POLLED, HORNED, SCURRED – A REVIEW
Speckle Park are to be a polled breed. Scurs are not horns. And though they may appear similar they arise from a different genetic basis on two different chromosomes. The main points are:
Speckle Park are a polled breed. Speckle Park have been marketed, promoted and advertised as a “polled breed” since their beginning. A naturally or genetically polled breed as opposed to mechanically “polled,” that is, “polled” by mechanically removing horns or scurs. CSPA By-laws (15, 4d) prohibit the registration of horned Speckle Park. These same By-laws do no prohibit the registration of animals with scurs, but scurs are a reportable genetic condition and are to be recorded on the application for registration and the registration certificate which is also to be amended if the scurs occur after registration (By-laws, 19, 2).
Polled is assumed to be the desired trait and the following statements are written with that in mind.
What follows is a concise summary. The more detailed and technical presentations may be found many places on the internet. For example, the research from the University of Saskatchewan is available at http://homepage.usask.ca/~schmutz/polled.html
Polled / Horned
Polledindicates the absence of horns by virtue of the absence of the gene(s) responsible for producing horns. The polled gene is dominant to its horned counterpart. Polled animals may have scurs and in fact scurs will not occur if the animal is not polled. All Speckle Park fall into one of three category in regard to polled/horned. Scurs are a separate phenomenon and are dealt with below.
Pure for Polled (PP). Same as homozygous polled. This animal has two genes for polled.. This animal will not produce offspring horns because it does not possess any gene for horns.
My commercial cows have horns. How do I ensure all the calves are polled? Use a bull that is pure for polled.
How do I determine if an animal is pure for polled? There are two ways to conclusively demonstrate that an animal is pure for polled. The best and most accurate is a simple DNA test. The second is test breeding. When a bull is bred to 10 horned cows, and all the calves are polled, he is 98% likely to be pure for polled. This may be as accurate as DNA testing but just takes more time and resources.
What is double polled? There may be a confusion at this point. Double polled may be used by some to describe a animal both of whose parents were polled; but this does not ensure that the animal is pure for polled. An animal with two polled parents, if one or even both were heterozygous polled (Pp) could still have received a horn gene and thus still be a horn carrier. See below for an explanation of Pp. Others use double polled to describe a pure for polled animal such as the PP described above.
The DNA test on my animal came back “homozygous polled.” What does this mean? “Homozygous polled” means the animal tested is PP, pure for polled.
Horned (pp). Same as homozygous horned. This animal does not carry any gene for polled. This animal is always horned unless mechanically dehorned after birth. This animal is incapable of producing polled calves unless bred to a polled animal.
The DNA test on my animal came back “homozygous horned.” What does this mean? “Homozygous horned” means the animal tested is horned. If no horns are visible, there are three possibilities: 1. The horns have been removed; 2. There has been a new polled mutation; or 3. An error occurred in the laboratory testing. Please report this finding to the CSPA Office.
Polled Horn Carrier (Pp). Same as heterozygous polled. Also known as a “horn carrier.” This animal carries both a gene for polled and a gene for horned. The poll gene is dominant and so this animal will look polled, that is, no horns. This animal will produce polled calves and horned calves. A horned carrier will leave half of his calves as horn carriers. This animal may show scurs. Every animal with scurs is heterozygous polled (Pp) which means carries the horn gene. When breeding this Pp animal to another Pp, half of the calves will be Pp (polled horn carriers), a quarter will be PP (pure polled) and the last quarter will be pp, actually horned. This is a travesty for any polled breed whether Speckle Park or Angus.
Why did my polled cow bred to my polled bull produce a horned calf? When the cow and the bull are both polled but horn carriers (Pp), each calf has a fifty percent chance of being a polled horn carrier (Pp), some (a twenty five percent chance) will be pure for polled (PP), and unfortunately others (a twenty five percent chance) will be horned.
My first cross commercial SP herd of cows all have at least one horned parent. They are polled but obviously horn carriers. How do I get the most polled calves out of these horn carrier cows? If you breed to a pure for polled (PP) bull, all the calves will be polled, and only 50% will be left horn carriers. If you breed your current herd to a polled horn carrier (Pp), 75% of the calves will be polled (some PP and others Pp) and 25% with actual horns. Likewise, viewing that same cross of horn carriers, if you use a Pp bull, 75% will remain horn carriers, either Pp or pp, and only 25% pure for polled.
