To an investigation on the use of fibre in low and high concentrated mink feed in the winter period, we used tree groups of 175 black mink females each. The control group (Kon) was feed a low concentrated feed, to that feed we added 15 % fibre (Fib1), to compare we added 15 % fibres to a high concentrated feed (Fib2).
If females are feed the same amount of energy, an addition of fibres and water to the feed, will increase time with feed on the cage. This is due to both an effect of bigger feed volume and that fibres increase the feeling of satiety by increasing the filling of the digestive system. Stereotypic behaviour is reduced significantly by using low energy feed and thereby a bigger feed volume. However females who reduce there activity have a bigger body score before flushing, and had a higher number of dead kits at birth.
Clausen, T. N., Hansen, S.W & Sandbøl, P. 2010. Low energy feed with barley hulls reduces stereotypies in the winter period. Annual Report 2009, 7-15, Danish Fur Breeders Research Center, Holstebro, Denmark.
There is evidence from several species (e.g. poultry) that selection can contribute to reducing aggression in groups, and selection thus could be one way of reducing aggression in groups of mink in group housing. On this background, a selection experiment was started, aiming at reducing the number of bite marks on the skin side. This study describes variation in bite marks in the first generation. The study includes evaluation of bite marks on a total of 640 mink in group housing and 289 of their full sibs in standard cages (two animals).In group housing significantly more bite marks are observed than on the corresponding full sibs in standard cages. In addition, there seems to be a weak relationship between number of bite marks in group housing and standard cages. In group housing the females are generally more bitten than males, though the most bitten male has on average more bite marks than the least bitten female. A higher correlation between number of bite marks are observed between animals of the same sex (the two males and the two females) than between sexes in group housing. This indicates that bite marks to a large extent is due to fights within sexes. A large variation between full sibs/cages was found in the number of bite marks. This indicates that genetic differences are an important factor contributing to the number of bite marks. Selection for reduced number of bite marks continues in the coming years.
Berg, P. & Møller, S. H. 2010. Possibilities for selecting for reduced aggression in group-housing. Annual Report 2009. 17-22. Danish Fur Breeders Research Center, Holstebro, Denmark.
The inheritance of black palate colour has been investigated in more than 1000 F2 animals derived from a cross between Wild-mink and "short nap" Black mink. A statistically significant relationship was found between the palate colour in parent and offspring. In addition was found a statistically significant relationship between the palate colour and a gene marker Mvi1950; but the inheritance of palate colour could not be explained by segregation of the alleles in one locus alone. Absolutely no relationship was found between the colour of the palate and coat colour scored from one to seven.
Christensen, K., Anistoroaei, R., Fredholm, M. & Nielsen, V. H. 2010. Inheritance of black palate in mink. Annual Report 2009, 23-25. Danish Fur Breeders Research Center, Holstebro, Denmark.
With special emphasis on the level of relatedness (R) within mink color types (Neovison vison) originating from different mink farms in Denmark we present here the results from a microsatellite analysis study. Large differences were observed in level of R (R range: 0.017-0.520) and in genetic distance (FST range: 0-0.29) between strains and farms. Moreover, we correlated the level of R and breeding result for individual mink populations and found a very strong and highly significant negative correlation between these two parameters (R2=0.60, p<0.001). To our knowledge this is the first time that such a correlation has been demonstrated in mink from commercial mink farms. As a result we suggest using microsatellite or an alternative type of markers e.g. VeraCode, SNPlex and Fluidigm EP1 systems, which can be utilized to evaluate level of R in mink strains with reproductive problems and apply information from genetic markers when e.g. buying in new breeding animals in order to optimize fitness. Alternatively this technique could also be employed in order to obtain heterosis within color types applying the genetic variation found within a color type. We hope that this new molecular genetic information can be applied in practical mink farming in the future.
