Pelt Size Research Articles

Genetic and Phenotypic Parameters for Pelt Quality and Body Length and Weight Traits in American Mink.

Understanding the genetics of fur characteristics and skin size is important for developing effective breeding programs in the mink industry. Therefore, the objectives of this study were to estimate the genetic and phenotypic parameters for pelt quality traits including live grading overall quality (LQU), live grading nap size (LNAP), dried pelt size (DPS), dried pelt nap size (DNAP) and overall quality of dried pelt (DQU), and body length and weight traits, including November body weight (Nov_BW), November body length (Nov_BL), harvest weight (HW) and harvest length (HL) in American mink. Dried pelt quality traits on 1195 mink and pelt quality traits on live animals on 1680 were collected from mink raised at two farms, in Nova Scotia and Ontario. A series of univariate analyses were implemented in ASReml 4.1 software to identify the significance (p < 0.05) of random effects (maternal genetic effects, and common litter effects) and fixed effects (farm, sex, color type, year, and age) for each trait. Subsequently, bivariate models were used to estimate the genetic and phenotypic parameters using ASReml 4.1. Heritability (±SE) estimates were 0.41 ± 0.06 for DPS, 0.23 ± 0.10 for DNAP, 0.12 ± 0.04 for DQU, 0.28 ± 0.06 for LQU, 0.44 ± 0.07 for LNAP, 0.29 ± 0.10 for Nov_BW, 0.28 ± 0.09 for Nov_BL, 0.41 ± 0.07 for HW and 0.31 ± 0.06 for HL. DPS had high positive genetic correlations (±SE) with Nov_BW (0.89 ± 0.10), Nov_BL (0.81 ± 0.07), HW (0.85 ± 0.05) and HL (0.85 ± 0.06). These results suggested that body weight and length measured on live animals in November of the first year were reliable indicators of dried pelt size. DQU had favorable genetic correlations with Nov_BL (0.55 ± 0.24) and HL (0.46 ± 0.20), and nonsignificant genetic correlations with DNAP (0.13 ± 0.25), Nov_BW (0.25 ± 0.25) and HW (0.06 ± 0.20), which made body length traits an appealing trait for selection for increased pelt size. High positive genetic correlation (±SE) was observed between LNAP and DNAP (0.82 ± 0.22), which revealed that nap size measurement on live animals is a reliable indicator trait for dried pelt nap size. However, nonsignificant (p > 0.05) low genetic correlation (±SE) was obtained between LQU and DQU (0.08 ± 0.45), showing that indirect selection based on live grading might not lead to the satisfactory improvement of dried pelt overall quality. The estimated genetic parameters for live grading, dried pelt quality, and body weight and body length traits may be incorporated into breeding programs to improve fur characteristics in Canadian mink populations.

Genome-Wide Detection of Selection Signatures for Pelt Quality Traits and Coat Color Using Whole-Genome Sequencing Data in American Mink.

Domestication and selection are the major driving forces responsible for creating genetic variability in farmed species. American mink has been under selection for more than 100 years for improved body size and pelt quality. This study aimed to identify the genomic regions subjected to selection for pelt quality traits, and coat color using the whole genome sequences of 100 mink raised in the Canadian Centre for Fur Animal Research (CCFAR) at Dalhousie Agriculture Campus (Truro, NS, Canada), and Millbank fur farm (Rockwood, ON, Canada). Measurements of three dried pelt characteristics (including pelt size (n = 35), overall quality of fur (n = 27), and nap size (n = 29)), and three coat color of Black, Stardust, and Pastel (Stardust_ Black (n = 38), and Pastel_Black (n = 41)) were used to assign animals to pairwise groups. Signatures of selection were detected using integrated measurement of fixation index (Fst), extended haplotype homozygosity (XP-EHH), and nucleotide diversity (θπ) tests. In total, overlapping top 1% of Fst and XP-EHH harbored 376 genes for pelt quality traits (110 for nap size, 163 for overall quality of fur, and 98 pelt size), and 194 genes for coat color (123 for Pastel_Black and 71 for Stardust_Black) were detected in different groups. Integrating results of Fst, and XP-EHH with the θπ test supported 19 strongly selected regions on chromosomes 3, 4, 5, 6, 7, 8, 9, and 10 that contained 33 candidate genes related to fur quality, hair follicle function, and pelt size traits. Gene ontology revealed numerous genes related to the hair cycle process and molting cycle process, epidermis development, Wnt signaling pathway and muscle development. This study provided the first map of putative selection signals related to pelt quality and coat color in American mink, which could be used as a reference for future studies attempting to identify genes associated with economically important traits in mink.

