in circles, seeks a birth site; some deer moo while pacing, show sunken flanks, frequent urination. At the onset of parturition, egg-white-like mucus flows from the vaginal opening, the deer repeatedly lies down and stands up, then discharges a pale yellow water blister, and finally delivers the fetus. Some first-time mothers or deer with vice habits become extremely frightened upon seeing the water blister, anxiously turning in circles or running. Most fawns are born with the head and both forelimbs presented first; a small number are born with both hindlimbs and rump presented first, which is also normal presentation. Positions other than these two are abnormal presentations requiring assistance.

Normal duration of labor is half an hour to 2 hours for multiparous females and 3 to 4 hours for primiparous females.

Precautions During the Fawning Period

The fawning pen should be clean. It should be thoroughly disinfected before the fawning period arrives, and clean bedding straw should be laid. Throughout the fawning period, the fawning pen should be disinfected every 10 days.

The fawning period should be kept quiet, and visitors should be declined.

Dedicated personnel should be assigned to watch during the fawning period. Dystocia should be promptly handled; deer with vice habits should be dealt with promptly, and various abnormalities in postpartum fawns should be closely monitored, with sick ones treated promptly.

During the fawning and nursing period, fawn protection rails should be set up in the pen.

Fawning records should be properly filled in.

Technical Measures to Improve the Reproductive Survival Rate of Velvet Deer

On the basis of proper selection of breeding males and females, mating pair selection should be well carried out

Selection and mating pair selection are closely related. They are two consecutive links in the unified process of continuously improving the quality of the deer herd and the entire breed. When selecting, comprehensive assessment must be made based on the deer's appearance, constitution, production performance, breed origin and offspring quality; mating pair selection is consciously done according to people's needs to improve deer quality. Therefore, only by addressing both can the overall quality of deer be improved.

Breeding females should have an optimal age structure

In the entire female herd, adult females should account for 77.3%, bred females 10.5%, and female fawns 12.2%. Such a structure is favorable for the normal development of the deer herd; otherwise, age gaps and developmental imbalance will occur.

Breeding females should have a reasonable nutritional level

Overly fat deer mostly fail to conceive because of abnormal follicle development, and thin deer also cannot come into estrus or ovulate normally. Therefore, breeding deer should be fed scientifically and reasonably.

Timely and rationally cull breeding males, females and reserve bred deer

Any deer with very low productivity, not conforming to the breeding direction, or with vice habits should be culled promptly; otherwise, it will affect the economic benefits and development of the deer industry.

Reasonably arrange the male-to-female ratio in mating groups

If the number of females is too large and exceeds the mating capacity of males, "missed estrus" will occur, especially in red deer, which are large and clumsy and cannot bear the burden of continuous mating. Therefore, a large number of females will result in a low conception rate.

For pregnant females, feeding management should be strengthened, appropriate nutritional levels maintained, deer pens should not be changed casually, and sudden disturbances, whipping and beating with sticks should be avoided.

All work during the fawning period should be done well to improve the survival rate of fawns.