What's In John's Freezer?

Why should you care
If you have to trim my hooves?
I’ve got to move with good feet
Or be put down fast.
I know I should trot
But my old vet she cares a lot.
And I’m still living on stone
Even though these feet won’t last.

(mutated from The Who, “Cut My Hair“, Quadrophenia… from the heyday of concept albums and grandiose rock!)

Talkin’ bout my osteitis

Day Four of Freezermas. Four posts to go. I can see through time… Hence the silly title for today’s concept album track. Quadrupedophilia did not have a good ring to it, anyway.

Stomach-Churning Rating: 4/10. Reasonably tame; bones and hooves. Some pathologies of those, but not gory.

If Quadrophenia was the story of a man with four personalities (metaphor for the four band members), then quadrupedopheniaphilia is the story of how diverse forms of four-legged animals have lots of problems because of our exploitation of them, which leaves a crisis to resolve: Who are we? Are we caring enough to fix a bad situation we’ve created for our four-legged ungulate comrades?

Four legs good, two legs bad? Not really. I featured ostriches earlier this week and two legs are indeed pretty good. Four-legged cats are great, too. But four-footed big beasties with deformed hooves: those are bad all around. That leads to today’s topic…

But hey, happy 205th funkin’ birthday Charles freakin’ Robert Darwin!

Charles Darwin on his horse “Tommy” in 1868- from the Darwin Correspondence Project, https://www.darwinproject.ac.uk/darwins-photographic-portraits

Today’s post concerns a phenomenon that (Western) civilization has wrought with large hoofed mammals, and evolution is a big part of it (as well as biomechanics and anatomy) . Cynical perspective, with some truth to it: We’ve evolved larger and heavier animals to either do harder and harder work on tough surfaces like concrete floors and tarmac roads, or to stand around while we gawk at them or wait for them to get fat and tasty. Either way, the outcome should come as no surprise: their feet, the interface of that hard ground and their body, eventually start falling apart.

I’ve posted about this several times with respect to rhinos and elephants (here and here and here and here and here), but this post hits closer to home: what goes wrong with the humble hoof of our friend the horse, cow, sheep or other ungulate. It’s where the rubberkeratin hits the road. Ungulates have not evolved to live on dirty, wet concrete floors; to be obese and inactive; or to have hooves that don’t get worn down. So they suffer when they do encounter those modern conditions.

“No foot no horse,” they say, and it’s so true- once the feet start to go (due to hoof overgrowth or cracks, abscesses or other trouble), it’s hard to reverse the pathologies that ensue (arthritis, osteomyelitis, infections, fractures, etc.) and the animals start going lame, then other limbs (supporting greater loads than the affected limb) start to go, too, sometimes.

Jerry the obese, untrimmed-hoof-bearing horse. “Turkish slippers” is an apt description. DM has more here.

We can do plenty about these problems, and the title track above explains one of them: trimming hooves. Hooves often get overgrown, and if animals are tame enough (requires training!) or are sedated (risky!), hoof care experts (farriers) can rasp/file/saw them down to a more acceptable conformation. If we don’t, and the animals don’t do the trimming themselves by digging or walking around or living on varied surfaces, then the feet can suffer. But there’s still not much evidence for most common species kept in captivity by humans that indicates what the best methods are for avoiding or fixing foot problems.

What we’ve been trying to do at the RVC is use our expertise in evolution, anatomy and biomechanics to find new ways to prevent, detect, monitor or reverse these foot problems. We had BBSRC grant funding from 2009-2012 to do this, and the work continues, as it behooves us to do… Past posts have described some of this research, which spun off into other benefits like re-discovering/illuminating the false sixth toes of elephants. We’re working with several zoos in the UK to apply some of the lessons we’re learning to their animals and management practices.

Above: Thunderous hoof impacts with nasty vibrations, and large forces concentrated on small areas, seem to contribute to foot problems in hoofed mammals. From our recent work published in PLOS ONE.

Foot health check on a white rhino at a UK zoo; one of the animals we’ve worked with. Photo by Ann & Steve Toon, http://www.toonphoto.com/

If it works, it’s the most satisfying outcome my research will have ever had, and it will prevent my freezers from filling up with foot-influenced mortality victims.

Again, I’ll tell this tale mainly in photos. First, by showing some cool variations evolved in the feet of hoofed mammals (artiodactyls and perissodactyls; mostly even/odd-toed ungulates of the cow/sheep and horse lineages, respectively). Second, by showing some pretty amazing and shocking images of how “normal” hooves go all wonky.

Two ways to evolve a splayed hoof for crossing soft ground: 2 toes that are flexible and linked to big pads (camel), and 2 main toes that allow some extra support from 2 side toes when needed (elk). At Univ. Mus. Zoology- Cambridge.

Diversity of camelid foot forms: big clunky, soft Old World camel feet and dainty, sharp highland New World camelids. [Image source uncertain]

Moschus, Siberian musk deer with remarkable splayed hooves/claws; aiding it in crossing snowy or swampy ground. At Univ. Mus. Zoology- Cambridge.

Tragulus, or mouse-deer, with freaky long “splint bones” (evolutionarily reduced sole bones or metatarsals) and dainty hooved feet. At Univ. Mus. Zoology- Cambridge.

Overgrown giraffe hooves. An all-too-common problem, and one we’re tacking with gusto lately, thanks to PhD student Chris Basu’s NERC-funded giraffe project!

Wayyyyyyyyy overgrown hooves of a ?sheep, from the RVC’s pathology collection.

Craaaaaaazy overgrown ?sheep hooves, from the RVC’s pathology collection.

If we understand how foot form, function and pathology relate in diverse living hoofed mammals, we can start to piece together how extinct ones lived and evolved- like this giant rhinoceros! At IVPP museum in Beijing.

So, what do we do now? If we love our diverse hoofed quadrupeds, we need to exert that quadrupedopheniaphilia and take better care of them. Finding out how to do that is where science comes in. I’d call that a bargain. The best hooves ever had?