From my horned cows and my polled SP bull, why are half of the calves still horned? The horned cows give every calf a horn gene. If the polled sire also carries the horn gene (Pp, heterozygous polled, horn carrier), he gives a poll gene to half of his calves and a horn gene to half. Every half receives a horn gene from its mother, and half receive a horn gene from the bull, so half of the calves will receive two horn genes and thus be horned. The other half will be polled but horn carriers.
Can I use the shape of the poll to determine is an animal is pure for polled (PP) or a polled horn carrier (Pp)? Many breeders have concluded that an animal with a “peaked” poll is pure for polled (PP) and that an animal with a broader flatter poll is a polled horn carrier and maybe even that it will develop scurs. This may be accurate. However, the surest way to make this determination is the DNA test for polled/horned.
The DNA test on my animal came back “heterozygous polled.” What does this mean? “Heterozygous polled” means the animal tested is Pp, that is, a horn carrier.
Scurs are horn like growths in the same place on the head as horns. Scurs have traditionally been called “wiggle horns” because they wiggle. Scurs are not attached directly to the skull but to the skin and so wiggle. Occasionally in much older animals scurs eventually do become attached to the skull and no longer wiggle. Scurs and horns are caused by different genes on two totally different chromosomes. There is no DNA test for scurs.
Most important about scurs. Recent research coming out of the University of Saskatchewan has confirmed on a molecular level what many breeds and breed associations have known from experience for many years.
SCURS WILL ONLY BE SEEN ON POLLED ANIMALS THAT CARRY A GENE FOR HORNS (Pp).
In other words EVER SCURRED ANIMAL IS A POLLED HORN CARRIER (Pp).
The implications of this statement proven from the research in Saskatoon are immense.
The inheritance of scurs is variable when in the presence of an X or Y chromosome.
The scur gene is not sex linked but it displays itself differently in bulls and cows.
REMOVING SCURS – A CAUTIONARY TALE
It has become the habit of some breeders to remove “scurs” for aesthetic reasons (the show ring), but make no mistake about it. Removing scurs helps marketing too. Here are some things to bear in mind.
How to tell a scur from a horn?
Horns, hooves, and hair are all the same type of cell material. A cow with damaged skin and hair cells over the ribs, can grow back a horn-like growth.
|Scurs are attached to the skin||Mature horns are attached to the skull|
|Scurs wiggle and hence their popular name “wiggle horns.” Scurs in very mature cattle can sometimes become attached to the skull so that they don’t wiggle.||Mature horns don’t wiggle.|
|The “scurs” “wiggled” until the calf’s second show season in one Australian example. Then the debate was on. Were these scurs that attached themselves or were they horns? A simple DNA test demonstrated the animal was homozygous horned, pp.||Horns on young calves also wiggle until they firmly attach to the skull usually no later than six months.|
|Scurs have a broader base; shorter length; scurs may look like shriveled horns.||Narrower base; longer than scurs.|
|Typically scurs may be as small as a man’s thumb nail.||Compare Longhorns|
|Scurs are almost solid.||Horns are hollow.|
|Scurs may be unilateral (only on one side)||Horns are typically bilateral.|
|Both scurs and horn continue to grow throughout life.|
|Scurs may be early or have a late onset (two years).||Horns are usually present at birth or very soon after. However in a rare case may not be there until fifteen months.|
|At least one gene for polled is present.||No gene for polled present.|
|Bananna scurs are very long (8 inches or more) and swing back and forth at the side of the head. Typically seen on rodeo bulls. At least one purebred SP bull has been photographed with “banana scurs.”||Bananna horns are actually scurs.”
The fifteen month old SP bull with 3 inch horn like growth bent backwards went on to develop a full set of banana scurs.
|The horn like growths on the head of a 15 month old bull calf which are bent back (from all the bulls sparring) are a scurs.||Horns don’t bend back.|
|Surgical removal of a scur only requires incision of the skin around the scur.||Surgical removal of a horn requires a more extensive surgery to remove the root growth cells from the skull. The incision is longer.|
|Removing scurs improperly (incompletely) will result in regrowth of the scurs.||Removing horns improperly (incompletely) without removing the root cells may result in regrowth of horns. Popularly speaking these may be called “scurs” by those who don’t know that “scurs aren’t horns.”|
|There is no DNA test to identify scur carriers. Some research has indicated that there may be as many as three genetic bases for scurs.||There is a DNA test for the presence of the gene for horns and polled.|