Commercial properties of unprocessed nutria skins. Sorting nutria skins

1.13, section 4

6. By Decree of the State Standard of January 14, 1992 N 7, the validity period was lifted

7. REISSUE (April 1997) with Change No. 1, approved in January 1992 (IUS 5-92)

This standard applies to tanned, undyed and dyed, unshorn and sheared, as well as with the awn removed, nutria skins intended for the manufacture of fur products.

The requirements of this standard in terms of sections 1, 3, 4 are mandatory.

1. TECHNICAL REQUIREMENTS

1.1. Nutria skins must be tanned in accordance with the requirements of this standard using technology approved in the prescribed manner.

1.2. The skins must be dressed in a layer with an even cut in the middle of the womb, preserving the fur of the head and symmetrically straightened.

1.3. The leather fabric should be soft, clean and give stretch in all directions.

1.4. The hair must be clean, combed, and evenly trimmed on shorn skins.

The hair of skins with the hair removed should consist of downy hair.

The hair of dyed skins must be free of stains and unpainted areas.

On dyed skins, transitions in color intensity from the ridge to the belly are allowed; from awn to down.

1.5. Tears, holes, and bald spots must be repaired without disturbing the symmetry of the skins.

1.6. (Deleted, Amendment No. 1).

1.7. The chemical and physical-mechanical properties of the skins must comply with the standards specified in Table 1.

Table 1


Indicator name
Mass fraction of moisture in leather fabric at the time of sampling, %, no more
Mass fraction of unbound fatty substances in leather tissue in terms of absolutely dry matter, %, no more
Mass fraction of chromium oxide in leather fabric in terms of absolutely dry matter, %, no more
undyed skins
dyed skins
Leather fabric welding temperature, °C, not lower
pH of water extract of leather fabric, not lower
Load when breaking a whole skin, N (kgf), not less
Color fastness of dyed skins to dry friction on a scale of gray standards, points, not less
black
in other colors

1.8. Depending on the color of the hair, nutria skins are divided in accordance with Table 2.

table 2


Coloring	Description of hair color
Skins, undyed, unshorn and shorn
Black	Covering hairs on the ridge are almost black to black, on the mantle from black to dark Brown; downy hair - from dark gray to dark brown
Brown	The covering hairs on the ridge are grayish-brown to dark brown; the hair on the mantle is lighter in color than on the ridge. The guard hairs on the ridge and sides have a zonal coloration; downy brown hair of varying intensity
Pastel	Covering hairs of pure brown color of varying intensity; downy hair - light brown to brown
Mother of pearl	Covering hairs are light brown to beige in color with lightened tips; on the mantle the hair color is lighter than on the ridge; downy hair - from beige to almost white. A yellowish tint to the coverts and downy hair is allowed
Golden	The covering hairs on the ridge are from orange to light yellow with a golden tint; on the mantle the hair color is lighter than on the ridge; downy hair is yellow in color of varying intensity. Darker tops of downy hair are allowed
	Covering and downy hairs are white.
Undyed skins with hair removed
Black	From dark gray to dark brown with a black tint
Brown	Dark brown on the ridge; brown or light brown on the tail
Dyed skins, unshorn, shorn, and also with the awn removed
Black	Black throughout
Colored	Various colors except black

Note. Nutria skins, uncut, undyed, of other colors are accepted by agreement with interested organizations.

1.9. Depending on the condition of the hair, nutria skins are divided into varieties in accordance with the requirements specified in Table 3.

Table 3


	Characteristics of the hair of the skins
	uncut	shorn	with removed spine
First	Full-haired, with a shiny awn, thick down and a well-furred belly	Dense, with shiny frequent awns and thick down.	Silky with thick fluff
Second	Less full hair, with underdeveloped awns and down, or less dense hair coat	Less dense, with thinning awns and down	Down is less dense and less silky

1.10. Depending on the presence of defects, nutria skins are divided into groups in accordance with Table 4.

Table 4


Name of the vice	Group
	first	second	third	fourth
1. Seams with a total length equal to the length of the skin	Up to 0.25 incl.	St. 0.25 to 1.00 incl.	St. 1.00 to 2.00 incl.	St. 2.00 to 2.50 incl.
2. Holes, bald patches, worn out hair, snacks, spots of a different color (pejins) by total area, %	Up to 0.5 incl.	St. 0.5 to 1.5 incl.	St. 1.5 to 3.0 incl.	St. 3.0 to 5.0 incl.
3. Exposure of hair follicles or through hair with total area, %	Up to 3.0 incl.	St. 3.0 to 10.0 incl.	St. 10.0 to 20.0 incl.	St. 20.0 to 40.0 incl.
4. Brokenness (section) of the spine, total area, %	Up to 1.0 incl.	St. 1.0 to 5.0 incl.	St. 5.0 to 10.0 incl.	St. 10.0 to 15.0 incl.
5. Presence of spine on skins with removed spine total area, %	Not allowed	Up to 5.0 incl.	St. 5.0 to 10.0 incl.	St. 10.0 to 15.0 incl.
6. Absence of parts of the skin		Heads	Heads with necks

Notes:

1. The size of the defects indicated in subparagraphs 2-5 of the table is determined by the area of the smallest rectangle into which these defects fit.

2. Defects located at a distance of no more than 1 cm from the edge of the skin and spots of a different color (pink marks) on the head are not taken into account.

3. Skins cut along the ridge are classified as defect group “four”.

1.11. More than one defect of this group is not allowed on skins.

In case of a combination of various defects, the following is allowed:

on skins of group “second” - no more than two defects of group “first”;

on skins of group “third” - no more than two defects of group “second”;

on skins of group “four” - no more than two defects of group “third”, or a combination of one defect of group “third” and two defects of group “second”, or four defects of group “second”.

With the combination of one defect of the highest group and one defect lower group the skin is transferred to the next lower group.

1.12. The quality of the skins is assessed in accordance with the application.

1.13. Labeling, packaging of skins - according to GOST 19878 with the following addition:

The following quality characteristics must be marked on the leather fabric of each skin:


by color	by variety	by groups
unpainted	first - 1	first - 1
black - 1	second - 2	second - 2
brown - 2		third - 3
pastel - 3		fourth - 4
mother-of-pearl - 4
golden - 5
white - 6
painted	area, dm
black - 1
colored - 2.

(Changed edition, Amendment No. 1).

2. ACCEPTANCE RULES

GOST 9212
The measurement result is rounded to 1.0 dm.

3.10. Measuring the skin, seams and cutting height are carried out with a metal ruler or tape measure with a division value of 1 mm.

4. TRANSPORTATION AND STORAGE

Transportation and storage of skins - in accordance with GOST 19878.

(Changed edition, Amendment No. 1).

APP (recommended). TABLE assessing the quality of processed nutria skins in percentage


		Group of vices
first	second	first	second	third	fourth

Note. Skins that do not meet the requirements of Table 3 of this standard, skins with defects exceeding the norms established for group "four", as well as skins with very sparse hair, half-haired skins, skins of cubs with plump hair must have a quality rating of no more than 25 % of the assessment of the quality of skins of the first grade and group “first” of the corresponding color.

(Changed edition, Amendment No. 1).

The text of the document is verified according to:
official publication
M.: IPK Standards Publishing House, 1997

Of the various physical and mechanical properties of raw fur skins highest value when determining their use value have the following:

Properties of hair: height, density, length of individual categories of hair, thickness of individual categories of hair, softness of hair, elasticity, curlability, tensile strength of hair, shine.

Properties of the skin: thickness, tensile strength.

Properties of the skin as a whole: weight of the fur skin, area, heat-protective properties and wearability.

Properties of hair

Hair height is the shortest distance from the skin to the ends of the covering hair, taking into account the angle of the hair in the skin. The hair of nutria is low and adjacent.

An indicator of hair density for fur is usually considered to be the number of hairs (pieces) per 1 cm2. In animals leading a semi-aquatic lifestyle, as a rule, the hair on the scalp is thicker than on the ridge. By direct calculation of the number of all types of hair per unit area, it was established that there are about 5.9 thousand hairs on the dorsal area, 14.0 thousand hairs on the calves, and 12.5 thousand hairs on the sides.

The hair of nutria consists of three types of hair: guide, guard and down. Hair of these types differs in shape, length and fineness, and morphohistological structure.

