Abstract #M302

# M302
Effects of selected feed additives to improve growth and health of dairy calves.
L. Salazar1, C. Cortinhas*2, T. Acedo2, P. Rotta1, M. Fontes1, V. Morais1, A. Machado1, A. Sguizzato1, M. Marcondes1, 1Federal University of Vicosa, Vicosa, MG, Brazil, 2DSM Produtos Nutricionais Brasil SA, Sao Paulo, SP, Brazil.

We aimed to evaluate the effect of supplementation of monensin (MON), probiotics or essential oils on performance and health of suckling dairy calves from 6 to 60 d of age, and its residual effect 15 d after weaning. Fifty Holstein calves were fed 5 L/d of raw milk and starter feed. The products were provided by DSM Brasil SA, and the treatments were control, MON (30 mg/kg of starter), probiotic E. faecium (PROB, 70 mg/kg of starter, cfu/kg 7.0E+09), essential oils (EO, 300 mg/kg of starter; composed by thymol, guaiacol, eugenol, vanillin, salicylaldehyde and limonene), and EOPROB (treatments PROB + EO). The DMI and fecal score (scored from 1 to 4) were daily measured, and animals were weighed every 15 d. Two 48 h digestibility trials were performed at d 20–28 (period 1) and 50–56 (period 2), with total feces collection. The experiment was designed in completely randomized blocks with 10 replications, and date of entrance was used as block. Treatment effects were tested using ANOVA and means were compared by Student's t-test at P < 0.10. In digestibility trials, periods were included as repeated measures. The DMI before weaning was greater for EO (903.03 g/d) compared with MON (794.34 g/d) and EOPROB (783.12 g/d) (P < 0.05). The EO (P < 0.026) and MON (P < 0.010) improved health and decreased the incidence of diarrhea demonstrated by the lower fecal score. Average daily gain (ADG) did not differ among treatments (P > 0.10) before weaning. After weaning, EO had greater ADG (917.50 g/d) compared with control (615.80 g/d) and PROB (592.60 g/d). Feed efficiency of EO (0.72 g/g) improved over control (0.36 g/d), MON (0.49 g/d) and PROB (0.36 g/g). During the digestibility trials, greater intakes of DM (1097.80 g/d), CP (237.91 g/d), and NDF (268.59 g/d) were observed during period 2 compared with period 1 (P < 0.001). Animals fed PROB had greater intakes of DM (P < 0.022; 1184.56 g/d), CP (P < 0.022; 254.63 g/d) and NDF (P < 0.030; 320.36 g/d) than animals fed EOPROB. Digestibility of NDF was greater in animals fed MON (P < 0.012). In summary, EO can replace MON to improve the health of young dairy calves and can be used as an alternative to prevent diarrhea.

Key Words: essential oils, probiotic, dairy calf