CC BY
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Robert Glogowski, Malgorzata Majewska ©
Warsaw University of Life Sciences, Warsaw, Poland
DESCRIPTIVE ANALYSIS OF SELECTED HAIR AND PELT PARAMETERS OF GREENLAND NUTRIA (Myocastor coypus Mol.) FUR COAT IN THREE AGE GROUPS
Abstract
Nutria pelt is a valued product, which can be gained with relative low costs of nutrition and housing. Their fur coat consists of dense delicate, dense underfur and long glossy guard hair. 12 nutria skins were examined for raw/tanned pelt and hair parameters in three age groups (13, 9 and 6 months). Materials from spring and autumn pelting were evaluated by precise detailed laboratory analysis. Samples were collected from ventral, dorsal and rear skin. Fur coat fibers of both layers were measured and counted in lanameter.
Pelt size and weight was higher in older animals.
Longest guard hair were on the dorsal samples, in spring approx. 7cm and in autumn approx. 8cm. Older nutrias had thicker guard hair and underfur in autumn. In spring samples younger nutria had thicker guard hair.
Key words: nutria, fur coat, pelt, hair parameters
Introduction.
Nutria fur coat is considered as an important product for fur industry, although in some countries in wild they are regarded as a pest, what leads to eradication campaigns [2,9]. There is a stable offer for an articles made from nutria with soft fox collars. The guard hair and underfur fibers were analyzed in detail, giving particular results for each major region of the pelt.
Task, the aim of the article.
In this study we present descriptive analysis of young and adult Greenland nutria selected pelt properties, for both sexes. The age criterion may lead to description of the optimal pelting time.
Material and methods.
12 Greenland nutrias in various age and sex were randomly selected in extensive farm in eastern Poland. They were housed in typical pens without access to water pools.
Their balanced nutrition based on farm produced food: root crops and cereals.
The following nutrition ratios were used on the farm. Both autumn and spring rations were applied twice a day, in the morning and in the evening. In autumn nutrias get brewed cereals, wheat bran and hay. In the evening chopped beetroot was distributed.
In spring, first they get brewed cereals with steamed potatoes and later that day fresh clover has been served ad libitum.
© Robert Glogowski, Malgorzata Majewska, 2009 138
The codes for experimental specimens in 3 age groups presents Table 1. _Table 1. The code scheme for experimental animals._
13am 13sm 13af 13sf 9am 9sm 9af 9sf 6am 6sm 6af 6sf
13, 9 ,6 - months of age A - autumn pelting (November) S - spring pelting (April) M - male F - female
Between 22 and 34 week of life growing nutrias are in second moulting. In adult nutria fur coat moulting is constant with some seasonal increase. Filistowicz et al. [5] underlined positive genetic correlations between total license score and fur coat quality higher than corresponding phenotypic correlations in Greenland nutria.
The animals were siblings in age groups. All pelts were collected in regular planned pelting by farmer. At the time of slaughter (6-7 month of life) typical nutria body weight averages >4.0kg [8]. Mertin et al. [10] report live weight of 3 years old, Standard nutria males above 7.0kg and in females mean body weight approx. 6.5kg.
Raw pelts were weighted and their surface was calculated. Than all pelts were put on a specialized wooden drying boards. After drying, they have been removed and tanned. Afterwards the length and weight measurements were repeated. The pelt surface was calculated using the following equation: (a + b) X h/2 where:
a - the width of the pelt at pectoral limbs b - the width of the pelt at rear limbs
h - the length of the pelt from the tip of the nose to the tail's root Fig.l. Locations of hair sample collection.
2 - mid-dorsal
3 - rear-lateral
Square (approx. 1cm2) samples of tanned skin with hair were cut from the
pelt. All hair were shaved possibly close to the skin surface. Fig. 1 shows points on
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the pelt, where samples were cut of the skin. The significant correlation between data from dorsal and ventral samples let Hanusova et al. [6] conclude that standard sampling location would be enough to compare animal groups. There were influences of genotype on hair mineral content in samples taken from dorsal and ventral parts of nutria body.
Guard hair and under fur were separated. Length of all the guard hair from the sample was measured with 0.5cm accuracy.
