[Jacob-list] horns (and eyelids)

[Neal and Louise Grose]

Forward swept horns and split upper eyelid disorder (SUED) are related subjects in my opinion. These are not single gene traits, and culling a ewe for these reasons alone seems excessive.

The split eyelid seems to be a direct result of the polycerate gene. The split in the embryonic horn bud continues down along the skull to the eye socket. IN GENERAL, the more severe the distance between the horns, the worse the eyelid split. There are exceptions, as my good friend Mary Ellen pointed out when she had a fused horn ewe with SUED. However, in our flock, we have more of a tendency for the horns to be too close together; and, in 20 years, we have had one ewe with the condition, but have had a number of rams. I suspect that testosterone exaggerates the problem. (There is only so much room on those little pumpkin heads.)

Like most things having to do with Jacob Sheep, what we really want is a medium animal. We want between 40 and 60% black. We want a sheep that is smaller than those hogs and cows that we see masquerading as sheep in show rings, but not one that is to small to raise twins. We want medium (not mediocre) fleece. We don't want coarse boned sheep. And we want horns that are not too far forward or fused together. 

While polycerate is a single dominant gene, and polled is a single gene, position is due to the expression of MANY genes which are additive. I do not think that breeding to a 2 horned ram helps. If you want "correct" polycerate sheep, then we need to breed to and select for medium expression in the horns.

Neal Grose

  ----- Original Message ----- 
  From: ACAMDA at aol.com 
  To: jacob-list at jacobsheep.com 
  Sent: Thursday, February 28, 2008 10:16 AM
  Subject: [Jacob-list] horns


  Are forward curving horns passed on?

  We have a 4 horn 2 year old ewe with top forward curving horns.  They're beautiful, strong horns, they just point in the wrong direction.  Mother is a nice four horn, father was passing thru, but he seemed to have good horns.  

  We're unsure what to do with her.  Freezer?

  Kathey







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