Rosalind
several things have been used to stain keratin but none have been used with consistent success because most do not penetrate the entire thickness of the skin or in this case hoof.
One of the most permanent would be Procion dyes. These can be applied locally but like silver nitrate they act as fixing agents. Squier and Hill cited the rate of turnover of human skin using dansyl chloride, or
tetrachlorosalicylanilide in 2-methoxyethanol. Squier and Hill. "The Effects of aging on oral mucosa and skin" CRC Press. Boca Raton. 1994.
In marking the keratin you may be interfering with the rate of growth.
Barry

Aidan Schurr wrote:

> Silver nitrate solution would work well (reduce it with formalin probably).  Anything would be prone to wearing off over time though, so maybe you would need something that would soak in a bit?  Just a thought...
>
> I could make some jokes about you Aussies and your sheep, but that would just be too easy!! (and they'd probably come straight back at me!)
>
> *grin*
>
> Cheers,
> Aidan
> New Zealand
>
> __
>
> aidan schurr  b.m.l.sc
> section head, histology
> hutt valley district health board
> lower hutt
> new zealand
>
> aidan.schurr@hvh.co.nz
> ++64 4 570 9173
>
> >>> "Dalefield, Rosalind" <Rosalind.Dalefield@li.csiro.au> 2/08/2001 >>>
>
> Can anyone suggest something that will permanently stain keratin?
>
> This is actually for keratin in the living animal; I want to mark the (light
> colored) hooves of Merino sheep so I can track rate of hoof growth. But I
> figured Histonetters would have some good ideas...what stains just won't
> come off your fingernails!?
>
> Thanks in advance,
>
> Rosalind Dalefield BVSc PhD DABVT DABT
> Senior Research Scientist, Toxicology
> Plant Toxins Unit
> CSIRO
> 5 Portarlington Rd
> Private Bag 24
> Geelong
> VIC 3220
> Australia
>
> Phone 61 3 5227 57