University research station trials were conducted to identify the best calf housing methods for organic dairy calf health and welfare. Five replicated trials were conducted over three fall and two spring calving seasons (total 345 calves) to compare individual (I), paired (P), or group (G) housing and pasturing with their dams (D). Calves in treatments I, P, and G were separated from their dams from 3 days to weaning age (63 days) and fed 10 liters of milk/day. Treatment D calves were pastured in a cow-calf group and nursed ad libitum (D).

Treatment D calves gained 17% more weight than I, P, or G calves. Treatment G resulted in significantly more illness and higher health care costs than I or P, whereas treatment D did not. Both G and D calves had more beneficial lactobacteria in their gut microbiomes than I or P. However, first-lactation cows raised with dams on pasture (D) were significantly more restless or hostile during milking than I, P, or G. cows.

Thirteen dairy farmers were interviewed to document calf housing practices and health outcomes. Farmers who kept calves with their dams for at least three days reported better calf health and lower costs than those who separated calves within 48 hours after birth. They also cited pneumonia as the most challenging calf health problem.