The animal welfare charity has a team of inspectors working around the clock to help provide food, bedding and shelter for non-infected farm animals — they cannot be taken to lush pasture because of foot and mouth movement restrictions imposed to prevent the spread of the disease.
But the RSPCA says sources of bulky foodstuffs such as haylage, silage, hay and straw appear to be running dry and, together with Noel Edmonds, the organisation is appealing for anyone who can offer stocks of the food.
The RSPCA has also contacted MAFF to ask it to consider allowing access to tons of bagged food which is currently standing unused on farms which have had contact with the disease.
Noel Edmonds, whose farm at Jacobstowe is in the centre of the Devon disease outbreak, said: 'It is heartbreaking to see the distress caused to our many farming neighbours and friends at seeing animals starved because of the shortage of food.
'I would urge MAFF to think of these living, hungry animals and to allow this bagged food, the covering of which can be easily disinfected, to be released to feed them.
'The RSPCA's efforts are helping thousands of animals and the food is needed urgently.'
RSPCA Inspector Tony Woodley said Noel and his wife Helen had been doing tremendous work behind the scenes to source food from other parts of the country, store it and distribute it but it was now becoming clear that supplies were running low.
'The farmers we are working with in many cases don't want to have their animals slaughtered under the welfare disposal scheme and we're trying to do everything in our power to help them save their flocks and herds,' he said.
'We have plenty of 'concentrate' and processed forms of food but these cannot be given to animals without the bulky roughage and that is what we are running out of.'
Any farmers who have stocks they do not need or anyone who has supplies of haylage, silage, hay and straw are being asked to come forward. They should contact the RSPCA on 0870 5555999.