Guide hairs are the longest of the hairs covering the nutria's body. Their shape is lanceolate; length at the ridge - 41-70 mm, fineness - 189-258 microns. In a cross section, three layers are distinguished: cuticular, cortical and medullary. The guard hairs also have a lanceolate shape, but flattened. They have a well-defined grain, a thinned neck and base of the hair. Arranged in several tiers, the guard hairs well protect the underfur from external factors. The length of the spine is 20 - 37 mm, fineness - 39 - 211 microns. On a cross section of hair, three layers are also distinguished. Downy hair is the shortest and thinnest. They make up 92-97% of the total amount of hair on the skin. The grain of downy hair is not pronounced, the shaft is crimped. The length on the spinal part of the skin is 15-26 mm, fineness is 12-15 microns. Hairs in the skin tissue of nutria are arranged in groups of 20-150 pieces. Since the process of hair growth, especially in young animals, is continuous, groups can include growing hair (with the presence of a core layer in the root part) and completed growth (without a core layer in the root part). The length of hair in different topographic areas of nutria skins is not the same. Most long hair located on the ridge, the lower one - on the womb. Based on the length of the covering and down hairs, the area of the skin can be divided into four zones.

Table 2 - Hair length on nutria skins

The length of nutria hair is directly dependent on the age of the animals.

Softness of the scalp - a feeling of the degree of elasticity of the scalp when it is compressed. The hair of nutria consists of very thick (especially on the head), silky down, covered with a thick, long, coarse spine.

Elasticity is the property of hair to return after creasing to its original or close to it state. Guard hairs are much more elastic than down hairs. During molting, elasticity is at its lowest. The less elasticity of the hairline, the easier it becomes felted (feltability is the property of hair, when entangled with each other, to form dense felt-like masses, the defect is “matted hairline”).

Hair tensile strength is the ability to resist external forces that destroy its integrity or change its shape. Tensile strength is determined by the force that must be applied to break their rod. The strength of hair largely determines the durability of fur products. The tensile strength of guard and guide hairs usually greatly exceeds that of down hair.

The coloring of semi-finished fur products depends on the content of pigments (dyes) in the hair shafts. Currently, nutria are bred with standard (wild) and colored forms of fur color. On the farms of our country, amateur nutria breeders breed more than 10 different color forms of nutria. The development of colored nutria farming was facilitated by the population's demand for products made from such skins. On nutria skins, spots of a different color (pejins) are a defect.

Gloss is the ability of the surface of the hair to reflect the rays of light falling on it. The degree of shine depends on the size, shape and location of the cuticle scales, as well as on the structure of the hairline: guard and guide hairs increase shine, downy hairs make the hairline matte. An indicator of the quality of nutria skin is the pronounced shine of the coat.

Properties of the skin

In adult nutria, the epidermis is distinguished in the skin tissue with a different number of layers depending on the presence or absence of the intensity of the anlage, growth and formation of new hair. The number of these layers can vary between 2-5. In the dermis there is a well-defined thermostatic layer, penetrated by hair roots located at an angle of 35-400, including horizontally intertwined collagen, elastin and reticulin fibers, cellular elements, sebaceous and sweat glands. The thickness of this layer is 70-90% of the entire thickness of the leather fabric. The reticular layer is somewhat less pronounced, mainly consisting of tightly intertwined collagen bundles with a looped structure. This layer reaches its greatest development in the period preceding the most intense periods of hair shedding (spring/autumn). At this time, the mesh layer can account for 20-25% of the total thickness of the skin tissue, during the formation and growth of new hair - 12-15%. Under the reticular layer is subcutaneous fatty tissue. In young nutria, the skin is different in that it has no reticular layer at all, thin weakly intertwined collagen fibers, small sebaceous and sweat glands, hair roots with the tops of the bulbs lying on the surface of the fatty tissue.

The thickness of the skin depends on the topographic area, the time of extraction, gender and age, and the individual characteristics of the animal. The skin tissue of nutria skins is medium in thickness and elastic.

The skin of nutria varies in thickness in different topographic areas: it is thickest on the ridge (from the middle of the ridge to the root of the tail), less thick on the sides, head, and tail, and thin on the womb.

The depth of growing hair is 800-850 microns, finished growth is 350-400 microns, with the thickness of the skin tissue being 1100-1200 microns.

The tensile strength of the skin determines the wearing time of fur products made from skins. The tensile strength of leather fabric depends on the topographic area on the skin. Thus, the strength of the longitudinal straps on the ridge is 20.7, the transverse ones are 4.9 kg, and on the womb, respectively, 5.8 and 2.0 kg.

Properties of skins in general

The size of the skin is determined by its area. The area of the skin depends on the sex and age of the animal, individual characteristics and habitat. The area of the skins also depends on the method of preservation. During fresh-dry canning, the area of the skins is reduced by approximately 10% of the area in the paired state.

The area of nutria skins is determined by multiplying the length measurements from the middle of the interocular to the line connecting the lateral points of the rump by twice the width in the middle of the length of the skin.

In raw materials, the length of nutria skins of various sizes ranges from 35-75 cm, width - 25-53 cm. The area ranges from 600 to 2000 cm2.

The weight of the skins depends on the thickness of the skin tissue, the thickness and length of the hair, the area of the skins, the season of extraction (or slaughter) of the animals, preservation methods and other factors.

Thermal protective properties primarily depend on the air that is between the hairs of the skin and inside the hair in their core channels, as well as on the density of the skin tissue. The longer and thicker the hair and the denser the skin tissue, the higher the heat-protective properties of the skin.

In nutrias, the heat-protective properties of fur also depend on the age of the animals. In nutria with secondary hair, this indicator is 0.418 W/mChk, at 7 months of age - 0.193, at 10 months of age - 0.282; for skins of the 1st grade - 0.186, for the second - 0.140.

The durability of the skin is determined by the degree of resistance of its hair and leather tissue to various destructive influences that it experiences during operation. The wearability of a fur product determines the duration of its use.

Nutria have average fur wear. If the wearability of otter fur is taken as 100%, then the wearability of natural nutria fur is 50%, and plucked fur is 25%. According to commodity experts, the durability of nutria fur is equal to 5 seasons (one season includes 4 months).

From the above it is clear that all the properties of nutria skins are influenced by many factors: breeding work, feeding, maintenance, age of the animals, slaughter season, etc. Therefore, it is important for nutria farmers to constantly improve the selection of animals, observe optimal slaughter times, and improve the primary processing of raw materials. A standard assessment of raw materials is required, taking into account objective quality indicators.

Introduction

The main component of business in the international fur trade is the products of fur farms. Today there are more than 7 thousand of them in the world, including about 5 thousand in European countries alone.

The industry of caged fur farming dates back to 1927, since that time it has developed relatively rapidly, developing new and new regions: Kaliningrad, Leningrad, Moscow regions, the Far East, Karelia, Tatarstan. Already in the 1960s. last century, it became a leader in the global fur business.

IN former USSR About 600 agricultural enterprises were involved in fur farming. The country then occupied a leading position in the world in fur production - up to 16 million skins per year (with world production of 35-40 million). In some years, its sales volume reached $150 million. This met the needs of light industry and export supplies. Today, world production is more than 60 million skins per year, and in Russia - less than 3 million pieces, there are approximately 30 enterprises, or 5% of the previously operating ones, and several small farms in Yakutia and Taimyr.

The main reason for the sharp decline in fur production is the unpreparedness of farms to work in new economic conditions and incorrect credit and financial policies. With Russia's transition to market relations, the agro-industrial complex in general and fur farming in particular found itself in a difficult situation. During the market transformation of the agricultural economy, connections between producers and processors of fur farming products, as well as prices for industrial resources consumed in fur farming, were destroyed.

As a result of the “price scissors,” there was a decline in the solvency of most domestic farms, which led to violations of the technology of raising livestock, its simplification, reduction in the use of vitamins, vaccines, the range and quality of the feed itself, which sharply affected the productivity of fur farming. The size of the skins and their quality have decreased. The gene pool has been significantly lost, especially the rare mutant types that are in demand by buyers today. The industry today needs qualified personnel.

A significant reduction in production volumes, an obsolete production and technical base, leads to a shortage of huge financial resources for our country.

Over the past 10 years, which have not been prosperous for the Russian economy, the number of nutria in the country has also decreased significantly, although interest in them has not disappeared. Unlike carnivorous fur-bearing animals, when growing nutria, mainly plant feed is required. And from this point of view, the population gives preference to their maintenance. Farm owners receive skins of various colors from these animals, from which they sew relatively inexpensive fur products that are affordable to many residents of our country. Moreover, the development of nutria farming also has social significance, increasing employment of the population in villages and small towns, as well as promoting self-sufficiency not only in fur clothing, but also in dietary meat.

The value of nutria skin is determined by the totality of its commercial qualities: size, color, hair strength and thickness, fur height, degree of defects, wearability, etc. The indicated properties of the skins depend on the age of the nutria and the timing of their slaughter, as well as on the hereditary characteristics and health of the animals, conditions of detention and quality of food. According to the purpose course work was the compilation of characteristics of the commercial properties of unprocessed nutria skins, as well as the determination of their dependence on the color type.

