Through the tail end of her pregnancy, my mare Freyja lost some weight/muscle off her topline. She didn't have a lot to start with, she was malnourished when I got her, I got her in good shape through riding her by the end of fall, but now she's lost it again. Since delivering her foal on April 5th, she's already picked up a good bit of weight, her ribs have disappeared, but her spine is still more prominent than I would like to see. Her hindquarters have filled back in decently behind her hip, but from withers to loin she's still pretty prominent. She's sleek and her coat shines like she's been polished, just glowing with good health, and hasn't limped a step in several months (she had on again/off again soundness problems last year). I'm really anticipating starting to ride her again. I want to give her a full 30 days after she foaled out, but I also don't want to throw a saddle on her and start riding when her spine is all bony. I've always heard the best way to build a topline is riding varying terrain at a walk, and lunging a lot. She doesn't lunge - I didn't bother to teach her when I got her (D'oh) and she's clearly never been taught - not sure that's something I want to tackle while she has a baby at heels, either. (she is the type of horse that's so laid back you have to wake her up to move. She has very little "go" to her) Any other tips, or should I just pad her well and start riding her little at a time?
This picture is older, from shortly after she foaled, so her ribs are not visible anymore, and she's more muscled over her hips, but her back looks pretty much the same.