>What would it take to make beef production more efficient?
Nothing. Large animals that live long lives are inefficient by their very nature. The bigger an animal is, the more of its energy consumption goes to maintenance rather than growth. And the longer it lives before reaching slaughter weight, the more that inefficiency compounds. If you somehow turned cattle into 5 pound animals that mature in 6 weeks, they would be efficient, but they also wouldn't really qualify as cattle any more and their meat would likely be noticeably different than beef.
Nothing. Large animals that live long lives are inefficient by their very nature. The bigger an animal is, the more of its energy consumption goes to maintenance rather than growth. And the longer it lives before reaching slaughter weight, the more that inefficiency compounds. If you somehow turned cattle into 5 pound animals that mature in 6 weeks, they would be efficient, but they also wouldn't really qualify as cattle any more and their meat would likely be noticeably different than beef.