1. Biological features of nutria

Nutria is a large mammal leading a semi-aquatic lifestyle, belongs to the order of rodents, the only species of the nutria family, and constitutes an ancient and separate group of animals that received the Latin name Myocastor coypus M. back in the 18th century.

Nutria is native to South America. At first, local residents harvested nutria in significant quantities for their tasty meat. Only many years later was interest shown in fur. Intensified fishing caused severe damage to the numbers of these animals, and since the 30s of the 20th century, many countries began to breed them in cages. Nutria were brought to Russia in 1930 for breeding in the southern regions of the country, in particular in the Krasnodar region, where the Severinsky state farm was organized. Currently, nutria has become a common animal in homesteads and farms, although in terms of distribution and popularity it is still significantly inferior to rabbits. These animals are bred in a wide variety of climatic zones - from semi-desert regions to the cold expanses of Siberia.

Nutria leads a semi-aquatic lifestyle. Favorite habitats are reservoirs with low-flow or stagnant water: swampy river banks, reed-cattail lakes and swamps with rich aquatic and coastal vegetation.

Adult animals weigh 5-7 kg, and well-fed animals reach 10 kg or more. The body length of an adult animal is up to 60 cm, the tail is up to 45 cm. Males are slightly larger than females.

Nutria's body is heavy; the head is massive, with disproportionately small eyes and ears. The eyes are at forehead level, providing the animal with good review. The limbs are relatively short. The muzzle is blunt, with long whiskers. The incisors are bright orange and grow throughout the life of the nutria as they wear down.

Under natural conditions, nutria are active mainly at night. The animal feeds on rhizomes, stems and leaves of reeds and cattails. Additional food includes reeds, water chestnuts, water lilies, and pondweeds. It rarely eats animal food (leeches, mollusks), with a lack of plant food.

Nutria swims and dives well. Can stay under water for up to 10 minutes. On hot days it is less active and usually hides in the shade. It is not adapted to living in freezing bodies of water - it does not build a reliable shelter from the cold and predators, and does not store food for the winter, as the beaver, muskrat and other rodents do. Nutria can tolerate frosts down to -35° C, but is generally not adapted to life in cold climates.

Nutria has well-developed hearing - it becomes alert even at the slightest rustle. Despite the apparent clumsiness, she runs quite quickly, making jumps, but gets tired quickly. Vision and smell are less developed.

The body structure has a number of anatomical features associated with a semi-aquatic lifestyle. For example, the nasal openings of nutria are equipped with obturator muscles and can close tightly. The lips are separated in front and close tightly behind the incisors, which allows the nutria to chew off plants under water without allowing water to enter the oral cavity. There are membranes between the toes of the hind limbs (except for the outer one). The tail is round in cross-section, almost hairless and covered with small dark gray scales and sparse coarse and long hair; when swimming, it serves as a rudder. The mammary glands and nipples (4-5 pairs) are located high on the sides of females, which allows the cubs to feed while in the water.

Nutria can reproduce all year round and is quite prolific. If males are constantly active and can cover a female at any time of the year, then in females activity appears periodically every 25-30 days. The duration of estrus is from 2 to 4 days. One nutria can produce 2-3 litters per year, usually in spring and summer. Pregnancy lasts 127-137 days; There are 4-5 puppies in a litter, sometimes more. Newborn puppies are sighted, covered with hair, with erupted incisors, can run, swim, and are very mobile. They weigh on average 175-250 g. Only the female produces offspring. Breastfeeding lasts up to 8 weeks; At the age of 3-7 months, puberty occurs. The lifespan of nutria is 6-7 years, but the period of economic use does not exceed 4 years, since the productivity of nutria quickly decreases with age.

.1 Seasonal and age-related changes in nutria hair

To obtain high-quality raw materials, nutria growers need to know the main structural features of nutria skins, age-related and seasonal changes in the process of their growth.

Changes in hair growth in nutria are determined by several factors. First of all, age variability. In the fur industry, nutria skins of any age group are used, except for animals with primary downy hair.

Changes in hair depending on the age of the animal can be considered in three periods.

The first is embryonic, when the processes of development of the skin and primary hair cover occur in the conditions of the uterine life of the organism, starting from approximately 2 months of age. Hair laying occurs sequentially: first on the head, then on the ridge and womb. The growth of primary hair continues after the birth of puppies and is completed by 35 - 40 days of age, i.e. approximately the end period dairy nutrition young animals

The second is when secondary hair formation occurs. In babies, the formation of secondary hair occurs already at 1-2 days of age. Secondary hair growth continues until 3-5 months of age. As the puppy grows and the body area increases, primary hair gradually falls out, and the growth of secondary hair intensifies, starting from 1.5-2 months of age. By this time, the amount of primary hair on the skin is 45%, and by 3 months of age - 25%. It should be noted that in winter, the formation of secondary hair is delayed for 15-25 days, which is why the process of hair change is less noticeable than in summer. Subsequently, until approximately 5 months of age, new hair grows, which compensates for the thinning of fur that occurs due to the intensive growth of the young and the concomitant increase in body surface. The process of primary hair loss (juvenile molting) ends by 110-120 days.

The third period is characterized by a change from secondary hair to tertiary, i.e., to the hair of an adult animal, which is thicker and longer. This period lasts from 150-165 days of age to 210 days, after which new hair growth occurs at a slower pace. The onset of the next molting in young individuals is preceded by abundant desquamation of the epidermis and thickening of the dermis, where the laying of new hair follicles occurs. In the process of changing from secondary to tertiary hair, the amount of hair per 1 cm2 of skin increases by 20-25%.

Table 1 - Changes with age in the length and thickness of various categories of hair in standard nutrias

Hairline
	Length, mm	Thickness, microns	Length, mm	Thickness, microns

Guide hair
Primary
Secondary
Tertiary
guard hairs
Primary
Secondary
Tertiary
Downy hair
Primary
Secondary
Tertiary

The structure and quality of nutria fur undergoes changes during the periods from birth to maturity: the thickness of hair - guides - increases by 60%, downy hair - by 37%; their length increases by 23 and 54%, respectively; the cortical layer relative to the core increases by 6%; the number of hairs per unit area of the skin increases by 3-4 times, especially downy ones (at the age of 7 months, per 1 cm2 of covering hair - 365 units, downy ones - 11,178; at 1.5 months - 258 and 2894 units, respectively).

The variability of the hair coat also depends on the season of the year - this is a change in hair coat (molting) depending on the climatic cycles of the year. Nutria molt is diffuse (permanent), proceeds unnoticed, throughout the year some hair falls out, and new ones grow to replace them. With the acclimatization of nutria in the northern regions, seasonality appeared in the quality of hair: from November to March, the amount of hair loss decreases, since in winter, under the influence of sub-zero temperatures, the molting process of nutria slows down.

With the onset of spring, the winter hairline becomes dull, the covering hair breaks, matted fluff appears in the groins, on the thighs, and a weakening of the strength of the connection between the hair and the skin is observed. The summer fur of nutria differs from the winter one. The downy hair of summer fur is shorter by 15-35%, thinner by 4.8-16.3% and less tensile strength - by 10% in comparison with winter downy hair. Summer nutria fur is also less dense. Thus, the number of downy hairs per 1 cm2 of skin area is 12 thousand on the womb in summer and 13 thousand hairs in winter; respectively, on the ridge 4.9 and 6.3 thousand. The noted structural features of the summer hair coat - sparse hair, shorter length and strength of down - make summer skins less valuable.

Seasonal molting begins at 5 - 6 months of age, when the secondary hair coat is replaced by “adult” fur. In animals born in May, the change of secondary fur occurs in the autumn-winter period - from mid-September to mid-November; for those born at the end of November - in the spring, from April to June. By the end of the second month after the onset of molting, that is, by the age of 7-8 months, the total amount of hair decreases by 25% compared to the initial figure. Secondary hair falls out completely by this time.

The physical maturity of nutria begins, but in order to obtain a skin of the 1st grade (with lower cultivation costs), the animals can be slaughtered at 6-7 months of age, when the weight of the animals stabilizes, their physical growth stops, the size of the skins does not increase, i.e. feed costs are not covered. In addition, when slaughtered at 6-7 months of age, there are almost no fights in the group of young animals raised, and, therefore, few bites on the skin tissue. Slaughter of nutria summer period is impractical, because 1st grade skins during this period account for only 5%, second grade - 56%, third grade - 29%, non-standard - 10%. When nutria are slaughtered from November to February, the skins of the 1st grade make up 55%, the second - 41%, the third - 5%. The period of age change in the hair growth of young nutria is extended, but by 6-7 months of age the amount of hair that has finished growing averages 80-90%.

1.2 Color forms nutria

Nutria were brought to Europe in 1926 from Argentina, where the first farms for breeding these animals appeared, but France and Germany, and then Italy and other countries, took the lead in breeding nutria under artificial conditions. It was in Europe that herds of colored nutria were mainly created.

