Abstract
Background
A prior report demonstrated that intervertebral disc disease (IVDD) risk varies in dachshunds by size-coat type, suggesting that coat and size genes affect IVDD risk. The furnishings (wire) coat gene, R-spondin-2, affects disc health in dogs, making such a role plausible.
Hypothesis/Objectives
Identify differences in spinal health metrics (SHMs): by coat type, within a coat type by size, and by size-coat type.
Animals
Dachshunds (n = 4295) with known SHMs.
Methods
Retrospective study reporting SHMs by coat and size type in dachshund populations in the United Kingdom (UK), Norway, and Denmark. For the UK population, a binary logistic regression was fitted with owner-reported disc disease status (yes vs no) as the outcome variable. For Denmark and Norway, populations were analyzed using proportional-odds ordinal logistic regression models, with calcification number (KN) groups (K0, K1/2, K3/4, and K5+) as the ordinal outcome.
Results
In all 3 populations, smooth coat was associated with worse SHMs compared with other coat types (eg, Norway vs long; odds ratio [OR], 2.11; 95% confidence interval [CI], 1.58-2.83; overall OR range, 1.81-2.59). Within a coat type, size was inconsistently associated with SHMs. In 12 of 15 comparisons, small smooth dachshunds had worse SHMs compared with other size-coat types (eg, Norway vs standard long; OR, 3.56; 95% CI, 2.19-5.79; range, 1.80-5.40).
Conclusions and clinical importance
Dachshund spinal health varies by coat and inconsistently by size type. Coat and size genes may be factors that determine IVDD risk in dachshunds.
Keywords: intervertebral disc disease, FGF4L2, FGF5, RSPO2, canine notochord, nucleus pulposus, body size reduction
Introduction
In dachshunds, intervertebral disc disease (IVDD) is a substantial health problem characterized by disc calcifications.1,2 The calcification number (KN) is the number of disc calcifications on whole spine radiographs taken between 2-4 years of age and has been shown to be stable in 2-4-year-old dachshunds.3,4 In dachshunds, KN is heritable,5,6 and the risk of IVDD is higher in dogs with higher KN.7–9 Prevalence of signs of IVDD in dachshunds by KN is: 7% for K0, 12% for K1/2, 23% for K3/4, and 69% for K5 + .10
Research into the genetic basis of disc calcification led to the discovery of a dominant fibroblast growth factor-4 retrogene insertion on chromosome 12 (FGF4L2)11 with a high allele frequency in dachshunds (0.88-0.92)10,12 and associated with IVDD risk.11 Later, a gene dose effect for FGF4L2 was demonstrated in dachshunds, with 1 copy of FGF4L2 being associated with lower KN than 2 copies.10 Currently, it is unknown to what extent FGF4L2 genotype determines IVDD risk as compared with other factors. In one report, dachshunds of certain coat-size type combinations (standard wire, standard long, and miniature long) were less frequently affected with IVDD13, suggesting a possible role of coat and size genes in IVDD risk.
Two genes, fibroblast growth factor 5 (FGF5) and R-spondin-2 (RSPO2) determine the coat types (smooth, long and wire) seen in dachshunds.14 R-spondin-2 upregulates a pathway with a demonstrated effect on disc calcification in dogs,15 suggesting that coat genes could influence IVDD risk. Six genes in various combinations determine small body size in dogs,16 but the gene combinations that result in the 3 dachshund sizes (large to small: standard, miniature, and kaninchen) are poorly understood. In dachshunds, breeding is restricted by coat and size type, with coat type typically prioritized over size. Because different genes control coat type and body size, reporting IVDD risk by size-coat type may obscure differences in disease risk related separately to coat or size type. Our aims were to follow the priority of dachshund breeders (coat>size) and identify differences in spinal health metrics (SHMs): by coat type, within a coat type by size, and by size-coat type. We hypothesized that: smooth coat is associated with worse SHMs than long and wire coat; within a coat type, small size is associated with worse SHMs than standard size; and, small smooth dachshunds have worse SHMs than other dachshund types.
