I'm going through this with one of my dogs. He had 3 teeth pulled Tuesday. Same thing low phosphorous. So any way I started giving him IP-6 powder on his food.
Alternative Health & Healing Newsletter - June 1999
IP-6 is found naturally in plants, cereals and legumes (peas, beans). Because of its high phosphorus content, IP-6 is also important for the production of ... http://www.ghchealth.com/jun-99.html
I buy mine from I-Herb. Jarrows formula.
I feed my dogs 100% raw diet and was quite surprised that he was low.