Ua 004 64

At 5 d of age, accelerometers (UA-004-64; Onset Computer Corp., Bourne, MA) were placed on each calf’s right or left hind leg with Vetwrap cohesive bandage (3M Products, St. Paul, MN) as previously described by Calvo-Lorenzo et al. (2017) (link). A custom-designed dummy nipple with a sensor (described by Hulbert et al., 2015 ; created by Meter Mall USA, Marysville, OH) was left in the bottle holder of the hutch from 5 to 68 d of age, except during MR feedings. The sensor was located in a dummy nipple, and when the calf manipulated the nipple (suck, head butt, push), the sensor activated the attached event-recording logger (UX90-001Ml; Onset Computer Corp.). At midnight at 6 d of age, the accelerometers and event loggers began recording every 30 s each time the calf manipulated the dummy nipple (at a rate of 1 Hz), respectively. Every 1 to 3 wk, all logging devices were removed, data were downloaded, and loggers were refixed to the calves and hutches. Automated logger data were downloaded and processed using methods previously described (Ledgerwood et al., 2010 (link); Hill et al., 2013 (link); Hulbert et al., 2015 ); standing duration and pacifier use (min/d) were the main variables of interest. The observed dummy nipple was correlated (r = 0.98; P ≤ 0.001) with the sensor-activated event-recording logger in a previous study (Ruiz, 2019 ).