Materials and methods
Our retrospective study assessed SHMs in dachshunds from the United Kingdom (UK), Norway, and Denmark. The UK population consisted of all dachshunds ≥10 years old in the online 2021 DachsLife survey (supplemental data) for which responses to questions about the occurrence of signs of IVDD were received (n = 1134). The SHM evaluated in the UK population was owner-reported signs of disc disease (ORSDD). Coat and size type data from dogs ≥10 years with ORSDD was provided by Dachshund Health UK. The Norwegian and Danish populations consisted of all dachshunds with KN recorded to their respective national public database as part of IVDD breeding management programs (Norwegian: n = 1170, 2002-2024; Danish: n = 1991, 1992-2023). Calcification number was determined in dogs 2-4 years old. The SHM evaluated in the Danish and Norwegian populations was the KN group (very low IVDD risk = K0, low IVDD risk = K1/2, average IVDD risk = K3/4, high IVDD risk = K5+). Data from the public database was provided by the Dansk Gravhundeklub and the Norwegian Federation of Dachshund Clubs and included KN, coat, and size type for each dog. Before analysis, the Danish and Norwegian datasets were assessed for comparability. Differences in the distribution of KN groups across coat–size strata were identified between the populations. Therefore, analyses were conducted separately by country to avoid potential confounding associated with population-level heterogeneity. Additional details about this statistical approach are included in the Appendix. In each population, the SHM was compared across coat type, size type within a coat type, and all coat-size type combinations. Because of the small numbers of kaninchen dachshunds, kaninchen and miniature were combined into a single group designated “small”. All analyses were performed using statistical software (JMP Student Edition 18.2.0; JMP Statistical Discovery LLC, Cary, NC). Six coat and size combinations (long/small, long/standard, wire/small, wire/standard, smooth/small, smooth/standard) were included as categorical fixed effects in the regression models. For the UK population, a binary logistic regression was fitted with ORSDD status (yes/no) as the outcome variable. For Denmark and Norway, populations were analyzed separately by country with proportional-odds ordinal logistic regression models, with KN group (K0, K1/2, K3/4, or K5+) as the ordinal outcome. Post hoc pairwise comparisons were obtained from model-estimated contrasts of the regression coefficients among coat types within each size category and among sizes within each coat type. Results are reported as odds ratios (OR) with 95% confidence intervals (CI). Statistical significance was set at P-values <.05.
Results
Distribution of spinal health metrics by population
In the UK population, the highest proportion of ORSDD was seen in smooth dachshunds of both sizes (Table 1). In the Norwegian population, the highest proportion of dogs in the K5+ (worst) KN group was seen in smooth dachshunds of both sizes, whereas the lowest proportion of dogs in the K0 (best) group was seen in small smooth dachshunds (Table 2). In the Danish population, the highest proportion of dogs in the K5+ (worst) KN group was seen in smooth dachshunds of both sizes, whereas the lowest proportion of dogs in the K0 (best) group was seen in smooth dachshunds of both sizes and standard long dachshunds (Table 3).
Table 1.
Distribution of owner-reported signs of disc disease (ORSDD) by size and coat type in the UK population.
| Size + coat type | No ORSDD (N) | No ORSDD (%) | ORSDD (N) | ORSDD (%) | Total (N) |
|---|---|---|---|---|---|
| Small, long | 195 | 80.25 | 48 | 19.75 | 243 |
| Small, wire | 134 | 72.43 | 51 | 27.57 | 185 |
| Small, smooth | 302 | 64.95 | 163 | 35.05 | 465 |
| Standard, long | 43 | 89.58 | 5 | 10.42 | 48 |
| Standard, wire | 103 | 84.43 | 19 | 15.57 | 122 |
| Standard, smooth | 47 | 66.20 | 24 | 33.80 | 71 |
| Total | 824 | — | 310 | — | 1134 |
Table 2.
