Reproduction & Breeding

Inflammation of the uterine lining (endometrium), often through ascending germs after breeding, foaling or with disturbed self-cleaning of the uterus. One of the most common causes of subfertility (failure to conceive) in the mare.

A disturbed or difficult course of birth in which foal and/or mare are at risk without help — usually through malposition, malposture or malpresentation of the foal. In the mare the expulsion phase is exceptionally short and powerful, so any delay quickly threatens the life of mare and foal.

Absent or incomplete passing of the placenta (fetal membranes) after foaling. Unlike in the cow, this is an emergency in the horse: if the placenta does not pass completely within a few hours (rule of thumb about 3 hours), life-threatening uterine inflammation (metritis), endotoxaemia and, as a consequence, laminitis threaten.

Congenital failure of one or both testicles to descend into the scrotum; the retained testicle lies in the inguinal canal or abdominal cavity. Affected stallions (rigs) often show stallion-like behaviour despite an apparently incomplete castration.

Premature death and expulsion of the foetus. One of the most important infectious causes is the equine herpesvirus (EHV-1), which can trigger single abortions up to abortion storms in the herd. Abortion material and amniotic fluid are highly contagious.

Foals are born without their own antibodies and depend on taking up immune substances (IgG) from the first colostrum. If too little colostrum is taken up in the first hours of life (failure of passive transfer), immune protection is lacking — the main risk factor for a life-threatening blood poisoning (sepsis) of the newborn.

Hereditary malformation of the intestinal nervous system in foals born pure white to spotted parents. The cause is a variant in the EDNRB gene: heterozygous carriers are completely healthy and show the frame overo pattern, while homozygous foals have no functioning intestinal nerve cells and cannot move the gut contents along. The trait is unambiguously identifiable by gene test — which makes the case entirely avoidable.

Hereditary disorder of the anchoring between epidermis and dermis. In homozygous foals the skin detaches over large areas at the slightest friction, as does the hoof horn. In the Belgian draught breeds the cause is a variant in the LAMC2 gene. Carriers are completely healthy; the trait is unambiguously identifiable by gene test and therefore avoidable.

Hereditary disorder of the skin barrier in the Akhal-Teke. Homozygous foals are born without a coat; the skin barrier is incomplete, fluid loss and infections follow. The cause is a recessive variant in the ST14 gene. Carriers are healthy and normally coated.