In undomesticated animals information about the production and composition of milk over time is still scarce. In general, for most mammals it is known that milk composi­tion changes across lactation, is different for male and female offspring, and even that marsupials, such as kangaroos, can simultaneously produce milk of different compositions for young of different ages. Such parallel milk production of dif­fering compositions has not yet been studied in single-offspring placental mammals, but may help to explain behavioural pro­cesses like allosuckling (feeding the young of other adults) and lateralized suckling preferences. In this study we analysed the production and composition of milk in red deer throughout the lactation period and now confirm for the first time that there are axial differences present. The front teats, which are the favoured suckling positions of the deer’s offspring, produce