TRIENNIAL LACTATION SYMPOSIUM/BOLFA:Historical perspectives of lactation biology in the late 20th and early 21st centuries1

Abstract

The latter half of the 20th century and the early portion of the 21st century will be recognized as the "Golden Age" of lactation biology. This period corresponded with the rise of systemic, metabolomic, molecular, and genomic biology. It includes the discovery of the structure of DNA and ends with the sequencing of the complete genomes of humans and all major domestic animal species including the dairy cow. This included the ability to identify polymorphisms in the nucleic acid sequence, which can be tied to specific differences in cellular, tissue, and animal performance. Before this period, classical work using endocrine ablation and replacement studies identified the mammary gland as an endocrine-dependent organ. In the early 1960s, the development of RIA and radioreceptor assays permitted the study of the relationship between endocrine patterns and mammary function. The ability to measure nucleic acid content of tissues opened the door to study of the factors regulating mammary growth. The development of high-speed centrifugation in the 1960s allowed separation of specific cell organelles and their membranes. The development of transmission and scanning electron microscopy permitted the study of the relationship between structure and function in the mammary secretory cell. The availability of radiolabeled metabolites provided the opportunity to investigate the metabolic pathways and their regulation. The development of concepts regarding the coordination of metabolism to support lactation integrated our understanding of nutrient partitioning and homeostasis. The ability to produce recombinant molecules and organisms permitted enhancement of lactation in farm animal species and the production of milk containing proteins of value to human medicine. These discoveries and others contributed to vastly increased dairy farm productivity in the United States and worldwide. This review will include the discussion of the centers of excellence and scientists who labored in these fields to produce the harvest of knowledge we enjoy today.

Invited Review: Increasing Milk Yield and Negative Energy Balance: A Gordian Knot for Dairy Cows?

“…Similarly, in Germany, a rise has been reported from 2.600 kg in 1950 to 8557 kg in 2022 as the mean for all breeds [2]. This rapid expansion in production "will be recognized as the "Golden Age" of lactation biology" [3].…”

Progress in Research on Key Factors Regulating Lactation Initiation in the Mammary Glands of Dairy Cows

“…In addition to growth factors, many factors (including cytokines, signaling molecules, and proteases) are pivotal to the efficiency of substance metabolism, transformation, and uptake in cows. This, in turn, plays a significant role in the hormonal regulation of lactation [ 12 ], and also substantially impacts the structural development of the mammary gland and the cow’s lactation performance. This review synthesizes recent research progress on many key lactation factors and provides a powerful rationale for the study of lactation initiation.…”

ADSA Foundation Scholar Award: A role for serotonin in lactation physiology—Where do we go from here?

“…As recently reviewed by Collier and Bauman (2017), the latter half of the 20th century and early portion of the 21st century represents a "golden age" of lactation biology. Numerous recent studies have focused on a variety of new biological influences, such as serotonin and epigenetic effects of heat stress, on the mammary gland, and subsequent effects on milk yield and maternal health.…”