'Parasitic twinning' could explain calf born with two extra legs

Key points

• A calf born in southern Queensland with two extra legs growing from its head has made a full recovery after surgery. The heifer, nicknamed Spider, was operated on when she was just over a week old.
• Imke Tammen, a University of Sydney researcher, says parasitic twinning could explain the condition, where an embryo starts to split into two but does not separate fully.
• Pittsworth veterinarian Megan Smith, who has practised for 20 years, performed the surgery at minimal cost after the owners considered putting the calf down.