Rex rabbit, scientific name Rexrabbit, is a typical skin rabbit. Because its fur is soft and dense, resembling a otter, it is commonly known as Rex Rabbit in our country. With the improvement of people's living standards and the increase of awareness of wildlife protection, Rex rabbit skin has become a high-grade suede material that replaces wild animal hides and has high economic value. At present, the price of first-class cooked skin is 60-70 yuan per sheet, 40-50 yuan for second-class cooked skin, and 20- 30 yuan for third-class cooked skin. The international fur market has great demand for high-quality rex rabbits, especially in markets such as the United States, Japan, Europe and Hong Kong and Macau. China Rex Rabbit Breeding has covered dozens of provinces across the country. Rex rabbit fur products have entered the international market and have created a large amount of foreign exchange for the country.
The purpose of feeding rabbits is to produce high quality rabbit skin while producing rabbit meat. After experiencing high prices from the peak of 2004 to early 2005, the price of rabbit skins fell from wave to wave in 2005-2006, and the recent market price has fallen by 15%-20% compared with the same period in 2004. While prices are falling, the quality requirements are tightening. The basic trend of the current market is: a special grade of leather is still well-selling, the middle of the skin appears to be slow-moving, and no one is interested in the low-grade skin below the third level. Recently, many rabbit farms produce only 60% to 70% of hides, and the rest are “defectives†that cause pressure storage. It can be seen that due to the maturity of the market and the development of the industry, people have put forward higher requirements for the quality of rabbit fur. The quality of rabbit skin is basically in short supply, while the market for low quality hides is shrinking. The fur quality has become the development of the rabbit industry. bottleneck". This article reviews and analyzes the factors affecting the quality of Rex rabbit fur and the improvement measures for the reference of the rabbit breeding and scientific personnel.
Factors Affecting Rex Rabbit Fur Quality
There are many factors that affect the quality of Rex rabbit fur, including breeds, nutrition and feed, disease prevention, slaughter and skinning, and processing methods.
Variety selection
Variety factors are the key to determining fur quality. If the breed is not pure, the breed is degenerate or the body shape becomes small, it will directly affect the color of the fur, lose the original color characteristics, there are mixed hair color, thin villi, density, poor flatness, small skin area, etc. Rex rabbit fur quality can not meet the requirements. According to the general rules, the rex rabbit has a large body shape, large area of ​​fur, and high commodity value. Therefore, it is important to pay attention to the breeding and breeding of rabbit breeds. We must strictly eliminate rabbits that do not meet the standard of breeding rabbits and breed high-quality core rabbit breeds to effectively improve the quality of rabbit fur.
Nutrition and feed
Nutrition and feed have a great influence on the quality of fur. If the long-term nutrition level is low, the growth and development of rabbits will be hindered, the individuals will become smaller, and the area of ​​the skin will not conform to the grade. Petersen et al. fed free-feeding or restricted-feeding (75% free-feeding) rabbits (rex rabbits were born in June and slaughtered in December). The results showed that compared with the free-feeding group, the weight-reducing group rex rabbits lost weight 11%, carcass moisture content increased by 4.1%, protein content increased by 0.7%, fat content decreased by 4.9%, these effects are statistically significant; the restricted food group's hair fiber was significantly longer than the free-feeding group (3.8 cm and At 2.9 cm), the area of ​​the skin was significantly smaller than that of the free-feeding group (a decrease of 5%). However, if there is excess nutrients, there will be cases where the abdomen hairs have not been exchanged and the back hairs have been replaced. This will also have an adverse effect on the quality of the fur.
Among nutritional factors, energy and protein in the diet are the main factors affecting the growth and fur quality of fur animals. According to reports, when dietary digestive energy was 10.88 MJ/kg, crude protein was 18.5%, and crude fiber was 12%, rex rabbits grew faster and their fur quality was better. Ren Keliang et al (2004) studied the energy and crude protein requirements of growing rabbits from weaning to slaughter, and showed that low-energy and high-protein diets (digestive energy 10.97MJ/kg, crude protein 18.98%) and high-energy and high-protein diets (Digestive energy 11.31 MJ / kg, crude protein 19.36%) is conducive to the quality of Rex rabbit coat. The lack of protein in feeds, especially the deficiency of sulfur-containing amino acids, can lead to degeneration of hair quality, loose hairiness, decreased strength of wool fibers, and a significant increase in hair hair. Studies have confirmed that supplementing sulphur-containing amino acids (methionine and cystine) in the long-haired rabbit diet can significantly increase rabbit hair production (38.5%) and high quality hair ratio (19.9%). When a proper amount of methionine was added to the diet to increase the content of sulfur-containing amino acids to 0.70%, the amount of wool produced was significantly increased, and the quality of rabbit hair was also improved. However, the excessive addition of methionine (such as when dietary sulphur amino acids reach 0.96%) has a negative effect on hair production.
