Two companies based in the United States have been given government grants of $3m to investigate whether cloned cows could provide a defence against bio-terrorism.

The companies – Hematech and the Dynport Vaccine Corporation – aim to develop animal clones which can produce antibodies to botulinum toxin in their blood.

Botulinum toxin has been developed and used as a bio-weapon in several countries, and the US Government fears it may be used in any future bio-terrorist attack on America.