Forensics (2) - Grey Day

One mechanism often overlooked for producing colour in the Ouessant is age greying. From  sutble shading  to sometimes quite striking effect it is often to  be found in evidence even in relatively young sheep.
In terms of the genetics of age greying it is strongly  familial and thought to be dominant. Its identification can sometimes be difficult when considered along side other genetics such as the colour modifying gene but it has one defining feature and that is the prescence  of  white fibres which  are most obviously secondary fibres. In the Ouessant with its primitive double fleece this can be useful in confirming identification.

Historical confirmation for age grey comes in one beautifully observed text of The Mouton Breton from 1860. I have previously posted the text in its entirety HERE but the relevant phrase reads.

"Quelques-uns sont gris ; ceux-là ont ordinairement la laine dure et longue et ressemblant à du crin"

The reference to age grey becomes immediately clear with the qualification that the greys have a wool which is hard, long and resembles horsehair. It is the reference to secondary or hair fibres that makes this text so descriptive. The "grey" described is typical of age grey - a  white and black mix of secondary fibres and is most striking in those Ouessants with  coarser less woolly fleece. 

 
Both this photo and the above photo are of black Ouessants  each has a different fleece and yet they both share a coarse differentiated secondary fibre and each is  uniformly "grey" all over. I have yet to come to any definative conclusions on age grey genetics but there is a similarity of presentation that has me asking plenty of  questions with regards to age grey its  inheritance and  expression with various fleece types.

Interestingly in this sample of berlinge  from a black Mouton des landes de Bretagne it is possible to see the coarser white fibres in the weave, age greying is extremely common in the breed. I personally make no selection for or against age-greying, historically  it would appear that  selection has been  based on utilisation  by  colour and / or fibre type for different purposes and  not in eradicating age grey.