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Simple Summary: Here, we aimed to characterize the structural features, to descript the bedding material, and to observe the management practices of compost (CBP) barns in the state of Kentucky (USA). These systems allow thermal comfort for animals, as well as better hygiene conditions for cows. All CBP barns showed structural variations. Sawdust and wood shavings were the most used materials in beds and coliforms E. coli, Bacillus, and Streptococcus were present in the CBP barns with a lower moisture content. In addition, the most frequently cited benefits of the CBP barn include increased cow comfort compared to free stalls; increased cow cleanliness; low maintenance; its ability to work well for heifers and lame, fresh, problem, and old cows; and its ability to allow natural resting positions with no free stalls. This study was conducted to describe the building layout and dimensions, characterize the bedding material, and observe the management practices in 42 compost-bedded pack (CBP) barns in Kentucky (USA). The average herd size found in the study was 90 cows and the breeds consisted of Jersey (6.8%), Holstein (72.7%), and mixed (20.5%). The average CBP barn dimensions were 49.1 m (length) by 21.9 m (width). Many of these barns had feed alleys and driveways; overshot ridges with frequent orientation from NE to SW; and green sawdust, kiln-dried sawdust, or a mixture of both as the most common bedding materials. The bed-turning process was performed mechanically at depths of less than 0.25 m, and the loading of fresh material was performed every one to five weeks, varying by season, weather conditions, barn size, and cow density. The average bedding moisture content was found to be 59.0% (wet bulb—w.b.) and ranged from 36.2 to 71.8%. Coliforms were not present in barns that had a higher compost temperature, and the E. coli, Bacillus, and Streptococcus counts were higher in the barns that had a lower moisture content. In conclusion, it was observed that heterogeneous management was used among the barns and that the producers were satisfied with the compost barn system. [ABSTRACT FROM AUTHOR]

Simple Summary: Among animal facilities, compost-bedded pack (CBP) barns have attracted a lot of attention from milk producers and the scientific community. Systematic investigation of the main thermal, chemical, and physical properties of bedding materials in CBP barns is of environmental and economic relevance, helping dairy producers operate these beds properly. Here we assessed 42 CBPs in the state of Kentucky (USA), aiming to study the thermal, chemical, and physical properties of bedding materials. We found that thermal conductivity increased with increasing particle size. Regarding chemical features, the assessed CBPs were similar when considering the bedding materials. The particle weight fraction found in CBPs might result in excessive water retention and low aeration. Based on these main results, we concluded that many dairy producers could use the bedding compost to fertilize their crop fields and avoid over-applying nutrients, and reduce water pollution. The thermal, chemical, and physical properties of compost bedding materials play an important role in every phase of compost production. Based on this, we aimed to assess the thermal, chemical and physical properties of bedding materials for compost-bedded pack (CBP) barns. The database for this study was registered from 42 CBP barns, distributed throughout the state of Kentucky (USA). The thermal conductivity showed a linear relationship with moisture content and bulk density, while thermal resistivity decreased with increasing particle size. The bedding moisture average was 46.8% (±11.5). The average finer index (p < 0.05) was the highest weight percentage (30.1%) in the samples studied. Water-holding capacity (WHC) increased with increasingly fine particle size. The higher bulk density value was 3.6 times that of the lowest bulk density value. The chemical characterization of the bedding material provided the following results: 42.7% (±3.8%) C, 1.6% (±0.4%) N, and 28.2 (±8.0) C:N ratio. However, thermal properties are strongly dependent on particle size. Producers can use the bedding material as fertilizer in their crops, due to the chemical characteristics of the materials. Beds with good physical and chemical properties improve their moisture content. [ABSTRACT FROM AUTHOR]

Featured Application: The findings are highly relevant for the roof design in naturally ventilated compost bedded pack barns. Compost bedded pack (CBP) barns have been receiving increased attention as an alternative housing system for dairy cattle. To create a satisfactory environment within CBP barns that promotes a good composting process, an adequate air movement and minimal temperature fluctuations throughout the building are required. Therefore, a study based on compost barn structure model employing techniques of dimensional analysis for naturally ventilated buildings was developed. Three-dimensional computational fluid dynamic (CFD) simulations of compost barns with different ridge designs and wind direction, along with the visual demonstration of the impact on airflow through structure were performed. The results showed that the barn ventilation CFD model and simulations were in good agreement with the experimental measurements, predicting the airflow through the CBP barns structure for alternative roof ridge types adequately. The results also indicate that the best roof configuration in the winter was the open ridge with chimney for a west to east wind direction. [ABSTRACT FROM AUTHOR]