Photo of Chondrodysplastic Steer Joint

[Kirk- Cascade Herd US]

Interested in comments regarding this photo, especially from Louisa Gidney

1. This is the joint of a two year old Chondrodysplastic steer with arthritic joints.

2. The other joints were also deformed and arthritic.

3. This steer was born on the breeder's farm to a chondro-Dexter mother.

4. This steer was otherwise very healthy, but at a very young age his stiff legged movements were that of a heavily-affected chondrodysplastic animal.

5. This steer's non-chondro brother had a completely normal walk, and completely normal joints at slaughter time.

6. This steer never had any injuries, no bruising, and no scar tissue. Again, other joints were also in classic chondrodysplasia arthritic condition.

7. The chondrodysplastic mother is still doing ok at age nine, but that's typical for females. Female chondrodysplastic cows tend to get bad at age 10-12.

[Louisa Gidney]

I'm used to dealing with prepped dry bones, so don't find this image easy to interpret. The foreground looks like a distal femur and the background a scapula glenoid. From here, the lesions look like osteochondrosis, which occurs in other cattle breeds and other species and is not a manifestation of chondrodysplasia. I went into this in tedious length in my thesis. The aetiology is a vexed issue but is may be environmental rather than genetic in origin, certainly in my own herd. That said, it appears to manifest most commonly in males but this largely reflects the fact that most studies have taken samples from steers in abattoirs.
I regularly encounter minor OC lesions on archaeological bones and I certainly have examples on modern non-short Dexter steers and bulls. The minor lesions have no visible impact in life. I have had one short-leg steer in 30+ years of breeding with severe congenital malformation of the carpal joint on the front leg. This was a difficult birth and required friendly farmer with calving jack for the delivery, only time this has been necessary. The cow was over 12 & had an arthritic hip joint. She was due for culling after this calf. The problem with the birth turned out to be that the ilial wings had fused to the sacrum, so the birth canal was constricted. This is a regular feature in mature males but the first example I've ever come across in a female.
So, in summary, there are always going to be one-off examples of congenital and pathological conditions in any population, including humans.

[JamsHundred]

Kirk,

You have plastered that unsupported photo everywhere without any identifying information. I saw another breeder inform you he had seen a video of this calf in a debris filled field where injury was more likely than not and you still are passing off a myth. I can show you a better photo than that and the story posted on the same chat group and the arthritis had NOTHING to do with dwarfism.

I have bred dwarf Dexters for 25years and I’ve never had a Dexter with an appearance like photos you publish nor aberrant walking gaits as you claim. You have NEVER raised the dwarf Dexters and have not a scintilla of knowledge of these fantastic little cattle that supplied to the breed the cherished traits that set them apart from other breeds. Furthermore, we all are aware of how to manage dwarf breedings so as to retain the positives and minimize the negative if we choose.

So YOU do not want dwarf cattle. OK go breed what you do want. However, when you remove the dwarf genes you remove the Dexter. There is NOT a single Non-dwarf Dexter that will fulfill the promise of minimal forage to maximum advantage as the dwarf does. The other traits that are treasured in this breed also are maximized in the dwarf cattle. It is just that many modern breeders are not aware of what they are missing for they do not have the experience of the loss.

You do not have dwarf Dexters. Why are you so obsessed about demonizing them. It’s no skin off your nose that there are some of us who do know their value. Or is the wonder of the little dwarf still perceived as some kind of threat to your profit margin as more and more breeders are returning (in the US) to the foundation of the breed.

Time to cut your bait. Looks like you missed snagging a fish.

Judy
USA

[Mark Bowles]

All my cows are short legged (dwarf as you call them) and I have been keeping them 20 years now, my cows generally age to around 14/15 although I have a 16 and half year old at the moment and she is in calf again. Never had problems like you describe and I certainly would not be without my shorts, only drawback is a 1 in 4 chance of a short steer that unfortunately hits the profit margins for the beef being that bit smaller.

[Louisa Gidney]

The following are the criteria used for the identification of osteo-arthritis in human and animal palaeopathology:
At least three of the following four changes should be found
i) grooving of the articular surface of the bone
ii) eburnation
iii) extension of the articular surface by new bone formation
iv) exostoses around the periphery of the bone.
Differential diagnosis is an important concept in palaeopathology, and I suggested osteochondrosis as I cannot observe a minimum of three of these bone modifications in this photograph.

[Kirk- Cascade Herd US]

All my cows are short legged (dwarf as you call them) and I have been keeping them 20 years now, my cows generally age to around 14/15 although I have a 16 and half year old at the moment and she is in calf again. Never had problems like you describe and I certainly would not be without my shorts, only drawback is a 1 in 4 chance of a short steer that unfortunately hits the profit margins for the beef being that bit smaller.

A breeder in the US says her chondrodysplastic-dwarfs tend to collapse from arthritis at age 12-13. Beryl Rutherford stated that most of hers started to show early arthritis at age 10, while her non-chondro Dexters often made it to age 20.

Mark do you test 100% of your animals for Chondrodysplasia? can you please post your BD1 chondrodysplasia test results for all your chondrodysplasia BD1 positive animals that have lived well past age 13 with no signs of joint problems?

