The use of Information and Communication Technologies (ICT) in livestock is not new; applications in this field cover from simple animal identification to complete traceability systems. The monitoring of vital signs of livestock is an issue of farming in which ICT is applied. This paper presents a systematic literature review of proposals for monitoring vital signs in different types of livestock. For this purpose, PRISMA methodology has been applied, with its three phases: Planning, Conducting, and Reporting. Papers from journals and conferences, between 2017 and 2023, have been considered. Long-range monitoring of signs, such as movement, geo-position, body temperature, or heart rate, are the main trends of the analyzed papers and commercial products. Therefore, there are opportunities for developing devices or products that monitor other vital signs, like blood pressure or blood oxygen saturation.