All hair from the sample were prepared in glycerin and their thickness was measured in lanameter by microprojection method according to polish norm PN-72/P-04900. Mean thickness of all visible fibers was calculated.
Results of researches.
In polish phenotype norms for nutria, fur quality is the most substantial group of indices (9 points out of total number 20). Other two categories of evaluation are: body size with constitution and colour and clarity of fur coat. Candidate reproduction animals may be evaluated after 5th month of age, in every season. Practically, during farm license by commission of National Animal Breeding Center, quality traits are being evaluated manually.
Although nutrias are small herbivorous mammals like rabbits, their growth, body size and carcass parameters differ. Chilled rabbit carcass weight in hybrid broiler lines averages from 1.59 to 1.62kg according to genotype [11]. The carcass weight of nutria in intensive and extensive housing and feeding system are different. Male nutria mean carcass weight was significantly higher in intensive production farms than in extensive system, respectively 4.71 and 3.99kg. In female carcass there is lighter difference between intensive and extensive production system, mean weight respectively 3.83 and 3.64kg [1].
In this study body size and pelt properties were consent with other Authors (Table 2). Nutria body size growth may continue up to 30th month of life. At about 810th month of age, they are usually ready for pelting [7].
Table 2. Main parameters of body, carcass and pelts.
Animal Live weight (kg) Carcass weight (kg) Raw pelt length (cm) Tanned pelt length (cm) Raw pelt surface (cm2) Tanned pelt surface (cm2) Raw pelt weight (g) Tanned pelt weight (g)
13am 6,40 4,50 80,0 69,5 2448,00 2224,00 307,80 219,00
13sm 5,00 3,10 87,0 68,0 2131,50 1904,00 277,40 166,40
13af 5,50 3,80 83,0 70,0 2199,50 1890,00 302,40 201,80
13sf 4,90 3,10 82,5 63,0 2062,50 1874,25 261,80 179,60
9am 5,70 3,80 80,0 72,0 1976,00 2034,00 287,60 195,00
9sm 5,00 3,00 84,5 61,0 2070,25 1555,50 267,00 162,80
9af 5,40 3,80 80,0 68,0 2144,00 2091,00 276,40 199,40
9sf 4,60 2,80 79,5 64,0 1749,00 1808,00 256,80 171,60
6am 3,00 2,10 71,0 61,5 1526,50 1537,50 182,00 142,20
6sm 4,30 2,60 82,0 60,0 1763,00 1560,00 243,80 159,60
6af 2,90 1,90 68,0 56,5 1530,00 1384,25 155,40 114,60
6sf 3,80 2,30 77,0 63,0 1694,00 1685,25 237,80 147,20
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Nutria fur coat consists of two layers, guard hair and underfur. Guard hair are long and thick. Usually they are considered unwanted in fur coat. In common practice they are being trimmed by fur manufacturers. In our study guard hair were counted in all samples (Table 3), and divided into 0.5cm length classes, which enabled us to describe the variation in length (Table 4 and graphs 1-3).
In our study the longest guard hair were present in mid-dorsal samples independently of age class or sex of the animal. In all age groups greatest number of guard hair was also in mid-dorsal samples. The number of guard hair grows with the age of animals (between 12-15%).
Table 3. The quantities of guard hair in sampling points.
Total number of guard hair
Code Sampling point
13am 469
13sm 1 265
13af 265
13sf 232
13am 774
13sm 2 636
13af 453
13sf 355
13af 539
13am 3 518
13sf 357
13sm 304
9af 502
9sm 1 306
9am 282
9sf 242
9af 670
9am 2 601
9sm 541
9sf 506
9af 579
9am 3 475
9sm 373
9sf 289
6am 529
6sm 1 282
6sf 265
6af 185
6af 596
6sm 2 483
6am 399
6sf 339
6af 508
6am 3 384
6sm 338
6sf 338
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Table 4. The number of guard hair in 0,5cm length classes.
