Research Article
Dorota Kołodziejczyk 
, Stanisław Socha
Siedlce University of Natural Sciences and Humanities, B. Prusa 12/14, 08-110 Siedlce, Poland
Abstract. The aim of the study was to comparatively analyze the body type traits in mink of different color variants, over a period of a few years, compared against the current mink evaluation standard. The mink were managed on mink farms located in northwestern Poland. The analysis covered the years 2011–2018. A statistically significant effect of color variant, year of assessment and farm, on which the license took place, was found. The highest average grades for the type were achieved by the mink in 2014, while the color variant achieving best grades was Standard mink. Sapphire mink attained a similar rating. The variability of the assessment of the mink type, measured by the coefficient of variation, ranged within 24.86–33.99%, depending on the adopted criterion. The mink with grade B were characterized by the highest percentage share among the tested animals. These represented 45% of all mink assessed.
Keywords: mink, type traits, color variant, variability
The history of mink farming is over one hundred years old, and intensive work on adapting these animals to farm conditions has been going on for 90 years. Ongoing selective breeding has produced over 200 coat-color variants of mink which are farmed today, with new variants still emerging every now and then [Piórkowska 2018Piórkowska, M. (2018). Hodowla mięsożernych zwierząt futerkowych – kierunki zmian [Breading carnivorous fur-bearing animals – trending changes]. Wiad. Zoot., 54(4), 166–177 [in Polish]. Google Scholar].
Most Polish farms manage several different varieties of mink, however – as reported by Jeżewska-Witkowska et al. [2014]Jeżewska-Witkowska, G., Kujawski, H., Kasperek, K., Horecka, B., Zoń, A., Piórkowska, M. (2014). Inwentaryzacja wielkości populacji norek, lisów pospolitych, lisów polarnych, jenotów i tchórzy utrzymywanych na polskich fermach [Inventory of the size of the population of minks, red foxes, polar foxes, raccoon dogs and polecats kept on Polish farms]. Wiad. Zoot., 52(1), 3–10 [in Polish]. Google Scholar – brown-color variants prevail. An upward trend is also visible in White Hedlund, Cross, and Sapphire varieties. Also, despite a clear decline observed lately, the Standards are still the largest group of mink bred and farmed in Poland [Święcicka et al. 2016Święcicka, N., Bernacka, H., Openchowska, M. (2016). Liczebność populacji norek różnych odmian barwnych hodowanych na fermach objętych oceną wartości użytkowej i hodowlanej w latach 1999–2013 [Population of minks of different color varieties bred on farms covered by the utility and breeding value assessment in the years 1999-2013]. Wiad. Zoot., 54(2), 3–15 [in Polish]. Google Scholar].
Coat quality and body size are the most important goals of fur-bearing animals farming, and mink is no exception. There are not many reports in the literature that compare the quality of coat in different mink color variants using licensing assessments collected over a long period of time. It should also be emphasized that there are no reports that characterize the variability and changes in the course of assessments, or that would document an increase or decrease in the phenotypic progress in terms of the current mink evaluation standard [KCHZ 2010KCHZ (2010). Krajowe Centrum Hodowli Zwierząt: Wzorzec oceny fenotypu lisów pospolitych, polarnych, norek, jenotów i tchórzy hodowlanych [National Center for Animal Breeding: Standard for type evaluation of red fox, Polar fox, mink, raccoon dogs, and polecats]. Warsaw [in Polish]. Google Scholar]. Hence this research analysis, which we think may cotribute to the knowledge in this area.
The aim of the study was to comparatively analyze the body structure traits in mink of different color variants, taking into account differences in individual years (depending on the breeding farm), compared against the current mink evaluation standard [KCHZ 2010KCHZ (2010). Krajowe Centrum Hodowli Zwierząt: Wzorzec oceny fenotypu lisów pospolitych, polarnych, norek, jenotów i tchórzy hodowlanych [National Center for Animal Breeding: Standard for type evaluation of red fox, Polar fox, mink, raccoon dogs, and polecats]. Warsaw [in Polish]. Google Scholar].
