Abstract #T257

# T257
Supplementation of lactating cows with a blend of essencial oils or monensin: Thermoregulation and blood variables.
R. B. Silva1,2, W. R. Silva1, C. D. S. Oliveira1, A. C. C. Lacreta Junior1, L. H. L. Chalfun1, R. C. Araujo3, R. A. N. Pereira2,4, M. N. Pereira*1,2, 1University of Lavras, Lavras, Brazil, 2Better Nature Research Center, Lavras, Brazil, 3Grasp Industria e Comercio, Curitiba, Brazil, 4Minas Gerais State Ag Research Enterprise (Epamig), Lavras, Brazil.

Capsaicin can promote peripheral blood flow and essential oils can have digestive and systemic action in mammals. We evaluated the effect of a blend of capsaicin, carvacrol, cinnamaldehyde, and eugenol (CEO. 176 mg/kg of TMR DM) relative to monensin (MON. Fifteen mg/kg of TMR DM) or control (CTL) on body homeothermy and systemic variables of dairy cows. Thirty individually fed Holsteins (189 ± 83 DIM) received a standard TMR for 14 d and a treatment for 56 d, in a covariate adjusted randomized block design with repeated measures over time. Pre-planned contrasts were: C1) CTL vs. CEO and C2) CEO vs. MON. Treatments had no effect on the concentrations of plasma D-lactate, BHBA, aspartate, and gamma-glutamyl transferases at 12-h post-feeding on d 25 and 53 and glucose on d 14, 25, 39, and 53 at 0, 4, and 12 h post-feeding (P ≥ 0.30 for C1 and C2). The CEO increased pO2, the % oxygen saturation of hemoglobin, and the % oxygen of total volume in jugular blood on d 24 and 52 (P ≤ 0.03 for C1 and C2). On d 26 and 58, the diameter of the caudal artery evaluated by doppler-image ultrasonography tended to be larger on CEO than CTL (P = 0.08 for C1) and artery area was increased (P = 0.04 for C1). Blood flow and pulsatility did not differ among treatments (P ≥ 0.30 for C1 and C2). Rectal temperature (RT), skin surface temperature (ST), and respiratory frequency were measured at 3–4 d intervals (16 measures) at 8, 16, and 22 h. Cows on CEO tended to have lower RT at 16 h (P = 0.12 for C1), but did not differ at 8 h and 22 h (P ≥ 0.22 for C1 and C2). The proportion of cows with rectal temperature ≥39.2°C at 16 h was 18.7% for CEO and 30% for CTL and MON (P = 0.02), and at 8 h 10.4% and 19%, respectively (P = 0.02), with no treatment effect at 8 h (6%. P = 0.37) (GENMOD of SAS). The ST of CEO cows at 8 h was higher than CTL (P = 0.01 for C1) and tended to be higher than MON (P = 0.07 for C2). Respiratory frequency did not differ (P ≥ 0.43 for C1 and C2). The CEO increased the sweating rate (P = 0.05 for C1 and C2) and the evaporative heat loss (P = 0.01 for C1 and P = 0.12 for C2) measured once per week. The CEO increased heat dissipation and oxygen concentration in blood of dairy cows, showing to have systemic action.

Key Words: capsaicin, essential oils, monensin