A fire at Roleystone Horse and Pony Sanctuary, near Bradford, caused an estimated £5,000 worth of damage on Saturday, 13 August.
Equipment destroyed included rugs, headcollars, the winter supply of hay and straw and enough electric fencing to enclose four acres three strands high.
The 40x15m storage outbuilding was also lost — during the winter it houses stables and quarantine pens — and the cost of the re-build will be added to the estimated damage costs.
The alarm was raised by the next-door neighbour at 10.30pm who said that she could see flames “leaping over the top of her hedge.”
Chairman of the trust, which currently is looking after 30 horses, Dianna French said: “What used to be our rugs are now just melted blobs with the odd buckle.
“With winter on the horizon we are launching a major appeal, that building was used for storage but we use it for some stabling over the winter.
“It was probably just yobs seeing other parts of the country burning and thinking they could do the same — we’ve had little bits of trouble in the past, but nothing like this.”
Roleystone Sanctuary cares for and rehomes unwanted animals including horses, ponies goats, cats, chickens, dogs and pigs.
To help with the appeal visit www.roleystonesanctuary.org.uk