Thursday, November 24, 2016

Information on Sheep with Horns

Polled is a term given to sheep without horns, the animals with horns are said to be non-polled. The poll being the highest point on the animals head, roughly between the ears. 

Some sheep breeds have no horns in the rams (males) or ewes (females), while others have only the rams with horns, a few have horns on the ewes too. Some breeds can have sheep that are both polled, or non-polled. Scurred is a term given when an animal has small, poorly formed, horns, and these are more common in ewes.

When people consider what breed of sheep they wish to have, horns, or lack of horns, should be a consideration, as for some people horns are an advantage, and for others they are a disadvantage.
Six month old ram lamb.

Advantages of Horns on Sheep

Horns make great handles. When a sheep is caught there really isn't much to hold on to, especially with the wool sheep, a rope around the neck, or a halter, can be used, but horns are far easier to hold onto and offer excellent control of the head.

Horns can add value, as a mature ram with a good set of horns will often sell higher, and in some areas are very sought after by hunters (certain breeds of sheep in particular).


Disadvantages of Horns on Sheep

Large horns prevent sheep from getting their heads into the feeders.

Horns can get stuck in the wire fences. This is more of a concern in lambs whose horns are small enough to fit through a fence along with their head, but will catch when the lamb pulls its head back.

When the lamb is still nursing, and its horns are growing, they can hurt the ewes udder, and underside.
Although sheep do not fight aggressively as some animals they do head butt each other, in play, and at feeding times. When sheep have horns such action can be more of a concern, while they don't intentionally hurt each other with their horns, they may lock and as such when rams are penned together they should be checked regularly.

When damaged (which occurs more often in young, and scurred sheep) damaged horns from can result in bleeding which can be a problem, or lead to infection.

When sheep are not using to being handled, the horns can be dangerous to the human handler, or can be dangerous if a ram is aggressive to humans.

If not curved correctly they can go into the animals head, or eye, a serious problem, and should be removed if this is a concern.

One of my ewes, featuring 5 horns (two smaller).


What are Horns?

Horns start growing from a horn bud which can usually be seen when the lamb is born. In rams the horns grow faster than in ewes, and often become larger. Horns stay on the animal for its lifetime (unlike antlers which shed seasonally). In sheep that do grow horns, they grow the most in the first two years.
Horns grow from the skull and are a boney structure, make of keratin. The center of a living horn has blood flowing through it will will result in bleeding if broken.

Sheep Horn Genetics

Horn presence is controlled by three genes, P (dominant for Polling), p (sex linked for non-polled) and p' (produces horns in ewes as well as rams). Each sheep has 2 genes and depending which ones they pass this will determine if their offspring are to be born with, or without, horns. Note that of course some breeds are always polled so all animals of that breed would be PP and could never pass on a gene for horns.

As an example two sheep who are both polled (no horns) might have the genes Pp. Each would have a 50/50 chance of passing on the P gene for Polling, or the p gene for non-polling. For every 4 lambs the chances are that 1 would be PP, 2 would be Pp, and 1 would be pp, as such only one in four lambs would have horns, and only if it was a ram as this gene is sex linked. The other three lambs would be polled and there would be no physical way of determining which was PP and which was Pp.

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