Effects of feed energy and protein level on growth and pelt parameters in blue foxes (Vulpes lagopus) in the late growing-furring period

The aim of the present study was to determine whether a decrease in feed energy content would prevent extreme body weight (BW) gain and fatness in blue foxes in the late growing-furring period, without compromising pelt quality or pelt size. BW gain, body mass index (BMI), body condition score (BCS), and pelt characteristics were studied in 60 blue foxes divided into four equal-sized groups from mid-October until pelting (50 days). Experimental diets in were “high energy – high protein”, “high energy – low protein”, “low energy – high protein”, and “low energy – low protein”. High-energy diets contained 19.3 MJ metabolisable energy (ME) in kg dry matter (DM) and high-protein diets contained digestible crude protein (DCP) 20% of ME. Low-energy diets contained 16.3 MJ ME in kg DM and low-protein diets DCP 17% of ME. Feeding was gradually increased towards ad libitum. Reduced ME intake had no effect on pelt size or pelt quality. High-energy feeds resulted in heavier animals with higher BMI. However, the final BW exceeded 20 kg and BCS was “fat” or “extremely fat” in all groups.

PSVII-39 Late-Breaking Abstract: Enhancing production and Aleutian disease resilience in mink through advanced genomics

Abstract The fur industry is one of the oldest and the most historically significant industries in Canada. The industry has used American mink (Neovison vison) as the major source of fur for decades because of their high-quality fur and wide range of colours. This project will seek to (1) create the first accurate whole-genome sequence assembly of mink using next-generation sequencing technology to help understanding the biology and evolution of the order Carnivora, (2) design a robust and informative SNP assay for genomics discovery in mink, (3) discover genome structure and signature of selection as well as identify new genetic variants explaining variation in economically important traits, and (4) identify the genetic relationships among these traits including feed efficiency, Aleutian disease resilience, fur quality, reproductive performance, growth rate and pelt size. One hundred mink DNA samples from the Canadian Centre for Fur Animal Research at Dalhousie Agriculture Campus (Truro, Nova Scotia), and one breeding population (Millbank Fur Farm Limited, Rockwood, Ontario) were sequenced using next-generation whole-genome sequencing with more than 30x coverage to create the first SNP assay for American mink. A DNA panel composed of these sequenced mink from five color-types were assembled to identify the most homozygous individual as the reference animal for whole-genome sequence assembly development. The phenotypic data and DNA samples from 3,323 animals were collected and will be genotyped using the customized assay. The ultimate objective is to develop new tools for implementation of marker assisted selection or genomic selection in mink breeding programs for development of superior, highly efficient, and healthy animals. This approach will help improve the overall performance of the North American mink industry, which is now in difficulty due to several economic factors such as the high price of feed, declining price of fur and prevalence of diseases.

12 Genetic and phenotypic parameters for Aleutian disease tests and their correlations with growth and pelt quality traits in American mink

Abstract Aleutian disease brings tremendous financial losses to the mink industry. The ineffective immunoprophylaxis, medication, and culling strategies have urged the mink industry to select mink with low quantitative enzyme-linked immunosorbent assay (qELISA) score or negative counterimmunoelectrophoresis (CIEP) test result. However, little is known about the heritabilities of qELISA and CEIP as well as their relationships with growth and pelt quality traits. The traits, including qELISA, CIEP, body length at harvest (HLEN), the size of dried pelt (SIZE), the overall quality of dried pelt (QUA), and the nap length of dried pelt (NAP), were measured on 1,683 American mink from the Canadian Center for Fur Animal Research (Nova Scotia, Canada) and Millbank Fur Farm (Ontario, Canada). Significance (P &amp;lt; 0.05) of fixed effects (sex, farm, age, and color) and random effects (common litter, permanent environment, and dam) were determined by univariate analyses, while genetic and phenotypic parameters for all traits were estimated under bivariate analyses using ASREML 4.1. Estimated heritabilities (±SE) were 0.41±0.07 for qELISA, 0.06±0.06 for CIEP, 0.39±0.06 for HLEN, 0.46±0.07 for SIZE, 0.25±0.06 for QUA, and 0.46±0.08 for NAP. The qELISA showed non-significant (P &amp;gt; 0.05) genetic correlations with HLEN (0.05±0.13) and dried pelt traits (0.02±0.18 with SIZE, -0.21±0.20 with QUA, and -0.13±0.16 with NAP). The CIEP only showed a significant (P &amp;lt; 0.05) negative genetic correlation with SIZE (-0.85±0.33). The moderate-to-high heritabilities of qELISA, HLEN, SIZE, QUA, and NAP indicated that these traits can be genetically improved through a genetic/genomic selection. The low and non-significant heritability of CIEP indicated the ineffectiveness of direct selection for this trait. The estimated genetic parameters for qELISA suggested that selection for lower qELISA scores may not interfere with the selection of pelt size and quality in the genetic improvement programs of American mink.

