LONG AND SHORT LEGGED
Chondrodysplasia in Dexter Cattle
The terms “Long-Leg” and “Short-Leg” when applied to Dexter cattle are not in reference to the height of the animal. They are colloquial terms adopted for describing animals carrying the Chondrodysplasia dwarfing gene (short-leg) and those animals that do not (long-leg). It is not always easy to tell which is which just by looking at them with a passing glance.
For as long as records go back there have been two distinct types of Dexter cattle. The English gentry preferred the short-leg type and it is still the most common type of Dexter shown in the UK.
Short-legged (carrier) and long-legged (non-carrier) animals are of the same merit with respect to the Australian Breed Standard for the purposes of breeding, registration and showing. Both types should be judged equally when shown and are assessed against the same criteria for Linear Classification by Holstein Australia.
Short-legs (carriers) should, as with their long-leg counterparts, be structurally correct other than the obvious variation of bone length. Being a “shortie” is not an excuse for poor conformation and the same scrutiny of structural correctness should be applied when selecting any animal.
Understanding Chondrodysplasia (BD1 & BD2)
Chondrodysplasia is a form of dwarfism and is similar to that which occurs in many cattle breeds and other species of mammals.
The dwarfing gene specific to Dexters was identified after Dexter Cattle Australia Inc. (DCAI) sponsored research into the occurrence of short-legged (dwarf) animals in the Australian Herd.
The research discovered an incomplete dominant gene, referred to as (BD1) This gene mutation is unique to Dexter cattle but not dissimilar to that found in other cattle breeds. A second form of the gene mutation (BD2) has a similar physiological presentation as (BD1). The BD2 mutation was found to have been unique to one foundation animal, Meadow Park Charles, and its descendants.
The identification of the BD1 & BD2 gene and the subsequent development of genetic tests put Australian Dexter breeders ahead of the rest of the world for herd management. Testing for the gene is now readily available and is a cost effective breeding tool.
Most Dexter cattle breeders in Australia have used testing over an extended period of time to establish a free by inheritance status for their animals.
If an animal has been tested for the gene and the results have been reported to Dexter Cattle Australia Inc. (DCAI) the Chondrodysplasia status of that animal will be shown on the animal's details in the DCAI Herdbook database and on the pedigree certificate. If the printed pedigree certificate was issued before the animal was tested the Chondrodysplasia status may not be shown.
Animals having a short-legged (carrier) parent should be tested in order to establish its carrier status. The BD1 & BD2 Chondrodysplasia gene mutation is lethal if two carriers are bred together and a homozygous calf carrying two copies of chondrodysplasia gene results. Knowing the status of the animals you are breeding with is important.
Short-legs generally enjoy the same longevity, productivity and ease of calving as long-legs. They are reputed to be excellent feed converters and do well in most conditions. Long and short leg animals are equally renowned for excellent productivity as milkers and beef producers.
Dexters are a naturally small breed but extremes of size, particularly very small animals, should be avoided in order to maintain practical breeding herds.
Article written by Roz Michelini and originally published on the previous DCAI website.