In addition, the lack of vitamins and trace elements often causes the coat to fade, become fragile, and even depilate. Biotin is an important water-soluble sulfur-containing vitamin that is widely involved in the body's metabolism; due to the low concentration of biotin in the natural world and limited bioavailability, deficiency and lack of biotin can also occur, resulting in disorders of the body's metabolic function, resulting in retinal rabbit production performance The decline and the weakening of disease resistance and lead to a decline in fur quality. When choline is synthesized in vivo, methionine is supplied to the methyl group, ie, 3 molecules of S-adenosylmethionine are consumed each time the body synthesizes 1 molecule of choline; in the absence of choline, the kidney is damaged, and the fur is rough and sparse. Intensify methionine deficiency.
Copper is a component of tyrosinase, which catalyzes the formation of melanin from tyrosine, and copper deficiency causes the coat to fade. Copper can oxidize sulfhydryl groups to disulfide bonds to promote hair growth. The bending of the hair is determined by the disulfide groups in the hair proteins. The disulfide group determines the presence of copper in keratin protein synthesis. Copper deficiency affects keratin protein synthesis. The various amino acids in the polypeptide chain are linked to each other, thereby causing abnormal changes in the hair fibers, reducing bending, weakening the hair's tension and elasticity, and reducing textile performance. The addition of a certain percentage of copper to the diet has a positive effect on the growth of rabbit hair. The effect is significant when the additive amount is 50 mg/kg; the effect on the skin thickness is significant when the added amount is 10 mg/kg. With the increase in the amount of supplementation, the thickness of the skin plate decreased, showing a dose effect. This may be related to the different amounts of copper applied to different tissues in rabbits.
Disease prevention and treatment
If the cage is wet, the sanitary conditions are poor, and the rabbit body is not clean, the rex rabbit fur will be messy and heavy will lead to various diseases. The occurrence of the disease not only adversely affects the health and growth of the rabbit, but also affects the quality of the fur. Some diseases may even directly cause damage to the skin and coat and reduce the quality of the fur, such as rickets, rabbit lice, aphids, dermatomycosis, subcutaneous abscesses, etc., which can make the rex fur uneven or cortical ulceration into a hole; Rex rabbit cortex is weak and boring, the skin is rough, soft, poor toughness, fur irritability, lack of luster, lost the value of the skin system.
Slaughter age
Age has a great influence on the quality of fur. In general, the quality of adult rabbit skin is better than that of young rabbit skin. In the young rabbits before April, due to lack of fullness of the villi, the replacement of the fetal hairs was not completed, the quality of the plate was thin, and the product value was not high. 5-month-old to 6-month-old rabbits weighing 2.5 to 3 kilograms in body weight, dense villi, lustrous lustre, moderate plate thickness, and removed skin to reach a skin area standard. good. Aged rabbit skin has dry hair, poor wool fiber pull, dark color, hard and coarse plate quality, and low commercial value.
Take skin season
The skin season had little effect on young rabbits, but adult rabbits and older rabbits had the best quality of winter hides. The picking season is best chosen at the end of winter and early spring, from November to March of the following year. At this time, the fluff is rich, the gloss is good, and the quality of the board is excellent. Because of the cold weather in winter, the rabbit fur is thick and long, the hair surface is neat, the color is lustrous, and the quality of the plate is thick; in the spring when adult rabbits and old rabbits are furry, the rabbit fur is long and thin, and the underlying cashmere is sparse, and the hair surface is not neat. Rough quality, poor quality; hot summer weather, short and thick hair, thin cashmere, thin and hard skin, dark yellow, the worst quality, low value of use; autumn climate is suitable, rich feed, plush dense While flush, but still relatively short, the quality of the board is relatively thick, and its quality is second only to Dongpi. Therefore, in actual production, we must adhere to timely skin ageing, preferably in the late winter and early spring, less peeling of spring skin, forbidden to peel Xiapi.
Adult rabbits change their hair once a year in the spring and autumn, claiming that they are seasonally moulted, and the lengths of the puffs taken during the moulting period are not uniform, they are easily detached, and the quality is lowest. Do not exchange fur should become a precept. Check whether hair replacement is being carried out by hand: open the hair by hand, if it is found that the hair is easy to fall off, and a short hair fiber grows, it is the beginning of hair exchange.