Performance in blue fox (Vulpes lagopus) fed low-protein diets supplemented with DL-methionine and L-histidine

The effects of low-protein diets supplemented with DL-methionine (MET) and L-histidine (HIS) on growth, pelt size and pelt quality were studied in two performance trials conducted at the Kannus Research Farm Luova Ltd, Finland. Both trials were conducted with 200 blue foxes, caged male-female pairs, initial age on average 20 weeks (trial 1) and 25 weeks (trial 2). In trial 1, diets contained digestible crude protein (DCP) 24%, 20% and 16% of metabolisable energy (ME). In trial 2, diets contained DCP 20%, 16.5% and 13% of ME. In both trials, the middle protein level was fed with or without MET and the lowest protein level was fed with MET and with or without HIS. In trial 1, blue foxes showed the greatest average daily gain (ADG) in the highest protein diet. Pelt size and pelt quality were not affected. In trial 2, blue foxes showed the greatest ADG in the low-protein groups. Pelt size and pelt quality were not affected.

Risk aversion affects economic values of blue fox breeding scheme.

The profit and production of an average Finnish blue fox farm was simulated using a deterministic bio-economic farm model. Risk was included using Arrow-Prat absolute risk aversion coefficient and profit variance. Risk-rated economic values were calculated for pregnancy rate, litter loss, litter size, pelt size, pelt quality, pelt colour clarity, feed efficiency and eye infection. With high absolute risk aversion, economic values were lower than with low absolute risk aversion. Economic values were highest for litter loss (18.16 and 26.42 EUR), litter size (13.27 and 19.40 EUR), pregnancy (11.99 and 18.39 EUR) and eye infection (12.39 and 13.81 EUR). Sensitivity analysis showed that selection pressure for improved eye health depended strongly on proportion of culled animals among infected animals and much less on the proportion of infected animals. The economic value of feed efficiency was lower than expected (6.06 and 8.03 EUR). However, it was almost the same magnitude as pelt quality (7.30 and 7.30 EUR) and higher than the economic value of pelt size (3.37 and 5.26 EUR). Risk factors should be considered in blue fox breeding scheme because they change the relative importance of traits.

Genetic parameters of pelt character, feed efficiency and size traits in Finnish blue fox (Vulpes lagopus)

Pelt character traits (size, quality, colour clarity, darkness) are important economic traits in blue fox breeding. Better feed efficiency (FE) is another economically important and new breeding goal for fur animals. The purpose of this study was to determine the correlations between pelt character traits, FE and size traits and to estimate genetic parameters for pelt character traits. Pelt size (pSIcm ) had a high positive genetic correlation with animal grading size (gSI), final body weight (BWFin), body length and daily gain (DG), and a moderate correlation with body condition score (BCS). Animal body length and BCS (describing fatness) were considered as genetically different traits. Genetic correlations between pelt quality and size traits were estimated without precision and did not differ from zero, but colour clarity (pCL) had a low antagonistic genetic correlation with FE. Pelt size and DG had a favourable genetic correlation with FE but a fairly high unfavourable genetic correlation with dry matter feed intake. The current emphasis on selection for larger animal and pelt size improves FE indirectly, but selection for larger pelt size favours fast-growing and fat individuals and simultaneously increases feed intake. The detected genetic connections between FE, size, feed intake and pCL should be taken into account in the Finnish blue fox breeding programme.

