When passive transfer fails, feed efficiency and growth rates suffer, says Mike Van Amburgh, dairy nutritionist at Cornell University. Researchers compared the performance of calves with good passive transfer — as measured by a blood serum protein level of 5.5 milligrams per deciliter or greater — to calves with poor passive transfer in three controlled field studies conducted in New York. Here is what they found:
Dry matter intake was equal.
The feed efficiency and growth rate of calves with poor passive transfer was just 50 percent of their counterparts.