The study is an analysis of different coat-color variants of mink kept in the northwestern part of Poland in breeding mink farms. All the studied farms were well-equipped and fit to both breeding herd management and offspring rearing. The analysis involved mink body traits assessed during the licensing according to the new evaluation standard [KCHZ 2010KCHZ (2010). Krajowe Centrum Hodowli Zwierząt: Wzorzec oceny fenotypu lisów pospolitych, polarnych, norek, jenotów i tchórzy hodowlanych [National Center for Animal Breeding: Standard for type evaluation of red fox, Polar fox, mink, raccoon dogs, and polecats]. Warsaw [in Polish]. Google Scholar]. In 2010, the numerical grading scale was replaced by letter-marked grades and now the phenotype rating is expressed by the letters A, B+, B or C. The current mink evaluation standard specifies the requirements of each class in great detail. A mink receives one cumulative grade for all the traits. Mink of a grade A, B+, and B are intended for further breeding. Those with a grade C should be culled from the breeding herd [KCHZ 2009KCHZ (2009). Krajowe Centrum Hodowli Zwierząt: Wzorzec oceny pokroju norek, [National Center for Animal Breeding: Mink type evaluation standard]. Warsaw, 18 [in Polish]. Google Scholar].
|
Table
1. Number of mink under evaluation in relation
to color variant and year of license |
||||
|
Color variant – Odmiana barwna |
n |
|
License year – Rok oceny |
n |
|
Pastel – Pastel |
157966 |
|
2011 |
29783 |
|
Pearl – Perła |
44540 |
|
2012 |
43840 |
|
Black Cross – Krzyżak |
1997 |
|
2013 |
26708 |
|
White Hedlund – Biała Hedlunda |
4918 |
|
2014 |
29331 |
|
Palomino – Palomino |
9305 |
|
2015 |
38620 |
|
Sapphire – Szafir |
15978 |
|
2016 |
28960 |
|
Platinum – Platyn |
5100 |
|
2017 |
27260 |
|
Standard – Standard |
1200 |
|
2018 |
16502 |
|
Total – Łącznie |
241004 |
|
|
241004 |
The following assumption was made: animals that received grade A were assigned the grade 5 in the calculations, B+ received grade 4, B grade 3 and C grade 2 (Polish school grade scale was used for the purpose).
The evaluation was carried out in 2011–2018, on nine mink farms (numbered 1 to 9), on a total of 241,004 mink belonging to eight color variants (Table 1).
Statistical parameters of the herd were estimated in accordance with the commonly accepted principles. Each trait was analyzed against a constant mathematical model, using analysis of variance, testing the significance of the factors: year of assessment, farm (farmer) and color variant: $$Y_{ijkl} = \mu + a_i + b_j + c_k + e_{ijkl}$$ where:
\( Y_{ijkl} \) – trait level,
\( \mu \) – population average,
\( a_i \) – effect of color variant,
\( b_j \) – effect of the license year,
\( C_k \) – effect of farm (farmer),
\( e_{ijkl} \) – random error.
Statistical computations were performed using the SAS package [SAS 2014SAS (2014). User's Guide. Version 9.4 Edition, SAS Institute Inc., Cary, NC. Google Scholar]. The descriptive statistics include arithmetic means, standard deviations, standard error and coefficients of variation. The significance of differences between means was tested using the post-hoc Tukey HSD test [SAS 2014SAS (2014). User's Guide. Version 9.4 Edition, SAS Institute Inc., Cary, NC. Google Scholar].