In our country, according to GOST, nutria are divided into six color groups: black, brown (standard, silver and brown colors), pastel, white, pearlescent (all skins obtained from beige, white Italian and pearlescent nutria) and golden (lemon, golden) .

Standard nutria (wild type) are the most common color type of these animals, resembling the wild form and varying from grayish to dark brown and sometimes blackish brown. The most typical fur color is dark brown, which is determined mainly by the color of the covering hair. They are shiny and zonally colored. Therefore, the intensity of pigmentation of dark-colored and light-colored areas of the covering hair determines the presence of different shades of the general color of standard nutria. On the mantle the covering hairs are lighter in color than on the ridge. Animals have downy hair of brown color of varying intensity and shades. Downy hair is characterized by weak crimp, which can contribute to the appearance of fur matting.

Black nutria were bred in Argentina and brought to our country in 1966. Purebred black nutria have an even black awn and dark gray underfur. Zone-colored hair occurs in small tufts behind the ears. When crossing black nutrias with standard ones, puppies are obtained with a uniform color: pure black or dark brown - they do not have zoned hair on the back and sides. However, with age, the color of the offspring, as a rule, changes and acquires a zonal character, clearly expressed in the head and sides. Such nutria are called black zonal.

Beige nutria - imported from Italy in 1958 along with pearlescent and pink nutria. They are distinguished by brown fur with a smoky tint. The color of the animals varies from light beige to dark beige with a smoky silver veil, which is created by the white color of the tips of the covering hairs. The underfur is light beige to brown. The skins are in constant demand among the population.

White Azerbaijani nutria were bred in 1956. They are characterized by the pure white color of the downy and covering hairs. In some animals, up to 10% of the hair can be pigmented - around the eyes, ears and at the root of the tail. The color of the spots can be any: black, standard, pastel, golden, beige, etc. The skins of such nutria with pigmentation on the back may be in high demand.

White Italian nutrias were imported from Italy in 1958. These animals have white guard hair and down, but, unlike the white Azerbaijani nutria, with a creamy tint.

Pearlescent nutrias were obtained by crossing beige and white Italian animals. These nutria are similar in color to beige, but more light tone. Their typical fur color is silver-gray with a cream tint. The awn is zonally colored, the underfur is bluish-cream.

Silver nutrias are crossbreeds obtained by crossing standard type females with beige and white Italian males. The fur is characterized by an overall dark gray color, cleaner than that of standard nutria. The skins of silver nutria make beautiful fur coats.

Golden nutria were introduced in 1960. These animals are characterized by a bright yellow (golden) color, the underfur is light golden. On the ridge the color of the fur is bright, on the womb it is somewhat lighter.

Pastel nutrias are obtained by crossing pure black nutrias with white Italian, pearl and beige. The general color of the skins is brown, varying from light beige to chocolate. The color of the down and covering hairs is the same. The skins are in constant demand, so pastel nutria are widespread on farms.

Lemon nutrias are a lighter yellow color than golden nutrias. They were obtained by crossing golden animals with white Italian, pearlescent and beige nutria.

In our country, through selection, the May type of standard nutria, adapted for keeping indoors, was created (1988), and the Krestovsky type of pastel animals with a dark chocolate color (2000).

It can be assumed that in the country, especially in the southern regions, nutria of various rare types are bred on private farms. However, neither regional organizations nor the Information Support Center have information about the existence of such farms and the breed composition of the herds in them.

.3 Commercial properties of nutria skins

Of the various physical and mechanical properties of raw fur skins, the following are of greatest importance in determining their use value:

Properties of hair: height, density, length of individual categories of hair, thickness of individual categories of hair, softness of hair, elasticity, curlability, tensile strength of hair, shine.

Properties of the skin: thickness, tensile strength.

Properties of the skin as a whole: weight of the fur skin, area, heat-protective properties and wearability.

Properties of hair

Hair height is the shortest distance from the skin to the ends of the covering hair, taking into account the angle of the hair in the skin. The hair of nutria is low and adjacent.

The hair of nutria consists of three types of hair: guide, guard and down. Hair of these types differs in shape, length and fineness, and morphohistological structure.

Guide hairs are the longest of the hairs covering the nutria's body. Their shape is lanceolate; length at the ridge - 41-70 mm, fineness - 189-258 microns. In a cross section, three layers are distinguished: cuticular, cortical and medullary. The guard hairs also have a lanceolate shape, but flattened. They have a well-defined grain, a thinned neck and base of the hair. Arranged in several tiers, the guard hairs well protect the underfur from external factors. The length of the spine is 20 - 37 mm, fineness - 39 - 211 microns. On a cross section of hair, three layers are also distinguished. Downy hair is the shortest and thinnest. They make up 92-97% of the total amount of hair on the skin. The grain of downy hair is not pronounced, the shaft is crimped. The length on the spinal part of the skin is 15-26 mm, fineness is 12-15 microns. Hairs in the skin tissue of nutria are arranged in groups of 20-150 pieces. Since the process of hair growth, especially in young animals, is continuous, groups can include growing hair (with the presence of a core layer in the root part) and completed growth (without a core layer in the root part). The length of hair in different topographic areas of nutria skins is not the same. The longest hair is located on the ridge, the shorter one - on the womb. Based on the length of the covering and down hairs, the area of the skin can be divided into four zones.

Table 2 - Hair length on nutria skins

The length of nutria hair is directly dependent on the age of the animals.

Properties of the skin

The depth of growing hair is 800-850 microns, finished growth is 350-400 microns, with the thickness of the skin tissue being 1100-1200 microns.

Properties of skins in general

In raw materials, the length of nutria skins of various sizes ranges from 35-75 cm, width - 25-53 cm. The area ranges from 600 to 2000 cm2.

In nutrias, the heat-protective properties of fur also depend on the age of the animals. In nutria with secondary hair, this indicator is 0.418 W/m×k, at 7 months of age - 0.193, at 10 months of age - 0.282; for skins of the 1st grade - 0.186, for the second - 0.140.

1.4 Sorting nutria skins

Nutria skins are sorted according to GOST 2916-84 “Untreated nutria skins”. This standard applies to uncured nutria skins, cage-bred and hunted.

Nutria skins must be removed from the carcasses using a “tube” with a cut along the rump and along the border of the hairless part of the paws and tail, preserving the head. The skins must be cleaned of meat, cartilage, tendons, blood from the skin and hair; degreased without damaging the hair roots; mounted on straighters without excessive stretching with a ratio of length to width of 3:1, preserved in a fresh-dry method and dried with the skin or hair facing out (skins coming from specialized fur farms must be dried with the hair facing out).

Nutria skins, depending on the color of the hair, are divided into color types:

Black skins should have black or almost black hair on the ridge, black to dark brown hair on the belly, and dark gray to dark brown down.

Brown skins should have ridge hair ranging from grayish brown to dark brown. The color of the hair on the skull is lighter than on the ridge. The guard hairs on the ridge and sides have a zonal coloration; the downy hairs are brown in color of varying intensity.

Pastel skins should have hair of a pure brown color of varying intensity, downy hair - from light brown to brown.

White skins - white hair.

Golden skins should have hair on the ridge ranging from orange to light yellow in color with a golden tint, hair on the womb should be lighter in color than on the ridge, downy hair should be yellow of varying intensity. Darker tops of downy hair are allowed.

Pearl skins should have a light brown to beige hair coat with lightened tops of the covering hairs. The color of the hair on the skull is lighter than on the ridge; the downy hair is from beige to almost white. A yellowish tint to the coverts and downy hair is allowed.

Nutria skins, depending on the quality of the hair, are divided into varieties: variety - Full-haired, with a shiny awn, thick down and well-furred dermis; variety - Less full-haired, with insufficiently developed awns and down or less dense hair.

Depending on the presence of defects, nutria skins are divided into defect groups in accordance with the requirements specified in table. 3.

Table 3 - Defect groups for nutria skins

Name of the vice
				fourth

Tears and seams total length, cm				>25.0 up to one times the length of the skin; skins torn across or with a cut along the ridge line
Holes, worn out places, sections of the v.p., spots of a different color (pejins) with a total area, cm2
Draft, piled-up snacks, matted hair with total area, cm2
Bald spots with total area, cm2
Missing skin parts	Cut out the lower part of the womb up to 5.1 cm from the line between the side points of the rump	Heads.	The cut out lower part of the womb is 5.1 - 10.0 cm from the line between the side points of the rump

Notes:

Heads with necks

Skins with pezhins on the head, with overgrown or single not overgrown bites, with defects on the lower edge of the womb up to 5.1 cm, with a cut along the midline of the womb are classified in the “first” group.

Defects on the head and neck are assessed no higher than the discounts established for the shortage of these parts of the skin.

For different defects located on the same area of the skin (flaw on defect), one largest defect is taken into account.

