Injecting milk into a pumpkin vine has been said to be a myth. I've never heard of a "seasoned" grower doing this.
I never heard of someone watering with milk. May get a little calcium boost? I wouldn't water with milk personally. If your serious about growing a giant, I'd get one, or more of Don Langevin's books on the subject.

Douglas

A 10:1 mixture of water and unpasturized milk can be used for a preventative fungicide for powdery mildew. I would recommend a Fish and Kelp Fertilizer 1 ounce per gallon along with 2 ounces of Molasses sprayed as a foliar. For the soil Manure and Compost.

Where would one get unpasturized milk if there was no farm close by? Is dry milk unpasturized?