Profitable blue fox production: Economic values for Finnish blue fox

A bio-economic model was created to simulate production of an average Finnish blue fox farm. The studied traits were pelt quality, pelt size, pelt color clarity, litter size, pregnancy (barren or non-barren), and felicity (includes both aborting and females losing all pups before pups are 3 weeks). Marginal economic values of traits were estimated by the numeric approximation of the partial derivate of the profit function with respect to those traits. Economic weights of traits were obtained by multiplying the marginal economic values by genetic standard deviations. Felicity, pregnancy, and litter size had the highest economic weights (26.80, 19.74, and 18.36 EUR/σa, respectively). Economic weights of pelt quality, length, and color clarity were 7.17, 5.24, and 0.33 EUR/σa, respectively. Changes in production environment (feed and price, improvement in fertility) had only minor effect on relative economic weights. Generally, an unfavorable change in environmental variables increases the relative weight of pelt quality.

Genetic parameters for Finnish blue fox population: litter size, age at first insemination and pelt size

Pelt size has increased rapidly in the Finnish blue fox population during the last decade. However, average number of pups per mated female has slightly decreased after the mid-1990’s. In this study we estimated genetic parameters of litter size in the first two parturitions, age of female at first insemination, and pelt size with a linear multitrait animal model. Heritability of litter size in first and second parturition was 0.06 and 0.10, respectively. Heritability estimate for age at first insemination was 0.15 and for pelt size 0.29. Genetic correlation between pelt size and first litter size was –0.30, between first and second litter size 0.76, and between second litter size and age at first insemination 0.70. Thus, genetic correlation between fertility and pelt size was unfavorable.;

Group housing in row cages: an alternative housing system for juvenile mink

We studied a group housing system as an alternative to the traditional pair housing of juvenile mink. The focus was on both the welfare and production of mink. The pairs were housed in standard mink cages, whereas the groups were in row cage systems consisting of three standard mink cages connected to each other. The welfare of the mink was evaluated by behavioural observations (stereotypies and social contacts), evaluation of the incidence of scars assumed to be caused by biting, and adrenal function (serum cortisol level after adrenocorticotropic hormone (ACTH) administration and adrenal mass). Feed consumption, pelt length, quality and price were used for comparing the two housing systems from the economic point of view. Although the incidence of scars showed that there might have been more aggressive behaviour among the group-housed than among the pair-housed mink, this was not observed unambiguously in behavioural observations, and, at least, aggression did not cause mortality or serious injuries to the animals as has been observed in some earlier studies. In addition, the housing system did not affect pelt size, and, although the quality of the pelts was slightly lower in the group than in pair-housed mink, there was only a tendency for lower pelt prices. The lower pelt prices in the group-housed mink might even be partially compensated for by the group-housed mink eating 10% to 20% less in the late autumn, due to thermoregulatory benefits, than their pair-housed conspecifics. The results on the frequency of stereotypic behaviour (but not adrenal function) suggest that the group-housed animals were possibly less stressed than the pair-housed animals. Group housing of juvenile farmed mink in a row cage system cannot be recommended before the effects on welfare and production are clarified in further studies.

Genetic parameters in Finnish blue fox population: Pelt character and live animal grading traits

Finnish blue fox farmers breed for increased litter size and pelt size, and improved fur quality. Some farmers select pelt size and fur quality indirectly using live animal evaluations (grading traits). In order to be able to define breeding goals properly, heritabilities and genetic correlations were estimated for size traits and fur quality traits. There were four pelt character traits (pelt size, pelt colour darkness, pelt colour clarity and pelt quality) measured on dried skins, and six grading traits (animal size, grading colour darkness, grading colour clarity, underfur density, guard hair coverage and grading quality). The data included 54,680 animals born during the years 1987–2002, originating from seven farms. The heritabilities were high for pelt colour darkness and grading colour darkness, moderate for pelt size and low for other traits. In general, heritability of a pelt character trait was higher than its corresponding grading trait. Genetic correlations within the pelt character traits were low (∼0.11) and within the grading traits mainly moderate or high (∼0.44). There was high genetic correlation between pelt darkness and grading darkness, pelt quality and grading density, pelt size and animal size; between pelt quality and grading quality and between pelt colour darkness and grading guard hair coverage. This suggests that selection of pelt character traits via grading traits in most cases is relatively effective.

