How Much IgG Does A Calf Need?
A blood serum concentration of 10 g IgG/L serum is considered minimal for disease protection. Failure of Passive Transfer (FPT) is the term used to define the condition of calves with less than 10 g IgG/L serum. To avoid FPT an average size calf must consume 100 g of IgG within a few hours after birth. This is based on the assumption that an 88 pound calf’s body contains 3.5 L of serum, and 35% of the IgG ingested is absorbed across the intestinal wall. Consequences Of FPT Research at the Clay Center, Nebraska, USDA experiment station compared beef calves with adequate serum IgG concentrations to those with inadequate passive immunity. Calves with FPT were 6.4 times more likely to be sick within the first 4 weeks of life and 5.4 times more likely to die before weaning. Also, weaning weights of calves with FPT were 35 pounds less than calves with adequate passive immunity. Reasons For FPT When a calf is not able to nurse a healthy cow within two hours after birth, it will likely experie
