Wrth brisio, pennir gwerth anifail ar y farchnad ar sail y pris y gellid yn rhesymol ei gael am yr anifail hwnnw pe bai ar werth ar y farchnad agored a phe na bai’n dioddef o TB neu wedi dod i gysylltiad â TB.
The valuation determines the market value of an animal based on the price the animal might reasonably obtain if it was for sale in the open market and was not affected or exposed to TB.