Search

Chronic progressive lymphedema (CPL) is a well-known problem in the Belgian draft horse. However, tools for clinical diagnosis have not been standardized. Therefore, the exact disease prevalence and the possible CPL risk factors have not been investigated in the Belgian breed yet. The aim of the present study was to assess a uniform CPL clinical examination method to increase diagnostic objectivity as well as to determine the occurrence and severity of lesions. Using univariate and stepwise multivariable logistic regression models, the association of factors, such as age-gender interaction, coat color and season, with CPL occurrence was examined. In this study, it was demonstrated that CPL is highly prevalent in the Belgian draft horse: 60.66% of the horses of the total sample were affected, including a large proportion of young horses (< 3 years), whereas 85.86% was affected in a subset of older horses (≥ 3 years). In the latter, the lesions were more explicit as CPL is a chronic disorder. In some horses (i.e. 14% of the yearlings), mild clinical symptoms appeared at approximately the age of one, while distinct onset of the disease occurred from the age of three onwards. The factors age-gender interaction, coat color and season, which are significantly associated with CPL occurrence, were identified and quantified. In this study, a standardized diagnostic protocol is proposed that will enhance future data collection and furthermore will offer a foundation for quantitative genetic research. Ultimately, it will help to reduce CPL occurrence in the Belgian draft horse by means of selection.

Belgian draught horses (BDH) are susceptible to chronic progressive lymphedema (CPL). The main cause is a failure of the lymphatic system of skin and subcutis, resulting in excessive protein rich interstitial fluid (lymphedema). Symptoms are mainly restricted to skin anomalies and deformations of the lower limbs. Initial signs (from 1.5 yr) are often missed in younger horses, however, with disease progression, increased disability frequently justifies early euthanasia in older horses (from 6 yr). As a genetic background is suggested and disease prevalence in BDH approaches 70%, urgent measures are needed. The aim of this study was to estimate genetic parameters for CPL in a BDH population. Analyses were performed on two datasets, comprising clinical examinations (CPL-scores), collected at official horse contests and stable visits throughout Belgium. The first dataset comprised all collected data, whereas in the second data set, scores for horses younger than 3 years were omitted. Age (years), coat color and sex were included as fixed effects, whereas date of recording was a random effect. Variance component estimates were obtained using the REML method (VCE6) by means of an animal model. Heritability coefficients (standard error, SE) for CPL ranged from 0.25 (0.07) to 0.46 (0.09). Phenotypic and genetic correlations (SE) for CPL-scores between fore -and hind limbs were high and respectively counted 0.85 and 0.96 (0.02). Date of recording was a factor of importance, where the proportion of variance (SE) ranged from 0.16 (0.05) to 0.22 (0.04). To improve reliability of estimated breeding values, continued collection of CPL-scores is advised. This study indicates the potential to reduce chronic progressive lymphedema occurrence in BDH through selection. ispartof: 64th annual EAAP meeting vol:131 issue:6 pages:522-528 ispartof: location:Nantes status: published

The objective of this review was to summarise and evaluate the current state of knowledge about chronic progressive lymphoedema in draught horses. Clinical signs of this multifactorial disorder are mainly restricted to the lower limbs, comprising progressively deteriorating skin, swelling and deformation. Although typical lesions were first reported at the beginning of the 20th century, chronic progressive lymphoedema was recognised as a specific syndrome only in 2003, and since then research has driven forward. Despite the high prevalence in some breeds and the serious economic impact, the pathogenesis is not fully understood, and the available treatment options remain symptomatic and noncurative. There is a need to improve diagnostic techniques and to develop selection tools.