ENZYMATICALLY PREHYDROLYZED SOYBEAN MEAL FOR MINK (Mustela vison) I. NUTRITIVE VALUE FOR GROWTH AND FURRING

Experiments were conducted to measure the nutritive value of dehulled soybean meal (SBM) prehydrolyzed for 5 h with pancreatin, pepsin or papain. In these studies, a conventional meat-based diet and an unhydrolyzed SBM diet were used as control diets. For the pancreatin experiment, the levels of SBM used in the wet diet (35% DM) were 5, 10 and 15%, whereas, for the pepsin and papain experiment, only a 10% SBM level was used. Results indicate that the introduction of SBM in a growing-furring mink diet for partially replacing animal proteins led to a reduction in body weight gain and to some reduction in pelt size, but the quality of the fur remained essentially the same. There was some improvement of body weight gain from feeding hydrolyzed SBM, especially at the 10 and 15% levels, but pelt length and fur quality were unaffected. Key words: Mink, growth and furring, soybean meal, enzymes

Effects of Feeding Frequency and Intensity on Growth, Body Composition, Organ Scaling and Fur Quality of Farmed Raccoon Dogs

Abstract Effects of dietary dilution, plane of energy intake and meal frequency on growth, body composition, organ sizes and fur quality parameters were studied on farmed raccoon dogs (Nyctereutes procyonoides Gray 1834) during the growing period (July-November). Meal frequencies were manipulated by two fasting arrangements: (1) animals without feed twice a week (Wednesday and Sunday), but other days fed ad libitum, (2) two-day ration offered every other day. Feed dilution was achieved by mixing low-energetic brewers' mash (25%; w/w) with basal feed. Both the diluted and the basal diets were offered as restricted or ad libitum portions. Live weight curves of the experimental groups were similar (p>0.05). Energetic efficiency of the animals was clearly better on mash than on basal diet. Daily feed spillage was highest in mash groups whereas feed remains in these groups were the lowest. No significant differences in the carcass content of ash, lean or fatty tissues between different feeding groups were found. With increasing age (and body weight) the amounts of carcass ash, protein, fat and energy increased. In adult animals, there were a positive correlation between carcass weight and carcass energy (r=0.87), fat (r=0.83) and protein (r=0.82). In general, no marked differences in fur quality parameters between different groups were found—the only exception being animals fasted twice a week whose mass and quality of fur was poorer (p<0.05) than that in other groups. The quality of fur was better in animals of longer and heavier pelts, i.e. in animals of big body size. The weights of visceral organs in various feeding groups did not differ significantly from each other. This supports earlier findings that no reliable conclusions can be drawn regarding the previous dietary history of the animals from their organ sizes. It is concluded that raccoon dogs naturally are accustomed to utilize effectively the energy of meals irrespective of their frequencies. Thus, restricted feeding in an attempt to avoid excessive fattening probably results in a simultaneous restriction in protein accumulation, and in a smaller pelt size.

Relationship of Pelt Size, Weight, and Age for Beaver

Relationship of Pelt Size, Weight, and Age for Beaver

NUTRITIVE VALUE OF RAPESEED FLOUR FOR MINK: EFFECTS ON LIVE PERFORMANCE, NUTRIENT UTILIZATION, THYROID FUNCTION AND PELT QUALITY

A trial for testing the replacement value of rapeseed flour (RF) (blend of Brassica napus and campestris) for raw meat was conducted with growing-furring mink. The RF contained 67% crude protein and approximately 1/10 of the quantity of glucosinolates normally found in commercial meal. Forty male pastel mink were fed diets containing 0, 6.5, 13.4 and 20% RF (dry-matter basis) from the end of July to pelting. On a dry-matter basis, the diets contained approximately 41% protein and the percentages of protein as RF protein were 0, 4.3, 9 and 12.4. Initially, the animals ate significantly (P &lt; 0.05) more feed and grew significantly (P &lt; 0.05) faster on the 0 and 6.5% RF diets, but later, weight gain and feed consumption were the same for all groups (P &gt; 0.05). After 70 days on trial, weight gain was less (P &lt; 0.05) on the 20% RF diet compared with the 0 and 6.5% diets. There was a significant (P &lt; 0.05) reduction in the apparent digestibilities of dry matter, gross energy and nitrogen, and in nitrogen retention for the mink receiving the diets containing 13.4 and 20% RF. Mink fed the 20% RF diet showed significant (P &lt; 0.05) thyroid hypertrophy, but at slaughter serum protein-bound iodine level was the same (P &gt; 0.05) for all groups. There was little difference among groups with respect to pelt size and pelt quality.