I own cattle and am an outfitter, so I have several biases on this one. For the most part, ranching in our area is good for deer. The main benefit has been water developoment. The deer, antelope and elk really benefit from that. And most ranches in our area are private and have moderate stocking rates. So the cattle move around and are OK.
But in some cases, overgrazing causes problems. With the current drought, there are plenty of places that are grazed way too hard, but it is a reality; ranchers need to make a living. But wildlife lack cover and undesirable species are on the increase on many of our range lands.
I also see what I call spatial displacement with cattle and deer. If cattle are grazing a pasture, the deer often move out. This is especially true with mature bucks. They seem to avoid the chaos in general.
Anyway, it's a trade-off. The feed provided by alfalfa or irrigated meadows that are primarily for cattle really help deer. So does the water development. But sometimes they compete for space and resources.