ANOVA of mink evaluation results showed a statistically highly significant effect of farm, color variant and year when the evaluation took place. Also other authors [Kołodziejczyk and Socha 2006Kołodziejczyk, D., Socha, S. (2006). Variability in reproduction traits of standard and pastel mink (Mustela vison Sch.). Acta Fytotech. Zootech., Mimoriadne Číslo, 182–185. Google Scholar, Felska-Błaszczyk et al. 2008Felska-Błaszczyk, L., Najmowicz, M., Sulik, M., Błaszczyk, P. (2008). Wybrane parametry rozrodu norek (Neovison vison) różnych odmian barwnych w aspekcie długości ciąży [Selected reproduction parameters of mink (Neovison vison) of different color varieties in terms of gestation length]. Rocz. Nauk. PTZ, 4(4), 147–157 [in Polish]. Google Scholar, Ślaska et al. 2009Ślaska, B., Rozempolska-Rucińska, I., Jeżewska-Witkowska, G. (2009). Variation in some reproductive traits of mink (Neovison vison) according to their coat colour. Ann. Anim. Sci. 9(3), 287–297. Google Scholar, Święcicka et al. 2011Święcicka, N., Kubacki, S., Zawiślak, J., Gulda, D., Drewka, M., Monkiewicz, M. (2011). Estymacja nieparametryczna cech pokroju szynszyli odmiany standard względem wieku zwierząt ocenianych podczas licencji [Non-parametric estimation of chinchilla conformation traits of the standard variety in relation to the age of animals assessed during the license]. Roczn. Nauk. PTZ, 7(4), 33–43 [in Polish]. Google Scholar, Kołodziejczyk et al. 2013Kołodziejczyk, D., Gontarz, A., Socha, S. (2013). Analysis of conformation traits of New Zealand White rabbits on a breeding farm. Acta Sci. Pol., Zootechnica, 12(4), 17–28. Google Scholar and Seremak et al. 2013Seremak, B., Felska-Błaszczyk, L., Dworecka, M., Dziadosz-Styś, M., Lasota, B. (2013). Analysis of litter sizes at birth and 7 days of nursing in mink (Neovison vison) of Black Velvet, Hedlund White, and Silverblue color types. Acta Sci. Pol., Zootechnica, 12(2), 39–48. Google Scholar] report that the sources of variation we analyzed often show a significant or highly significant effect on the utility traits of fur animals. The utility traits in question are reproductive parameters and those related to coat quality [Dziadosz et al. 2010Dziadosz, M., Seremak, B., Lasota, B., Masłowska, A., Mieleńczuk, G. (2010). Analiza wybranych cech reprodukcyjnych samic norek (Neovison vison) różnych odmian barwnych na przestrzeni kolejnych lat badawczych [Analysis of selected reproductive parameters of female mink (Neovison vison) of different color varieties over consecutive research years]. Acta Sci. Pol., Zootechnica, 9(4), 71–80 [in Polish]. Google Scholar].
Tables 2–4 present the statistical characteristics (means, standard deviations, standard error and coefficients of variation) of the general evaluation of the body shape depending on the license year, color variant and the farm on which the assessment was made. The coefficient of variation of the attained grades ranged from 24.86 to 33.99%. Standard mink were characterized by the highest coefficient of variation, and also the highest average score (Table 2). A similar level was achieved by Sapphire mink, while the average of other color variants differed significantly from the results of gained by the Standard and Sapphire mink. These results seem to confirm those reported by Socha and Markiewicz [2003]Socha, S., Markiewicz, D. (2003). Porównanie cech wielkości zwierząt i jakości okrywy włosowej norek (Mustela vison Sch.) odmiany standardowej i szafirowej [Comparison of body size and coat quality in mink (Mustela vison Sch.) of the Standard and Sapphire color variant]. Ann. UMCS, 21(2)(62), 65–70 [in Polish]. Google Scholar, who claim that both Standard and Sapphire mink were characterized by good parameters of fur quality and a high general assessment score. Similar results were obtained by Kołodziejczyk and Socha [2008]Kołodziejczyk, D., Socha, S. (2008). Analysis of conformation traits in mink of standard and palomino colour types. Proc. IX Int. Sci. Congr. in Fur Animal Production, Halifax, Nova Scotia, Canada, Scientifur, 32(4) 59-62. Google Scholar regarding the assessment of mink of selected color variants. Here also Standard mink achieved good grades. The average overall grade for Standard mink was 18.5 points, which may correspond to class B+ or even A.
