Kay Kay

I have a mixed breed dog who is three years old. She was a Humane Society rescue, so we're not entirely sure of what breed she is, but we think that she's either an Australian Shepherd / Greyhound mix or a Border Collie / Greyhound mix. She is almost solid white (except for her head, which is black and brown) with very long fur.

She's currently having severe issues with shedding. I bathe her regularly, brush her (even with a brush that gets to the undercoat), but she is still continuing to loose a significant amount of fur. I just had her to the vet and she's totally fine health-wise. Does anyone know of anything that I could try to stop this awful shedding? Could it just be the time of the year?