	Table 4 - Assessment of the quality of nutria skins in percentage
				fourth

Defect group

Poorly defatted nutria skins are accepted with a 10% discount on the quality assessment of the skins.

Nutria skins with defects exceeding the tolerances for the “fourth” group, skins with a cut out belly more than 10 cm from the line between the side points of the rump are assessed no higher than 25% of the quality assessment of skins of the corresponding color, first grade and first group. The skins are rotten, burnt, damaged by moths and skin beetles, with very sparse hair, half-haired, skins of cubs with plump hair are classified as non-standard.

Characteristics of defects

The quality of skins depends not only on their natural properties, but also on various damage to their hair and skin tissue. All these defects reduce the value of harvested fur raw materials, complicate its processing, and deteriorate the quality of manufactured products.

There are intravital defects - those that arose on the skin during the life of the animal, and post-mortem defects - those formed during the extraction of the animal, or during the initial processing, storage and transportation of skins.

A wiped area is an area of the skin with partially or completely destroyed hair due to mechanical damage.

A bite is an area of skin with damage to the skin tissue and hair due to a bite.

Spots of a different color (pezhina) are a section of the skin that has a clearly defined hair color that contrasts with the main one.

Hair matting is the tangling of hair to the point of forming a felt-like mass that cannot be combed.

Sectioned hair is a break in the tops of the covering hair.

Posthumous defects:

Tears are linear holes in the leather tissue of the skins without loss of its area, usually occurring when the leather tissue is under strong tension when removing and editing the skins.

Hole - an opening in the leather weave with loss of area.

A bald spot is an area of skin with completely lost hair due to the action of microorganisms on the skin tissue.

Draft - exposure of hair roots from the skin tissue. This happens when the skin is degreased unskilled, when a sharp, deep-cutting tool is used, thereby exposing the roots of the hair, cutting off their bulbs.

One of the reasons for the appearance of such defects as loose hair, prelines, bald spots is a violation of the drying regime of raw materials, especially on wire-type rules, in conditions when the relative air humidity is 20-40%, and the temperature rises to 40-500. At the same time, the surface of the leather fabric dries out greatly, while the inner layers remain wet. The optimal temperature for drying nutria skins can be considered to be 27-300C, relative air humidity - 55-60%. At high temperatures The possibility of collagen welding or keratinization cannot be ruled out either.

By improving the methods of shooting, degreasing, straightening, and drying skins, their quality can be significantly improved.

1.5 The current state of the industry, the main economically useful qualities of nutria

In Russia as a whole, as of July 1, 2006 (based on the results of the All-Russian Agricultural Census of 2006), the nutria population totaled 564.2 thousand heads:

in the Central Federal District - 4.6 thousand heads (Kostroma region - 1.7, Belgorod region - 1.0 thousand heads),

in the Northwestern District - 0.3 thousand heads,

in the Southern Federal District - 551 thousand heads (Krasnodar Territory - 299, Stavropol Territory - 143.1, Rostov Region - 83.5 thousand heads),

Volga Federal District - 7.9 thousand heads (Kirov region - 6.9 thousand heads),

Ural Federal District - 0.1 thousand heads,

Siberian Federal District - 0.3 thousand heads,

Far Eastern Federal District - 0.1 thousand heads.

At this stage, the state of nutria farming remains difficult. The number of nutria herds is decreasing (in 2008, the number of females in the main herd on Russian farms was 0.9 thousand heads). At the moment, nutria are bred on individual farms and it is almost impossible to count the number of livestock.

The main economically useful qualities of nutria, which could ensure the profitability of the industry - nutria farming, are determined by the value of environmentally friendly, high-quality and beautiful fur raw materials obtained from animals, delicious dietary medicinal meat, as well as significant by-products. The share of skins in total revenue is 80-85%, meat - 15-20%.

Nutria skins are currently used both in their natural form and with the use of various treatments. They are used to make coats, jackets, men's and women's collars and hats. The skins are cut along the ridge, since the belly of the skin is more valuable. Nutria fur is convenient for deceivers: plucked nutria (with the guard hairs removed) is very similar to plucked mink and beaver, so it is often offered under the guise of these more expensive furs.

Nutria meat in a number of countries in Europe and America has long been recognized as nutritious, medicinal and valued more than beef. From one adult nutria a marketable carcass weighing 3...3.5 kg is obtained, and from 6-8-month-old young animals - 2...2.5 kg. The slaughter yield is 52-55%. The carcass is distinguished by its meatiness - bones together with the head make up 12-15%, while in pigs and cattle it is 18-20%. The energy value of 100 g of medium fat meat is 203 Kcal (0.85 MJ). The completeness of protein in nutria meat in terms of content and ratio of essential amino acids is 81.5% (beef - 80%). Nutria meat contains relatively a lot of non-protein nitrogenous substances (4...5%), stimulating appetite and secretion of the digestive glands. The meat has an intense red-brown color, as it contains an increased amount of muscle hemoglobin (myoglobin), which is typical for semi-aquatic animals - 800...1000 mg% versus 150-200 mg% for agricultural animals. Therefore, it is particularly useful for people with anemia, as well as kidney diseases, diabetes mellitus.

Nutria fat contains many unsaturated fatty acids, including essential ones: linoleic and linolenic acids, which are necessary for the normal functioning of the human body. It has been proven that regular consumption of nutria fat is a preventive measure against pulmonary diseases. Its digestibility is 90-93%.

By-products of nutria farming are also aimed at increasing the profitability of production. Thus, animal manure is further used for its intended purpose in the form of fertilizer. Nutria excrement is characterized by a very high nitrogen content, which makes it possible to significantly reduce the rate of application of organic fertilizers per unit area of arable land. It is possible to use fat removed from the skins of slaughtered animals: either for the production of cosmetics or for animal feeding. Skin and hair trimmings, as waste from the processing of fur raw materials, are in demand in the manufacture of souvenir haberdashery.

Thus, it is obvious that nutria farming is an almost waste-free production, and all products obtained from animal farms can provide additional income, helping to increase the profitability of the industry.

2. Experimental part

.1 Object of study

nutria skin cover marketable

To carry out the experimental part, the purpose of which was to determine the dependence of the commercial properties of nutria skins on the color type, the object of study was skins of the following colors: brown - in the amount of 10 pieces, pastel - in the amount of 8 pieces. All skins are preserved using a fresh-dry method (which meets the requirements of GOST 2916-84 “Uncured nutria skins”). The studied nutria skins are part of the collection of the Department of Commodity Science and Technology of Raw Materials of Animal Origin named after. S.A. Kasparyants.

The basis of the study was the consideration of the commercial properties of nutria skins in the following topographic areas: the ridge and the womb.

2.2 Research methods

.2.1 Methods for researching the commercial properties of hair

The height of the hairline is determined with a millimeter ruler as the shortest distance from the skin to the tips of the covering hairs, taking into account the angle of the hair in the skin.

Measuring the length of the hair is carried out by accurately measuring the length of hair of different categories (guide, guard and down), shaved from different parts of the skin (ridge, womb). A sample from each topographic area of hair of each category - 25 pieces (small sample). The hair is placed on paper of a color so that the hair shafts are clearly visible. Glass is placed on the paper. Then each hair is straightened with dissecting needles and measured with a millimeter ruler (that is, we determine the true length).

Hair density was determined by direct counting of hair on an area of 0.25 cm² and subsequent multiplication by 4 to characterize density per 1 cm².

To measure the thickness of hair of each category, preparations are made, for which cut pieces of hair are placed on a glass slide, the slide is covered with glycerin, and a cover glass is placed on top. The thickness of the guide and guard hairs was measured in grann, the thickness of down hairs was measured in the middle of the shaft. Before starting to measure hair thickness, the value (price) of one division of the ocular micrometer was established, which was 4.0 microns.

The softness of the hair is expressed through the softness coefficient - the ratio of the thickness of the guard hair (μm) to the length of the guard hair (mm), followed by multiplication by 10-3.

The color and shine of the hair is determined organoleptically by examining each skin.

.2.2 Methods for researching the commercial properties of the skin

The thickness of the skin of the skins was determined using a Meissner thickness gauge in two topographic areas - the ridge and the womb, in millimeters.

.2.3 Methods for researching the commercial properties of skins in general

The mass of nutria skins is determined on working scales, the measurement results are given in grams.

2.2.4 Method of statistical data processing

Statistical data processing is necessary to get an idea of the entire sample of fur raw materials, its quality and the possibility of further processing by industry in one direction or another. In the process of statistical data processing, the following indicators were determined:

The arithmetic average is determined by the formula:

The standard deviation is determined by the formula:

(2)

The coefficient of variation:

(3)

The average error characterizing the accuracy of measurements is determined by the formula:

(4)

2.2.5 Sorting nutria skins

Sorting of nutria skins was carried out according to GOST 2916-84 “Untreated nutria skins”. Based on this GOST, the skins were divided into color types, varieties and defect groups. The main provisions of this document are given in paragraph 1.5 of this course work.

