No I agree with you about being horse-mad, but they AREN"T, so that's why I think it's so silly.
The thing I most object to is having it on the invitation like that, asking for money. Really crass.
If you would prefer not to receive certain types of toys and stuff I understand, not this!

If DD had taken a practical interest, I certainly would have bought her a pony/horse, as I think that would be a passion I would like her to have, but no unfortunatley!