Progress 07/01/06 to 06/30/07
Outputs
OUTPUTS: The main goal of this project was to determine if oral administration of flunixin meglumine reduces pain associated with disbudding of neonatal dairy calves. Secondary goals were to validate an external heart rate monitor and a salivary cortisol assay that could be used to measure pain responses. Five calves were used to develop a reliable method for collecting saliva. Calves were gently restrained in their hutches and allowed to suck on a gloved finger(s). While suckling, a cotton swab was inserted into the mouth. Two minutes of suckling was sufficient to saturate the swab. This typically yielded at least 500 uL of saliva, which was enough for the cortisol assay. Ten calves were subjected to a short-duration, non-invasive stress test in order to generate resting (low cortisol) and stressed (high cortisol) salivary samples needed to validate the cortisol assay. Resting samples were obtained as described above. Calves were then transported a short distance and secured in a
chute that was tilted 90 degrees to restrain them on their side. They were held in this position for 10 minutes. After returning the chute to normal position, saliva was collected. Serum was collected at the same times as saliva to determine if salivary cortisol responses paralledl serum cortisol responses. The stress test resulted in an average 2.4-fold increase in serum cortisol concentration. Preliminary results suggest that some calves had a similar (2- to 3-fold) increase in salivary cortisol concentration, whereas others had no increase. However, validation of the salivary cortisol assay is still ongoing. Three calves were used to determine appropriate electrode placement sites and adhesion methods for the external heart monitor. To validate the heart monitor, resting and rapid (isoproterenol-induced) heart rates obtained with the monitor were compared with those simultaneously obtained by ECG. Statistical analysis of the data is currently underway. For the main study, video
cameras were positioned to allow constant surveillance of calf behavior. Holstein calves 6 to 11 days of age were used. Twenty-four hours before disbudding, calves were moved to pens for acclimation, and the external heart monitor applied. At the evening feeding (8:00 p.m.), calves were administered milk replacer containing 2-mL of flunixin meglumine or placebo (2-mL of saline). Flunixin meglumine or placebo was again administered at the morning feeding (8:00 a.m.), 4 hours before disbudding. Immediately before disbudding, saliva was collected to establish resting cortisol concentration. Disbudding was performed in a standard manner using a commercial cauterizing disbudding device. Saliva was collected every 30 minutes for 4 hours, to determine effects of disbudding on salivary cortisol concentration. Heart rate and behavior were monitored continuously for up to 24 hours. Healing of the dehorning site was monitored on a weekly basis. Videotapes are being analyzed to quantify a variety
of behaviors (standing, lying, ear flicking, tail twitching, head rubbing, etc). Heart rate data are also being analyzed. Salivary cortisol results are pending.
PARTICIPANTS: Dawn Morin, DVM, MS. Principal investigator. Responsible for overall conduct of the project. Linda Brown, CVT. Co-investigator. Participated in animal handling, animal procedures, data collection, and sample analysis. Vickie Jarrell, PhD, Co-investigator. Participated in animal handling and data collection. Richard Wallace, DVM, MS. Co-investigator. Participated in animal handling and animal procedures. Anne Barger, DVM, PhD. Co-investigator. Performed serum cortisol analysis. Peter Constable, DVM, PhD. Collaborator. Assisted with heart rate validation and statistical analysis Thomas Graves, DVM, PhD. Collaborator. Assisted with salivary cortisol assay.
TARGET AUDIENCES: The target audiences are dairy producers, veterinarians, and animal welfare scientists. Data analysis is ongoing, so findings have not yet been disseminated.
PROJECT MODIFICATIONS: We had initially hoped to measure skin temperature at two locations adjacent to each disbudding site, using a hand-held infrared thermometer. However, calf movement made it difficult to maintain constant distance from the sites and consistently hit the targets. We were fortunate to gain access to an infrared thermographic camera, which shows skin temperature patterns over the entire area surrounding the disbudding sites. Although only a subset of calves have been monitored with the camera, this adjunctive study should give enable us to detect post-operative inflammation and determine if flunixin meglumine reduces inflammation.
Impacts
Results are expected to facilitate objective assessment of pain in neonatal calves disbudded using cautery. Oral administration of flunixin meglumine is inexpensive and convenient compared with other anesthetic or analgesic methods used when dehorning calves. If oral administration of flunixin meglumine reduces physiological or behavioral signs of pain in disbudded calves, it could be a useful strategy to improve animal well-being.
Publications
- No publications reported this period
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