Early weaning: new insights on an ever-persistent problem in the dairy industry.

It is common practice in the dairy industry to separate the calf from the cow immediately after parturition, and in most parts of the world calves are housed individually during the milk-feeding period. Early and abrupt separation has major implications for the calf's physical and psychological development. In this Research Reflection short review we present and discuss the main housing systems and management practices regarding early weaning in today's dairy industry. Main benefits and disadvantages are critically addressed, and possible future research suggested. Furthermore, major policy issues related to consumers, scientific recommendations and economic performance of farms have been identified, as well as future drivers for more viable housing solutions for neonatal calves. This review serves as an introduction and preamble to the second section of this Special Issue, which is dedicated to cow-calf contact management systems.