2.3 Own research

.3.1 Measuring the mass and area of brown and pastel nutria skins

Table 5 - Results of measurements of the mass and area of nutria skins of different color types

		Area, cm2
Brown skins











Pastel skins

Calculations of statistical indicators for the mass of skins:

The arithmetic mean value of the mass of the skin, g (formula 1):

Standard deviation, g (formula 2):

Average error, g (formula 4):

Calculations of statistical indicators for the area of hides:

Arithmetic mean value of skin area, cm2 (formula 1):

Standard deviation, cm2 (formula 2):

Coefficient of variation, % (formula 3):

Average error, cm2 (formula 4):

Table 6 - Weight and area of nutria skins (brown skins n=10; pastel skins n=8)

Conclusions: The average weight of nutria skins of the brown color type was 214.6 ± 16.4 g. The value of the standard deviation, which characterizes the deviation of mass from the average value, was ± 49.3 g; the coefficient of variation is 22.98%. These data indicate that the studied sample was not equal in mass.

The average weight of pastel-colored nutria skins was 175.5 ± 9.6 g. The standard deviation was ±25.3 g; the coefficient of variation is 14.44%. These data indicate the average equality of the studied sample in terms of mass.

The average area of brown nutria skins is 1022.7 ± 41.55 cm2, the standard deviation is 124.65 cm2, the coefficient of variation is 12.9%, which indicates the average equality of the sample in terms of skin area.

The average area of pastel nutria skins is 936 ± 16.53 cm2, the value of the standard deviation is 43.72 cm2, the coefficient of variation is 4.67%, which indicates that the studied sample is equal in area of the skins. In general, we can conclude that brown nutria skins (derived from standard-colored nutria) are larger in size than pastel nutria skins. This is due to the fact that in relation to the standard type nutria, longer selection work was carried out in the direction of increasing the size of the skins obtained from them.

2.3.2 Measuring hair parameters for nutria skins

Table 7 - Results of statistical processing of hairline height in various topographic areas (n=25)

Conclusions: The height of the hair on skins of the brown color type was 10.1 ± 0.05 mm on the ridge, 8.72 ± 0.17 mm on the womb; on pastel colored skins - 9.0±1.15 mm and 8.12±0.14 mm, respectively. The coefficients of variation in terms of hair height on skins of the brown color type were 2.58% on the ridge, 9.66% on the womb; on pastel-type skins - 8.48% and 8.93%, respectively. From which it follows that the studied samples are equalized according to this indicator. The height of the hair on the casing of both color types of nutria is slightly lower than on the ridge.

The hair height of pastel-colored nutrias is lower than that of brown nutrias, which is determined by the length of the hair that makes it up.

Table 8 - Results of statistical processing of hair length measurements of different categories (n=25)

Nutria color type	Topographer. plot	Hair lengths of different categories
		Guides
		Хср ± m, mm	Хср ± m, mm	Хср ± m, mm
Brown

Pastel

Conclusions: The longest hair on nutria skins is the guide hair. Its length on brown skins was 58.9±0.44 mm on the ridge and 46.2±0.61 mm on the womb, on pastel skins - 53.2±0.43 mm and 43.1±0. 36 mm respectively. The guard hair occupies an intermediate position in this indicator; its length on brown skins was 47.7 ± 0.34 mm on the ridge and 38.2 ± 0.38 on the womb, on pastel skins - 45.8 ± 0, 27 mm and 36.0±0.42 mm, respectively. The shortest hair is downy, its length on brown skins is 14.0±0.33 mm on the spinal part, 12.1±0.32 mm on the womb; on pastel-type skins - 12.8±0.29 mm and 10.7±0.23 mm, respectively.

The hair cover of nutria of both color types is equalized along the length of the guide and guard hairs, both on the ridge and on the womb; Along the length of downy hair, the hair cover is of average uniformity (the coefficient of variation slightly exceeds 10%). This result is due to the fact that the length of downy hair also depends on the degree of crimp of the hair. The longest hairline is on the ridge, the lower one is on the womb.

The length of hair of various categories on the skins of pastel nutria is slightly less than that of brown nutria.

Table 9 - Results of statistical processing of hair thickness measurements of different categories (n=25)

Nutria color type	Topographer. plot	Hair thickness of different categories
		Guides
		Хср ± m, µm	Хср ± m, µm	Хср ± m, µm
Brown

Pastel

Conclusions: The hair cover of the studied nutria skins is equalized by the thickness of the guide and guard hairs, and the average equalization by the thickness of downy hairs. The highest thickness indicator is for the guide hairs; on brown skins it was 146.2±0.48 µm on the ridge and 135.9±0.51 µm on the belly; on pastel-type skins - 143.1±0.29 µm and 135.9±0.29 µm, respectively. Slightly thinner than the guard hair - on brown skins - 135.0±0.57 µm on the ridge, 94.4±0.52 µm on the casing; on pastel-type skins - 128.6±0.39 µm and 90.4±0.74 µm, respectively. The thinnest and most delicate hair is downy hair, its thickness was 13.2±0.19 µm on the spinal part and 10.2±0.23 µm on the belly of brown type skins, 11.6±0.27 µm and 10.2± 0.30 microns on pastel-type skins. In addition, hair of all categories on the scalp is less thick than on the ridge.

In pastel and brown nutrias, the hair thickness of all categories differs slightly; in pastel nutrias, the hair thickness is slightly thinner.

Table 10 - Results of measurements of hair density in various topographic areas (n = 3)

Conclusions: The hair cover of nutrias of brown and pastel color types is most dense on the womb (14500-15500 pieces/1 cm2), the most sparse on the spinal part (7000-7200 pieces/1 cm2), which is associated with the semi-aquatic lifestyle of nutrias . The hair density of pastel-colored nutrias is higher than that of brown nutrias, but these data may be erroneous due to the fact that a very small sample was studied for this indicator (n = 3).

Table 11 - Results of calculating the softness coefficient

Conclusions: The softness coefficient on the back part of brown skins was 2.83*10-3, on the belly - 2.47*10-3; on pastel-type skins - 2.80*10-3 on the ridge, 2.51*10-3 on the womb.

The figure for the coefficient of hair softness in nutrias of both color types on the womb is less than on the spinal part, which indicates that the hair in this topographical area is softer and more delicate. The softness coefficient for the studied color types of nutria is approximately the same, which is associated with slight differences in the thickness and length of the guard hairs of both types.

.3.3 Measuring the thickness of the skin tissue of nutria skins of different color types

Table 12 - Results of statistical processing of data on the thickness of the leather tissue of brown and pastel nutria skins

Conclusions: The data presented in Table 11 indicate that samples from nutria skins of brown and pastel color types are of average equality in the thickness of the skin tissue. Moreover, the thickness of the skin tissue on the ridge is higher than on the womb.

The thickness of the skin tissue of brown skins (1.25±0.05 mm) exceeds this figure for pastel-colored nutria skins (1.01±0.06 mm) on the ridge, on the womb (0.85±0.04 mm and 0. 63±0.04 mm, respectively). This is due to the fact that more active breeding work is being carried out with regard to brown nutrias, aimed at improving the commercial properties of the resulting fur raw materials.

2.3.4 Sorting of unprocessed nutria skins

Table 13 - Results of sorting the studied nutria skins

Color type

Def group

Quality, %

Number of heads

Brown

Wiped area (10.1

62 (10% for poorly degreased skin)

Brown

Gap (length 5.1 to 10.0 cm)

Brown

Wiped area (10.1

Brown

Gap (length from 5.1 to 10.0 cm), hole (S to 10.1 cm2)

Brown

Wiped area (10.1

Brown

Holes and bald spots (10.1

Brown

Wiped area (S up to 10.1 cm2)

Brown

Wiped area (S up to 10.1 cm2)

90 (10% for poorly degreased skin)

Pastel

Rip (length from 5.1 to 10.0 cm), abraded area (S to 10.1 cm2)

65 (10% for poorly degreased skin)

Pastel

Wiped area (S up to 10.1 cm2), holes (10.1

Pastel

Wiped area (10.1

Pastel

Bald patch (S up to 10.1 cm2), light felting

Pastel

Hair section (S up to 10.1 cm2)

70 (10% for poorly degreased skin)

Pastel

Wiped area (10.1

Pastel

Conclusions: The most common defect based on the results of sorting nutria skins was the intravital defect “wiped place”. There are also common defects on nutria skins that occur when removing the skins - tears and holes, which indicates poor-quality primary processing.

On nutria skins, such a defect as poor fat-freeness is often found, for which a 10% discount is set, which also indicates a low level of primary processing.

