question about chondrodysplasia carrier

[Barb Koth]

I am planning on buying my first Dexter heifer this week. She is not registered and I plan on milking her. She is short legged. The owner has not said if she has been tested for Chondrodysplasia carrier. Is this something that I should insist on? If she is a carrier will she have bulldog calves? If she is bred to a non-carrier will she have normal calves? Could someone please explain this to me. I have been reading on the internet, but am still confused. Thank you

[marion]

Hi Barb, Congratulations on your new Dexter. Here is a link to the ADCA article on Chondrodysplasia..marion

www.dextercattle.org/genCDChondroarticle.htm

[Clive]

"Short legged and chondro carrier go together."

That wouldn't always apply in the UK (and I think Australia, not totally sure on that one). Herds like Woodmagic (and now others) have bred short non-carriers. Woodmagic's are short, not just small. They are also stocky and beefy which doesn't always come out in the photos. I had the pleasure of visiting Woodmagic just a few weeks ago and meeting Beryl Rutherford for the first time. We too have bred a few short ('ish) non-carriers, but not as stocky yet....ask me again in twenty years time . If it can be achieved you can breed short animals without having a long-leg every other calf, and no chance of bulldogs at all, with good predictability.

In a way it's a shame the word short was ever used to describe a condition because it makes it difficult to describe your animals that are simply short, without having to explain that they aren't carriers.

[kansasdexters]

Hi Genebo,

Take a look at Hiyu Woodlark, her photo is posted on DexterCattle2's front page and in the ADCA Online Pedigree. Woodlark tested as a HN, homozygous normal, non-carrier of Chondrodysplasia. She is 40-inches tall, measured at the hip and she is a very substantial cow with short legs.

I would not describe her as being a "miniature" Dexter. She is 50% Woodmagic breeding and it really shows in the shape of her head and proportions of her body (long, deep, wide body). She turned 15 years old this year.

Like many traits, stature is determined by more than one gene. The chondro gene can affect stature significantly, but its effect is amplified or diminished based on the presence or absence of other "modifier" genes that can also affect bone growth. That's why we see some Chondro-carriers that have an exaggerated dwarf-like appearance and others that are very well proportioned. That's also why we see some chondro non-carriers that are tall and rangy looking and others that are very well proportioned. There is a range of sizes and shapes in both chondro-carriers and in chondro non-carriers.

Remember that the chondro gene is only one gene out of the thousands of genes that influence the outcome of an animal's phenotype.

Best Always,

Patti