Crowded freestall pens: what a 2012 review found about overstocked dairy cows
In 2012 researchers from the University of British Columbia and Cornell University reviewed what happens when dairy cows outnumber the stalls and feed places in their pen. The review covered how crowding changes the cows’ behaviour and metabolism.
What the study did and found
The paper, “The behavioral and physiological consequences of overstocking dairy cattle”, appeared in the proceedings of the American Association of Bovine Practitioners in 2012 (Huzzey et al., 2012a). Julie Huzzey, Marina von Keyserlingk and Thomas Overton of British Columbia and Cornell review research on crowded freestall pens.
The review reported that crowding cuts lying and feeding at peak times and raises displacements, above all for subordinate cows; in one cited study, cows at 1.5 per stall lay down 1.7 hours a day less (Huzzey et al., 2012a). A Cornell trial in 40 dry cows housed two to a stall found slightly higher NEFA and glucose (Huzzey et al., 2012b).
The authors concluded, with some caution, that these changes may raise a cow’s risk of disease, low yield or poor fertility. They advised 60 cm of bunk and one stall per cow, headlocks or feed partitions, and no crowding around calving.
Why it is cited
In six pages the paper brings together the behavioural evidence on crowding, early cortisol studies and the first measurements of its effect on energy metabolism.
It also frames the problem in simple per-cow benchmarks, stalls and centimetres of bunk per cow, which later welfare codes also use (National Farm Animal Care Council, 2023).
The review leans mainly on its authors’ own trials, and its new physiological evidence comes from one crossover study of 40 dry cows (Huzzey et al., 2012b). Its figure that 43% of US freestall farms fell short on stalls inverts the USDA table, where about 43% met the one-stall benchmark (USDA APHIS VS CEAH, 2010).
Later work supports the behavioural findings more firmly than the physiological ones: EFSA concluded in 2023 that cows need at least one cubicle each (EFSA Panel on Animal Health and Animal Welfare (AHAW) et al., 2023), while trials in dry and close-up cows found little effect on stress or metabolic markers (Fujiwara et al., 2019; Miltenburg et al., 2018).
The topic today
Canada’s 2023 code, in force since April 2024, caps free-stall density at 1.2 cows per stall, falling to 1.0 from April 2031 (National Farm Animal Care Council, 2023). In England, Defra recommends about 5% more cubicles than cows (Department for Environment, Food & Rural Affairs, 2003).
For the current picture, see our explainer Overstocking and Dairy Cows: Lessons from a 2012 Review.