Risk factors for morbidity in 1- to 9-day-old dairy calves following caustic paste disbudding

Calfhood morbidity is an important issue on commercial dairy operations, with substantial production and welfare impacts. The objective of this observational study was to evaluate potential risk factors for morbidity, including disbudding, disbudding pain control, serum total protein (STP) concentrations, and haptoglobin concentrations in young dairy calves. A total of 140 heifer calves from a commercial dairy farm in southwestern Ontario, Canada, were enrolled at 1 to 9 d of age and followed for 1 wk. Calves were scored at enrollment for several health parameters using a scale from 0 to 3, with 0 representing normal and 3 representing severely abnormal. Calves were only included if they were considered healthy enough to participate using cut points of <3 for rectal temperature and fecal score; ≤2 for nasal discharge, ocular discharge, and cough score; and 1 for ear position, navel score, and joint score. To ensure that only calves that were considered healthy on the baseline day were included, 17 calves were excluded from analysis, resulting in a total of 123 calves. These calves were a part of a disbudding trial, with 100 disbudded using a commercial caustic paste and 23 sham disbudded with a placebo paste. The disbudding paste (commercial or sham) was applied to calves on enrollment day (baseline) with health scoring at baseline and 3 and 7 d later. The following health outcomes were analyzed: diarrhea (a fecal consistency score of ≥2), respiratory disease (a total respiratory score of ≥5), and general sickness [suffering from either diarrhea, respiratory disease, or a navel or joint infection (joint or navel score of ≥2)]. The following variables were assessed for association with the outcomes: STP, inadequate transfer of passive immunity (<5.2 g/dL STP), pain control treatment for disbudding (lidocaine nerve block alone, meloxicam alone, lidocaine nerve block and meloxicam, no pain control, sham), disbudding (disbudded or sham), and haptoglobin concentrations (taken on the baseline day, +3 d and +7 d). We did not detect any relationship between the development of a health outcome of interest (diarrhea, respiratory, or sick) and disbudding or pain control on any of the days following disbudding. However, for every 1 g/dL increase in STP concentration, calves had 0.24 and 0.33 times the odds of suffering from diarrhea or any sickness event, respectively, 3 d after disbudding. At 3 d after disbudding, for every 0.1 mg/mL increase in haptoglobin concentration on that day, calves had 1.34 and 1.20 times the odds of having diarrhea or a general sickness, respectively. These findings suggest that disbudding itself or the pain control method does not appear to influence health after the procedure when healthy calves are disbudded. Calves developing an illness 3 d after disbudding were more likely to have had lower STP concentrations and increased haptoglobin concentrations.