Hi Fiona:
just a point on the growth of bovid horns. The growth takes place
principally in the basal part, i.e. proximally where you find the largest
diameter. What has happened in you case is that the horn has started to grow
in one way and then at one point the growth in diameter increased faster
than lengthwise growth, and thereafter growth seems to have proceeded in
"normal" way. Growth of horns are influenced by sex hormones. I cant tell
the sex from the photo but perhaps it could be a case of castration. There
are some papers on ageing and sexing and evidence for castration of horn
cores (e.g. Armitage for cattle, Hatting for sheep).
Leif Jonsson
Göteborgs Naturhistoriska Museum
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