The objective of this case-control study was to assess the association between bovine respiratory disease score, determined by a scoring system (BRDs), and plasma Haptoglobin concentration (Hp). Four dairy operations located in the central San Joaquin Valley of California participated in this study (A, B, C, D) during the months of April to September, 2013. At each location, heifer or bull dairy calves were identified using as treatments BRDs-positive (n = 150); and randomly chosen calves within the same age group, sex, and breed (Jersey or Holstein) served as controls (Con; n = 356). Whole blood was collected, and plasma Hp concentrations were measured using a colorimetric method base on peroxidase activity. In addition, each calf had a respiratory examination via thoracic auscultation (Au) and Ultrasound (Us). Haptoglobin data were analyzed using the MIXED procedure of SAS using age as a covariate with BRDs as the fixed effect in the statistical model with breed, sex, Au, Us, or location analyzed separately. Some Con calves had abnormal Au (n = 22; 15%) and some of the BRDs calves had normal Au (n = 113; 32%). Preliminary results showed that BRDs-positive calves with abnormal Au and Us tended to have higher Hp (P = 0.10 and P = 0.13 respectively). Location accounted for variation in Hp (P = 0.01); Control calves at D had greater concentrations of Hp than Con calves at the other locations. In addition, BRDs-positive calves at A had lower Hp than BRDs-positive calves at the other locations. Further investigation is needed to determine if Hp can serve as a biological marker for respiratory disease in BRDs-positive or negative calves with abnormal Au and Us. Also, baseline concentrations for haptoglobin may need to be established for specific locations.