Graduate Student Literature Review: Mammary gland development in dairy cattle-Quantifying growth and development.

Mammary gland development research in dairy cattle has improved tremendously over the years, ranging from palpation to methods such as DNA and RNA sequencing, histological imaging, and medical imaging. Despite these advancements, limited evidence relating milk production with early mammary development exists due to incomplete and conflicting data. Further, data are typically not collected longitudinally in the same animals allowing for repeated measures analysis. Additional research is necessary to better understand development of the mammary gland and its direct relationship with subsequent ability to produce milk. As ultrasound has been shown to be a reliable method of visualizing mammary gland structure and parenchymal composition throughout the different stages of development in dairy cattle, it is possible that ultrasound technology can be used in future research to monitor and visualize longitudinal mammary development in dairy cattle noninvasively, and identify quantitative features indicative of milk production potential without culling. Identification of features indicative of higher milk production potential would not only aid in the selection of replacement heifers, but also has potential applications to human medicine with possible prediction of lactation potential in humans.