Among the studied sample of brown-type nutria skins, 50% of the skins turned out to be of the first grade, 50% - of the second grade; among pastel nutria skins: first grade - 63%, second grade - 27%.

% of brown nutria skins were assigned to defectiveness group 1, 30% each - to defectiveness groups 2 and 3; 37.5% of pastel nutria skins are assigned to defectiveness groups 1 and 2, 25% - to defectiveness group 3.

“Fur head” is the skin of a fur-bearing animal, the quality of which is accepted as 100%. By calculating the number of heads, the cost per batch of fur raw materials is established. The number of fur heads for the brown nutria sample was 7.74, and for the pastel nutria sample - 6.47. These figures indicate the average quality of these samples.

conclusions

Based on the results obtained during our own research, the following conclusions can be drawn:

Nutria skins of the brown type with an average weight of 214.6 ± 16.4 g have an area of 1022.7 ± 41.55. Pastel-type nutria skins are smaller in size compared to brown-type skins - the area of the skins is less by 86.7 cm2 (by 8.5%), the weight is by 39.1 g (by 18%); with an average mass of 175.5 ± 9.6 g, their area is 936 ± 16.53 cm2.

The studied sample of brown nutria skins was not equalized in terms of mass (22.98%), average equalized in terms of area (Cv=12.9%); the sample of pastel skins was equalized by area (4.67%), average equalized by weight (Cv=14.44%). The equality indicators for the sample of pastel skins are higher.

In general, the height of the hairline of pastel-colored skins is less by 1.1 mm (10.1%) on the spinal part, and by 0.6 mm (6.9%) on the womb. Skins of both color types are equalized according to this indicator.

The length indicators of all categories of hair on the skins of brown nutria are higher than on the skins of pastel nutria. The greatest difference is noted in the length of the guide hairs, which on brown skins are 5.7 mm (9.7%) longer on the spine and 3.1 mm (6.7%) longer than on pastel skins. The smallest difference in the length of downy hair was 1.2 mm on the ridge, 1.4 mm on the womb. The difference in the length of the spine was 1.9 mm on the ridge, 2.2 mm on the womb. Skins of both color types are equalized in the length of the guard and guide hairs, and in the length of the down hairs - average equalization.

The thickness of the hair on the ridge of the skins of both color types differs slightly (the hair on pastel skins is thinner); the difference in the thickness of the guide hair was 3.1 microns, the guard hair - 6.4 microns, and the down hair - 1.6 microns. In terms of the thickness of the hair on the casing, the indicators are the same (the average thickness of the guide hair is 135.9 microns, down hair - 10.2 microns) with the exception of the awn (on pastel-type skins this indicator is 4 microns lower). The hair of these skins is equalized by the thickness of the guide and guard hairs, and averagely equalized by the thickness of the fluff.

The softness coefficient on skins of both color types differs slightly; on brown skins it was 2.83*10-3 on the ridge, 2.47*10-3 on the belly; on pastel-type skins 2.80*10-3 and 2.51*10-3, respectively. Consequently, the hair of nutria is softer on the womb, since the spine on the womb is slightly shorter than on the ridge, but much thinner and more delicate.

The density of hair on the skins of pastel nutria is slightly higher in comparison with brown skins, by 200 pieces/1 cm2 on the ridge, by 860 pieces/1 cm2 on the womb, by 560 pieces/1 cm2. The thickest hair in both color types of skins is on the womb, less dense on the ridge, which is associated with a semi-aquatic lifestyle.

The thickness of the leather tissue on pastel-type skins is lower by 0.24 mm on the ridge and by 0.23 mm on the womb. The coefficient of variation for all measurements of skin thickness exceeded 10%, which indicates the average equality of the samples for this indicator.

Thus, we can conclude that nutria skins of pastel and brown types differ slightly in their commercial properties. The skins of pastel nutria are smaller in size, and their hair density is higher. Also, the skins of pastel nutria are distinguished by greater softness of the hair on the ridge, i.e. in general, the hair of such skins is more delicate than that of brown skins, but this can negatively affect the wearability of the skins (since the spine is thin, it does not protect the down hair well from damage). But pastel skins are in great demand among manufacturers of finished products, which is associated with the beautiful, attractive color of the hair; such skins can be used in their natural form, without dyeing.

The quality of the samples of nutria skins of both color types according to the sorting results is average, since the number of heads was 7.74 pieces. for brown skins (out of 10 skins), 6.47 pcs. - for pastel skins (out of 8 skins). The percentage of first grade skins among brown skins was 50%, among pastel ones - 63%.

The most common defect based on the results of sorting nutria skins was the lifetime defect “worn place”, which may be associated, on the one hand, with the low level of nutria content in farms, and on the other hand, this defect is most often observed in animals with overripe hair and is one of signs of spring molting. There are also common defects on nutria skins that occur when removing the skins - tears and holes; There are poorly defatted skins. This indicates a low level of primary processing.

The presence of defects on the skins reduces the usable area of the skins that can be used by industry, the yield of finished products decreases, more waste is generated, and the processing of such skins becomes more labor-intensive.

By improving the system of keeping and breeding animals, methods of shooting, degreasing, editing, and drying skins, their quality can be significantly improved.

List of used literature

1. Alexandrov V.N. Homestead farming: rabbits, nutria / V.N. Alexandrov. - St. Petersburg: Agropromizdat, 1999. - 237 p.

2. Balakirev N.A. State and prospects for the development of nutriculture in Russia / N.A. Balakirev // Bulletin of the Russian Academy of Agricultural Sciences. - 2004. - No. 1. - With. 59-60.

Balakirev N.A. The crisis of caged fur farming, the reasons for its occurrence and ways out / N.A. Balakirev // Chief livestock specialist. - 2011. - No. 1. - With. 47-50.

Balakirev N.A. State and prospects of caged fur farming in Russia / N.A. Balakirev // Rabbit breeding and fur farming. - 2011. - No. 3. - With. 15-17.

Bondarenko S.P. Dressing and production of products from nutria and muskrat skins / S.P. Bondarenko. - M.: AST, 2002. - 157 p.

Gladilov Yu.I. How many rabbits and nutria are there in Russia? / Yu.I. Gladilov // Rabbit breeding and fur farming. - 2010. - No. 1. - With. 14-15.

GOST 2916-84. Untreated nutria skins. - M.: IPK Publishing House of Standards, 1997. - 7 p.

Kladovshchikov V.F. Stimulate the development of nutria and rabbit breeding / V.F. Storekeepers // Rabbit breeding and fur farming. - 2002. - No. 3. - With. 23.

Komarova L.G. Commercial properties of nutria skins / L.G. Komarova, Z.G. Hasanova // Commodity science and technology of raw materials and products of animal origin. - 1997. - p. 17-22.

Kuznetsov B.A. Fundamentals of merchandising of fur raw materials / B.A. Kuznetsov. - M.: State Publishing House of technical and economic literature on procurement issues, 1952. - 507 p.

Luppova I.M. Biological features and economically useful qualities of nutria / I.M. Luppova // Agrarian science - agriculture. - Barnaul: Alt. state agrarian univ. - 2008. - p. 327-330.

Pereverzeva A.D. Commodity research of fur raw materials / A.D. Pereverzeva. - M.: Economics, 1982. - 240 p.

Firsova N.M. Dressing of fur, sheepskin and leather / N.M. Firsova. - Rostov-on-Don: “Phoenix”, 2007. - p. 95-111.

Shevchenko A.A. Nutria: biological features, maintenance, breeding, diseases and treatment / A.A. Shevchenko, L.V. Shevchenko. - M.: Aquarium, 2004. - 157 p.

The commercial value of nutria skin is determined by the degree of hair development, color, size and strength of the skin tissue (hide). Therefore, the larger the nutria, the greater its value.

One of the most important features that determine the quality of nutria skins is the thickness of the hair. The durability, beauty and warmth of the skin depend on it. If there is a thick awn, the downy hair is completely covered on all parts of the body. The density of the down is determined by the width of the strip of skin that is formed when the down hair is pulled apart. When determining the grade of nutria skin, the main attention is paid to the thickness of the fur on the abdomen, as the most valuable part of the skin.

Hair density depends on the season of the year, the age of the nutria, the level of feeding, and the hereditary characteristics of the nutria. However, it has been established that even under equivalent feeding and housing conditions, hair density may vary in different individuals at the time of slaughter. These differences are primarily due to hereditary inclinations. Therefore, it is necessary to select nutria with thicker fur for the tribe, since this trait is mainly inherited.