Slaughter and skinning methods
Improper method of slaughtering, such as bloodletting with a knife, lethal death or vinegar killing, can often cause blood smears and severely affect the quality of fur. Therefore, the method of execution should be based on the principles of simplicity, rapid death, no contamination of the skin, keeping the body clean and not affecting the quality of the fur. The method of execution can be used neck displacement, rod strike, electric anesthesia and air injection. After the slaughter of rabbits, the bodies should be placed in a clean, cool place, and peeled off as soon as possible. Avoid stacking for a long time to prevent the heat from affecting the quality of the fur. If the skin is not properly skinned or the technique is not skilled enough, it will result in lack of material, incomplete skin shape, or molting (back skin length, short abdominal skin, short back skin, or long abdominal skin length), affecting the quality of fur.
Processing Technology
Processing technologies include peeling, air-skinning, skin storage, dyeing, and skin-repairing technologies. If the processing is unreasonable and improper shaping, it will cause “wrinkle plate†or skin shape is not complete; when the fresh skin is treated improperly, it will damage the hair follicle, make the skin plate discolored, plush off; drying is not timely or improper method, leather The board will be mildewed, "oil burned", "cold simmered", etc.; the supporter will use too much force or support to pull too much. After the skin is dry, the legs and the abdominal skin will be thin as paper, and the skin will be easily damaged; During drying or storage, if the smoking time is too long, the skin will dry yellow and lose its oily luster. If improper storage during the storage and transportation process, insects, rodents, discoloration, mildew, etc. will occur, while the quality of the fur will be reduced, and the use value will be lost.
Relief fur quality improvement measures
Strengthen variety breeding
A good breed should be selected based on the breed characteristics of the Rex rabbit. Usually the breed Rex rabbit has the following characteristics: the selected coat length is about 1.6 centimeters, the wool fiber diameter is 18 micrometers to 19 micrometers, the density is large, the coat hair is less, the length is uniform, the orderliness is uniform, the color is shiny, and the beautiful Colorful, rich in rebound, strong in life; short limbs, compact abdomen, well-balanced body structure, small head-width, large eyes, round eyes, clear-looking eyes, long and straight ears, short bald tails, clear flesh, The hind paws are large; the physique is robust, the growth and development are rapid, and the body has a high performance of producing meat; the reproductive function is strong, the genetic property is stable, and the fertility is strong.
At present, there are three strains of U.S., German and French. These three strains have their own strengths. From the perspective of fertility, the American Rex rabbits are the highest, and the German Rex rabbits are the lowest. From the perspective of growth rate, the German Rex rabbits have the greatest growth potential. Therefore, the American female rabbits can be used as the first female parent and the German or French female rabbits can be used as the first male parent to crossbreed; the hybrid female rabbits can then be used as the second generation female parent to crossbreed with the German male rabbits. The offspring of three-way hybrids were directly fattened. Practice has proved that through the offspring produced by cross-hybridization, the growth effect is better than any pure breed rabbit.
Reasonable nutrition
During the period from weaning to 3 months of age, the rabbit's nutritional level should be guaranteed, and it should be allowed to eat freely. It should make full use of its early growth characteristics and tap the genetic potential of its growth so that young rabbits can eat more quickly. This is due to the positive correlation between the differentiation of hair follicles and the increase in body weight in rabbits, that is, the greater the body weight, the greater the hair follicle density. The differentiation of hair follicles is mainly in the early stage, so grasping early fattening is effective in improving the quality of fur. Long-term production practices have proved that achieving uninterrupted growth before 3 months of age is very effective for improving the coat quality, weight, and skin area of ​​commercial rabbits.
During this time, concentrates rich in protein and sulfur-containing amino acids should be supplied and sufficient green feed should be provided, with a reasonable mix of green and blue concentrates. In addition to the full price of concentrate preparation, sulphur-containing amino acids should be added in particular, the content of which can reach 0.6%; vitamin D, its content is higher than other rabbits, 1 kg of concentrate contains 800IU ~ 1000IU vitamin D3, To promote the growth and development of early bones in rex rabbits, so that they can grow into large enough bodies when slaughtered; in addition, add oils such as linseed, cotton, etc. to increase the gloss of the fur. Dietary nutrient levels are recommended as follows: crude protein 16% to 17%, crude fiber 14% to 16%, crude fat 2%, and digestive energy 2300 kcal to 2600 kcal per kilogram. The average daily feed 50 grams to 120 grams.
