The effects of blindfolding on behavior and heart rate in beef cattle during restraint

Use of a blindfold or hood during handling and restraint has been suggested for many wild and captive animals. Two experiments were conducted to determine the effects of blindfolds on beef cattle during restraint. In Experiment 1, 60 beef heifers, naı̈ve to the restraint facility, were randomly assigned to either visual restriction (blindfold) or no visual restriction (control) and tested daily during a 4-day trial to determine the effects during restraint. Heart rate (HR) was measured via telemetry, during a baseline period prior to treatment and continuously recorded during a 1-min period of restraint, which included some manipulation of the animal. Manipulation was initiated 15 s into the restraint period. Two persons simultaneously approached the animal one on either side, grasped the ears, and touched the neck, sides and rump to simulate normal management tasks. Electronic strain gauges attached to the head gate quantified the animal’s struggle during this procedure. These were used to determine the average and maximum exertion forces upon the head gate during restraint. The association between treatment, sample time (day 0–4), animal weight and the various outcome measures were analyzed using a generalized estimating equation method. Mean HR of heifers did not differ at the end of the treatment (95.04±4.66 bpm ) (P=0.64), but the HR tended to decrease more for blindfolded heifers compared to controls during restraint (average decrease 16.3±3.2 bpm and 14±2.9 bpm, respectively) (P=0.10). The average exertion forces applied by blindfolded heifers against the head gate were 23% lower (P<0.05) during the 1-min period and maximum forces were 28% lower (P<0.01). Heart rate and exertion forces declined over the 4 days for both treatment groups (P<0.001). In Experiment 2, 93 commercial beef calves (average age 92.9±2.0 days) were randomly assigned to either visual restriction (blindfold) (n=46) or no visual restriction (control) (n=47) treatments. Behavioral responses to treatment were quantified by measuring the amount of movement and recording the number of vocalizations while the calves were restrained for 1 min on a calf tilt table. Movement was recorded by an electronic device attached to a weighing platform that held the tilt table. After 30 s of restraint, one experimenter touched the animal’s ear while the other touched the neck, to simulate ear tagging and vaccination. Blindfolded calves moved 44% less than the control group (P<0.01). However, the number of vocalizations that occurred during the 1-min test period did not differ (P>0.05) between treatments. Overall, blindfolding cattle reduced the amount of struggle and tended to lower heart rate. Therefore, blindfolding may be advantageous during the routine invasive procedures commonly performed on cattle.