|
Table
2. Statistical description of mink type
evaluation in relation to color variant |
|||||
|
Color variant – Odmiana barwna |
N |
x̄ |
SD |
SE |
V |
|
Pastel – Pastel |
157966 |
2.84a |
0.843 |
0.002 |
29.62 |
|
Pearl – Perła |
44540 |
2.85a |
0.833 |
0.004 |
29.26 |
|
Black Cross – Krzyżak |
1997 |
2.75b |
0.789 |
0.018 |
28.75 |
|
White Hedlund – Biała Hedlunda |
4918 |
2.82a |
0.904 |
0.013 |
32.03 |
|
Palomino – Palomino |
9305 |
2.65c |
0.770 |
0.008 |
29.11 |
|
Sapphire – Szafir |
15978 |
2.93d |
0.918 |
0.007 |
31.31 |
|
Platinum – Platyn |
5100 |
2.74b |
0.822 |
0.012 |
29.96 |
|
Standard – Standard |
1200 |
2.98d |
1.012 |
0.029 |
33.99 |
|
a, b, c…
– means marked
with different letters differ significanlty at P
≤ 0.05. |
|||||
|
Table
3. Statistical description of mink type
evaluation in relation to license year |
|||||
|
License year – Rok oceny |
N |
x̄ |
SD |
SE |
V |
|
2011 |
29787 |
2.69a |
0.763 |
0.005 |
28.32 |
|
2012 |
43840 |
2.83b |
0.861 |
0.004 |
30.49 |
|
2013 |
26708 |
2.78c |
0.797 |
0.005 |
28.69 |
|
2014 |
29331 |
3.24d |
0.916 |
0.005 |
28.29 |
|
2015 |
38620 |
2.88e |
0.851 |
0.004 |
29.54 |
|
2016 |
28960 |
2.58f |
0.722 |
0.004 |
27.98 |
|
2017 |
27260 |
2.92g |
0.838 |
0.005 |
28.72 |
|
2018 |
16502 |
2.77c |
0.827 |
0.006 |
29.90 |
|
a, b, c…
– means marked with different letters differ significanlty at
P ≤ 0.05. |
|||||
|
Table
4. Statistical description of mink type
evaluation carried out on selected mink farms |
|||||
|
Farm – Ferma |
N |
x̄ |
SD |
SE |
V |
|
1 |
56880 |
2.67a |
0.744 |
0.003 |
27.90 |
|
2 |
27394 |
3.01c |
0.873 |
0.005 |
29.02 |
|
3 |
24604 |
3.25d |
0.938 |
0.006 |
28.85 |
|
4 |
27976 |
2.66a |
0.725 |
0.004 |
27.22 |
|
5 |
11050 |
3.14b |
0.984 |
0.009 |
31.37 |
|
6 |
4540 |
3.10b |
0.985 |
0.015 |
31.74 |
|
7 |
26738 |
2.62e |
0.796 |
0.005 |
30.44 |
|
8 |
842 |
2.64ae |
0.655 |
0.023 |
24.86 |
|
9 |
60980 |
2.85f |
0.825 |
0.003 |
28.90 |
|
a,
b, c… – means
marked with different letters differ significanlty at P
≤ 0.05. |
|||||
Sapphire mink variant does not belong to those commonly bred in our country. Animals of this variety largely come from imports, hence the higher average overall rating in Sapphires may somewhat point to the need to intensify breeding work in this direction, so that native animals can match the quality of coat mink bred abroad.
There were no significant differences between the average grades for Pastel, Pearl and White Hedlund mink. These averages were at a very similar level, respectively, 2.84, 2.85 and 2.82 (Table 2). Palomino mink was characterized by the lowest average rating.
The coefficient of variability in the assessment grades by individual color variants ranged from 28.75 to 33.99%. The Standards exhibited the highest variability (Table 2).
