(1) In this section -
"excess" means the excess of the relevant amount over the value of the stock to which this section applies at the beginning of the accounting period in which the disposal takes place;
"relevant amount" means the amount of any income received by a person as a result, or in consequence, of a disposal of stock to which this section applies;
"stock to which this section applies" means all cattle forming part of the trading stock of the trade of farming where such cattle are compulsorily disposed of on or after the 6th day of April, 1993, under any statute relating to the eradication or control of diseases in livestock:
Provided that, for the purposes of this section, all cattle shall be regarded as compulsorily disposed of where, in the case of any disease eradication scheme relating to the eradication or control of brucellosis in livestock, all eligible cattle for the purposes of any such scheme, together with such other cattle as are required to be disposed of,