On-farm approaches to increase whole-milk total solids: Effects on performance and health of dairy calves.

This study aimed to evaluate the performance, metabolism, and health of Holstein calves fed whole milk adjusted for 15% TS by adding a commercial solids corrector (245 g/kg CP, 48 g/kg crude fat, 90 g/kg of mineral, and 3 g/kg of ADF) using 2 practical approaches: daily adjustment based on a Brix refractometer reading, or the addition of a fixed amount of the corrector based on mean milk solids content. Thirty newborn male Holstein calves were assigned to one of the 2 treatments: (1) fixed, in which whole-milk solids were adjusted using a fixed dose of 25 g/L, and (2) Brix, in which whole-milk solids were adjusted based on a daily Brix refractometer reading. Treatments were randomly assigned within blocks formed based on BW and birth date (2 calves per block). The experimental period lasted 56 d, during which calves were fed 6 L/d of the respective liquid diet and had free access to water and starter concentrate. Daily adjustments based on the Brix refractometer reading improved total liquid diet, as well as protein and lactose intake. However, calf performance and health indicators did not differ between treatments. Total serum protein concentration was greater in calves fed milk corrected using the fixed dose. Additionally, creatinine concentration was influenced by the interaction between treatment and age, with a trend toward greater concentrations in calves fed milk adjusted using the daily Brix refractometer reading at 2 wk of age. Overall, both strategies for increasing TS in whole milk (Brix refractometer and fixed dose) resulted in comparable performance and health outcomes and may serve as practical on-farm approaches for managing dairy calves.