AbstractWet winter conditions can create animal welfare issues in feedlots if the pen surface becomes a deep, wet, penetrable substrate. Feedlot pens with a clay and gravel base (N = 30) bedded with 150 mm (W15) and 300 mm (W30) depth of woodchips were compared to a control treatment with no bedding over a 109-day feeding period, while irrigated to supplement natural rainfall. The pad substrate was measured for variables which would affect cattle comfort and value of the substrate for composting. The penetrable depth of control pens was higher than both woodchip-bedded treatments from week 2, and increased until the end of the experiment. Meanwhile these scores were steady for W30 throughout the experiment, and increased for W15 only after week 10. Moisture content of the pad was higher throughout the experiment in the control pens than in the woodchip-bedded pens. In the control pens, the force required to pull a cattle leg analogue out of the pen substrate was three times that required in woodchip-bedded treatments. The W15 treatment increased C : N in the substrate to the upper limit of suitability for composting, and in W30, C : N was too high for composting after a 109-day feeding period. Overall, providing feedlot cattle with 150 or 300 mm of woodchip bedding during a 109-day feeding period improved the condition of the pad substrate for cattle comfort by reducing penetrable depth and moisture content of the substrate surface stratum, but composting value decreased in W30 over this feeding period duration.