By Angie Wilson
Compost-bedded packs (CBP) are a loose-housing system for dairy cattle designed to improve cow comfort. This study aimed to 1) characterize management practices, pack conditions and herd performance, and 2) investigate management practices associated with pack conditions and herd performance on Ontario CBP dairy farms. Commercial CBP farms (n=25) in Ontario, Canada, were visited six times every two months from April 2022 to April 2023. General management practices were recorded. At each visit, twelve spots across the pack were measured for temperature at 30cm depth and sampled for moisture content. A subset of cows was scored for gait (1-5 scale), injury (0-3 scale), and cleanliness (1-4 scale). Outcome variables were herd-level, with farm as the experimental unit.
Multivariable linear regression models and a logistic regression model for cleanliness (proportion of the herd scored as clean; score=1) were constructed using PROC GLIMMIX (SAS v.9.4), including the repeated measure of visit with subject as farm. Farms averaged (±SD) 83 ± 48 lactating cows on the pack and 11.5 ± 3.61m2 of space per cow. The herd-level prevalence of non-lame cows was 93.2 ± 5.84%, and the herd-level prevalence of non-injured hocks and knees was 99.7 ± 1.04% and 99.2 ± 2.09%, respectively. Packs with lower moisture were associated with increased odds of a higher herd proportion with clean flanks/hips (OR 2.64 [95%-CI 2.57-2.71], P=0.024). Lower pack moisture was associated with less frequent bedding additions (F1,93=6.87, P=0.010). An interaction occurred between tilling depth and space per cow (F1,40=10.70, P=0.002), where deeper tilling was associated with lower moisture as space per cow increased. Higher pack temperatures were associated with lower moisture (F1,121=20.82, P<0.001) and deeper packs (F1,118=10.70, P=0.002). Overall, management relating to moisture control can influence pack conditions and herd performance. Our results support positive injury and gait scores of cows housed in CBPs.
