Efficacy of oral meloxicam as primary pain mitigation following caustic paste disbudding of three day old Holstein calves1.

The purpose of this study was to investigate the effects of perioperative administration of oral meloxicam prior to and following the application of caustic paste to disbud neonatal dairy calves. Sixty-one 3-4-d-old Holstein heifer calves were randomly assigned to one of four treatment groups of 15-16 calves. The treatment groups were: 1) M1, caustic paste disbudding and oral meloxicam (45 mg) with a placebo 24 h later; 2) M2, treatment M1 followed by a second 45-mg dose of meloxicam 24 h later instead of placebo; 3) CONTROL, treatment M1 with placebo in place of meloxicam; and 4) SHAM, sham disbudding with placebo in place of meloxicam. Infrared thermography was used to quantify eye and horn bud temperatures. Pressure algometry was used to measure Mechanical nociceptive threshold (MNT) surrounding the horn bud. Average daily gain and body weight (BW) were obtained by weighing each animal throughout the study and calculating the changes over time. Plasma was collected and analyzed for cortisol and substance P concentrations. Substance P and cortisol decreased in all animals over time, regardless of treatment. Mean plasma substance P concentration across all time points was greater (P < 0.05) in the SHAM group than M1 or M2 but not different (P > 0.05) than the CONTROL group. The MNT and ocular temperatures decreased over time across all treatments (P < 0.05). Mean BW increased over time across all treatments (P < 0.05). A significant interaction (P < 0.05) between treatment and sampling time was observed at 12 h following treatment application for both mean horn bud temperature and the ratio between horn bud and ocular temperature. Overall, the results of this study suggest that meloxicam administration at a dose of 45 mg per animal may have limited influence as the primary modulator of pain and inflammatory response in calves that have been disbudded with caustic paste at 3 d of age.

An observational field study on the effects of changes in shadow contrasts and noise on cattle movement in a small abattoir.

This observational field study examined the effect of changes in shadow contrasts on the floor and noise on balking behavior during handling. Seventy-four Bos taurus beef cattle were observed during handling at a small abattoir. Shadow contrast type (none, soft, sharp) was recorded during three stages of handling (unloading, lairage to single-file alley and into stun box). Cattle balking behavior (stop, put head down, back up) and aversive handling (electric prod, tail twist) were recorded for each shadow contrast type and the presence or absence of a noisy rendering truck. Sharp contrast shadows increased balking behavior compared to soft contrast shadows or none during unloading (X2 = 12.4, P < 0.001). The noisy truck increased balking behavior during handling from the lairage holding pens to the single-file alley (P < 0.001) and during movement into the stun box (P = 0.001). Sharp contrast shadows on the floor from lighting changes and noise from the truck increased balking behavior in cattle.

Evaluation of intramuscular injection of oxytetracycline for use as an experimental model to induce pain and assess the efficacy of pain mitigation strategies in dairy cows.

OBJECTIVE: To evaluate IM injection of oxytetracycline as an experimental model to induce pain and assess the analgesic efficacy of flunixin meglumine (FM) in dairy cows. ANIMALS: 15 healthy nonlactating Jersey (n = 10) and Holstein (5) cows. PROCEDURES: In the first of 2 experiments, 5 Jerseys were administered oxytetracycline (10 mg/kg, IM), divided between the right side of the neck and left hind limb. The left side of the neck and right hind limb received sham injections. Cows were also randomly assigned to receive FM (2.2 mg/kg, IV; n = 3) or an equal volume of saline (0.9% NaCl) solution (0.044 mL/kg, IV; control; 2) once daily for 5 days. The mechanical nociceptive threshold (MNT) was measured before oxytetracycline administration and at predetermined times after each injection of the assigned treatment. Experiment 2 was similar to experiment 1 except it involved 5 Jerseys and 5 Holsteins, oxytetracycline was injected only in a hind limb, and the assigned treatment was administered for 10 days. RESULTS: For both experiments, mean MNT for the oxytetracycline injection site was consistently less than that for the sham injection site in the hind limbs, and mean MNT at the hind limb oxytetracycline injection site for FM-treated cows was greater than that for control cows beginning on day 3. CONCLUSIONS AND CLINICAL RELEVANCE: IM injection of oxytetracycline in a hind limb reliably induced signs of pain in dairy cows and, with validation, might be useful as an experimental model for assessing pain mitigation strategies in cattle.