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Chronic Progressive Lymphedema (CPL)
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Chronic Progressive Lymphedema (CPL) is a serious and potentially debilitating disease of the lymphatic system in most draft horse breeds, especially those with feather. Prior to WW II, draft horses of all breeds had less CPL and less feather. The emphasis on breeding more bone and feather in the Belgian horse in Europe has resulted in a significant increase in the presentation of CPL. To this end, the American Brabant Association is focused on producing a working draft horse with healthy legs of the type seen prior to the 1950s. A system of evaluation has been developed for the purposes of breeding horses with healthy legs. This system closely follows the recommendations put forth in the De Keyser PhD thesis.
The evaluation involves observation and palpation of each of the horse’s legs looking for CPL characteristics (bumps, folds, nodules, scaly patches, sores, and edema). Each leg is then given a score and the scores are averaged to obtain the overall CPL leg score and letter (AA, A, B, C, D). Ideally the horse’s first evaluation should be performed at the start of the breeding career, at ages 2 to 4 years. The horse should be re-evaluated when fully mature between ages 7 to 9 years. This enables the owner and potential buyers to assess the progression of disease in a given animal.
Paramount at this time is breeding toward healthy legs. Choosing a mate for a given horse must include a careful analysis of CPL of the horses. When comparing CPL scores among potential mating pairs, the percentage of European Belgians must be considered. A 50% European Belgian stallion with a CPL rating of “B” at eight is not comparable to a 100% European Belgian stallion with a CPL rating of “B” at age eight. The 50% stallion is showing worse CPL at that age than the 100% stallion even though their ages and scores are the same. We expect lower percentage horses to present less CPL than higher percentage horses at the same age. Complicating the issue is the fact that until you have a large foal crop from any particular stallion, you do not know his prepotencies in passing the CPL genetics down the line. It could be that the hypothetical 50% “B” rated horse passes less CPL to his offspring than the less affected 100% “B” rated horse. And this does not take into consideration the mare. The selection of a mate should take into consideration the CPL scores of both mare and stallion. “A” rated horses should be used as much as possible. High percentage and 100% stallions should be mated to clean legged low percentage mares. The converse is true as well. High percentage mares, especially those with “B” or “C” ratings should be mated to clean legged low percentage stallions.
The evaluation involves observation and palpation of each of the horse’s legs looking for CPL characteristics (bumps, folds, nodules, scaly patches, sores, and edema). Each leg is then given a score and the scores are averaged to obtain the overall CPL leg score and letter (AA, A, B, C, D). Ideally the horse’s first evaluation should be performed at the start of the breeding career, at ages 2 to 4 years. The horse should be re-evaluated when fully mature between ages 7 to 9 years. This enables the owner and potential buyers to assess the progression of disease in a given animal.
Paramount at this time is breeding toward healthy legs. Choosing a mate for a given horse must include a careful analysis of CPL of the horses. When comparing CPL scores among potential mating pairs, the percentage of European Belgians must be considered. A 50% European Belgian stallion with a CPL rating of “B” at eight is not comparable to a 100% European Belgian stallion with a CPL rating of “B” at age eight. The 50% stallion is showing worse CPL at that age than the 100% stallion even though their ages and scores are the same. We expect lower percentage horses to present less CPL than higher percentage horses at the same age. Complicating the issue is the fact that until you have a large foal crop from any particular stallion, you do not know his prepotencies in passing the CPL genetics down the line. It could be that the hypothetical 50% “B” rated horse passes less CPL to his offspring than the less affected 100% “B” rated horse. And this does not take into consideration the mare. The selection of a mate should take into consideration the CPL scores of both mare and stallion. “A” rated horses should be used as much as possible. High percentage and 100% stallions should be mated to clean legged low percentage mares. The converse is true as well. High percentage mares, especially those with “B” or “C” ratings should be mated to clean legged low percentage stallions.
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Jason Julian and Dr. Karen Gruner discuss CPL in the video.
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Horse's CPL Evaluation Reports are shared here
to help you make breeding choices that improve the health of the American Brabant. |