Distribution of calcification number (KN) groups by size and coat type in the Norwegian population.
| Size + coat type | K0 (N) | K0 (%) | K1/2 (N) | K1/2 (%) | K3/4 (N) | K3/4 (%) | K5+ (N) | K5+ (%) | Total (N) |
|---|---|---|---|---|---|---|---|---|---|
| Small, long | 113 | 34.1 | 118 | 35.6 | 58 | 17.5 | 42 | 12.7 | 331 |
| Small, wire | 26 | 26.5 | 38 | 38.8 | 19 | 19.4 | 15 | 15.3 | 98 |
| Small, smooth | 7 | 10.8 | 20 | 30.8 | 15 | 23.1 | 23 | 35.4 | 65 |
| Standard, long | 101 | 32.1 | 126 | 40.0 | 46 | 14.6 | 42 | 13.3 | 315 |
| Standard, wire | 102 | 43.6 | 78 | 33.3 | 35 | 15.0 | 19 | 8.1 | 234 |
| Standard, smooth | 32 | 25.2 | 45 | 35.4 | 21 | 16.5 | 29 | 22.8 | 127 |
| Total | 381 | — | 425 | — | 194 | — | 170 | — | 1170 |
Table 3.
Distribution of calcification number (KN) groups by size and coat type in the Danish population.
| Size + coat type | K0 (N) | K0 (%) | K1/2 (N) | K1/2 (%) | K3/4 (N) | K3/4 (%) | K5+ (N) | K5+ (%) | Total (N) |
|---|---|---|---|---|---|---|---|---|---|
| Small, long | 75 | 20.7 | 159 | 43.8 | 78 | 21.5 | 51 | 14.0 | 363 |
| Small, wire | 53 | 18.3 | 109 | 37.7 | 62 | 21.5 | 65 | 22.5 | 289 |
| Small, smooth | 6 | 7.4 | 25 | 30.9 | 23 | 28.4 | 27 | 33.3 | 81 |
| Standard, long | 19 | 12.3 | 64 | 41.6 | 40 | 26.0 | 31 | 20.1 | 154 |
| Standard, wire | 177 | 22.2 | 286 | 35.9 | 187 | 23.5 | 146 | 18.3 | 796 |
| Standard, smooth | 39 | 12.7 | 91 | 29.5 | 83 | 26.9 | 95 | 30.8 | 308 |
| Total | 369 | — | 734 | — | 473 | — | 415 | — | 1991 |
Results by coat type
In each of the three populations, smooth-coat dachshunds had increased odds of worse SHMs than other coat types, but no difference was found in SHMs across wire and long coat types. The association between coat type and SHMs is summarized in Table 4.
Table 4.
Likelihood of worse spinal health metric in dachshunds by coat type.
| Population | Metric | Coat | Number | Odds ratio | Compared to | Number | P-value | 95% CI |
|---|---|---|---|---|---|---|---|---|
| United Kingdom | ORSDD | Smooth | 536 | 2.41 | Long | 291 | <.01 | 1.70-3.40 |
| United Kingdom | ORSDD | Smooth | 536 | 1.81 | Wire | 307 | .03 | 1.32-2.50 |
| United Kingdom | ORSDD | Wire | 307 | 0.75 | Long | 291 | .17 | 0.51-1.12 |
| Norway | KN group (ordinal) | Smooth | 192 | 2.11 | Long | 646 | <.01 | 1.58-2.83 |
| Norway | KN group (ordinal) | Smooth | 192 | 2.59 | Wire | 332 | <.01 | 1.87-3.58 |
| Norway | KN group (ordinal) | Wire | 332 | 0.82 | Long | 646 | .10 | 0.64-1.04 |
| Denmark | KN group (ordinal) | Smooth | 389 | 2.10 | Long | 517 | <.01 | 1.65-2.67 |
| Denmark | KN group (ordinal) | Smooth | 389 | 1.97 | Wire | 1085 | <.01 | 1.60-2.44 |
| Denmark | KN Group (ordinal) | Wire | 1085 | 1.07 | Long | 517 | .51 | 0.88-1.29 |
Results by size within each coat type
Within a coat type, size was inconsistently associated with SHMs. In the UK population, more ORSDD was seen in small dachshunds than standard dachshunds in the wire coat type only (Table 5). In the Norwegian population, small dachshunds of the smooth and wire coat types were more likely than standard dachshunds to be in a high KN group (Table 5). In the Danish population, small dachshunds of the long coat type were less likely than standard dachshunds to be in a high KN group (Table 5). In general, long coat dachshunds had better SHMs that did not vary by size in 2 of the 3 populations, whereas smooth coat dachshunds had worse SHMs that did not vary by size in 2 of the 3 populations. For wire-coat dachshunds, SHMs did vary by size in 2 of the 3 populations, with small size associated with worse SHMs. When size mattered, the most frequent association was with small size and worse SHM, but in the Danish long coat dachshunds small size was associated with better SHM.
