Effects of disbudding on behavior and heart rate during jugular venipuncture in dairy calves.

Disbudding is a common painful procedure that alters physiological and behavioral responses in calves. Other routine management procedures are commonly performed on calves while these disbudding wounds are healing, such as vaccine injections, jugular venipuncture to check for passive immunity, and ear tagging. Although disbudding is known to cause long-lasting pain, the effects of an additional invasive procedure on calf behavior and heart rate when wounds are present are understudied. To evaluate the effects of multiple, consecutive routine management procedures, we tested whether calves were more reactive to handling and a jugular venipuncture that occurred 3 d after caustic paste disbudding compared with those that were not disbudded. We assigned 26 heifers to 2 treatments at 3 d of age: sham handling (n = 13) or caustic paste disbudding (n = 13). Three days after paste was applied, heart rate and 3 behaviors (hindleg lifts, foreleg lifts, struggling) were observed while the calves were restrained and a jugular venipuncture was performed. Disbudded calves performed more hindleg lifts during the venipuncture than non-disbudded calves (mean ± SE: paste = 7.5 ± 1.1; control = 4.1 ± 0.6 lifts/min), although we found no evidence of a significant difference in average heart rate (mean ± SE: paste = 142 ± 4; control = 148 ± 7 beats/min), foreleg lifts (mean ± SE: paste = 3.3 ± 0.4; control = 2.9 ± 0.5 lifts/min), or struggling (mean ± SE: paste = 0.03 ± 0.01; control = 0.03 ± 0.01 proportion of handling time). However, foreleg lifts and struggling were likely hindered by the restraint used. Similarly, heart rate may have reached a ceiling effect associated with the stress of handling. The difference in hindleg lifts provides preliminary evidence that disbudded calves are more responsive to the combination of handling and jugular venipuncture 3 d later than non-disbudded controls.