Larsen, P. F., Bækgaard, H., Sønderup, M., Møller, H. H., Hansen, B. K., Nielsen, V. H., Demontis, D., Loeschcke, V. & Perfoldi, C. 2010. Level of inbreeding and genetic distance in Danish farm mink (Neovison vison). Annual report 2009, 27-31, Danish Fur Breeders Research Center, Holstebro, Denmark
To continue the investigations on the need of protein, fat, carbohydrates and amino acids in the gestation period (April 4 to April 26) we used 6 groups each consisting of 134 brown mink females. The females were fed with feed from the local Feedkitchen until April 6, thereafter the protein content was varied in the groups from 35 to 45 percent of metabolisable energy from protein (MEp) fat was varied from 40 to 55 MEf and carbohydrates was varied from 10 - 20 MEc. After April 26 these females had 30 MEp until day 28 in the nursing period, thereafter feed from the local feed kitchen was used. Only females giving birth between April 26 and May 5 was included in investigation.
The results showed no significant difference between any of the groups, so the current recommendations for protein and amino acids in the gestation period will not be changed.
Clausen, T. N. & Sandbøl, P. 2010. Protein to mink in the gestation period. Continued investigations, Annual Report 2009, 33-37, Danish Fur Breeders Research Center, Holstebro, Denmark.
To an investigation on optimal feeding of mink kits in the early growing period, we used 7 groups consisting of 135 wildtype mink females and their kits. Until the kits were 28 days we used feed kitchen feed, after that feed with different amounts of protein were used until 12 weeks of age.
The results confirmed what we have found earlier. Kits in the period 4 to 8 weeks, need 45 percent of the metabolisable energy from protein (MEp) combined with a low amount of carbohydrates (10 and 15 MEc). In the period 8 to 12 weeks, the body weight increase is equally good in kits fed 35 MEp and 45 MEp. Further the body weight increase is reduced with increasing carbohydrates in that period. Kits feed 30 MEp from 4 to 12 weeks are smallest at pelting. The amino acid recommendations for that period, seems to be sufficient.
Clausen, T. N. & Sandbøl, P. 2010. Mink kits, optimal growth and good skin size. Annual Report 2009, 39-44, Danish Fur Breeders Research Center, Holstebro, Denmark.
To the investigation of increasing amounts of glycerol 0 - 2 - 4 - 6 - 8 percent to mink kits in the growing period, we used 5 groups of 132 wildtype mink kits each. The results showed that we can use up to 8 % glycerol instead of 8 % cornstarch, with reservations to changes in feed consistency. Glycerol should be analysed for Na and methanol before use. The skin quality was best at 8 % glycerol and no cornstarch, also it seems that glycerol reduces the liver fat content.
Clausen, T. N. & Sandbøl, P. 2010. Glycerol in mink feed in the growing- furring period. Annual Report 2009, 45-50, Danish Fur Breeders Research Center, Holstebro, Denmark.
To investigate the effect of L-met or DL-met to mink in the growing-furring period, we used 7 groups of 132 wildtype male- and female mink kits each. To a control feed with low methionine we added L-met or DL-met up to a calculated content of 0.10, 0.13 and 0.16 g digestible met / 100 kcal. The heaviest male kits and the longest skins at pelting were seen in the group with the highest addition of DL-met. From an analysed content of 0.14 g met / 100 kcal and more the skin size and pelt quality was good, and existing norm is adequate. Further it seems that the animals are able to use some of the D form of methionine, as an addition of DL-met in twice the amount of L-met gave better results.
Clausen, T. N. & Sandbøl, P. 2010. Investigation on the effect of L- and DL- methionine to mink in the growing-furring period. Annual Report 2009, 51-56, Danish Fur Breeders Research Center, Holstebro, Denmark.
