TY - JOUR
T1 - A comprehensive evaluation of microchips to measure temperature in dairy calves
AU - Woodrum Setser, M. M.
AU - Cantor, M. C.
AU - Costa, J. H.C.
N1 - Funding Information:
We gratefully acknowledge the students who helped with this project: Mathilde Campedelli, Clémence Dudouit, Justine Alary, Morgan Falk, Nichole Thomas, Brendan Mitchell, Emily Rice, Carissa Truman, Katie Simmons, Abby Varney, and Michela Bernarding. We also thank the staff of the University of Kentucky's Coldstream Dairy Research Farm (Lexington, KY) who helped in this experiment, especially Joey Clark, Amelia Fendley, and Matt Collins. We thank the staff at the University of Kentucky Meats Laboratory, especially Brock Billingsley and Greg Rentfrow for their assistance with the slaughter and retrieval of the microchips. The authors have not stated any conflicts of interest.
Publisher Copyright:
© 2020 American Dairy Science Association
PY - 2020/10
Y1 - 2020/10
N2 - Elevated temperature is often an indicator of an immune response and used in the diagnosis of illness in dairy calves; however, measuring rectal temperature is labor intensive and often not measured daily on the farm. The objective of this study was to measure body temperature using a microchip and determine an appropriate implant site that would passively read body temperature in dairy calves. First, the precision of the temperature microchips and the rectal thermometer were tested ex vivo. Then, Holstein bull calves (n = 12) at 14 ± 12 d (mean ± SD) of age were implanted with microchips subcutaneously by the scutulum of the ear, subcutaneously in the upper scapula (SCAP), and intramuscularly in the trapezius muscle of the neck. One week after implantation, a temperature reading was taken for every microchip implant site using a radiofrequency ID (RFID) reader, as well as rectally and in the tympanic membrane using a digital thermometer every 60 min for 24 h in each calf (hereafter, the hourly study). Additionally, microchip readings and rectal temperatures were taken daily at 0800 h from 8 wk of age (n = 9; 57 ± 12 d of age) until 2 wk postweaning for a subset of the bull calves used in the hourly study (hereafter, the daily study). In the ex vivo trial, the microchip readings were very highly correlated with the rectal thermometer (r = 0.96), and the average coefficient of variation between microchip readings was very low (0.12 ± 0.03%). The relationships between the microchip readings within ear, SCAP, and neck and rectal and tympanic temperatures were analyzed using Pearson correlations and Bland-Altman plots. The ear and neck readings were strongly correlated for the hourly study [individual animal correlation; median (Q1, Q3), r = 0.78 (0.73, 0.84)] and for the daily study [r = 0.79 (0.73, 0.89)] across calves. However, rectal temperature was not significantly correlated with ear, SCAP, neck, or tympanic temperature for the daily and hourly studies. Results suggest that temperature microchips measure temperature appropriately, but temperature is dependent upon the implant site in calves, and temperature measured at ear, SCAP, and neck implant sites cannot be used to estimate rectal temperature. Future research should determine thresholds for fever that are specific to implant sites in calves.
AB - Elevated temperature is often an indicator of an immune response and used in the diagnosis of illness in dairy calves; however, measuring rectal temperature is labor intensive and often not measured daily on the farm. The objective of this study was to measure body temperature using a microchip and determine an appropriate implant site that would passively read body temperature in dairy calves. First, the precision of the temperature microchips and the rectal thermometer were tested ex vivo. Then, Holstein bull calves (n = 12) at 14 ± 12 d (mean ± SD) of age were implanted with microchips subcutaneously by the scutulum of the ear, subcutaneously in the upper scapula (SCAP), and intramuscularly in the trapezius muscle of the neck. One week after implantation, a temperature reading was taken for every microchip implant site using a radiofrequency ID (RFID) reader, as well as rectally and in the tympanic membrane using a digital thermometer every 60 min for 24 h in each calf (hereafter, the hourly study). Additionally, microchip readings and rectal temperatures were taken daily at 0800 h from 8 wk of age (n = 9; 57 ± 12 d of age) until 2 wk postweaning for a subset of the bull calves used in the hourly study (hereafter, the daily study). In the ex vivo trial, the microchip readings were very highly correlated with the rectal thermometer (r = 0.96), and the average coefficient of variation between microchip readings was very low (0.12 ± 0.03%). The relationships between the microchip readings within ear, SCAP, and neck and rectal and tympanic temperatures were analyzed using Pearson correlations and Bland-Altman plots. The ear and neck readings were strongly correlated for the hourly study [individual animal correlation; median (Q1, Q3), r = 0.78 (0.73, 0.84)] and for the daily study [r = 0.79 (0.73, 0.89)] across calves. However, rectal temperature was not significantly correlated with ear, SCAP, neck, or tympanic temperature for the daily and hourly studies. Results suggest that temperature microchips measure temperature appropriately, but temperature is dependent upon the implant site in calves, and temperature measured at ear, SCAP, and neck implant sites cannot be used to estimate rectal temperature. Future research should determine thresholds for fever that are specific to implant sites in calves.
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U2 - 10.3168/jds.2019-17999
DO - 10.3168/jds.2019-17999
M3 - Article
C2 - 32828511
AN - SCOPUS:85089580678
SN - 0022-0302
VL - 103
SP - 9290
EP - 9300
JO - Journal of dairy science
JF - Journal of dairy science
IS - 10
ER -