[Jacob-list] Horn Genetics and a Feed Question

[Neal and Louise Grose]

I have noticed that good scientist never say "always" and "never". Unfortunately, I am not a good scientist, but most of what I say should be prefaced with "probably".

I should have said that we breed for medium distance between the horns. What we are really selecting for is the shape of the head. However, Neither should we be selecting for larger and larger horns. Our flock does not have robust horns, but we have never had a case of OCD either. 

In some ways, the selection of "proper" two-horned sheep is not the same as in four-horn sheep. The ram that we used that produced the most SUED also produced the most perfect two-horned ram I have ever seen. His horns swept out in a double curl and were over 30 inches from tip to tip. He also sired forward swept horns, even though his own horns looked OK. On closer inspection, there was considerable distance between the horns on the side.

We don't know what type of position expression to expect with a mating of 2 and 4 horn types. We can have SUED in a heterozygous sheep. In fact, I have seen SUED in a polled crossbred ram.

The polycerate gene appears to be a simple dominant to the two horn condition. This is similar to brown eyes in humans. If we have even one of the two melanin producing alleles at the melanin-for-eye locus, then we will have brown eyes. Only those of us with two defective alleles will have blue eyes.

B,B = brown eyes (homozygous brown)
B, notB (b) = brown eyes (heterozygous brown)
b,b = blue eyes (homozygous blue)
If we mate (B,B) X (B,b) all offspring will be Brown eyed, but 50% will pass on the defective gene 
If we mate (B,b) X (B,b) repeatedly, 75% will be brown eyed and 25% will be blue eyed and 50% will be heterozygous

Those of us with grey, green or golden eyes have a second gene interfering with the expression of these primary types. Also, (Betty, is there a theological term for "God laughs"?) there IS a rare recessive brown gene. Life is ALWAYS more complicated than we would like for it to be.

Polycerate in sheep works much the same way. Mating two heterozygous Jacobs will produce two-horned offspring 25% of the time. The catch is, we do not know that the animal is heter before hand, Likewise, I have seen two horned ewes mated to several four-horned rams before they ever produced a multi-horned lamb. Also, I suspect that there are secondary genes that muck up the works.

Feed:
1) You must find a mineral that states the copper level. Every decent mineral supplier over here on the humid coast does so. Go forth and complain. As an alternative, get dicalcium phosphate and feed grade lime and make your own mineral. That and salt will take care of the vast majority of the sheep's needs.

2) Yes, sheep can eat cottonseed, but it is high in fat. Feed less than what you would feed grain. You will need a good forage source as the primary feed.

Cottonseed hulls, on the other hand make an excellent forage substitute for those of us who are running out of hay. They are highly digestible fiber, but can be used to self-limit intake of other ingredients.

Neal Grose

  ----- Original Message ----- 
  From: Lynette Frick 
  To: jacob-list at jacobsheep.com 
  Sent: Friday, February 29, 2008 12:56 AM
  Subject: [Jacob-list] Horn Genetics and a Feed Question


  Hi Neal,

  I hope you don't mind this is mostly directed to you, but anyone else with answers please share:)

   This is really interesting. What exactly are you reffering to when you say, "medium expression in the horns"? Do you mean in the distance between them, or their thickness, or both? Sorry if I sound rediculous, I am truely fascinated with genetics...especially the genetics of Jacobs,  I just don't know/ haven't had enough time yet to make as many observations.  

  I have some more questions if you don't mind me asking:

  > How can a four horn ewe when bred to a two horn ram have two horn twins, or a two horn and a four horn twin? Both the four horn ewes where bred to the same two horn ram, while all my two horn ewes where bred to a four horn ram and all of them had four horn twins? Would that mean that the 4H ewes where heterozygous for the polycerate gene?

  >Have you found any issues that arise when using soley four horn stock in a breeding program?  

  >What do you suggest to improve hornset in two horn stock? I am having a problem with 2h ewes having narrow hornsets, and will that carry over into the four horn offspring?

  >Do you think that it would be best to breed my four horn and two horn stock as distinctly seperate groups, ie. two horn to two horn and four to four only to improve either one?

  --Some Feed Questions

   Can sheep have cottonseed? You mentioned that it can be used as  a fiber source for cattle on a high concentrate diet. I may be able to purchase a flock sized bit of it from our friend who is also the herdsman of a dairy with 2k head in the milking string (needless to say he has a few tons of it), but have never heard of sheep being fed cotton seed. If sheep can be fed cottonseed to help meet fiber reqs., what is the maximum sized alfalfa pellet that sheep can comfortably eat? I would like to be able to feed pellets when I don't have any pasture because I can store them better and they won't foof in the wool. 

  Ok, and last but not least: I am having a terrible time finding a quality sheep mineral here in the "Communist State of California" as my feed distributer calls it. I can't find loose mineral at all, and hate using blocks and tubs because how hard they are on the ewes teeth. Which mineral would you reccomend? I haven't even been able to get the feed company to tell me how much copper is in the stuff I'm feeding... they just keep saying that there's "No copper added" and I know that doesn't mean "no copper at all". One company that says No copper added, told my feed distributer that their Sheep block only contained 40ppm copper! I'm definately willing to go out of state to pick up minerals that won't kill  my sheep... or should I just feed the granualized sheep selinium salt that doesn't have all that other stuff in it? Do Jacobs really even need all the other stuff when they have good hay?


  Thanks a million in advance,

  Lynette Frick
  IDEAL FARM
  Jacob Sheep 
  www.idealjacobsheep.com/2008lambs.html 



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