To find the optimal level of phe+tyr for body growth and pelt colour and to find the importance of Fe, Cu and Zn for pelt colour, we used 5 groups of 142 black male and female mink kits each, and 2 groups of 122 wildtype male and female kits each. To a control feed with a low content of phe+tyr (0.41 g digestible phe + tyr / 100 kcal) we added phe + tyr up to a total content of 0.47 vs. 0.55 g digestible phe + tyr / 100 kcal. Further we had two groups with and addition of chelated minerals, cupper (Cu), zink (Zn) and iron (Fe) in two levels to the control feed.
The results showed a tendency towards the lowest weight at the lowest phe + tyr level and a tendency towards the darkest skins at the highest level, both in black and wildtype mink kits. Increased addition of minerals in the amounts used here gave a better body growth, there were no significant difference in skin length and pelt quality, but a tendency towards lower skin quality, and darker colour at the highest addition. The liver fat content was highest at the highest addition of chelated minerals. There was a tendency towards an increased liver mineral content when the feed mineral content increased, but no significant increase.
Clausen, T. N. & Sandbøl, P. 2010. Investigation on the importance of the aminoacids phenylalanine (phe) and tyrosine (tyr), and the minerals iron (Fe), cupper (Cu) and zink (Zn) on pelt colour in black and brown mink. Annual Report 2009, 57-65, Danish Fur Breeders Research Center, Holstebro, Denmark.
A dark and light sample of Glycerol was compared in a digestibility trial. The light Glycerol contained slightly more crude protein, fat, ash and salt (percentage of dry matter) and thus slightly less calculated crude carbohydrates than the dark sample. A discrepancy hydrates in the diets. The apparent digestibility of carborhydrates in both samples of Gly- cerol was 93 %.
Schulin-Zeuthen, M & Sandbøl, P. 2010. Apparent digestibility of Glycerol in mink. Annual Report 2009, 67-70. Danish Fur Breeders Research Center, Holstebro, Denmark.
Thirty-two pairs of male mink kits were allocated to four different diets four weeks post partum. The kits were weaned when they were 5-6 weeks old. The apparent and true digestibilities of the diets were calculated from quantitative collection of faeces when the kits were 6, 9 and 12 weeks old. The diets contained either 30% or 45% of the metabolisable energy (ME) from protein and 15% or 25% of ME from carbohydrate. The diet codes were HPHC (high protein, high carbohydrate; 45:25), LPHC (low protein, high carbohydrate; 30:25), HPLC (45:15) and LPLC (30:15). The apparent digestibility of nitrogen and amino acids was significantly lower on both LP than on the HP diets. The true digestibility on the LPHC diet was the same as on the HP diets except for methionine, leucine and valine, which were lower. The true digestibility of the LPLC was significantly lower than that of the other diets except for histidine. Both apparent and true digestibility of nitrogen, fat, energy, and amino acids decreased with age.
Hellwing, A. L. F., Hansen, N. E. og Tauson, A.-H. 2010. Apparent and true digestibility of nitrogen, fat, energy, and amino acids. Annual Report 2009. 71-78. Danish Fur Breeders Research Center, Holstebro, Denmark.
Two groups of 8 weeks old mink kits were offered a synthetic diet containing 17.5 % MEp corresponding to 50 % of the protein requirement of the kits. In one of these groups, soy lecithin replaced 5 % of the dietary fat fraction. A control group was kept under normal farm conditions offered a regular feed kitchen diet. The two restricted groups maintained weight (lecithin group) or loosed weight (synthetic control) during the 11 days of restriction. 2 weeks after conclusion of the restriction period, live weight of all mink kits were the same and therefore the two restricted groups was able to compensate growth.
Schulin-Zeuthen, M. & Sandbøl, P. 2010. Compensatory growth in mink kits (Mustela vison) following reduced protein intake after weaning. Annual Report 2009, 79-83, Danish Fur Breeders Research Center, Holstebro Denmark.
