Analysis of Issues in the Formulation and Use of Complete Feed for Ussuri Raccoon Dogs
The raccoon dog is an animal endemic to East Asia, mainly found in China, Russia, Korea, Japan, Mongolia and other countries, and is divided into many subspecies. The Ussuri raccoon dog is mainly distributed in China's Heilongjiang Province, the eastern and southeastern regions of Jilin Province, and northeastern Korea. At present, the vast majority of raccoon dogs bred in captivity in China are Ussuri raccoon dogs originating from Heilongjiang Province. The raccoon dog is one of the fur-bearing animals with high economic value. Compared with foxes and mink, it has the advantages of bearing more cubs, a high survival rate, being easy to raise, and having a stable market; therefore, in recent years the number of raccoon dogs raised in China has steadily increased year by year, with good momentum, and it occupies a very important position in fur-bearing animal rearing in China. The large-scale and industrialized rearing of raccoon dogs requires changing the situation in which the technological development of the feed industry lags behind that of rearing. It is necessary to drive and guide farmers to change traditional rearing methods, free themselves from the influence of the supply and price rises of fresh animal feed such as sea trash fish, and shift to the more scientific and rational rearing method of using complete compound feed. At present, special additive feed, concentrated feed, and complete feed for different species and different physiological stages of fur-bearing animals have come onto the market in an all-round way. The number of manufacturers involved has grown from a few at the beginning to hundreds now. Market competition is driving the technological progress of the industry and changes in raccoon dog rearing methods. The use of complete dry feed for feeding@#@252@#@has been accepted by more and more farmers and has become an inevitable choice for raccoon dog rearing to take the path of industrialized development. The author now puts forward his own views on several problems and experiences found in recent years in the formulation and processing of Ussuri raccoon dog feed and in the promotion and use of dry feed, for discussion by peers and reference by farmers.
1 Requirements for Various Nutrients
Scientifically, the nutritional requirements of animals require systematic study of the amounts needed by animals for maintenance, growth, reproduction, etc., as well as their proportional relationships with other nutrients, and ultimately the feeding standards are determined through feeding, digestion and metabolism trials; this standard is an important basis for scientifically formulating animal diets. At present, there is relatively little research data on the nutritional requirements of the Ussuri raccoon dog, far less detailed than that for livestock and poultry. In some feeding standards, there are problems such as the requirements for crude protein, calcium, phosphorus, and salt at different stages in the given diet being the same as those for foxes, the use of gross energy as the energy unit, and incomplete data on the requirements for various trace elements and vitamins. This not only causes some confusion in the formulation of dry feed diets and in users' selection of feed, but is also the main reason for the large differences in feeding effects among feeds from different manufacturers.
1.1 Crude Protein and Other Nutrients
Whether the requirements of raccoon dogs for crude protein, calcium, phosphorus, and salt at different stages are the same as those of foxes should, judging from the dietary characteristics of each in the wild and their digestive physiological characteristics, be lower than the requirements of foxes; but what standard is appropriate for the lower level? The author reduced the crude protein level of growing Ussuri raccoon dogs from 32%-28% in the dietary nutritional standard to 26%. Through feeding trials at more than 30 feeding farms (households) in Leting County, Hebei Province, it was found that the raccoon dogs grew well, and by the winter solstice their average body weight exceeded 6 kg, with some reaching 8.5 kg. This shows that the appropriate crude protein level in the diet of Ussuri raccoon dogs still needs support from some basic research.
1.2 Various Vitamins
Some nutritional standards and empirical formulas give the amounts of the main vitamins VA, VE, Vc, VB1, etc. Although the raccoon dog has a cecum about 7.5 cm long, and the microorganisms in the cecum can synthesize part of the B vitamins, under captive rearing conditions, due to differences in feed composition and sources, a deficiency of any vitamin can cause the corresponding deficiency disease; therefore, the supply of various vitamins must be ensured. For the requirements of certain vitamins, under the premise of lacking supporting research data, given that the digestive physiological characteristics of raccoon dogs are similar to those of pigs, the vitamin requirements of pigs at different stages can be referenced and appropriately adjusted for supply. In the diet of raccoon dogs during the reproductive period, the author added vitamins with reference to the vitamin requirements of pregnant sows, except for Vc, and feeding trials proved that the effects on estrus and mating were good.
1.3 Energy
Energy plays an equally important role as the protein requirement in ensuring the exertion of production performance such as normal growth and reproduction of animals. Some standards that use gross energy as the unit for the energy requirement of raccoon dog diets can only be used as a reference when developing formulas. Because different animals have different digestion and utilization rates for different feeds, and there are no data on the energy digestibility or metabolic rate of raccoon dogs for various feed ingredients, when formulating feed, under the premise of meeting the gross energy requirement, the digestion and metabolic rate of the feed can be obtained through digestion and metabolism trials and feeding trials.
1.4 Various Trace Elements
At present, research data are lacking, and studies on trace element deficiency or toxicity are also relatively few; however, the effects of trace elements on the production performance of various animals are very important. The author believes that the specific requirements can also reference the trace element requirements of pigs; but it must be pointed out that the use of high copper, high iron, and high zinc must be avoided, otherwise it may cause poisoning. Whether this is so still requires further research.
