[Jacob-list] Horns and offspring

[Melody]

Last year I had a 4-horned ewe (very nice horn placement and symmetry, although horns a bit small) lamb with twin 4-h rams. (Sire was 4-h, very nice horn placement)    I kept one lamb as a ram, the other I wethered (wool to nice to give up).  The intact lamb grew almost perfect horns.  Black, evenly spaced, upper horns curving just slightly backward, laterals  out and away from the face, the whole thing so symmetrical I was tempted to measure it to see if there was any difference at all--I sure couldn't see any.  Only fault was that they were a bit too close together, had very little space between uppers and laterals.  Now the wethered lamb--that was a different story.  It's a good thing for him he has good wool, or his name would be Chops.  On one side his upper horn  curves just slightly  outward , the lateral out and down, although tends to twist a bit There is a small space between them.  On the other side there is no space between the horn bases, and although they are not fused even at the base, the upper horn curves out and down and the lateral curves out and up so that they actually cross about 4-5 inches from the skull.  Is this a genetic thing or a developmental thing?  The "oddball" was a lot smaller than his twin at birth, and not as vigorous.  After the fact, I am hoping it is developmental with this individual, because I bred half my ewes to his twin brother.  (I know, I know, but I was so impressed with the good  one I didn't even think about the possibilities.  Live and learn.)   I guess I will start finding out in about a week, when the lambs start popping out.  
Melody at CritterLand
Redmond OR--anxiously awaiting the first spotted baby of spring!
  ----- Original Message ----- 
  From: Hobsickle at aol.com 
  To: jacob-list at jacobsheep.com 
  Sent: Saturday, March 08, 2003 9:19 AM
  Subject: Re: [Jacob-list] Horns and offspring


  Horn number apparently follows a simple Mendelian dominant/recessive with multiple horns (more than two) being dominant.  This means that your two-horned sheep carry two genes for two horns.  Your four horned sheep carry either two genes for multiple horns or one gene for multiple horns and one gene for two horns.  The exception to this is if the horn bud splits in early development, but doesn't separate sufficiently.  In this case they may rejoin (fuse) and look like a two-horn sheep.  (Usually these "false" two horns have a seam running long-ways through the horns.)

  The genetic control of horn shape and fusing (the later fusing that creates malformed horns) is apparently much more complicated.  It seems to be controlled by many factors and is not easily predicted.  (It has a lower "heritability" factor.)

  Switching back and forth with rams probably won't increase horn problems, other than in two horned sheep their really isn't a fusing problem period.

  -Dan



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