The saving comes from slaughtering the animals at the age of nine to 11 months old, much sooner than the average 24-month lifespan of standard cattle.
The animals used are dairy bulls, so the CO2 they emit is technically classified as a "by-product" of milk production and offset against the existing dairy farming process.
Dairy bulls would ordinarily be exported or slaughtered.
Asda said that as the animals are smaller in size portions are easier to manage and so the price is lower than standard beef.