Growth performance, metabolic and rumen profile, and health of calves fed condensed whey solubles with starter pellets

Our objective was to evaluate growth, metabolic and rumen profile, and health of calves supplemented with condensed whey solubles (CWS) on starter pellets. Forty-eight 2 d-old calves in huts were used in a 12-wk randomized complete block design study. Calves were blocked by breed (33 Holstein, 15 Brown Swiss), sex (30 female; 18 male), and birth date. Treatments were: 1) control (CON) with no supplement, 2) 40 mL/d CWS (CWSL), and 3) 80 mL/d CWS (CWSH) top-dressed on ad libitum-fed starter pellets. Calves were fed 2.83 L of pasteurized milk 2 × /d during wk 1 to 5, 1 × /d in wk 6, and weaned at d 42. Fecal scores (0 = firm, 3 = watery) and respiratory scores from the sum of rectal temperature, cough, ocular and nasal discharge scores were observed daily. Body weights (BW), frame measures, and jugular blood samples were taken 1 d/wk at 3 h post feeding. Rumen samples were taken wk 8 and 12 via esophageal tubing. Data were analyzed using MIXED procedures of SAS 9.4 with repeated measures. Significance was declared at P \u3c 0.05 and tendencies were 0.05 ≤ P \u3c 0.10. Total DMI (1.53, 1.64, and 1.67 kg/d; SEM = 0.73 for CON, CWSL, and CWSH, respectively) were similar, but had a treatment by time interaction, tending to increase with CWS post-weaning. Average daily gains (0.68, 0.72, 0.75 kg/d; SEM 0.06) were similar, but BW (69.5, 70.8, 73.2 kg; SEM = 1.59), withers heights (82.9, 84.2, and 84.1 cm; SEM = 0.82), and heart girth (92.7, 93.6, 93.8 cm; SEM = 0.66) tended to increase post-weaning with CWS. Other frame measures and BCS were similar. Health scores were not different, but post-weaning fecal scores (0.11, 0.09, and 0.13; SEM = 0.03) were firmer (P \u3c 0.01) for CWSL. Rumen VFA profiles, PUN (18.2, 17.7, and 17.6 mg/dL; SEM = 0.63), glucose (96.4, 100.5, and 104.8 mg/dL; SEM = 1.63), cholesterol (47.1, 49.3, and 51.5 mg/ dL; SEM = 2.34), triglycerides (15.8, 15.8, and 16.4 mg/dL; SEM = 1.17) and BHB (35.4, 35.1, and 36.0 mg/dL; SEM = 0.63) were similar. Supplementing CWS improved calf post-weaning intakes, growth, and fecal scores with maintained rumen VFA, and metabolic profile