Whether or not a heifer calf makes it as a lactating cow depends significantly on her lung health, according to Sam Barringer, DVM, dairy technical services manager for Merck Animal Health.

Barringer told the audience at the recent Vita Plus Calf Summit in Onalaska, Wis. that the lung is the “limiting organ” in calf development. “If you don’t get the lung right in the first year, you’re sunk,” said Barringer.

He believes a good share of lung damage occurs because calf-rearing facilities are designed for the comfort of people and not calves.

The veterinarian advocates lung scoring via ultrasound to evaluate management practices. It also is a useful tool for making young-heifer culling decisions. On a scale of 1 to 4, a “1” would be considered excellent condition, while a “4” would be extremely damaged. “For calves with a lung score of ‘3,’ 35 percent of them never will make the milking string,” he said. “That percentage is even higher for the ‘4’s.’ Actually, all of the ‘4’s’ should have serious consideration for culling.”

Eventually, other systems -- like reproduction and mammary system development -- take over in heifer-development prominence. But, for the first 12 months of life, “it’s all about the lung,” said Barringer.