What problems exist in China's fox farming industry? A few suggestions for reference
Over the past 20 years, China's fox farming industry has made considerable progress, but through our 10 years of fairly systematic investigation into the current feeding conditions of fox farms and households, we have found some noteworthy problems that affect reproduction and fur quality. The specific situation is reported as follows.
1 Feeding and feed
Currently, fox farms (households) across the country all use single-cage rearing in courtyards; they use complete feed supplemented with cornmeal, sea fish, freshwater fish, beef liver, various meat trimmings, and also add a small amount of other ingredients, boiled into a cooked porridge for feeding. Young foxes are fed 3 times a day, and adult foxes are fed 2 times a day.
Compared with Finland, which has advanced fox farming in the world, the feed composition of individual, collective, and small cooperative fox farms in China has a protein content 30%-40% lower, a fat content 30%-40% lower, while carbohydrates are 20%-40% higher. The low proportion of animal-based feed is a common problem in China's current fox farming industry, and this is also the main reason it is inferior to countries with advanced fox farming; the foxes raised are small in size and poor in fur quality. Therefore, it is suggested that the daily feed ration should be based on the standard of each animal's daily energy and digestible protein requirements, or on the standard of the percentage of crude protein contained per kilogram of feed, so that the animals' protein needs can be met. Digestible animal protein in the daily ration should not be lower than 90% of total protein.
2 Reproduction
Rearing personnel who have just started raising foxes have no experience in estrus identification and rely only on frequent teasing tests, lacking the necessary scientific methods. Even when a female fox is in estrus, they cannot tell the optimal mating time.
According to survey statistics from 30 fox farms (households), the empty pregnancy rate for natural mating is over 20%, and the empty pregnancy rate for artificial insemination is around 15%. The natural mating method uses repeated mating with multiple males. High-frequency mating not only causes a low utilization rate of breeding male foxes and a great waste of manpower and time, but also leaves pedigrees unclear. The exchange and shared use of breeding male foxes among various rearing households causes female foxes to be infected with Gardnerella and Pseudomonas aeruginosa, which easily leads to the spread of reproductive system diseases. Female foxes born that year come into estrus relatively late. Although the female fox shows good estrus signs, a male fox capable of mating cannot be found, because male foxes are in estrus for only 60-70 days, and the mating rate of female foxes born that year in estrus is only 93%. Breeding male foxes cannot be used rationally; some are made to mate once a day, and some are even made to mate 2 times. The male foxes cannot get proper rest, and frequent use leads to a decline in semen quality. When their semen is examined under a microscope, low sperm density and deformities are found. Such sperm cannot be used, and even if mating is achieved, pregnancy cannot occur. In addition, most male foxes cannot participate in mating, and the utilization rate for artificial insemination is only 70%, causing a waste of resources.
In fox farming production, there is a great gap in the reproductive rate of foxes in different places, which is closely related to the low feeding level (protein) during preparation for mating. In addition, improper management and poor rearing techniques will all affect mating and conception rates.
2.1 Feeding and management of female foxes during the mating period
In the investigation, it was found that there are many problems in the feeding and management of female foxes during the mating period. First, they are raised under relatively low nutritional conditions. Blue foxes have a very high litter size, with most female foxes giving birth to 10-13 cubs. If the utilization rate of protein feed is low, it will affect the growth and development of the cubs. Even if the female fox is successfully mated, if the protein feed does not reach the target, in some female foxes the fetuses are absorbed before even 30 days of visible pregnancy. Second, the female foxes are not fed well. When nutritional indicators do not reach the standard, the female fox's ovaries develop poorly and estrus symptoms are not obvious; even if mating is successful, conception will not occur.
2.2 Feeding and management of female foxes during gestation
During gestation, the female fox not only has to maintain her own metabolism, but also meet the nutritional needs of fetal growth and development. 60% of fox-raising households do not feed female foxes with complete feed. Female foxes are unable for a long time to receive animal-based feed such as small miscellaneous fish, resulting in a severe lack of protein feed, which delays estrus in female foxes. In some cases, even if mating is successful, miscarriage, stillbirth, or fetal absorption will occur after 35 days.
