Due to climate change, heat stress is a growing problem for the dairy industry. Based on this, annual economic losses in the dairy sector are verified mainly on a large scale. Despite several publications on thermal stress in lactating dairy cows in confinement systems, there need to be published reviews addressing this issue systematically. Our objective was to scientometrically analyze the effects of heat stress in dairy cows managed in a confinement system. Based on PRISMA guidelines, research articles were identified, screened, and summarized based on inclusion criteria for heat stress in a confinement system. Data was obtained from the Web of Science. A total of 604 scientific articles published between 2000 and April 2022 were considered. Data was then analyzed using Microsoft Excel and CiteSpace. The results pointed to a significant increase in studies on heat stress in lactating cows housed in confinement systems. The main research areas were Agriculture, Dairy Animal Science and Veterinary Sciences. The USA showed the highest concentration of studies (31.12%), followed by China (14.90%). Emerging themes included heat stress and behavior. The most influential journals were the Journal of Dairy Science and the Journal of Animal Science. The top authors were L. H. Baumgard and R. J. Collier. The leading institutions were the Chinese Academy of Agricultural Sciences, followed by the State University System of Florida and the University of Florida. The study maps the significant research domains on heat stress of lactating cows in confinement systems, discusses implications and explanations and highlights emerging trends.

In this study, we performed a systematic review to assess the effect of thermal stress on the behavior of lactating cows housed in compost barns. Peer-reviewed articles written in English that evaluated the effect of heat stress on the behavior of lactating cows raised in compost barns were used in this systematic review. The resulting articles (38) underwent a four-step PRISMA appraisal process and resulted in six articles that fitted our inclusion criteria. Our review highlighted that the temperature and humidity index prevailed among the studies to evaluate thermal comfort. Regarding the behavior, heat stress promoted decreases in feed events and the time that cows spent lying down. In contrast, there was an increase in events of visiting the water trough, the number of steps, agonistic behavior, and dyspnea. In conclusion, heat stress affected the behavior of lactating cows raised in compost barns; however, some care is needed in extrapolating our findings since this is a recent research area and further studies are needed.

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.

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.

The objective of this work was to evaluate the effect of nine years on seasonality, quality, composition, production and the trade price per liter of milk, on a dairy farm in the north of the state of Rio Grande do Sul. Data on fat, protein, lactose, total solids, defatted dry extract, and somatic cell count (SSC), total bacterial count (TBC), monthly sold milk production, average production per animal and trade price per liter of milk. For statistical analysis, analysis of variance was used considering the effect of the seasons (summer, autumn, winter and spring) and years, however, for Pearson's correlation, the objective was to observe the correlation between the value of the liter of commercialized milk in relation to the milk centesimal composition, microbiological quality and volume of traded milk. Winter and spring were characterized as the seasons with the highest volume of milk sold, the highest lactose levels, the lowest SSC and TBC levels. In relation to the price of the liter of traded milk, the seasons with the highest prices paid were autumn and winter, followed by summer and spring. In addition, this experiment showed that the main components responsible for formulating the price sold per liter of milk were SSC, protein TBC, lactose and volume sold. Thus, the seasons and the different years interfered in the composition, quality, production and price of a liter of milk.