Table 5.
Likelihood of worse spinal health metric in dachshunds by size within a coat type.
| Population | Metric | Coat | Size | Number | Odds ratio | Compared to | Number | P-value | 95% CI |
|---|---|---|---|---|---|---|---|---|---|
| United Kingdom | ORSDD | Smooth | Small | 465 | 0.95 | Standard | 71 | .84 | 0.55-1.60 |
| United Kingdom | ORSDD | Long | Small | 243 | 0.47 | Standard | 48 | .13 | 0.18-1.26 |
| United Kingdom | ORSDD | Wire | Small | 185 | 2.06 | Standard | 122 | .02 | 1.15-3.71 |
| Norway | KN group (ordinal) | Smooth | Small | 65 | 2.23 | Standard | 127 | <.01 | 1.29-3.82 |
| Norway | KN group (ordinal) | Long | Small | 331 | 0.99 | Standard | 315 | .92 | 0.74-1.31 |
| Norway | KN group (ordinal) | Wire | Small | 98 | 1.97 | Standard | 234 | <.01 | 1.28-3.03 |
| Denmark | KN group (ordinal) | Smooth | Small | 81 | 1.21 | Standard | 308 | .40 | 0.78-1.88 |
| Denmark | KN group (ordinal) | Long | Small | 363 | 0.65 | Standard | 154 | .01 | 0.46-0.91 |
| Denmark | KN group (ordinal) | Wire | Small | 289 | 1.19 | Standard | 796 | .16 | 0.94-1.52 |
Results by size and coat type combinations
In 12 of 15 comparisons of small smooth-coat dachshunds to dachshunds of other coat-size combinations, small smooth-coat dachshunds had the worst SHMs across all three populations (Table 6). The largest differences were seen in the UK and Norwegian populations, where small smooth-coat dachshunds had approximately 4.5-5.5 fold higher odds of worse SHM compared with other dachshund varieties.
Table 6.
Likelihood of worse spinal health metric in dachshunds by size + coat combination.
| Population | Metric | Size + coat | Number | Odds ratio | Compared to | Number | P-value | 95% CI |
|---|---|---|---|---|---|---|---|---|
| United Kingdom | ORSDD | Small smooth | 465 | 2.19 | Small long | 243 | <.01 | 1.52-3.17 |
| United Kingdom | ORSDD | Small smooth | 465 | 0.71 | Small wire | 185 | .07 | 0.48-1.03 |
| United Kingdom | ORSDD | Small smooth | 465 | 0.95 | Standard smooth | 71 | .84 | 0.56-1.60 |
| United Kingdom | ORSDD | Small smooth | 465 | 4.64 | Standard long | 48 | <.01 | 1.80-11.95 |
| United Kingdom | ORSDD | Small smooth | 465 | 2.93 | Standard wire | 122 | <.01 | 1.73-4.95 |
| Norway | KN group (ordinal) | Small smooth | 65 | 3.61 | Small long | 331 | <.01 | 2.22-5.87 |
| Norway | KN group (ordinal) | Small smooth | 65 | 2.74 | Small wire | 98 | <.01 | 1.55-4.84 |
| Norway | KN group (ordinal) | Small smooth | 65 | 2.23 | Standard smooth | 127 | <.01 | 1.29-3.82 |
| Norway | KN group (ordinal) | Small smooth | 65 | 3.56 | Standard Long | 315 | <.01 | 2.19-5.79 |
| Norway | KN group (ordinal) | Small smooth | 65 | 5.40 | Standard Wire | 234 | <.01 | 3.25-8.95 |
| Denmark | KN group (ordinal) | Small smooth | 81 | 2.79 | Small Long | 363 | <.01 | 1.80-4.32 |
| Denmark | KN group (ordinal) | Small smooth | 81 | 2.01 | Small Wire | 289 | <.01 | 1.29-3.14 |
| Denmark | KN group (ordinal) | Small smooth | 81 | 1.21 | Standard Smooth | 308 | .40 | 0.78-1.88 |
| Denmark | KN group (ordinal) | Small smooth | 81 | 1.80 | Standard Long | 154 | .02 | 1.11-2.94 |
| Denmark | KN group (ordinal) | Small smooth | 81 | 2.40 | Standard Wire | 796 | <.01 | 1.59-3.64 |
Feasibility of analyzing Norwegian and Danish data as a single pooled sample
