Try a product called BACTICOL.

It's the best I've ever used to protect my dogs from ticks. Bathing alone is not enough - you have to soak your dogs in the medicine i.e. put them in a tub or pool.

Second thing you need to go is call the pest control to treat your hse i.e. spray anti-tick medicine on the floor / walls.

Keep your dogs in a clean isolated place (away from the cows) until the tick problem is fully resolved. If left to get out of control the ticks can kill your dogs so be careful.

Good luck