Breeding Techniques for Improving the Survival Rate of Fawns

The survival rate of fawns is one of the important indicators of the reproductive performance of a deer herd. A survey of 5 deer farms at Ning'an Farm showed that the fawn survival rate could reach over 75% in good years, was less than 60% in poor years, and averaged around 65%. The survey data are now classified and analyzed statistically to identify the main factors affecting the fawn survival rate. Based on these factors, improvement measures are proposed.

1 Main factors affecting the fawn survival rate

Deaths of fawns caused by difficult birth accounted for 4.1% of the total number of births and 22% of fawn deaths. Most of these deaths resulted from delayed assistance during birth or poor assistance techniques.

Deaths of unknown cause accounted for 3.5% of the total number of births and 21.8 of fawn deaths. This refers to deaths for which a confirmed cause could not be found in the records, whether due to poor management or inadequate technical proficiency, making determination difficult.

Deaths caused by weak fetuses and malformations accounted for 3% of the total number of births and 17.1% of deer deaths. Nearly all weak and malformed fawns died. This was mainly caused by malnutrition during the doe's gestation period, disease, or genetic factors.

Deaths of fawns caused by vicious habits of the doe accounted for 2.9% of the total number of births and 16.1% of total fawn deaths, mainly due to undesirable behaviors such as the doe pawing at, biting, or refusing to nurse the fawn, which led to the fawn's death.

Fawn deaths from the “three inflammations”: omphalitis, pneumonia, and gastroenteritis are common diseases in fawns, and despite active treatment, deaths still inevitably occurred. The mortality rate accounted for 2.3% of the total number of births and 12.4% of fawn deaths.

Deaths from accidental injuries accounted for 1.8% of the total number of births and 9.3% of fawn deaths. This mainly refers to fawns killed by accidents such as being trampled, pinched, struck, or drowned.

2 Main technical measures for improving the fawn survival rate

2.1 The success rate of treating difficult births must be improved

At present, the success rate of assisting deer births on deer farms is very low, mainly due to problems with assistance techniques. Technicians on deer farms should receive planned technical training or exchange of experience regarding difficult births in deer, so as to improve the success rate of treating difficult births and reduce fawn deaths caused by difficult birth.

2.2 Strengthen the care of fawns

Deaths of fawns from unknown causes are mainly due to a lack of meticulous observation and nursing of fawns. Therefore, during the fawning period, the day-and-night duty system must be strengthened, and the entire process of each fawn from birth to standing with dry fur and achieving its first suckling must be monitored. Fawns abandoned by the doe should be foster-nursed or hand-fed as early as possible. In normal times, attention should be paid to observing the behavior of fawns, and any abnormality should be promptly investigated and treated.

2.3 Reasonably set up fawn protection pens

Fawn protection pens should provide a resting environment with thick bedding, warmth and dryness, and relatively dim light. In this way, fawns are willing to go inside to rest, come out to suckle only when hungry, and can develop the good habit of nursing on schedule. Once the herd is startled, fawns can go into the pens, avoiding injuries such as being trampled, pinched, or struck.

2.4 Create a quiet fawning environment

A noisy and restless environment puts does under a state of high tension, easily leading to difficult births or the formation of vices such as licking the anus or biting the tail. Therefore, sheds for does during fawning should be located in a secluded part of the deer farm, and during the fawning period the frequency of moving deer should be minimized; necessary moving of deer should be done patiently and carefully with steady movements, so as to minimize adverse stimulation to the does.

2.5 Supplement feeding for fawns in a timely and reasonable manner

From 15 to 20 days after birth, fawns begin to eat some roughage and concentrate feed along with the doe, and rumination also appears. At this time, troughs for feed and water should be set up in the protection pens, and a small amount of nutrient-rich mixed concentrate should be provided; roughage can be consumed together with the doe.

2.6 Strengthen feeding hygiene

Diseases such as the “three inflammations” in fawns are mostly caused by poor feeding hygiene. Therefore, during the fawning season, the pens should be cleaned once a day, sewage, manure, and urine must not accumulate in the pens, the bedding in the protection pens should be changed frequently, disinfection should be carried out regularly, and the hygiene management of feed and drinking water should be strengthened.

2.7 Strengthen the feeding of does during gestation and lactation

Does fed poorly during gestation produce thin, weak fawns that are difficult to keep alive. If does are malnourished during lactation and have poor milk production, the disease resistance of fawns declines. Therefore, does during gestation and lactation should be supplied with sufficient protein feed, vitamins, and mineral feed, so that the does maintain a body condition slightly above medium with no ribs visible.

2.8 Pay attention to exercise for does in the middle and late stages of gestation

Exercise during gestation in does can promote the body's assimilation, benefit the growth and development of the fetus, and also increase the tension of the uterine muscles and abdominal wall muscles, reducing the occurrence of difficult births. In the middle and late stages of gestation, does should be driven around the pen for 30 minutes to 1 hour each day, which is especially important for does kept in pens year-round.

2.9 Strengthen the culling of does to prevent close breeding

Some does that are old, thin and weak, have been ill for many years, or have vices of pawing, biting, or licking, as well as some fawns that have congenital diseases from birth, may have mothers that are carriers of undesirable genes. Strictly culling these does of poor quality is one of the means of improving the fawn survival rate. Certain hereditary diseases mostly appear in the offspring of close breeding. To prevent close breeding, deer farms should introduce breeding deer once every year or every second year for blood renewal; and several special-grade and first-grade breeding bucks should be used to form several sub-lines, thereby achieving the goal of improving the fawn survival rate.