The aim of the project was in a challenge model to measure the susceptibility of post weaning diarrhoea in mink kits. The kits were from litters fed a kit diet (high digestibility) and an ordinary farm diet, respectively. The project was performed during the first 7 days after weaning. The mink kits were orally challenged with coli bacteria (Escherichia coli O68) on day 1 and 2 after weaning. The frequency of mink kits with diarrhoea was not affected by the composition of the diets. The body weight and the body growth were not affected by the diet composition and the challenge with bacteria. The number of erythrocytes, the content of haemoglobin and the haematocrit value in the blood were higher in kits fed kit diet than in kits fed farm diet. The number of leucocytes and neutrophils in the blood and the plasma content of the acute phase proteins haptoglobin and fibrinogen were lower in kits fed kit diet than in kits fed farm diet. The thickness of the muscles in the last part of the small intestine, the area of the mucins on villi in the small intestine and the area of the mucins in the crypts in the last part of the intestine were higher in kits fed kit diet than in kits fed farm diet.
Damgaard, B.M., Hedemann, M.S. 2010. Susceptibility of post weaning diarrhoea in mink kits - Effects of diet composition. Annual report 2009, 85-90. Danish Fur Breeders Research Center, Holstebro, Denmark.
Previous epidemiological studies have shown an association between presence of mink astrovirus and pre-weaning diarrhoea in affected as compared to non-affected farms. In order to enable investigations on the spread of astrovirus infections in mink and to monitor production of antibodies following immunization or challenge experiments, a serological tool was needed. An indirect ELISA was developed using recombinant capsid protein of mink astrovirus as antigen. Plates were coated with capsid protein and incubated with the sera diluted 1:100. As secondary antibody, a horseradish peroxidase-labeled mouse anti-mustelid IgG was used. Development of the reaction was done with tetramethylbenzidine as substrate. The readings were done by measuring the optical density (OD) at 450 nm. This ELISA has been used in different studies, such as for determination of immunogenicity of the capsid protein, and detection of antibodies in sera from farms with and without clinical history of greasy kits. Production of specific antibodies could be detected with the ELISA in mink immunized with the complete and with two short variants of the capsid protein. Also, by means of this ELISA it could be demonstrated that antibodies to mink astrovirus are commonly present in farms reporting the wet kits syndrome. However, also on farms without wet kits antibodies to mink astrovirus could be detected, albeit with lower titres. It is concluded that the developed ELISA is a suitable tool for detection of antibodies against mink astrovirus. Also, the ELISA supports the evidence that infection with astrovirus is common in mink farms, and indicates that different presentations, from subclinical to overt clinical manifestations appear in different farms.
Ullman, K., Baule, C., Hammer, A.S., Hammer- Jensen, T. b>& Czifra, G., 2010. Evaluation of an ELISA for detection of antibodies to mink astrovirus. Annual report 2009, 91-96. Danish Fur Breeders Research Center, Holstebro, Denmark
Investigation on the courses of death among kits from 828 litters in the period from birth to August the first. The results showed that we loose many kits in connection with birth. Around ½ a kit per litter is stillborn. Since especially the fat females loose kits, feeding and control of body score in the winter and pregnancy period should be optimised. The rest of May only a few kits die, but when they start to eat, around 4 weeks of age, some kits gets diarrhoea and become unthrifty. To avoid that management at the farm is very important, good bedding materials, hygiene, optimal food quality, water supply and immediate treatment if there is diarrhoea. If those conditions are not optimal we further risk cannibalism among the kits. From the middle of June bladder infections is the main problem, the feed in that period should have acidifying properties and the water supply should be optimised.
Clausen, T. N., 2010. Kit death from birth to August the first.Annual Report 2009, 97-103. Danish Fur Breeders Research Center, Holstebro, Denmark.
To an investigation on the importance of the feed for urine pH we used 2 x 36 wildtype male and female mink kits. Urine samples for pH measurement were taken after a fasting period, and at different times after feeding. The results showed, that fasting urine pH is in the area 6.05 to 6.50. Consumption of feed influence the urine pH dependent on feed composition and amount. Urine pH is investigated 4 hours after feeding. If there is feed on the wire all day long, urine pH will not reach fasting level unless the feed composition act in direction of low urine pH or unless substances that lower urine pH is added. It is recommended that urine pH 4 hours after feeding is in the area 6.0 to 6.4.
