Assessment of blended sorbitol and mannitol as a glucogenic precursor for periparturient dairy cows

We evaluated effects of prepartum sugar alcohol supplementation on milk production and metabolic status in a commercial dairy herd. Multiparous (n = 101) Holstein dairy cows were utilized in a completely randomized design with two prepartum treatments: control (unsupplemented) or 100 g/d of sorbitol–mannitol blend (SMB) incorporated into a total mixed ration (TMR). Treatments were initiated 3 wk before expected calving and terminated at parturition. Milk production and composition was determined until 98 days in milk. Blood metabolite response was measured at 1 and 7 d postpartum. A single liver biopsy was obtained between 5 and 8 d postpartum. Treatment with SMB increased (P = 0.10) milk yield (45.5 kg/d versus 43.4 kg/d for SMB and control, respectively). Milk protein content was lower (P = 0.04) for the SMB treatment but milk protein yield was not affected. Milk fat content and yield, somatic cell count (SCC), and milk urea N concentrations were not affected by prepartum supplementation of SMB. Concentrations of glucose, β-hydroxybutyrate, and nonesterified fatty acids (NEFA) also were not affected by treatment. Hepatic concentrations of total lipid and triacylglycerol were not affected by treatment, although glycogen concentrations were lower in SMB treated cows. Prepartum supplementation of SMB increased milk yield in multiparous Holstein dairy cows, but did not alter metabolic characteristics during the periparturient period.