Code S Guard hair length classes (cm)
00,5 0,51 11,5 1,52 22,5 2,5 -3 33,5 3,5 -4 44,5 4,5 -5 55,5 5,56 66,5 6,57 7-7,5 7,5-8
13am 1 10 44 93 165 88 18 7 2 4 3
2 7 40 38 100 125 55 44 22 6 9 11 8 5 1 1
3 23 74 192 142 36 16 1 4 3
13sm 1 21 41 84 80 17 4 6 1
2 18 47 19 78 91 35 15 6 16 14 8 4 2
3 12 22 76 93 41 11 9 7 1 2
13af 1 21 41 84 80 17 4 6 1
2 8 44 68 138 102 56 37 41 21 31 17 4
3 12 102 166 118 63 17 14 7 1
13sf 1 22 38 39 77 32 6 4 2
2 10 27 29 30 71 37 13 7 14 5 6 5 5 2
3 7 32 79 104 43 32 10 4
9am 1 16 16 28 76 63 24 12 2 2 1
2 7 23 21 106 112 63 29 19 18 6 7 10 8 4 1
3 20 36 133 108 77 26 10 9 2 2
9sm 1 24 53 89 85 23 10 6
2 13 29 29 62 122 44 33 19 25 10 7 4 1
3 11 44 66 115 37 25 18 5 2
9af 1 23 40 83 165 81 28 9 5 7 5 1
2 7 33 29 66 103 69 48 24 18 15 35 6 1
3 24 67 156 165 55 32 11 7 4 2
9sf 1 12 31 92 62 17 9 1 3 1
2 18 38 30 43 91 45 32 17 18 14 4 5 8
3 8 27 92 86 28 17 7
6am 1 29 82 87 87 91 33 18 3 16 5 1
2 1 5 32 41 62 39 29 22 8 8 10 6 3 2 1
3 4 72 104 84 25 25 11 10
6sm 1 15 31 108 64 28 8 10
2 11 31 24 124 117 29 14 10 11 7 12 3 2
3 22 36 88 90 26 22 9 3 3 1
6af 1 11 24 38 37 27 9 11 2 1 1
2 16 41 52 93 80 63 33 21 8 8 8 3 6 4 2 1
3 48 118 130 113 45 14 5 4 4
6sf 1 17 26 93 74 21 11 6
2 24 44 27 67 61 26 4 5 2 9 6 5 1
3 5 34 97 108 26 11 11 8 1 2 1
S - sampling point number 142
Table 5. Mean thickness of guard hair fibers in sampling points (pm).
code 1 2 3
13am 100,31 125,82 110,67
13sm 80,37 84,30 75,89
13af 98,62 123,06 107,31
13sf 84,45 112,44 83,18
9am 84,48 92,12 130,00
9sm 79,50 104,78 73,52
9af 86,79 128,93 89,90
9sf 91,00 97,95 97,23
6am 125,20 127,80 85,63
6sm 111,22 111,67 62,50
6af 96,50 103,58 98,73
6sf 87,23 111,00 82,48
Table 6. Mean thickness of underfur fibers in particular sampling points (pm).
code 1 2 3
13am 10,90 13,25 10,37
13sm 10,28 13,17 10,35
13af 10,48 13,33 11,11
13sf 10,67 13,20 9,66
9am 5,84 13,71 11,16
9sm 9,77 12,93 10,42
9af 11,66 14,46 11,58
9sf 10,54 13,23 10,21
6am 10,53 10,10 9,80
6sm 10,62 12,32 9,99
6af 9,88 12,01 10,61
6sf 9,43 12,28 10,09
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Graph 1. The number of guard hair in anterio-ventral sampling point.
Graph 2. The number of guard hair in mid-dorsal sampling point.
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Graph 3. The number of guard hair in rear-lateral sampling point.
There was no evidence for considerable effect of pelting season nor sex on guard hair number in sampling point.
We present graphic results for 9 months old animals, as they were in most optimal pelting age.
In anterio-lateral sample, most of guard hair length was between 1-1.5 and 2-2.5cm. Most frequent guard hair length in second (mid-dorsal) sample was between 2 and 2.5cm. At rear-lateral side of the body the most numerous length class was between 1-1.5 and 1.5-2cm.
Independently of age or sex, definitely greatest number of nutria guard hair length was in class from 1-1.5 to 2-2.5cm.
Longer guard hair in nutria coat are less frequent.