Clausen, T. N., 2010. Importance of feed consumption for urine pH, Annual Report 2009, 105-109. Danish Fur Breeders Research Center, Holstebro, Denmark.
Mink were inoculated with two different Canine distemper viruses (CDV) - a Danish (DK91) virus strain and an American (Snyder Hill) virus strain. DK91 represents a circulating European wildtype genotype, while the Snyder Hill strain represents the American genotypes isolated before 1960. Clinical and paraclinical investigations of the mink were performed after inoculation. The wildtype CDVs investigated provoked marked virulence differences. The Danish wildtype showed a mildly virulent course in our natural host model, in contrast to the acute, severe disease outcome in the Snyder Hill challenged mink.
Furthermore, we investigated if DNA vaccine consisting of the genes from vaccine strains induced cross-protection against circulating European CDV. Our results indicate that DNA vaccine-induced immunity protected the mink against disease development. Further work on DNA vaccines against circulating wildtype CDVs could lead to new and safer strategies to control and to prevent distemper.
Nielsen, L., Søgaard, M., Jensen, T. H., Karlskov-Mortensen, P., Andersen, M. K., Jensen, T. D., Aasted, B., and Blixenkrone-Møller. 2010. Investigation of wildtype canine distemper virus and DNA vaccination in mink. Annual Report 2009, 111-118, Danish Fur Breeders Research Center, Holstebro, Denmark
Canine distemper virus and the closely related phocine distemper virus have an overlapping host range and both have induced disease among terrestrial and marine carnivores. We have characterized the distemper virus among the wildlife in Denmark from 2000 to 2003.
We have isolated viral RNA from the new wildtype CDVs, performed nucleic acid sequencing and determined the relatedness of the wildtypes. We found that the isolated virus from the investigated terrestrial carnivores (mink, badger, European polecat, beech marten and pine marten) were canine distemper virus, which was phylogeny separated from virus isolated from diseased seals. Our results revealed no direct epidemiological link between the two distemper viruses isolated from distemper cases among land-living carnivores and the marine carnivore.
Nielsen, L., Jensen, T. H., Hammer, A. S., Banyard, A. C., Barrett, T., Blixenkrone-Møller. 2010. Phylogeny investigation of new wildtypes of canine distemper virus. Annual Report 2009, 119-125. Danish Fur Breeders Research Center, Holstebro, Denmark.
DNA vaccination is a promising vaccination strategy with potentials for inducing immunity in young individuals because of the possibility to overcome maternally derived antibodies. However, the capacity of a DNA vaccine to induce immunity against CDV in young mink without maternal antibodies has so far not been described. In this study young mink kits (n=8) were vaccinated with DNA plasmids encoding the viral haemagglutinin protein (H) of Canine distemper virus (CDV). Virus neutralising antibodies (VN) were induced after 2 immunisations and after the third immunisation all kits had high VN antibody titres which remained for more than 4 months until challenge inoculation. The DNA vaccinated mink were protected against viremia, lymphopenia and clinical disease after challenge inoculation with a recent wild type strain of CDV. The T-cell immune response of the vaccinated mink was boosted by challenge inoculation indicating that the vaccine primed a memory response.
Jensen, T. H., Nielsen, L., Aasted, B. & Blixenkrone-Møller, M. 2010. DNA vaccination protects mink kits against distemper. Annual Report 2009. 127-133. Danish Fur Breeders Research Center, Holstebro, Denmark.
