[Jacob-list] Piebald spotting/"feotal attraction"

[Jacobflock at aol.com]

In a message dated 6/10/2004 2:51:34 PM Central Standard Time, 
patchworkfibers at alltel.net writes:

> Someone was wondering at what time during
> >gestation they "get their spots", this stillborn ram weighed approx. 1 lb 
> and
> >had pigmented skin.

The piebald area (white area) is formed at the neural crest.  The fiber 
"follicles" begin forming at about 5 weeks on the epidermis and "grow down" to the 
dermis; first on the face and poll, then neck to back legs.  By 8 or 9 weeks 
all the primary central follicles are developed.  Then, additional follicles 
start to grow around thge primary follicles.  From about 15 weeks to birth; 
primary follicles continuie to grow and secondary follicles (what we call wool 
follicles) begin to develop from the "outside" epidermis down to the dermis.  At 
birth, primary follicle production is complte, but some secondary follicle 
growth continues. Maybe 5 to 10 secondary folllicles develop for every primary 
follicle; and 5 to 10 ten "wool fibers" may use a single secondary follicle.  
Wool doesn't grow from primary follicles. At birth, primary follicles 
immediately begin to shed (this may go on for up to about a year) and secondary 
follicles explode in number ... and produce wool.

It is strange to think that "hair and wool grows out" and it is dependent on 
a foetal "follicle that grows in".  And the mystery of the process to produce 
the dominant black nape (that always shows in the Jacob) that is 
differentiated from the peibald white within days of fertilization.  Jacobs do not have 
seconday follicles on the poll, belly and lower limbs.  When you stop to think 
about what is actaully going on or appreciate what has gone on, it is a 
mysterious scheme.

Fred Horak
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