By Kendra Gillet
The objective of this study was to determine the effect of deep or shallow tilling depth on pack conditions, cow cleanliness, and lying behaviour in compost-bedded pack (CBP) dairy herds. Treatments were deep (D), where the pack was tilled 2x/d to 35-41cm or shallow (S), tilled to 20-25cm. Commercial CBP farms (n=8) in Ontario were assigned to one of two treatment sequences (D-S-D or S-D-S) in a switchback design. Farms were visited every 28 days at the beginning and end of each period from September-December 2023. Periods (D or S) lasted 4 weeks. CBP samples taken at every visit were analysed for depth temperature and moisture content. Cleanliness was scored live on a 1-4 scale during visits on the same 25 cows per farm; 6 areas per cow were scored then averaged. Data loggers collected lying behaviour on 8 cows per farm during the last 7d of treatment. All outcome variables are reported on a herd level, with the farm as the experimental unit. Tilling depth did not affect any of the outcome variables. Results are reported as lsmeans ± SEM. Temperatures were 32.6 and 30.8 ± 2.98°C (F1,12=0.99, P=0.339) at 20cm, and 33.3 and 32.1 ± 2.11°C (F1,11=0.98, P=0.344) at 37cm for D and S, respectively. Moisture was 63.4 and 63.0 ± 1.41% (F1,9=0.15, P=0.706) at the surface, and 63.6 and 62.5 ± 1.50% (F1,9=0.58, P=0.465) in the 20cm layer for D and S, respectively. Cleanliness scores were 1.55 and 1.56 ± 0.05 (F1,9=0.03, P=0.874) for D and S, respectively. Lying times were 11.0 and 11.1 ± 0.21 hr/d (F1,12=1.67, P=0.221) and number of bouts/d were 9.5 and 9.6 ± 0.63 (F1,13=0.32, P=0.583) for D and S, respectively. The results suggest that a short-term tilling depth change did not affect CBP moisture and temperature, cow cleanliness or lying behaviour.