In Cholewa et al. [3] mean length of guard hair and underfur in 26 weeks old nutrias have been described, for basic color varieties. Dorsal guard hair length was 76.8mm, and underfur 14.2mm. Lateral guard hair length was 68.7mm, with underfur 12.6mm. The Greenland nutria has shortest hair in comparison for e.g. Sapphire-blue and Standard. There were no differences in hair height between males and females.
Our results showed an universal tendency in underfur length, independently of sex and age. Mean length of underfur hair at 1st and 3rd sampling points was about 7mm. Mid-dorsal underfur average length was about 12mm.
In other paper Cholewa et al. [4] described nutria fur coat hair thickness. Guard hair layer had average 100-110^m and underfur from 13 to 14^m. Mean density of hair at 1mm2 of skin were as follows: 4 guard hair and approx. 150 underfur fibers. At abdomen there is 180, this part of the pelt is most valued. On
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lateral sides of the pelt there is about 130 underfur fibers, and on the dorsal sides only 80-90.
Table 5 and 6 show mean values of guard hair and underfur thickness obtained in our measurements. Guard hair in mid-dorsal region seems to be the thickest of all collected samples. No significant effects of sex on hair thickness can be demonstrated.
The values for underfur show similar tendency. Underfur in samples taken from the middle of nutria back, had highest average thickness.
Rear samples had slightly thicker underfur than anterio-ventral, practically in all age groups and sex.
Conclusions.
In comparison of the pelts form autumn and spring season, older nutria both guard hair and underfur were thicker in pelts collected in November than in April, especially in dorsal and rear samples. In spring pelts from younger animals, guard hair was thicker in dorsal and anterio-ventral samples. After moulting, adult fur coat has different thickness parameters.
Nutria pelts have quite good quality parameters but the interest for this product decreases. In Poland there are only four major nutria farms left. After long years of breeding efforts in nutria fur coat improvement, severe economic problems may cease options for further development.
Reference
1. Alt M., 2001. Fleischygienische Aspekte und Faktoren der Fleischqualität bei Sumpfbiberfleisch aus individueller Schlachtung. INAUGURAL DISSERTATION zur Erlangung des Grades eines Doktors der Veterinärmedizin an der Freien Universität Berlin.
2. Bollo E., Pregel P., Gennero S., Pizzoni E., Rosati S., Nebbia P., Biolatti B., 2003. Health status of a population of nutria (Myocastor coypus) living in a protected area in Italy. Research in Veterinary Science, 75, 21-25.
3. Cholewa R., Frindt A., Scheuring W., Szeleszczuk O., 2000. Chow i hodowla nutrii. Oficyna Wydawnicza Hoza, Warszawa [in polish].
4. Cholewa R., Pawliczak-Maj K., Szwaczkowski T., 2006. Genetic and environmental effects on body weight and fur height in nutria (Myocastor coypus L.). EJPAU 9/2 #24. Available Online: http://www.ejpau.media.pl/volume9/issue2/art-24.html
5. Filistowicz A., Gorajewska E., Przysiecki P., Calka M., 2006. The genetic parameters of conformation traits of Standard and Greenland nutria (Myocastor coypus). Acta fytotechnica et zootechnica - Mimoradne cislo. Nitra, Slovaca Universitas Agricluturae Nitriae, 113-115.
6. Hanusova E., Lohi O., Süvegova K., Mertin D., Stepanok V., 2000. Factors affecting the mineral composition of nutria fur (Myocastor coypus). Scientifur, 24 (3), 197-202.
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7. Jarosz S., 1993. Hodowla zwierz^t futerkowych. Wydawnictwo Naukowe PWN, Warszawa-Krakow [in polish].
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Summary
Nutria pelt is a attractive product, which can be obtained with relative low costs of the nutrition and housing of animals. Nutria skins were examined for the pelt and the hair parameters in three age groups (13, 9 and 6 months). The skin from the spring and autumn pelting were evaluated by deliberate laboratory analysis. Samples were collected from ventral, dorsal and rear skin. Fur coat fibers of both layers were measured and counted in the lanameter.
Older animals showed higher pelt size and weight then younger ones.
Longest guard hair were on the dorsal samples, in spring (approx. 7cm) and in autumn (approx. 8cm). Older nutrias had thicker guard hair and underfur in autumn then younger ones. In spring samples younger nutria had thicker guard hair.
Cmammx nadiumna do peda^ii 4.04.2009
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