"牛奶及乳品业" can be translated into English as "dairy industry" or "milk and dairy products industry".
"Dairy industry" is a more concise and commonly used term in English, referring to the entire sector involved in the production, processing, and distribution of milk and dairy products.
"Milk and dairy products industry" provides a slightly more detailed description, explicitly mentioning both milk and the broader category of dairy products.
In most contexts, "dairy industry" would be sufficient and appropriate.