In the sensitivity analysis combining Norwegian and Danish data, country was a highly significant predictor of KN score (likelihood ratio χ2(1) = 47.89, P < .0001), with Norwegian dogs having 1.77 times higher odds of a worse KN score compared with Danish dogs (OR, 1.769; 95% CI, 1.505-2.079). A significant interaction between size or coat type or both and country was also detected (likelihood ratio χ2(5) = 14.41, P = .01), indicating that the association between KN score and size or coat or both type differed between countries. Regardless, the main effect of size and coat type remained highly significant in the pooled model (likelihood ratio χ2(5) = 96.23, P < .0001), confirming that the primary conclusions of the country-stratified analyses were robust. These findings support the appropriateness of the stratified approach and are consistent with the risk of Simpson’s paradox if these two heterogeneous groups were to be pooled without accounting for country-level differences.
Discussion
In all three dachshund populations, smooth coat type was associated with worse SHMs compared with long and wire coat types, but no difference was found in SHMs between dogs with long and wire coat types. In general, small size was associated with worse SHMs, but this trend was observed in a minority of the groups, and in 1 group (Danish long coat dachshunds), small size was associated with better SHMs. The small smooth dachshund variety was consistently associated with worse SHMs compared with all other dachshund varieties. These findings confirm our hypotheses that in dachshunds, smooth coat type is associated with worse spinal health and also that the small smooth dachshund variety has worse spinal health than other varieties. However, our hypothesis that within a coat type, small body size is associated with worse spinal health was not fully supported by the data. Our results contribute to scientific understanding of the genetic basis of IVDD in dogs and could be explained by differences in segregation of FGF4L2 in dachshund subpopulations or by a direct effect of coat and size genes on spinal health.
Only one report has described differences in FGF4L2 allele frequency in dachshunds by coat type. In that study, the FGF4L2 allele frequency was lower in wire dachshunds (0.74, n = 87) than long (1.00, n = 35) or smooth (0.94, n = 32) dachshunds.7 However, that study also showed no difference in the prevalence of clinical signs of IVDD by coat type in a different group of 503 dachshunds,7 suggesting that the genotyped group of wire dachshunds might not have been representative of the overall population. No other published reports of variation of FGF4L2 allele frequency by coat type in dachshunds are available. However, in Sweden, Norway, and Finland, FGF4L2 genotype is recorded in public databases (Sweden: https://hundar.skk.se/avelsdata/Initial.aspx, Norway: https://www.dogweb.no/hundedatabase/ Finland https://www.kennelliitto.fi/en/breeding-and-health/breeding-database) as part of IVDD breeding management programs. Summary data from these databases is continuously compiled for annual presentation at a meeting of Nordic dachshund breed clubs. Review of the most current version of this genotype data from 3580 dachshunds (accessed February 13, 2026) shows that FGF4L2 allele frequency is not higher in smooth dachshunds than in wire or long dachshunds in any of the three countries (personal communication, M. Sundquist, 2026). Although interpretation of this data is limited by lack of randomization (the decision to genotype a dog is left to the owner), currently available data does not support the conclusion that the results of our study are explained by differences in segregation of FGF4L2.