Necrotizing and eosinophilic myopathia was first observed in farmed mink kits in Denmark in August 2008. During the following months the disease was identified on altogether 13 farms in the south-western part of Denmark. In 2009 outbreaks appeared on 6 farms. A total of 202 mink kits with myopathia were included in this investigation. Histopathology showed necrotizing myopathia with fragmentation, hyalinization and atrophy of muscle fibres. Inflammatory cell infiltrations varied from primarily eosinophilic to predominantly mononuclear infiltrations. Differential count of blood samples from two mink showed increased numbers of eosinophilic cells. The disease affects mink of all colour types, which makes it unlikely to be inherited, though there may be genetic factors affecting the course of disease. Testing was conducted to determine the cause of the disease, including tests for specific viral diseases (canine distemper, Aleutian mink disease), tests for protozoa (Toxoplasma gondii, Neospora caninum), bacteria (general aerobic and anaerobic culture) and toxines (Narasin, Monensin, Salinomycin, Lasalocid, melamin) and blood analyses. The preliminary results are inconclusive and further investigations are necessary to identify the cause of the disease.
Hammer A. S., Jensen, T.H., Salomonsen, C. M., Harslund, J.L.F., Christensen, L. R., Chriel, M., Clausen, T. 2010.
Outbreak of masticatory myositis in farmed mink. Faglig Årsberetning 2009, 135-140. Pelsdyrerhvervets Forsøgs- og ForskningsCenter, Holstebro, Danmark.
Nest box design and type of nesting material affect kit survival and wellbeing. In this pilot study, 12 farms were involved. As background material in the nest was, Easy Stroe (trade name for heat-treated, forage harvester wheat straw), compared with shavings and short cutted barley straw were studied. As nesting material the long cutted barley straw was compared with the short cutted barley straw and the wood shavings. It was also investigated whether reduced nest box size had an impact. The Number of living and dead pups from 2 to 5 days of age and the number of living pups at 3 to 4 weeks of age were recorded. Easy Stroe compared to shavings as bottom material, showed a statistically significant difference in favour of Easy Stroe on a total number of pups at birth, the number of living pups at birth and the number of puppies at the second count.. There was no significant difference for kit loss between the first and second counts.
The study points to the importance of choice of nesting material and design. There was found a statistically significant difference of 0.20 kits/female for Easy Stroe over shavings, measured as living pups at 3 to 4 weeks of age. Moreover, future areas of focus will be discussed.
Sønderup, M., Bækgaard, H., Larsen, P. F. & Clausen, T. N. 2010. Importance of nest box size and material, for litter size, a pilot study. Annual Report 2009, 141-146. Danish Fur Breeders Research Center, Holstebro, Denmark.
In an attempt to reduce the loss of feed under the cages in early July, we placed metal plates in the bottom of 155 cages with wildtype mink kits. Feed consumption and body growth was registered in this group and in a control group (155 cages) without plates.
Feed consumption in early July can be reduced from about 9 % to about 2 % by using metal plates, and body growth tended to increase. The loss of food was reducer gradually to around 1.2 % in early August in cages without plates. However there are great variations from year to year depending of feed consistency, temperature, weather etc. By removing the plates in early September problems with lumps in the pelt was avoided.
Clausen, T. N., Blæsbjerg, M. & Sandbøl, P. 2010. Reducing feed loss in the growing period by metal plates in the cage. Annual Report 2009, 147-150. Danish Fur Breeders Research Center, Holstebro, Denmark.
The purpose of this investigation was to follow feed consumption and body weight growth in early and late borne mink kits. To the investigation we used one male mink kit from each of the 58 first borne wildtype litters (borne April 22 to April 26) and from each of the 52 latest borne wildtype litters (borne May 6 to May 14).
Body weight in early and late borne kits was equal at the same age, and the total food consumption from July to pelting was equal. In the beginning of the growing period, late borne kits eat less than early borne, but from September late borne kits eat more. Pelt quality, body length, skin length and body condition at pelting were equal.
Clausen, T. N. & Sandbøl, P. 2010. Importance of birth date on kit growth in the growing period. Annual Report 2009, 151-154. Danish Fur Breeders Research Center, Holstebro, Denmark.