First of all, a little about the structure of the skin tissue and hair of nutria. The skin of the nutria body consists of:

1) epidermis - the top layer of skin, consisting of integumentary epithelial cells that gradually die and are replaced by new ones;

2) dermis - a layer of skin tissue on which the epidermis lies. The strength of the skin depends on the degree of development and density of the dermis. The dermis is a relatively thick layer of connective tissue with 2 types of fibers - collagen (96-99%) and elastin (about 1.5%). Collagen fibers are located along the length of the body and only a small part is located in the transverse direction, and therefore the skin is more easily torn along than across.The strength and elasticity of collagen fibers depends on the drying temperature, and in order not to lose the strength of the skin, it is dried at a temperature not exceeding +30 degrees.Elastin fibers form a kind of network, are able to contract when dry, and when re-moistened, they restore their original elasticity. This allows, if necessary, to further process the skin and correct its shape.

3) under the dermis there is a fatty layer with loose connective tissue, which must be removed during primary treatment so that it does not affect the quality of drying and the strength of the skin.

4) the lowest layer of leather tissue - muscular - is a thin film, which is removed during the initial processing of the skins.

Nutria skin contains sebaceous glands, which protect the skin from drying out and give the hair softness and shine. Nutria skin is thicker on the spine and thinner towards the abdomen.

Hair is a derivative of the skin and is located on it in groups, in one group, depending on age and season, from 20 to 130 units. According to their function and their shape, nutria hair is divided into guides, guard hairs, down hairs (93-98%) and vibrissae (with great sensitivity - on the lips, eyebrows, cheeks). The fur on the abdomen is 2.5 times thicker than on the ridge.

Changes in hair growth in nutria are caused by several factors. First of all, age-related variability, consisting of three periods:

1) embryonic, intrauterine, starting from 2 months of age, hair is formed gradually from the head, then on the back, abdomen, and chest. The growth of primary hair continues after birth and is completed by 35-40 days of age (depositing time).

2) the formation of secondary hair occurs, the laying of which occurs almost immediately after birth. Secondary hair growth continues until 3-5 months of age. As the gut grows, primary hair gradually falls out, and secondary hair growth intensifies. Subsequently, until approximately 5 months of age, new hair grows, which compensates for the thinning of fur due to the intensive growth of the young. The process of primary hair loss (molting) ends by 110-120 days.

3) change from secondary to tertiary hair: the hair of an adult animal is thicker and longer. This period lasts from 150-165 days of age to 210 days, after which new hair growth occurs at a slower pace.

Seasonal hair loss (molting) has not been observed in nutrias; hair falls out and grows back imperceptibly throughout the year. Only with acclimatization of nutria in the northern regions did a slight decrease in molting in winter occur.

In different parts of the body, the commercial properties of hair and skin tissue are different. There is the concept of “topographic areas of the skin”: between the eyes, head, scruff, neck, shoulder, ridge, rump, side, chub, belly, thigh, paw, tail.

When assessing the commercial properties of nutria skin, first of all, the characteristics of the hair coat, its color, shine, height, evenness, fluffiness, softness, strength, and degree of felting are given.

High-quality nutria fur is highly valued by winter clothing manufacturers. It is lightweight, durable, and has a great appearance. In addition, due to its structure, this material repels water well, which is especially important in regions with frequent and heavy precipitation. But in order to use such products for as long as possible, you should familiarize yourself in detail with what nutria fur is and how to properly care for products made from it.

Description of nutria fur

The main feature of nutria skins, which distinguishes them from the fur of other similar animals, is its structure. This material consists of 93-95% downy hair, and the remaining part is occupied by hard guard hairs, guide hairs and vibrissae. Down warms the animal at low temperatures. It is twisted along the entire length of the hair. The awn and other villi are designed to protect the animal from mechanical stress and getting wet down, which helps retain heat in the body. About 15 thousand hairs grow on every square centimeter of animal skin area.

The initial color of nutria skins is brown with a brown tint. But during the selection work, breeders managed to increase the number of colors of animals to thirty. Of these, the most common are:

black;
white;
golden;
brown;
beige.

Properties and characteristics

In the clothing industry, nutria fur is highly valued due to the number of beneficial properties it possesses. The most prominent among them are the following:

soft silky texture and beautiful appearance, which gives a special effect to fur products;
high strength, making such fur resistant to mechanical damage;
low weight of skins used for the production of clothing and accessories;
characteristic shine.

It is also worth noting that such fur retains heat well and provides warmth. Products made from nutria fur will protect the owner even in harsh winters, and moisture protection and durability contribute to comfort in heavy rainfall and wind.

As for the main characteristics of such fur, they include:

Durability. Items made from nutria fur retain their spectacular appearance for 5–8 seasons.
Moisture resistant. The fleece in the fur ensures that when moisture gets on it, it slides off and does not penetrate into the down layer. Thanks to this, the animal can swim calmly in the water without getting wet.
Availability. Compared to the fur of other animals, nutria is much cheaper.
Wear resistance. This figure for nutria fur is at least 45–60%.

But, speaking about the properties and characteristics of such material, it should be noted that they are largely influenced by the method of growing livestock. Nutria skins that grew in their natural conditions are much more valuable. But before using them, they are given the desired color using special dyes.

How warm is it?

When purchasing fur products of this type, most buyers are immediately interested in how well such clothing will protect in the cold. It should be noted here that nutria fur is not as warm as, for example, beaver fur. But, despite this, it will protect its owner from the most severe winter frosts and wind.

In addition, the moisture resistance of the material helps protect even from heavy precipitation, and neither sub-zero temperatures nor snow and rain affect the quality of fur clothing. After wearing in difficult weather conditions, shake off the product well and dry at room temperature.

Disadvantages of clipped nutria

Processing fresh nutria skins is a painstaking process that involves a number of features. Many breeders, in the process of implementing it, supplement the basic algorithm of work by also cutting or plucking longer, coarse hairs. They do this in order to improve the appearance of the products and some other characteristics. For example, after cutting this fur, it becomes similar to more expensive mink. Also, externally, products made from such material look much more expensive and more impressive.

When describing the advantages of sheared fur, a number of significant disadvantages should also be mentioned, which must be taken into account when purchasing. These include the following points:

After cutting, such material retains heat less well. Many reviews from owners of clothes made from nutria fur indicate that products with long pile are much warmer in winter.
The awn is responsible for the special shine of the fur. After cutting her hair, he disappears, which not everyone likes.
After a haircut, upon contact with the pile, you can feel the rough “stumps” left after cutting long hair. This situation can be avoided if plucking is used to remove the spine. Furs treated in this way look more attractive.

Reference. Although this type of nutria skins has a number of disadvantages, it costs an order of magnitude higher on the market than fur with long pile. The reason for this is a more velvety and noble texture.

How to care for a fur product?

As already noted, products made from nutria fur are highly wear-resistant, moisture-resistant, and have a long service life. But all these points are fully accessible only if such clothes are properly cared for. Necessary care includes several main points:

Proper combing of fur. Over time, with frequent wear, the lint on a fur coat or other fur product can roll into tiny balls. Despite their small size, such lumps can significantly spoil the appearance of the product. In this case, they must be carefully combed out with an elastic comb.
After combing, the fur is cleaned. For light stains, it is enough to use regular hair shampoo or conditioner. It will additionally provide the fur coat with a pleasant smell. Sawdust is also often used, which is sprinkled on the contaminated area for a short period of time.
In case of severe contamination, the stuck together and stained pile is carefully treated with gasoline. The treated area is carefully wiped with a cloth in the direction of pile growth. After this, the product is hung on the balcony or near the window, where the unpleasant smell gradually disappears.
After cleaning is completed, the fur coat is combed out again with a comb.
If the product gets wet or snow has stuck to it, you should not leave it just like that. Immediately upon returning home, the fur coat or hat must be thoroughly and vigorously shaken off any remaining moisture. After this, the product is put on a hanger and allowed to dry completely. The product should be left as far as possible from any heating devices. After drying, the combing step follows again.
Fur items should be stored on separate hangers, preferably in special fabric covers. Moreover, by putting a fur coat in a crowded closet, the owner runs a high risk of deforming the shape of the hairs and ruining the appearance of the product. In addition, the temperature in a clogged wardrobe is always higher than in an empty one. This also negatively affects the quality of the fur.

Many women, in an attempt to give a new fur coat a pleasant smell, spray it generously and often with perfume.

Attention! This should be avoided, since the alcohol contained in perfume can greatly damage the color and quality of the hairs. Perfume should be applied exclusively to the lining.

And another important point is the fact that frequent wearing of a fur coat in cold weather contributes to its better storage and improvement of appearance. In turn, constant hanging in the closet, on the contrary, leads to caking of the fur and damage to it by moths.

Conclusion

Nutria fur is widely used in the production of fur products. The main reasons for its high value are the lightness of such material, its wear resistance, and waterproofness. In addition, products made from nutria skins retain heat well in moderate frosts and look impressive and rich. When purchasing fur clothing made from such material, be sure to familiarize yourself in advance with the main points of caring for it, as well as the rules for its optimal storage.