More than 140 dogs have been recovered in a joint operation involving several agencies in Co. Leitrim.
The ISPCA, together with Leitrim Animal Welfare, helped rescue the dogs from a property in a rural area of the county where they were living in 'deplorable conditions'.
The ISPCA said it is the largest cases of canine dog in the history of the State and required the co-operation of 4 organisations to work together in the operation.
The ISPCA, Leitrim Animal Welfare, Dogs Trust and County Veterinary Offices all contributed to the rescue.
Most of the dogs were Bichon Frise crosses, King Charles Cavaliers and Shih Tzus, ranging in age from puppies right through to mature dogs.
Majority had skin, eye & teeth problems
The majority were heavily matted and also suffering from skin, eye and teeth problems.
The ISPCA says the owner of the animals is a dog hoarder - a person who keeps and breeds dog without rehoming or having the necessary space, funding or ability to care for the animals.
She had been making efforts to feed them, but the ISPCA says the situation "had spiralled out of control due to the sheer number of animals".
Leitrim County Veterinary Officer James Madden described the situation as an extreme case of 'dog hoarding' - and said the woman was breeding some of the animals, but it would also appear that she was also taking in other abandoned animals at the property.
ISPCA Chief inspector Conor Dowling said "The condition of the animals was appalling, their coats were extremely matted and many had thick dreads of matted hair right down to their skin".
"Their coats were also matted with a mix of sawdust, dog faeces and mud and their legs were soaked in urine".
"Many of the animals were also suffering from eye problems and one had to have an eye removed while the ISPCA was forced to put another animal to sleep, which is hugely disappointing while being a mercy there wasn't more than one" he added.