Effects of Heat Stress in Dairy Cows Raised in the Confined System: A Scientometric Review

Simple Summary Studies on the effect of thermal stress on lactating cows have increased considerably in recent years. Feedlot systems for dairy cows have become popular around the world. This article aims to develop a scientometric analysis to evaluate studies on thermal stress in lactating cows housed in a free-stall, tie-stall, and compost-bedded pack barn system. A total of 604 studies from the Web of Science database was considered for this study. The data obtained from the Web of Science was exported to Citespace software. The most used keywords by the researchers were "heat stress", "dairy cow" and "cattle". The most relevant countries, authors, institutions, and networks of co-occurrences for our research were highlighted. This article provides a comprehensive review of thermal stress in lactating cows housed in confinement in the last 22 years and contributes to future research in this area. 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.