"Farmyard animals are not being yoked together to pull cars but the fat in their bodies is being converted into biodiesel to drive fleets of the future.
The fat, or tallow, from one poor deceased sheep will produce about eight litres of biodiesel.
That's about 6 1/2 sheep to fill the tank of Astra diesel hatchback, meaning you'll get about 105km out of one animal on Holden's published fuel economy figures.
Pigs are better for travelling longer distances, with one unfortunate beast giving Astra drivers about 140km. One cow will keep the engine running for almost 450km.
Chooks, however, will barely get you to the corner, with one chicken worth just 600m."