More Data on Variation Among Jersey Calves for Passive Immunity
Blood samples from ninety-seven 1 to 3 day-old Jersey calves from a three-state project in the United States of America were used to assess successful passive transfer of immunity from colostrum.
Overall, 90% of the calves had successful passive transfer of immunity.
Using blood serum total protein as a measure (cut point for success was 5.5):
Average = 5.8
Minimum = 3.7
Maximum = 8.4
Using Brix as a measure (cut point for success was 7.3):
Average = 8.9
Minimum = 6.5
Maximum = 12
The objective of the study was to validate a cut point for Jersey calves using the Brix refractometer. In contrast to the Holstein standard of 7.8, this project suggests using 7.3 as the threshold for measuring successful passive transfer of immunity for Jersey calves.
Reference: McCracken, M.M. and Others, "Technical Note: Evaluation of digital refractometers to estimate serum immunoglobulin G concentration and passive transfer of Jersey calves." Journal of Dairy Science 100:8438-8442 October 2017.