After that, the growth rate can be appropriately controlled. There are two methods, one is to slightly reduce the nutritional level of the diet; the other is to appropriately reduce the amount of feed, the daily feed concentrate can be reduced to 50 grams, but must feed the protein feed such as alfalfa, soybeans, sunflowers. The fattening technology that promotes the post-control can not only save feed, reduce feed costs, but also improve the quality of fattening rabbit skin without excess fat and connective tissue.
Pay attention to feeding management during the hair exchange period
Rex rabbits are divided into age-for-moth and season-for-moen. Age-based hair replacement mainly occurs in young rabbits and young rabbits. The first age-based mate was started around the age of 30 days after the rabbit was born, until the end of 130 days to 150 days, especially around 30 days to 60 days and 90 days of age. The second age-based hair replacement started at about 170 days, and the 210-day to 240-day-old period ended, and the hair replacement lasted longer, and some of them could reach 4 months to 5 months.
Seasonal hair replacement refers to spring rabbit hair replacement and fall hair replacement. Spring furry lasted longer, about 12 weeks; autumn furrows lasted for a short period of time, about 7 weeks to 8 weeks, until the end of December. If the first age-based moulting ends in the spring and autumn moulting season, then the second age-based moulting starts. Rex rabbits have weaker constitutions during the hair exchange period, reduced digestive abilities, less ability to adapt to the climate, and are vulnerable to colds and flu. Therefore, feeding and management should be strengthened during the moulting period to provide easily digestible, high-protein feeds. In particular, diets rich in sulphur-containing amino acids (eg, egg, cystine) may account for 0.6% of the diet, which is particularly advantageous for the growth of coats.
Strengthen disease prevention
The adoption of thorough comprehensive disease prevention and control measures to strengthen daily scientific feeding management and control of the occurrence and prevalence of major diseases (especially metabolic and parasitic diseases) is an important measure to improve the quality of fur. In terms of hygiene management, rabbithouses and rabbit farms should be regularly cleaned, and the rabbithouses should be kept clean, dry and hygienic. Disinfection should be done regularly.
Timely skin
According to the law of hair removal and body weight, it is one of the important measures to improve the quality of fur. According to observations, the rabbits in 120 days of age are mostly empty, soft, and not smooth enough, and gradually grow thicker and flatter with age. The fur quality after the first hair exchange is the best, and slaughtering and skinning are the most cost-effective. The second age-based hair replacement started at about 170 days, and the 210-day to 240-day-old period ended, and the hair replacement lasted longer, and some of them could reach 4 months to 5 months. Therefore, it is generally believed that young rabbits are best slaughtered between the first age and the second time, about 5 months old and weighing 2.5 kg to 3 kg. At this stage, the fluff is dense, bright and lustrous, the thickness of the plate is moderate, and the removed skin can meet the first-level skin area standard, and the fur quality is the best. Adults and older rabbits must miss the skin at the time of the hair replacement, but they are the best at the end of the winter and the beginning of the spring. This period has enough hairiness, good luster, tough skin, and high quality skin.
Attention to leather, processing and storage methods
It is advisable to take the method of “skinning after skinning, skin separation and then bleeding,†so that the skin is less defiled. The specific method of operation: After a rabbit has died of fainting after being struck by a rod or electric shock, the skin is peeled off into a flat leather tube facing outwards inside and out of the skin, and then the skin plate is pulled away from the ventral midline with a razor blade and flattened on the cardboard. Put small nails around the fur and let the fur dry. The overcast hair fur is paired with the fur and the skin is overlapped on the head and tail. Then, a small bundle of every 10 pieces of skin and a large batch of 50 pieces of leather are placed into the sacks, sprinkled with insect repellent and sealed.
During peeling, processing and storage, pay attention to the following issues: First, prevent the knife from injuring the skin and cause a hole during skinning; secondly, open the file along the ventral midline; otherwise, it will affect the specification of the skin type and reduce the area of ​​the skin; It is the oil on the skin that needs to be scraped, especially if the neck is to be scraped, otherwise it will affect the elongation of the skin or the defects of the neck after drying. The fourth is to create suitable conditions for temperature and humidity when drying, and it is best to use air drying. Dry with a heat source, temperature and humidity can not be too high, the optimum temperature is about 10 °C. Relative humidity of 55% to 65%, otherwise it is easy to cause boring board and cause hair loss; Fifth, after the skin board is dried, it is properly sorted and packaged, and the dried skin is finished and packaged in time. The rabbit fur is applied to the quilt and the skin. The board stacks the layers of the board. Do not fold when sorting the packaging, and keep the skin flat. Sixth, during the storage process, check it regularly and keep it properly. Prevent the occurrence of old skin, smoked skin, moldy skin, and suffocation.