Chronisch progressief lymfoedeem bij het Belgisch trekpaard in België: klinische fenotypering, prevalentie en analyse van risicofactoren

Abstract

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.

Prevalence of Chronic Progressive Lymphedema in the Rhenish German Draught Horse

“…In 912 draught horses, including all different German draught horse breeds, sex and linear regression on age were significant for the prevalence of CPL and number of limbs affected with CPL [ 1 ]. Both studies with 431 and 980 records of Belgian draught horses confirmed the significant effects of age and sex by age on CPL severity [ 2 , 24 ]. Stallions tended to develop CPL-lesions quicker than mares [ 24 ].…”

“…Chronic progressive lymphedema (CPL) is a common disease in draught horses [ 1 , 2 , 3 , 4 , 5 ]. The first reports of CPL in draught horses date from the early 1900s and indicate a considerable number of German draught horses were affected [ 6 , 7 ].…”

“…Black Forest and South German showed a lower prevalence, with estimates at 24.0 and 39.0% [ 1 , 10 ]. Studies from Belgium and USA reported CPL in the Belgian draught horse, Shire, Clydesdale, gypsy vanners, as well as the Friesian [ 2 , 3 , 5 ].…”

“…The characteristic clinical signs of CPL include progressive swelling, scaling, hyperkeratosis, crusts, skin folds, nodules, often with exudative wounds and ulcerations, fibrosis of the distal limbs, and, in some cases, verrucous lesions with clearly demarcated calluses and wart-like proliferations [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 ]. Secondary bacterial and recurrent parasitic infections may aggravate lymphedema and clinical signs [ 3 , 11 , 12 , 13 ].…”

“…In addition, we evaluated risk factors associated with CPL. We employed a CPL scoring system based on Wallraf [ 25 ], Affolter [ 3 ] and de Keyser et al [ 2 ] to be applied for each limb in order to monitor CPL-scores based on a standardised system.…”