The coat patterns of the Knabstrupper are a product
of the Leopard complex gene (Lp) which is dominantly inherited. This
gene is present in other breeds most notably the Appaloosa and acts
in the same way no matter which breed of horse it is present in.
The Lp gene produces three characteristics in a horse: mottled skin,
striped hooves and white schelra also known as the human eye. These
characteristics can appear on horses without the Lp gene but it is
highly unlikely to find all three in a non Lp carrying horse.
The effect of the Lp gene on a horse's coat is basically a command
to be white. The gene is a complex gene and works with a group of
modifiers called pattern genes. There may be up to thirty of these
pattern genes and it is not known exactly how these genes work. It
may be that all horses carry some form of the pattern genes. The
level of pattern on a horse is also affected by the horse's base
coat colour e.g. black, chestnut, bay etc.
all Knabstruppers have a unique coat pattern there are basic
patterns which range from top to toe leopard to just a little
roaning out and of course there are solid coloured horses. It should
also be noted that the Lp gene always carries the roaning effect,
not to be confused with the roan gene seen on non Lp carrying horses,
but the level of roaning produced may vary from a few hairs to outright
born with two Lp genes are called fewspot or whiteborn. They
are homozygous for Lp and will always pass on the Lp gene.
The level to which they pass their colour/ pattern on is dependant
on the pattern genes they pass on to interact with the Lp gene.
These homozygous horses can range from pure white to just having
a few white hairs and will usually only have a few spots or none
at all. They also usually have white hooves which helps to identify
them. For a horse to be homozygous for Lp both of its parents must
have been carrying at least one Lp gene.
horses with one Lp gene i.e. heterozygous will pass on Lp 50% of
the time when crossed with solid coloured non Lp carrying
horses and 75% of the time when crossed with another heterozygous
Lp carrying horse. It must be remembered that each mating to
a heterozygous Lp carrying stallion will be subject to these statistics
and although some stallions may have produced as much as 80% or as
few as 20% Lp carrying offspring to date the odds are reset
at each individual
Lp gene and its effects is a complicated subject and this is just
a very simple outline of it.