Screw Claw

We bought a bull last fall for use on American cows purely for terminal show steers.  All of our other bulls are pretty strong maternally, we just needed a bull that would add bone and power to commercial American females.  He’s actually a PHA carrier (not the bull mentioned here, but yes, I thought he had the PHA phenotype from when I saw him) and so we already knew he’s terminal.

He was sound as could be at the sale.  We watched his feet closely to make sure he was correct.  Everyone who saw him back home was impressed by how well he moved and how sound he was for such a muscular, big boned bull.  He was described as “extra sound in his structure” in the catalog.  Honestly, the only reason we got him was his extra skin (which is a plus for what we do), his lack of neck extension, and his PHA status.

Well, he came out of the pasture with a screw claw this spring.

For the record, if I were a show jock I wouldn't mention the above.  I just want you to realize how honest a guy you have the opportunity to listen to here.  Sometimes it feels like you take me for granted and don't appreciate me like you did when we first met.

Since then I’ve been trying to find out everything I can about screw claw.  Like a lot of things, everyone seems to know exactly how it works but virtually nobody agrees with each other.  Rather than pretending I can make any sense of it all, here's everything I've heard/read...

Source – First clubby expert

It’s an autosomal recessive trait that has a tendency to come up in Heat Wave lines (the bull is a grandson).  There are very popular club calf bulls with it.

Source – Second clubby expert

Sometimes it will happen but he’s not sure what the genetic process is on it.  It won’t show up in the steers since they are typically done by the time they would display it.  He uses bulls with it and he just manages it by trimming the hooves of the bull once or twice a year.

Source – First veterinarian

It’s always passed on and any bull with it should be condemned.

Source – Second veterinarian.

He agrees it’s an autosomal recessive trait.  He refuses to pass bulls on breeding soundness exams if they have it but wouldn’t necessarily condemn a bull with it.  The only way he’d recommend using a screw claw bull is if it is for a strictly terminal operation where you don’t keep the replacement heifers.

He’s seen entire herds destroyed by breeders who refused to face the facts and kept everything out of the bulls.  When asked about breeds that he’s seen it in he said “Maine, a little bit in Beefmaster, Simmental, Simmental, Simmental, and SIMMENTAL” and I don't think I can justly convey the emphasis he put on that last "Simmental".

He claims his belief of the autosomal recessive nature theory resulted from a research paper but didn’t remember where it came from (if you know what he was talking about, PLEASE let me know).  He laughed when I asked him about the Huang Shanks paper mentioned below.

Source – Blackewlls’ Five-Minute Veterinary Consult:Ruminant, 2008

“The conformation of cattle seems to predispose some beef cattle to this disorder.  Affected beef cattle are usually heavy muscled with a wide rump.”

“Aggressive corrective hoof trimming” may be considered for growing animals.  It “may have a genetic component.”

Source – “Within herd estimates of heritabilities for six hoof characteristics and impact of dispersion of discrete severity scores on estimates” – Y.C. Huang and R.D. Shanks, 1995

Abstract Here

The heritability of corkscrew claw was calculated to be .05 which is just about as low a heritability as you can get.

“Low heritabilities with a relatively large proportion of permanent environmental variance to additive genetic variance implied that response to selection for a single score of corkscrew claw, interdigital dermatitis and sole ulcers would be small.”

“Large proportions of environmental variances were consistent with two hypotheses: (1) corkscrew claw may be influenced by other diseases or inappropriate hoof care…”

So what does all of that mean?  Most likely it means somebody will come along and leave a comment that all of the sources are wrong and that they’re the one who really knows how it works.  Bottom line, I like to be all ears on stuff like this but the more people/sources I listen to, the less I think I’ve learned.

p.s. Picture of a corkscrew claw. We had the bull mentioned above corrected of I'd post a pic of it.

Dusty commented 6/17/2010 8:15:01 AM
What exactly is "screw claw"???
Chris commented 6/17/2010 8:38:30 PM
I am not sure if this is screw claw but I have seen long crossed toes on the rear hooves of sickle hocked cattle in the past. I figured it was due to the structure the rear leg and the front the hoof not wearing done.
Jeff Schroeder commented 6/17/2010 8:52:00 PM
I've seen that as well but on extremely old cows. While he has a ton of flex, the bull mentioned here would never be accused of being sickle hocked.
Neal commented 6/18/2010 9:17:58 AM
I had a two year old heifer that looked the same. The vet said it was screw claw and not to keep any of the heifers. By the way she is out of golden child.
Jeff Schroeder commented 6/18/2010 10:42:54 AM
And for those that don't know, Golden Child is a Heat Wave.
dragon lady commented 6/18/2010 2:23:45 PM
From Greenough "Lameness in cattle" (considered by some the cow foot bible)

Corkscrew claw
Definition- a corkscrew claw is a claw in which the abaxial wall, usually of the lateral hind claw, grows beneath the distal phalanx and displaces the sole dorsally giving the claw a twisted corkscrew appearance

Most descriptions are about 30 plus years old and from Europe- one study estimated 3% Holsteins had it

usually bilaterally on hind limbs
not obvious before age 3
bulls rarely have severe corkscrew claw, but lines of cows have traced to a single bull (note for this reason many believe a bull with corkscrew claw should not be used for breeding)

comment - there is no evidence that it is autosomal recessive - but there is a heritable component and environment likely may enhance expression

Jeff Schroeder commented 6/21/2010 9:32:17 AM
I've seen that resource but the fact that it claims it's not obvious before age 3 and that bulls don't express it caused me to ignore it.
Teresa Schoellkopf commented 3/13/2013 9:17:12 AM
Our Vet came out to our place yesterday to do all-around annuals and status on 2 pregnant cows. In the process, she had a second visit with a Dexter Bull Calf we purchased in a cow/calf pair last October.

She dehorned the bull calf On 10/19/2012, at the age of 6 months. At that time, she diagnosed possible ' Elfin Foot. ' Considering the minor appearance and the trauma he'd already been put through - said it would be safe for now, but to keep an eye and prepare to trim at a later date.

Upon treatment and examination yesterday, on 3/12/2013 - she asked what our plans were for this bull. When we mentioned breeding - her advice was to reconsider. She upgraded diagnosis to Screw Claw Foot. And she trimmed as much as possible.

This bull calf only turns 1 year old in a couple of weeks. We did not get into breeding for the purpose of selling live offspring for any reason with negative genetic flaws. We will be processing for the freezer.