In short, the requirements of raccoon dogs for various nutrients still require a large amount of basic research; in order to formulate more scientific and rational feeding standards to guide feed processing and the rearing industry, achieve true completeness and balance, and promote the process of industrialized development of the Ussuri raccoon dog.
2 Proportion of Plant-Based Feed
In zoological classification, the raccoon dog belongs to Mammalia, Carnivora, Canidae, Nyctereutes, and is a carnivorous animal. In the wild, the raccoon dog's diet is also very omnivorous. In terms of digestive tract characteristics, the length of the raccoon dog's digestive tract is 7.5 times its body length, while that of the fox is 3-4 times; the raccoon dog has a cecum 7.5 cm long, while the fox's cecum is degenerated; therefore, compared with the fox, the raccoon dog can be described as an omnivorous type among carnivorous animals, that is, the raccoon dog can digest and utilize more plant-based feed. Some materials believe that the proportion of plant-derived feed cannot exceed 30%-50%, which may be due to a lack of production practice. As to how to appropriately increase the proportion of plant-based feed used in raccoon dog compound feed, reduce formula costs, and ensure good feeding effects, the author believes there are mainly 3 key issues: ① Cooking of plant-based feed. If all the plant-derived feed ingredients used are cooked, the proportion used can be appropriately increased; ② Multiple combinations of plant-derived feed. Doing this can not only achieve nutritional complementarity, but also increase the proportion used; ③ Use of additives. Given the digestive characteristics of raccoon dogs, only by adding complex enzymes, feed yeast, probiotics, antibacterial and growth-promoting drugs, etc. that are beneficial to the digestion of plant-derived feed can the proportion be appropriately increased. The author increased the proportion of plant-derived feed in the feed of growing raccoon dogs to more than 80%, and no indigestion or growth inhibition was found in application.
3 Feed Processing Technology and Feeding Methods
3.1 Production and Processing Technology of Compound Feed
The production and processing of raccoon dog compound feed differs from the processing of pig and poultry feed. First, the fine grinding of raw materials; it is generally believed that fineness is one of the factors affecting digestibility. Second, the cooking treatment of plant-based raw materials; at present, extrusion technology is usually used, and this is one of the important factors affecting the feeding effect of the feed. Third, when processing extruded pelleted feed, consideration must be given to the amounts and addition process of some heat-sensitive additives to prevent nutritional damage and insufficiency during processing. This process has relatively high requirements for feed equipment, and ordinary small feed mills find it difficult to produce.
3.2 Feeding Methods for Compound Feed
At present, most manufacturers choose dry powder feed, and only a few manufacturers make extruded pelleted feed. The difference in feed form determines the difference in feeding methods and feeding effects. Comparatively speaking, neither requires cooking or boiling, and both have the advantages of saving time, labor, and effort, being convenient for storage, and not being prone to spoilage. In production, observation has also found that the method of dry feeding extruded pellets with free access to drinking water has more advantages: ① Dry powder feed can only be fed with added water. Although it is more suitable for traditional feeding methods, due to links such as powder feed transportation, water addition, and the feeding process, raw materials with high bulk density will sink, which will inevitably cause uneven nutrient intake among individual raccoon dogs in the group; in addition, after adding water, water will increase the opportunities for mutual contact among nutrients, and interactions among nutrients will destroy certain nutrients and reduce their potency. The use of extruded pelleted feed can overcome this problem. ② The raccoon dog's dentition is suitable for grinding food, and its chewing ability is relatively strong. It quickly accepts pelleted and blocky feed, and palatability is good. Moreover, chewing extruded pellets can increase saliva secretion and supplement the insufficiency of amylase in gastric juice. ③ The raccoon dog's digestive tract is short, and food remains in the digestive tract for a short time, affecting the digestion and absorption of nutrients in the feed. This is also one of the main reasons for requiring a change from traditional wet feed feeding; dry feeding of extruded pelleted feed will increase the retention time of feed in the digestive tract compared with feeding with added water, thereby improving digestibility. ④ Water is one of the most important nutrients in animal metabolism. Only by meeting the animal's water requirement can its performance be fully exerted. Feeding dry powder feed mixed with water and then providing drinking water is a great improvement over traditional wet feed feeding without drinking water in terms of meeting water needs; however, raccoon dogs like to drink clean water, and after drinking enough, they have the habit of using their toes to dirty clean drinking water and then walking away; therefore, feeding dry powder feed mixed with water followed by drinking water still cannot overcome the problem of insufficient drinking water. If extruded pelleted feed is fed, and then automatic drinkers are used to provide raccoon dogs with free access to drinking water, the raccoon dogs can drink clean water at any time according to their own needs. ⑤ Dry feeding of extruded pelleted feed is beneficial to fur cleanliness; it can overcome the shortcomings of feeding with mixed water, which contaminates the fur and causes fur tangling. Therefore, the author suggests that fur-bearing animal feed manufacturers produce and promote nutritionally complete extruded pelleted compound feed, which will further promote the process of industrialized raccoon dog rearing.