I have two mares which I have owned for 13 years. Jess is a 18 y o Welsh cross and Faeroe is a 16 y o Arab. The problem is that they both have swellings from their belly button to her nipples. One long lump which is central and right next to her belly button and one either side slighter nearer her nipples. The lumps are raised almost a centimetre. They are on good grass and have recently put on weight. I have been monitoring them and I am happy for them to put on some weight as they got thin in the winter. When I first noticed Jess' tummy, I was really worried, but the lumps are soft and not tender and it is strange for both mares to be affected. Faeroe can be a bit sensitive on her tummy, but both mares are okay if I press the skin and put on fly repellent.
Someone has suggested an adverse reaction to the flies? What do you think? Has anyone experienced the same thing? As I say I have had both mares for 13 years and never known such large swellings. I have been looking to see if there are any new weeds in the field which I had not noticed - which cause this reaction.