My guess is that your long-lived "shorts" haven't all been tested for Chondrodysplasia? There are lots of Dexters with short legs, that don't have Chondrodysplasia. I've seen lots of people claim that their "shorts" lived long healthy lives, but when I've asked to see the test results, they tell me the animals weren't tested.

[Kirk- Cascade Herd US]

I did some research on osteochondrosis/osteochondritis.

I found that it can be triggered by mutant ACAN (aggrecan) genes. Aggrecan is an important component of healthy cartilage. So it turns out that broken ACAN genes which are the cause of chondrodysplasia in Dexters, can also be the cause of osteochondritis.

My research also shows that in some animals, osteochondritis hits males at relatively young ages (5 months).

The steer in the photo, had a broken ACAN gene (BD1), which caused chondrodysplasia (deformed cartilage), and likely triggered osteochondritis (inflammation and splintering of cartilage and bone).

Here's information showing linkage of the ACAN gene to osteochondritis.

https://ghr.nlm.nih.gov/gene/ACAN#conditions

https://en.m.wikipedia.org/wiki/Osteoch ... _dissecans

[JamsHundred]

Wikipedia. Really? Most of the stuff there is agenda driven slanted to the writer’s stance on the topic. You probably wrote it. LOL.
“A breeder in the US”. HA, I do not believe you. Give me the breeders name. I have been on the forefront of fighting to protect the roots of this breed for years, and I know the breeders and I do not buy that propaganda. *I* am the longest and most consistent large herd that has bred the dwarf cattle, and dwarf to dwarf for years. You have never picked up a phone and asked me a single question. You run to books written by others with an agenda, (write a paper, get published, get a name, make a buck), many of whom have lost their honor in this modern world where a man’s word is no longer his bond, nor a bit trustworthy.

The Dwarf Dexter defined the Dexter breed. The traits with which they imprinted this breed are unique in all breeds. Tell me how many cattle of other breeds are in pastures at 13-14-15 dropping calves. It is rare breeders who even keep their non-dwarf carriers to that age.

In the Dexter breed there is little illness, disease, or defects. We are blessed. Other breeds, including the hallowed Angus are rife with genetic problems. We are so blessed to share our pastures with this unique breed.

Be it animal or human, we all face issues of aging, Wrinkles and gray hair, declining sight and hearing, bone loss and ARTHRITIS. My own arthritic joints were noticeable long before the equivalent cow age of 10. You go chat group to chat group making mountains out of molehills to what purpose? Just what is your goal? To encourage breeders to eliminate animals whose value to the age of 12, (arbitrarily chosen to fit your mold) are as good, and better, on average, as any other breed strolling pastures? Good grief Kirk, you need find perspective. And for sure some dwarf carriers so you can at least rattle on from a base of knowledge instead of those anonymous breeders who fill your email with blather. Or start listening to those of us who do have the experience. I suspect I have so many “broken acan” genes in my own phenotype I will never live long enough for them to resolve. . Hopefully I can lay low and avoid culling.

[Louisa Gidney]

As well as differential diagnosis, critical evaluation is also beneficial to research. Osteochondritis dissecans is a very specific condition. Osteochondrosis is used in a much more general way in palaeopathology to discuss lesions in hard tissue which are not covered by the vet literature, which is concerned with changes in soft tissue.
My thesis is online at http://etheses.dur.ac.uk/10561/ The bibliography contains the most commonly cited articles on osteochondrosis, for example Ytrehus et al 2007, Thomas & Johannsen 2011. These are available online.
Are the bones of this animal still extant? If so, it might be possible to arrange with Dr Deb Bennet to prep the specimens. Deb comes to England every year to work on the animal bones from Vindolanda Roman fort, so possible for us to meet up. We could then discuss any hard tissue lesions in a more dispassionate way in comparison with my reference collection.

[Kirk- Cascade Herd US]

This link down below shows that osteochondritis dissecans is often caused by defective ACAN genes creating aggrecan deficiency. BD1 Chondrodysplasia is a broken ACAN gene causing aggrecan deficiency.

" osteochondritis dissecans

At least one mutation in the ACAN gene has been found to cause osteochondritis dissecans. This condition is characterized by areas of bone damage (lesions) caused by the detachment of cartilage and some of the underlying bone from the end of the bone at a joint. Other common features are short stature and early development of a painful joint disorder called osteoarthritis.

The abnormal aggrecan protein is unable to attach to other components of cartilage. As a result, the cartilage is disorganized and weak.

disorganized cartilage network in growing bones impairs their growth, leading to short stature."

https://ghr.nlm.nih.gov/gene/ACAN#conditions

[Louisa Gidney]

We seem to be at cross purposes, yet again. You are obsessed with one possible diagnosis of the condition and are signally failing to examine any other potential aetiology. This is not the way in which scientific research is conducted in palaeopathology. Was the animal ever seen by a vet, either in life or at the abattoir? Were any samples taken for post-mortem veterinary analysis? Are there any clearer photos of the abnormalities?