Taste preference of Chlorella sp. algae from dairy wastewater by weaned dairy calves

The objective of this study was to evaluate the taste preference of calves fed Chlorella sp. microalgae produced from dairy lagoon wastewater. Six Holstein dairy heifer calves that were 12 to 14 wk of age (107 ± 3.8 kg of body weight) were fed 0 (control), 30, or 60 g of Chlorella sp. daily, and all calves were fed all treatments in a sequential elimination study. For the 7-d experiment, d 1 to 2 were for diet adaptation and d 3 to 4 were for data collection. During the final 3 d, the primary consumed treatment was removed to determine the second preferred treatment. Calves were ranked for total intake from the consumption of all treatments. The microalgae product used in this study was isolated from dairy wastewater lagoon, and microalgae biomass was produced using outdoor hanging bag bioreactors with Chlorella sp. to recycle the wastewater. The biomass was sterilized and kept frozen at -4°C until fed to calves. Calves were housed individually in hutches with outdoor access under solar panels, with free-choice water. Calves consumed more dry matter from control calf starter (3.4 kg/d) than from the starter with 30 g (2.42 kg/d) or 60 g (1.56 kg/d) of microalgae during the first 2-d period. During the second 2-d period (d 3 and 4), dry matter intake was reduced for the 60 g/d microalgae starter compared with the control and 30 g/d microalgae starters. Five of 6 calves in this study always ranked the control treatment first when given a choice and ranked the 30 g of microalgae starter second choice. Results indicated that microalgae may be added to calf starter; however, calves preferred calf starter without microalgae.