2.3 Breeding
Every year, each fox farm keeps some reserve female foxes for breeding, but they do not adjust blood relationships well. It is understood that currently 15% of fox farms (households) still have the problem of inbreeding in foxes. In recent years, farms and households in various places have exchanged breeding stock with one another. Some purchased male and female breeding foxes both come from the same farm, leading to inbreeding. For females subjected to artificial insemination, farms do not record the mating male's number, and artificial insemination stations do not ask about the female's parental origin; they inseminate whatever is brought in. Therefore, pedigrees are unclear and close-relative mating is unavoidable. The consequences are that foxes become smaller year by year, the survival rate of cubs is low, disease resistance declines, and growth is slow.
2.4 Ensuring cub survival at birth and feeding and management of fox cubs
After mating, blue fox females generally give birth in 52-54 days. At present, most blue foxes give birth to an average of 11 cubs per litter, with 9.5 surviving; silver foxes give birth to an average of 5.5 cubs, with 4 surviving. Some farms (households) have poor feeding and management; for example, if the whelping box is not cleaned and disinfected properly, the female fox is prone to illness about 1 week after giving birth, and some cubs may even die.
3 Disease prevention and control
Some fox farms (households) in China experienced canine distemper in 1989-1992, and the mortality rate of breeding foxes reached over 80%. At present, many fox-raising households have recognized the importance of using vaccines, but more than 15% of fox farms and households still do not pay attention to using vaccines. Some farms and households have not taken effective treatment measures against malignant infectious diseases, causing common fatal symptoms, especially abdominal bloating and bloody stool, to develop rapidly and resulting in fox deaths. Especially during the weaning and growing period of fox cubs, other symptoms such as neurological signs and some deaths of unknown causes also frequently occur.
4 Technical training
In recent years, some personnel have performed artificial insemination on foxes just after beginning to learn fox artificial insemination. Their skills are not solid, and after semen is collected they cannot assess it well. In some cases, immature sperm is used to inseminate female foxes, causing great losses to farms and households. Some personnel are also unskilled at artificial insemination. They use a wide-mouth cup to collect semen and bend the male fox's penis back to the lower rear of the buttocks for collection. This method has a poor collection effect, with very little semen collected, low sperm density, and poor quality. It also causes dust, sebum debris, hair, and other dirt from the fox's buttocks and abdomen to fall into the collection cup. Using this unhygienic semen to inseminate female foxes gives very poor results; in some cases, infection and suppuration occur before 30 days, causing the female fox to suffer endometritis and miscarry, with a low conception rate. The correct semen collection method is to collect along the natural direction and put the collection cup over the penis. In this way, dirt will not fall into the cup, and semen collection for each male fox can be completed in 40-50 seconds. This method yields a larger volume, higher density, and better quality. With correct collection, each collection is about 1 mL and contains 800-1.2 billion effective sperm.
5 A few suggestions
Nationally, superior-grade purebred breeding male and female foxes account for 20% of the total reared population, improved breeding foxes account for 60%, and local foxes account for 20%. If domestic fox farms and households do not strengthen complete-feed rearing of foxes, their fur will not reach superior grade. Therefore, during the rearing process, feed containing sulfur amino acids must be supplied during the winter fur growth period. Foxes implanted with melatonin must also be supplied with feed for the winter fur growth period in order to achieve the implantation effect. At present, 80% of fox farms and households have not participated in systematic training courses. It is suggested that local fox farming associations regularly hold technical training courses and invite experienced experts to teach, so as to improve their level of scientific fox farming.
Establish and improve fox farming association organizations. Through fox farming associations, an information network can be built to promptly provide market trends, technical information, and formulate various technical standards, thereby enhancing the cohesion of the broad body of fox-raising households. Most of China's fur animal farming industry is household-based, dispersed farming, with small scale, low technical content, poor risk resistance, and generally low fur quality. In the future, China's fox farming industry should start with production links such as feeding management and deep processing of products, improve the fox rearing environment, and ensure fur quality. Develop the raising of good breeds, realize the transformation of the fox farming industry from quantity-oriented to efficiency-oriented, improve fur quality, and promote the development of the fox farming industry.