Customs duty concession for imported liquid nitrogen plants for cattle breeding conditioned on technical and administrative certification. Exempts liquid nitrogen plants up to ten litres per hour, their accessories and spares imported for artificial insemination centres from customs duty in excess of a basic rate calculated at 35 per cent ad valorem and from additional duty, subject to production at import of a technical certificate confirming non availability of domestic manufacture and an administrative certificate confirming requirement for the stated purpose.