The coat types seen in dachshunds are determined by two genes, FGF5 and RSPO2.14 Smooth coat results from the dominant FGF5, wire coat results from the dominant RSPO2, and long coat results from the lack of functional FGF5.14 Dachshunds that lack long coat type (ie, smooth and wire dachshunds) have functional FGF5, which means that wire dachshunds have both RSPO2 and FGF5. Dachshunds that lack wire coat type (ie, smooth and long dachshunds) all lack RSPO2, which means that long coat dachshunds lack both RSPO2 and functional FGF5. Smooth coat dachshunds have functional FGF5 but lack RSPO2. Expression of RSPO2 activates the wingless-related integration site (WNT)/β catenin pathway,17 a pathway known to play an important role in intervertebral disc development.18 Downregulation of WNT signaling is associated with early intervertebral disc degeneration in dogs.15 Therefore, increased signaling in the WNT/β catenin pathway because of RSPO2 could explain the association between wire coat type and better spinal health in dachshunds.
Although the best described effect of the FGF5 gene in dogs is to arrest hair growth in the anagen phase, resulting in short (smooth) coat type,14 in general, the FGF family of genes influences embryonic development and homeostasis of various tissues, including the intervertebral disc.19,20 The FGF5 gene itself has no known role in intervertebral disc development or homeostasis, but is expressed in the notochord of embryonic chicks21 suggesting that such a role is possible. Short hair coat in dogs is not a recognized risk factor for IVDD, thus if FGF5 does play a role in the development of early disc degeneration, it may do so only when FGF4L2 is also present. A combined effect of FGF5 and FGF4L2 on IVDD risk could explain the higher risk of clinical signs of IVDD in predominantly short-coated breeds such as the dachshund and French bulldog compared with long-coated breeds such as the Cavalier King Charles spaniel and cocker spaniel,22 despite these breeds all having a similar FGF4L2 allele frequency.12,23 This possible role of coat type genes in risk of clinical signs of IVDD in dachshunds is summarized in Table 7.
Table 7.
Possible role of coat type genes in IVDD risk in dachshunds.
| Coat type | Genotype | Effect on IVDD risk |
|---|---|---|
| Smooth | FGF5 | Detrimental |
| Long | No functional FGF5 | Protective |
| Wire | FGF5 and RSPO2 | Detrimental + very protective = net protective |
Abbreviation: IVDD = intervertebral disc disease.
Dachshund morphology is defined by both decreased limb length and variable body size. A retrogene insertion, FGF4L1, is responsible for most of the decrease in limb length seen in dogs, with FGF4L2 contributing to decreased limb length to a lesser degree24 and also conferring IVDD risk.11 Various combinations of six genes are responsible for small body size in dogs, but within a single breed, the specific combinations of body size genes vary from dog to dog.16 The general pattern is that small dogs are homozygous for one or more of the genes associated with small body size.16 The gene combinations that result in small or standard size are not well understood in dachshunds, but an individual dachshund’s morphology likely results from the combined effects of multiple body size genes and the limb length genes FGF1L2 and FGF2L2. Given the complexity of the genetics of body morphology, it is not surprising that an inconsistent association between body size and SHMs was observed in this study. It is possible (or even likely) that multiple different combinations of body size genes determine size in dachshunds, and that each combination has a different effect on spinal health. Until the gene combinations that determine body size in dachshunds are elucidated, it may be difficult to discern differences in risk of clinical signs of IVDD relating to body size in this breed. Although the results of our study demonstrated significant differences in only some groups of dogs, the general trend was toward an association between small body size and worse spinal health.
A limitation in applying the results of our study is that all three populations studied are European. In the included countries, breeding across coat type is prohibited, and breeding across size type is either limited (Norway and Denmark) or prohibited (UK). This situation is in contrast to the United States and other countries, where no similar restrictions exist, and breeding across coat or size type occurs regularly in a minority of dogs. The magnitude of the association between coat or size type and spinal health might differ in dachshund populations depending on the degree of breeding restriction by coat and size type. Because of the simple-dominant inheritance pattern of coat type genes, this may be less true for the association between coat type and spinal health than for that between size type and spinal health. However, although the genetic factors that influence risk of clinical signs of IVDD might be more easily detected in these European dachshund populations, similar factors are likely present in all dachshund populations. An additional limitation is that the UK population is assessed by a different metric (ORSDD) than the Norwegian and Danish populations (KN group), which could introduce different biases into the populations. For example, the high number of responses to the owner survey suggest that the UK population correlates more with the general dachshund population whereas the Norwegian and Danish populations are predominantly comprised of dogs under consideration for breeding. However, because similar trends are identified across both types of populations, the approach used in our study may strengthen the findings.
