Evaluating the efficacy of maternal bovine appeasing substance (MBAS) in reducing stress and enhancing growth performance in dairy calves after disbudding

Calves from three dairy farms in Texas were transported to a commercial heifer rearing ranch (d -1), weighed, and randomly assigned to one of four treatment groups before hutch placement: 1) CON (n = 30), receiving only paste; 2) MBAS (n = 30), receiving 5 mL of MBAS above the muzzle and 5 mL behind the poll (100mg/mL); 3) AA-CON (n = 30), receiving an analgesic (transdermal flunixin meglumine; 3.3 mg/kg BW) and anesthetic (2% Lidocaine; 2 mL/horn bud); 4) AA-MBAS (n = 30), receiving both MBAS and AA. MBAS was applied upon arrival, d -1, followed by the administration of AA 24 h later (d 0) and the application of caustic paste within 10 min. Blood was collected via jugular vein within 1 h before disbudding (0hSERUM), 4 h post-disbudding (4hSERUM), and 7 d later (d7SERUM). Tail hair samples were collected on arrival (d-1HAIR) and 14 d later (d14HAIR), and BW was measured on d -1, 14, 28, 65 and weaning to calculate ADG. Number of treatments for pneumonia, bloat, fever, diarrhea, navel infection, and total treatments until weaning were recorded. Calf was considered the experimental unit for all analyses. Differences in initial BW, ADG, and cortisol concentrations (hair and serum) were analyzed for the fixed effects of MBAS, AA, and their interactions, with random variables for calf within MBAS × AA × farm and farm itself using the MIXED model procedure. Cortisol concentrations included covariates of 0hSERUM for 4hSERUM and d7SERUM, and d-1HAIR for d14HAIR. Significance was declared at P ≤ 0.05 and tendencies at P ≤ 0.1. Cortisol concentrations increased from d-1HAIR to 14dHAIR and for all calves and tended (P = 0.07) to be higher in calves not treated with AA. Interestingly, calves that received MBAS or AA had a numerical decrease in before and after disbudding serum cortisol, whereas calves that did not receive AA or MBAS had an increase. For MBAS treated calves, 4hSERUM tended (P = 0.10) to be lower than non-MBAS treated calves. Calves treated with MBAS had a higher ADG until d 14 (P = 0.03) and tended (P = 0.08) to be greater until d 28. The only impacts on the number of treatments observed were that MBAS calves tended (P = 0.08) to receive more treatments for fevers compared with non-MBAS treated calves. Supplementary files for serum cortisol, hair cortisol, number of disease treatments, BW and ADG are included.