Everything you wanted to know about JEB (EI)!

Junctional Epidermolysis Bullosa - JEB

What is JEB?

JEB is an abbreviation for Junctional Epidermolysis Bullosa which is the new name for the old disease called E.I. (Epitheliogenesis Imperfecta) or hairless foal. This is just a lot of scientific jargon and terms that describe a skin defect that is terminal in certain newborn Belgian foals. This is a simple recessive genetic mutation that occurred many generations back.

How do I identify if a foal has JEB?

This genetic mutation results in the defective production of a skin protein that holds the skin to the body. The foals are typically born alive and well, but soon develop patches of hair and skin loss over points of wear. These patches soon become larger and encompass large areas of the foal’s body. Hoof attachment is also dependent on this protein and with its absence leads to the loss of the hoof wall. The foal dies or is euthanized for severe infection and discomfort at 3 to 8 days of age. The foals also have another important feature and that is the front teeth are in at birth with many oral ulcers also present.

What is the history of JEB?

JEB is not a new problem to Belgian breeders and we have been plagued with this annoyance for centuries. There are scientific reports of this condition dating back to 1934 in Sweden, 1936 in the Netherlands and 28 cases reported in Germany from 1935 to 1944. This condition is not only isolated to the Belgian horse but similar conditions are also reported in the American Saddlebred and even humans. It was through the human research being conducted by the French and the collaboration with Dr. John D. Baird of the University of Guelph, (Ontario) the gene site of the mutation was isolated on January 24, 2002. The isolation of the site removed the largest obstacle in developing a test to identify our carrier and non-carrier horses of the defect.

How do the genetics work with this genetic mutation?

There are three types of genetic animals with this disease:

1) Lethal JEB foals (J/J)-these horses die shortly after birth and never reproduce.

2) Carrier horses (N/J)-these horses carry the genetic mutation and it is the breeding of two carrier horses that allows the birth of a JEB foal. Breeding two carrier horses results in the following offspring:

25% Non-carrier offspring (N/N)

50% Carrier offspring (N/J)

25% Lethal JEB foals (J/J)

3) Non-carrier horses (N/N)-these horses do not carry the genetic mutation and the breeding of two non-carrier horses results in all their offspring being non-carriers. The breeding of a non-carrier to a carrier horse results in the following offspring:

50% Non-carrier offspring (N/N)

50% Carrier offspring (N/J)

The take home message with the genetics of this defect; Do not breed two carrier horses together. By avoiding this combination we will never have another lethal JEB foal again. A successful breeding program can be accomplished by breeding known carriers, as long as they are mated with known non-carriers.

How do I identify which of my horses are carriers and non-carriers?

We no longer have to guess and hope that our breeding program is not breeding two carriers together leading to the production of a lethal JEB foal. The Belgian Corporation has contracted with the Veterinary Genetics Lab at UC Davis, California to handle the genetic testing for the JEB condition and to handle the testing for our parentage verification. Only registered animals can be tested. The owner of the horse submits the registration papers and appropriate fees to the Canadian Belgian Horse Association office requesting the JEB test. The CBHA office will then send back to the owner bar-coded paperwork and an envelope. Within this envelope you place the mane or tail hairs of the appropriate horse. These hairs must be pulled and not cut. If the horse is less than 1 year old it is recommended that you pull tail hairs and if greater than 1 year old that you pull mane hairs. Approximately 50 hairs are required for the test.

The roots (bulb) of the hair is what contains the DNA needed for the testing. These hairs can be pulled by the owner of the horse and does not require a veterinarian. The hair samples are very stable and do not require refrigeration or special express mailing.

The lab will then do the genetic testing to determine the carrier or non-carrier status and then parentage verification to confirm it was the animal specified. The results will then be returned to the Belgian office and printed on the registration papers as “carrier of JEB” or "non-carrier of JEB". The registration papers will then be returned to the owner.

Is the Canadian Belgian Horse Association making this test mandatory?

The test is only mandatory for new breeding stallions. If your stallion has been blood-typed or DNA recorded for registration of his offspring his testing is totally voluntary, but if he has not been blood-typed or DNA recorded it is mandatory for him to be JEB tested and DNA tested before his offspring can be registered. In the US Blood typing is being replaced by DNA testing. All mares are strictly a voluntary program. All results will be placed on the registration certificates allowing public access to these results.

What does the test cost us?

For years this problem has been a source of rumor and innuendo with breeders as well as cause for concern. We not only financially lose the sale of the lethal foal but also wasted a whole year of the mare’s reproductive life incubating a terminal foal. The Canadian Belgian Horse Association is ready to initiate testing and for the first 6 months the test will be at a reduced rate of $120 per animal. After 6 months the mandatory test for new breeding stallions will be $140 per animal, the voluntary test for existing breeding stallions will be $120 per animal, and the voluntary test for mares is $120 per animal.

For years this problem has been a very sensitive issue with the Belgian Draft horse and has caused many sleepless nights for concerned breeders. We can now rest assured that we have the tools in front of us to manage this condition and move the Belgian breed into the future.

 Thank you to the US Belgian Draft Horse Corporation

who has kept in close communication and shared information with us, thus resulting in having the same rules and implementation dates in the U S and Canada. This is to the benefit of all breeders. The cost to the Canadian breeder is higher because of the exchange rate, since the laboratory costs (Davis CA) are in US funds.

Volunteer Research 

Thank you to everyone whom assisted in the research for the past number of years, by calling Dr Baird when you had an affected foal or by having your horses tested on a continuous basis. In order to print the results on a horses registration certificate a laboratory signed report from Davis California is required.

Dr John D. Baird 

Last but foremost we would like to Thank Dr John Baird for his dedication effort and hard work on this project. In his words, "I was obsessed and one pedigree lead to another to another and to another evening spent doing research". Dr Baird  gave us an in depth report in the 2002 Christmas issue of the Canadian Belgian Banner. We also invited Dr Baird to give a presentation at the CBHA 2003 annual general meeting in London, Ontario.  Dr Baird is a professor, Large Animal Medicine, Department of Clinical Studies at the Ontario Veterinary College, University of Guelph.

Implementation Date

The original start date for the above was November 1 2002.  This has been revised  to December 1 2002.


Send the horses registration certificate and the required fee into the Canadian Belgian Horse Association office and a bar code and instructions will be sent to you. Please allow a minimum of 6 - 8 weeks for testing. Please stay tuned to the CBHA website at www.canadianbelgianhorse.com for updates.

To return to the Blood Typing and DNA Testing page, click here.