When it comes to the year of assessment, the best results were recorded for minks assessed in 2014 (Table 3). The mean obtained by the animals differed statistically significantly from the mean obtained by the animals in the remaining years of assessment. It should be noted that the year of the license had a statistically significant effect on the results and each the means differed significantly from each other (Table 3).
Better grades obtained by mink in 2014 may indicate a particularly beneficial effect of environmental factors on the body size and coat quality. According to Gugołek [2017]Gugołek, A. (2017). Zależność między masą ciała a jakością okrywy włosowej zwierząt futerkowych [Relationship between body weight and fur coat quality]. Zw. Fut., 19–20 [in Polish]. Google Scholar, the most important environmental factors include: care, nutrition and housing conditions. The author further emphasizes that nutrition is responsible for fur density and the overall coat quality.
One of the many factors influencing the quality of fur is the work flow and management of the farm. The farmer’s responsibility is to create appropriate housing conditions, provide proper nutrition, and to ensure that good husbandry and veterinary care are provided [Zieliński and Ślaska 2015Zieliński, D., Ślaska, B. (2015). Wykorzystanie testów behawioralnych w ocenie temperamentu mięsożernych zwierząt futerkowych [The use of behavioral tests in assessing the temperament of carnivorous fur animals]. Wiad. Zoot., 53(3), 54–59 [in Polish]. Google Scholar]. According to Nabożny [2015]Nabożny, M. (2015). Charakterystyka organizacji korzeni włosowych w skórze zwierząt futerkowych z uwzględnieniem gęstości okrywy włosowej [Characteristics of the organization of hair roots in the skin of fur animals, including the density of the coat]. Wiad. Zoot., 53(2), 112–121 [in Polish]. Google Scholar, fur density is a result of the conditions that prevail on the farm, because the coat has a heat-insulating function, and whether it fully utilized depends – according to Fish et al. [2002]Fish, F.E., Smelstoys, J., Baudinette, R.V., Reynolds, P.S. (2002). Fur does not fly, it floats: buoyancy of pelage in semi-aquatic mammals. Aquatic Mammals, 28(2), 103–112. Google Scholar – on the environment of the animal’s habitat. This is confirmed by Święcicka et al. [2011]Święcicka, N., Kubacki, S., Zawiślak, J., Gulda, D., Drewka, M., Monkiewicz, M. (2011). Estymacja nieparametryczna cech pokroju szynszyli odmiany standard względem wieku zwierząt ocenianych podczas licencji [Non-parametric estimation of chinchilla conformation traits of the standard variety in relation to the age of animals assessed during the license]. Roczn. Nauk. PTZ, 7(4), 33–43 [in Polish]. Google Scholar, who point to the fact that the proper microclimate on the farm is a factor determining the quality of the coat.
The conducted research shows that the best parameters of the assessed traits, and thus the best average body rating, were characteristic for animals from farm No. 3. This average was statistically significantly different from the others (Table 4). The mink from farm number 7 achieved the lowest average grade.
Fig. 1. Percentage of evaluated mink in each grade
Rys. 1. Udział ocenianych norek (w %) w poszczególnych klasach oceny w analizowanym okresie
The results are not used here to judge which of the studied farms is the best one. Our observations, however, may by a hint the farmers that breeding work should be intensified and animal welfare should be taken into account more seriously. It is known that every farmer treats their animals in a very individual way. If the farmer ignores the negative signs and neglects the housing quality and welfare conditions, this will translate into the quality of the final product, which in turn may jeopardize the profitability of the farming effort.
