Twenty-nine ponies died after being left to live in appalling conditions, a court has been told.
A mother and daughter from a village near Southampton are appearing at New Forest Magistrates Court charged with causing unnecessary suffering to animals.
Debra Green, 41, and her daughter Michelle, 19, from Holbury, each deny four charges in the trial which began on Tuesday.
Jeremy Green, prosecuting for the RSPCA, said 12 ponies were already dead when found in a field on December 2006 and another 17 had to be shot.
He said the horses were lying or standing in mud and their own excrement and were suffering severe respiratory infections.
But an expert witness for the family, Madeline Forsyth, said the ponies’ deaths had been caused by a bacterial infection unconnected to the wet and muddy conditions.
The case continues.