Marathon Wagyu sire performance and progeny data

Carcase data is what a carcase actually measured at the abattoir: its weight, marbling, eye muscle area and marble fineness. It matters because it is a result rather than a prediction. Breeding values estimate what an animal should produce; carcase data records what its progeny did produce on the rail.

Because only some progeny end up with carcase results. Many are kept as breeders or sold as bulls and never go to a feedlot, and not every animal that is finished returns carcase data. The figures here count only the progeny Marathon Wagyu has abattoir results for, so they are always lower than a sire's total AWA progeny count and the two are not directly comparable.

No. Many are external sires used through artificial insemination or embryo transfer, from studs including SUMO Cattle Co, Statkar Farms, Trent Bridge and Codenwarra. What belongs to Marathon Wagyu is the progeny and the carcase results: these are Marathon cattle, finished and measured, whoever the sire belongs to. Where semen is available through Marathon it is marked on the sire, and the averages here describe the sires in this data rather than a herd Marathon owns.

DMS is the digital marbling score taken from an MIJ camera image of the cut surface. AUS marble score is a visual grade from 2 to 9 assigned by a grader, while DMS and marbling percentage are measured from the image itself, so they resolve differences that a visual score rounds away.

Marble fineness describes how finely the intramuscular fat is distributed rather than how much of it there is. A higher figure means finer marbling. Across Marathon Wagyu progeny it correlates positively with marbling percentage and negatively with carcase weight and eye muscle area, which is the usual trade-off between marbling and growth.

Ten or more carcases is a reasonably reliable sample. Below five, a single exceptional or poor carcase moves the average a long way, which is why every sire here carries a colour-coded carcase count: green from ten, amber from five, red below five.

Marbling for age is the MIJ digital marbling percentage divided by half the kill age in months. A carcase at 30% and 30 months scores 2.0, and one at 45% and 30 months scores 3.0. Marbling keeps building for as long as an animal is fed, so a raw percentage favours the steer killed later; dividing by age puts steers killed at 28 months and 36 months on the same footing. It is calculated by Marathon Wagyu from measured carcase results and is not an AWA breeding value, index or percentile.