It will have no effect or should have no effect on the price of beef, dairy cattle are not fed to fatten like a beef for slaughter, they are fed a specific diet to maximize milk production, and dairy cattle are very very lean. They might sell the meat for some other purpose but a dairy cows entire life is producing milk, as such they really aren't too suitable for human consumption if as they get near the end of that life. I live in an area with lots of large dairies and feed lots and have both worked around dairies (not as an employee of the farm but doing construction for the farmer). Dairy cows are fed a diet thats high in protein, cows for slaughter a diet high in carbs, the same thing happens to cows that happens to humans on similar diets, one gets you slimmer the other makes you bigger. I am being very general because my knowledge in the area cattle is limited by conversing with the farmers and ranch hands on places we worked.