The results of our study are important to researchers, but also to stakeholders with an interest in improving spinal health in dogs, including dog breeders, dog registries, and legislators. Although a substantial proportion of the increased risk of clinical signs of IVDD seen in dachshunds may be accounted for by FGF4L2, the results of our study suggest a more complex picture in which multiple genes play a role in IVDD risk. A pattern in which gene combinations that affect IVDD risk vary by breed may prove to be the rule across dog breeds. Therefore, simplistic approaches to IVDD prevention, such as excluding dogs with a single gene from the breeding population, may result in the loss of valuable healthy genetics, causing more net harm than good. Our results support the understanding that IVDD is a polygenetic disorder and indicate that the polygenetic nature of this disease should be considered by researchers and stakeholders who aim to decrease the prevalence of clinical signs of IVDD in dogs.
Conclusions
Dachshund spinal health varies consistently by coat type and inconsistently by size type. In dachshunds, smooth coat type is associated with worse spinal health than is long or wire coat type. A protective effect of RSPO2, the gene that determines wire coat type, and a detrimental effect of FGF5, the gene that determines smooth coat type, may explain the observed differences. In general, small body size was associated with worse spinal health, but this finding was only significant in some of the groups studied. The complexity of the genetics of small body size in dogs may obscure the effect of body size on spinal health in this breed. Coat and size type should be considered by researchers and stakeholders concerned with IVDD and spinal health in dachshunds.
Supplementary Material
Acknowledgments
The authors thank Dachshund Health UK, the Norwegian Federation of Dachshund Clubs, and the Dansk Gravhundklub (Danish Dachshund Club) for providing the data analyzed in this report.
Abbreviations
- IVDD
intervertebral disc disease
- UK
United Kingdom
- FGF4L2
fibroblast growth factor 4 like 2
- CDDY
chondrodystrophy
- KN
calcification number), SHM, spinal health metric
- ORSDD
owner-reported symptomatic disc disease
- FGF5
fibroblast growth factor 5
- RSPO2
R-spondin-2
- WNT
wingless-related integration site
- FGF4L1
fibroblast growth factor 4 like 1
Appendix
To address the possibility that Norwegian and Danish data could be analyzed jointly, a sensitivity analysis was conducted in which data from both countries were pooled and country (Norway vs Denmark) was included as an independent covariate in the ordinal logistic regression model. An interaction term between country and size/coat type was also evaluated. This analysis was performed to assess whether the primary conclusions derived from the country-stratified models were consistent with a pooled approach.
Contributor Information
Madison Hopper, Department of Clinical Sciences, College of Veterinary Medicine, Auburn University, Auburn, AL 36832, United States.
Chin-Chi Liu, Office of Research and Graduate Education, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803-8410, United States.
Colleen Embersics, Department of Veterinary Clinical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803-8410, United States.
Arturo Otamendi, Neuro Vet, Pleasant Hill, CA 94523, United States.
Stacey Sullivan, Department of Clinical Sciences, College of Veterinary Medicine, Auburn University, Auburn, AL 36832, United States.
Author contributions
Madison Hopper (Formal analysis, Investigation, Methodology, Writing—original draft, Writing—review & editing), Chin-χ Liu (Formal analysis, Methodology, Visualization, Writing—review & editing), Colleen Embersics (Writing—review & editing), Arturo Otamendi (Writing—review & editing), and Stacey Sullivan (Conceptualization, Formal analysis, Investigation, Methodology, Project administration, Supervision, Writing—original draft, Writing—review & editing)
Conflicts of interest
Stacey Sullivan is a dachshund breeder. The other authors declare no conflicts of interest.
Funding
Authors received no specific funding for this work.
Off-label antimicrobial declaration
Authors declare no off-label use of antimicrobials.
Institutional animal care and use committee or other approval declaration
Authors declare no institutional animal care and use committee or other approval was needed.
Human ethics approval declaration
Authors declare human ethics approval was not needed.
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