Fig. 2. Number of mink in each grade by calendar year
Rys. 2. Udział ocenianych norek (w szt.) w poszczególnych klasach oceny z uwzględnieniem roku kalendarzowego
Fig. 1 presents the percentage distribution of mink by evaluation grade. The mink with grade B were most common and represented 41.5% of studied population. Slightly fewer, 39.9%, were mink with grade C. Also in the research of Zawiślak et al. [2016]Zawiślak, J., Święcicka, N., Bernacka, H. (2016). Wyniki oceny pokroju zwierząt futerkowych hodowanych na polskich fermach objętych oceną wartości użytkowej i hodowlanej w latach 2010–2014 [The results of the assessment of the type of fur animals bred on Polish farms covered by the utility and breeding value assessment in 2010–2014]. Wiad. Zoot., 54(2), 16–22 [in Polish]. Google Scholar on the assessment of fur-bearing animals, most mink received grade B. The proportion of this grade ranged between 31 and 36%. On the other hand, the share of animals in class A reached 20.6% on average, which was four times higher than in our research. Unfortunately, this indicates that the number of animals with an excellent appearance and very good condition, as well as a dense, elastic and silky coat has decreased, despite an intensive breeding effort aimed at improving the body shape. The reason for this may be not so much a decrease in the quality of the coat of these particular mink, but rather a more restrictive assessment criteria applied by the licensing referees. This, in turn, is dictated by the high standards set by the auction houses. The coat characteristics and body size have a strong impact on the final price of the pelt [Zieliński et al. 2016Zieliński, D., Ślaska, B., Zoń, A., Rozempolska-Rucińska, I. (2016). Comparative analysis of variation of conformation traits in different-colour minks. Pol. J. Nat. Sci., 31(2), 191–197. Google Scholar], so these traits are of great economic importance. As Wierzbicki [2005]Wierzbicki, H. (2005). Breeding value evaluation in Polish fur animals: Factors affecting pelt prices in the international trading system. Czech. Anim. Sci., 50(6), 266–272. https://doi.org/10.17221/4167-CJAS stated, breeders of fur animals should focus on the genetic improvement of the body size and the quality of their coat. Both features have a significant share in the overall volatility of the price and, according to Wierzbicki [2005]Wierzbicki, H. (2005). Breeding value evaluation in Polish fur animals: Factors affecting pelt prices in the international trading system. Czech. Anim. Sci., 50(6), 266–272. https://doi.org/10.17221/4167-CJAS, these are 60% for pelt size and 28% for coat quality. In assessing the coat, the referees take into account hair density, length, elasticity and silkiness [KCHZ 2009KCHZ (2009). Krajowe Centrum Hodowli Zwierząt: Wzorzec oceny pokroju norek, [National Center for Animal Breeding: Mink type evaluation standard]. Warsaw, 18 [in Polish]. Google Scholar].
Analyzing the distribution of mink in individual assessment classes over the period of time, a downward trend can be seen not only within class A, but in all assessment classes (Fig. 2). This is due to the decreasing number of mink breeding herds. According to the National Center for Animal Breeding [KCHZ 2018KCHZ (2018). Krajowe Centrum Hodowli Zwierząt: Hodowla zwierząt futerkowych w 2017 roku [National Center for Animal Breeding: Fur-bearing animals farming in 2017]. Warsaw [in Polish]. Google Scholar], in 2017 the number of females of breeding herds decreased by 6118 heads compared to 2016. The decreasing number of fur animals on farms does not apply to mink only, but also other species such as red and polar foxes, nutria or polecats [KCHZ 2018KCHZ (2018). Krajowe Centrum Hodowli Zwierząt: Hodowla zwierząt futerkowych w 2017 roku [National Center for Animal Breeding: Fur-bearing animals farming in 2017]. Warsaw [in Polish]. Google Scholar]. This is probably related to the growing number of attacks of radical animal-rights groups on farms specializing in fur-bearing animals [Jakubowski 2017Jakubowski, T. (2017). Komu przeszkadza hodowla zwierząt futerkowych [Who is disturbed by fur farming]. Hod. Zw. Fut., 74, PZHiPZF, June [in Polish]. Google Scholar].
Received: 20 Nov 2019
Accepted: 6 Dec 2019
Published online: 27 Dec 2019
Accesses: 1136
Kołodziejczyk, D., Socha, S., (2019). Analysis of body type evaluation of different color variants of farmed mink (Mustela vison Sch.) against current evaluation standard. Acta Sci. Pol. Zootechnica, 18(4), 23–28. DOI: 10.21005/asp.2019.18.4.03.
