[Jacob-list] Smooshed or Deformed Hoof/One case

[Jacobflock at aol.com]

In the September 2000 JSC Journal an incident of acdactyly was reported in a 
ewe lamb (a triplet with normal siblings) which included congenital missing 
hoof wall and missing distal phalanx and undivided hoof.  The findings were 
made by a veterinarian upon xray and physical examination.

The evidence supported a probable conclusion of high inbreeding.  A review of 
the pedigree revealed the ewe (Ramona) had an inbreeding coefficient of 0%, 
the ram (Sherlock) had a coefficient of 2.5%; the subject ewe lamb with 
adactyly had a coeeficient of 22.3%.  This coeeficient may be understated 
because (absent a complete pedigree) no relationship between Limper B97 and 
Limper B98 was assumed nor was any relationship between Atwood's Brutus and 
Atwood's Tripee assumed.   

Generally, the assumption is in the favor of "no relationship" if a 
relationship cannot be documented or parentage is unknown.  "No relationship" 
notwithstanding, the gene puddle at a single farm with a single ram is a 
stretch of the "no relationship" assumption.  In fact, buying "unknown" sheep 
at a local sale barn may be more closely related to your own flock than the 
sheep within the flock.

"Inbreeding" of course does not cause a problem but it often 'causes' a 
potential soundness (esthetics aside) problem to be seen.  For example, thin 
hoof walls, might become the "smooshed" or "deformed" hoof walls cited by 
Mary Ellen.  A lack of soundness in the parents is manifest in the inbred 
offspring ... yes, strengths are also manifest ... bite, legs and vertebrae, 
eyes, ears, and even hooves, etc.

Congenital defects may be caused by environmental factors.  The incidence is 
often helpful in separating a genetic source from an environmental source. 
Each case must be reviewed and documented on its own.  The breeding of 
Twinkletoes" was an "accidental" ram escape, observed, recorded, the ewe was 
seperated and subsequent effects observed and reviewed; environmental issues 
far less probable because there have been no other incidents.  "Smooshed or 
deformed hooves" may be syndactyly (fusion).  Some syndactyly has been 
associated with environmental factors such as noxcious plants.  

Some congenital defects are "mutations" looking for an explanation ... two 
scrotums and another, a hemophredite.  

A thank you to those who continue to report and follow-up on some of these 
congenital defects.  It is important for understanding the gene puddle and 
environment; for monitoring the breed and the health of the breed.  
Conservation depends on conversation.

Fred Horak